,british ,airships3 ,past1 ,present and ,future by ,george ,whale 7,late ,major1 ,r4,a4,f47 ,,chapter ,i ,,introduction ,,chapter ,,ii ,,early ,,airships ,,and ,,their ,,development ,,to ,,the ,,present ,,day ,,chapter ,,iii ,,british ,,airships ,,built ,,by ,,private ,,firms ,,chapter ,,iv ,,british ,,army ,,airships ,,chapter ,v ,,early ,,days ,,of ,,the ,,naval ,,airship ,,section--,,parseval ,,airships1 ,,astra-,,torres ,,type1 ,,etc4 ,,chapter ,,vi ,,naval ,,airships3 ,,the ,,non-,,rigids-- ,s4,s4 ,,type ,,coastal ,,and ,c ,,star ,,airships ,,the ,,north ,,sea ,,airship ,,chapter ,,vii ,,naval ,,airships3 ,,the ,,rigids ,,rigid ,,airship ,,no4 #a ,,rigid ,,airship ,,no4 #i ,,rigid ,,airship ,,no4 #bc ,,class ,,rigid ,,airship ,,no4 #bc ,x ,,class ,,rigid ,,airship ,,no4 #ca ,,class ,,rigid ,,airship ,,no4 #cc ,,class ,,chapter ,,viii ,,the ,,work ,,of ,,the ,,airship ,,in ,,the ,,world ,,war ,,chapter ,,ix ,,the ,,future ,,of ,,airships ,,chapter ,i ,,introduction ,lighter-than-air craft consist of three distinct types3 ,airships1 which are by far the most important1 ,free ,balloons1 and ,kite ,balloons1 which are attached to the ground or to a ship by a cable4 ,they derive their appellation from the fact that when charged with hydrogen1 or some other form of gas1 they are lighter than the air which they displace4 ,of these three types the free balloon is by far the oldest and the simplest1 but it is entirely at the mercy of the wind and other elements1 and cannot be controlled for direction1 but must drift whithersoever the wind or air currents take it4 ,on the other hand1 the airship1 being provided with engines to propel it through the air1 and with rudders and elevators to control it for direction and height1 can be steered in whatever direction is desired1 and voyages can be made from one place to another--always provided that the force of the wind is not sufficiently strong to overcome the power of the engines4 ,the airship is1 therefore1 nothing else than a dirigible balloon1 for the engines and other weights connected with the structure are supported in the air by an envelope or balloon1 or a series of such chambers1 according to design1 filled with hydrogen or gas of some other nature4 ,it is not proposed1 in this book1 to embark upon a lengthy and highly technical dissertation on aerostatics1 although it is an intricate science which must be thoroughly grasped by anyone who wishes to possess a full knowledge of airships and the various problems which occur in their design4 ,certain technical expressions and terms are1 however1 bound to occur1 even in the most rudimentary work on airships1 and the main principles underlying airship construction will be described as briefly and as simply as is possible4 ,the term lift will appear many times in the following pages1 and it is necessary to understand what it really means4 ,the difference between the weight of air displaced and the weight of gas in a balloon or airship is called the gross lift4 ,the term disposable1 or nett lift1 is obtained by deducting the weight of the structure1 cars1 machinery and other fixed weights from the gross lift4 ,the resultant weight obtained by this calculation determines the crew1 ballast1 fuel and other necessities which can be carried by the balloon or airship4 ,the amount of air displaced by an airship can be accurately weighed1 and varies according to barometric pressure and the temperature2 but for the purposes of this example we may take it that under normal conditions air weighs #ge lb4 per #a1jjj cubic feet4 ,therefore1 if a balloon of #a1jjj cubic feet volume is charged with air1 this air contained will weigh #ge lb4 ,it is then manifest that a balloon filled with air would not lift1 because the air is not displaced with a lighter gas4 ,hydrogen is the lightest gas known to science1 and is used in airships to displace the air and raise them from the ground4 ,hydrogen weighs about one-fifteenth as much as air1 and under normal conditions #a1jjj cubic feet weighs #e lb4 ,pursuing our analogy1 if we fill our balloon of #a1jjj cubic feet with hydrogen we find the gross lift is as follows3 #a1jjj cubic feet of air weighs #ge lb4 #a1jjj cubic feet of hydrogen weighs #e lb4 ------ ,the balance is the gross lift of the balloon #gj lb4 ,it follows1 then1 that apart from the weight of the structure itself the balloon is #gj lb4 lighter than the air it displaces1 and provided that it weighs less than #gj lb4 it will ascend into the air4 ,as the balloon or airship ascends the density of the air decreases as the height is increased4 ,as an illustration of this the barometer falls1 as everyone knows1 the higher it is taken1 and it is accurate to say that up to an elevation of #aj1jjj feet it falls one inch for every #a1jjj feet rise4 ,it follows that as the pressure of the air decreases1 the volume of the gas contained expands at a corresponding rate4 ,it has been shown that a balloon filled with #a1jjj feet of hydrogen has a lift of #gj lb4 under normal conditions1 that is to say1 at a barometric pressure of #hj inches4 ,taking the barometric pressure at #b inches lower1 namely #bh1 we get the following figures3 #a1jjj cubic feet of air weighs #gj lb4 #a1jjj cubic feet of hydrogen weighs #d4fg --------- #fe4cc lb4 ,it is therefore seen that the very considerable loss of lift1 #d4fg lb4 per #a1jjj cubic feet1 takes place with the barometric pressure #b inches lower1 from which it may be taken approximately that #a_/cj of the volume gross lift and weight is lost for every #a1jjj feet rise4 ,from this example it is obvious that the greater the pressure of the atmosphere1 as indicated by the barometer1 the greater will be the lift of the airship or balloon4 ,temperature is another factor which must be considered while discussing lift4 ,the volume of gas is affected by temperature1 as gases expand or contract about #a_/ejj part for every degree ,fahrenheit rise or fall in temperature4 ,in the case of the #a1jjj cubic feet balloon1 the air at #cj inches barometric pressure and #fj degrees ,fahrenheit weighs #ge lb41 and the hydrogen weighs #e lb4 ,at the same pressure1 but with the temperature increased to #ij degrees ,fahrenheit1 the air will be expanded and #a1jjj cubic feet of air will weigh only #gj4i lb41 while #a1jjj cubic feet of hydrogen will weigh #d4g lb4 ,the lift being the difference between the weight of the volume of air and the weight of the hydrogen contained in the balloon1 it will be seen that with the temperature at #fj degrees ,fahrenheit the lift is #ge lb4 - #e lb4 #gj lb41 while the temperature1 having risen to #ij degrees1 the lift now becomes #gj4i lb4 - #d4g lb4 #ff4b lb4 ,conversely1 with a fall in the temperature the lift is increased4 ,we accordingly find from the foregoing observations that at the start of a voyage the lift of an airship may be expected to be greater when the temperature is colder1 and the greater the barometric pressure so will also the lift be greater4 ,to put this into other words1 the most favourable conditions for the lift of an airship are when the weather is cold and the barometer is high4 ,it must be mentioned that the air and hydrogen are not subject in the same way to changes of temperature4 ,important variations in lift may occur when the temperature of the gas inside the envelope becomes higher1 owing to the action of the sun1 than the air which surrounds it4 ,a difference of some #bj degrees ,fahrenheit may result between the gas and the air temperatures2 this renders it highly necessary that the pilot should by able to tell at any moment the relative temperatures of gas and air1 as otherwise a false impression will be gained of the lifting capacity of the airship4 ,the lift of an airship is also affected by flying through snow and rain4 ,a considerable amount of moisture can be taken up by the fabric and suspensions of a large airship which1 however1 may be largely neutralized by the waterproofing of the envelope4 ,snow1 as a rule1 is brushed off the surface by the passage of the ship through the air1 though in the event of its freezing suddenly1 while in a melting state1 a very considerable addition of weight might be caused4 ,there have been many instances of airships flying through snow1 and as far as is known no serious difficulty has been encountered through the adhesion of this substance4 ,the humidity of the air may also cause slight variations in lift1 but for rough calculations it may be ignored1 as the difference in lift is not likely to amount to more than #j4c lb4 per #a1jjj cubic feet of gas4 ,the purity of hydrogen has an important effect upon the lift of an airship4 ,one of the greatest difficulties to be contended with is maintaining the hydrogen pure in the envelope or gasbags for any length of time4 ,owing to diffusion gas escapes with extraordinary rapidity1 and if the fabric used is not absolutely gastight the air finds its way in where the gas has escaped4 ,the maximum purity of gas in an airship never exceeds #ih per cent by volume1 and the following example shows how greatly lift can be reduced3 ,under mean atmospheric conditions1 which are taken at a temperature of #ee degrees ,fahrenheit1 and the barometer at #bi4e inches1 the lift of #a1jjj cubic feet of hydrogen at #ih per cent purity is #fi4f lb4 ,under same conditions at #hj per cent purity the lift of #a1jjj cubic feet of hydrogen is #ef4i lb41 a resultant loss of #ab4i lb4 per #a1jjj cubic feet4 ,the whole of this statement on lift can now be condensed into three absolute laws3 #a4 ,lift is directly proportional to barometric pressure4 #b4 ,lift is inversely proportional to absolute temperature4 #c4 ,lift is directly proportional to purity4 ,,airship ,,design ,the design of airships has been developed under three distinct types1 the ,rigid1 the ,semi-,rigid1 and the ,non-,rigid4 ,the rigid1 of which the ,german ,zeppelin is the leading example1 consists of a framework1 or hull composed of aluminium1 wood1 or other materials from which are suspended the cars1 machinery and other weights1 and which of itself is sufficiently strong to support its own weight4 ,enclosed within this structure are a number of gas chambers or bags filled with hydrogen1 which provide the necessary buoyancy4 ,the hull is completely encased within a fabric outer cover to protect the hull framework and bags from the effects of weather1 and also to temper the rays of the sun4 ,the semi-rigid1 which has been exploited principally by the ,italians with their ,forlanini airships1 and in ,france by ,lebaudy1 has an envelope1 in some cases divided into separate compartments1 to which is attached close underneath a long girder or keel4 ,this supports the car and other weights and prevents the whole ship from buckling in the event of losing gas4 ,the semi-rigid type has been practically undeveloped in this country4 ,the non-rigid1 of which we may now claim to be the leading builders1 is of many varieties1 and has been developed in several countries4 ,in ,germany the chief production has been that of ,major von ,parseval1 and of which one ship was purchased by the ,navy shortly before the outbreak of war4 ,in the earliest examples of this type the car was slung a long way from the envelope and was supported by wires from all parts4 ,this necessitated a lofty shed for its accommodation as the ship was of great overall height2 but this difficulty was overcome by the employment of the elliptical and trajectory bands1 and is described in the chapter dealing with ,no4 #d4 ,a second system is that of the ,astra-,torres4 ,this envelope is trilobe in section1 with internal rigging1 which enables the car to be slung very close up to the envelope4 ,the inventor of these envelopes was a ,spaniard1 ,senor ,torres ,quevedo1 who manufactured them in conjunction with the ,astra ,company in ,paris4 ,this type of envelope has been employed in this country in the ,coastal1 ,c ,star1 and ,north ,sea airships1 and has been found on the whole to give good results4 ,it is questionable if an envelope of streamline shape would not be easier to handle1 both in the air and on the landing ground1 and at present there are partisans of both types4 ,thirdly1 there is the streamline envelope with tangential suspensions1 which has been adopted for all classes of the ,s4,s4 airship1 and which has proved for its purpose in every way highly satisfactory4 ,of these three types the rigid has the inherent disadvantage of not being able to be dismantled1 if it should become compelled to make a forced landing away from its base4 ,even if it were so fortunate as to escape damage in the actual landing1 there is the practical certainty that it would be completely wrecked immediately any increase occurred in the force of the wind4 ,on the other hand1 for military purposes1 it possesses the advantage of having several gas compartments1 and is in consequence less susceptible to damage from shell fire and other causes4 ,both the semi-rigid and the non-rigid have the very great advantage of being easily deflated and packed up4 ,in addition to the valves1 these ships have a ripping panel incorporated in the envelope which can easily be torn away and allows the gas to escape with considerable rapidity4 ,innumerable instances have occurred of ships being compelled to land in out-of-the-way places owing to engine failure or other reasons2 they have been ripped and deflated and brought back to the station without incurring any but the most trifling damage4 ,experience in the war has proved that for military purposes the large rigid1 capable of long hours of endurances and the small non-rigid made thoroughly reliable1 are the most valuable types for future development4 ,the larger non-rigids1 with the possible exception of the ,north ,sea1 do not appear to be likely to fulfil any very useful function4 ,airship design introduces so many problems which are not met with in the ordinary theory of structures1 that a whole volume could easily be devoted to the subject1 and even then much valuable information would have to be omitted from lack of space4 ,it is1 therefore1 impossible1 in only a section of a chapter1 to do more than indicate in the briefest manner a few salient features concerning these problems4 ,the suspension of weights from the lightest possible gas compartment must be based on the ordinary principles of calculating the distribution loads as in ships and other structures4 ,in the non-rigid1 the envelope being made of flexible fabric has1 in itself1 no rigidity whatsoever1 and its shape must be maintained by the internal pressure kept slightly in excess of the pressure outside4 ,fabric is capable of resisting tension1 but is naturally not able to resist compression4 ,if the car was rigged beneath the centre of the envelope with vertical suspensions it would tend to produce compression in the underside of the envelope1 owing to the load not being fully distributed4 ,this would cause1 in practice1 the centre portion of the envelope to sag downwards1 while the ends would have a tendency to rise4 ,the principle which has been found to be most satisfactory is to fix the points of suspension distributed over the greatest length of envelope possible proportional to the lift of gas at each section thus formed4 ,from these points the wires are led to the car4 ,if the car is placed close to the envelope it will be seen that the suspensions of necessity lie at a very flat angle and exert a serious longitudinal compression4 ,this must be resisted by a high internal pressure1 which demands a stouter fabric for the envelope and1 therefore1 increased weight4 ,it follows that the tendency of the envelope to deform is decreased as the distance of the car from the gas compartment is increased4 ,one method of overcoming this difficulty is found by using the ,astra-,torres design4 ,as will be seen from the diagram of the ,north ,sea airship1 the loads are excellently distributed by the several fans of internal rigging1 while external head resistance is reduced to a minimum1 as the car can be slung close underneath the envelope4 ,moreover1 the direct longitudinal compression due to the rigging is applied to a point considerably above the axis of the ship4 ,in a large non-rigid many of these difficulties can be overcome by distributing the weight into separate cars along the envelope itself4 ,we have seen that as an airship rises the gas contained in the envelope expands4 ,if the envelope were hermetically sealed1 the higher the ship rose the greater would become the internal pressure1 until the envelope finally burst4 ,to avoid this difficulty in a balloon1 a valve is provided through which the gas can escape4 ,in a balloon1 therefore1 which ascends from the ground full1 gas is lost throughout its upward journey1 and when it comes down again it is partially empty or flabby4 ,this would be an impossible situation in the case of the airship1 for she would become unmanageable1 owing to the buckling of the envelope and the sagging of the planes4 ,ballonets are therefore fitted to prevent this happening4 ,ballonets are internal balloons or air compartments fitted inside the main envelope1 and were originally filled with air by a blower driven either by the main engines or an auxiliary motor4 ,these blowers were a continual source of trouble1 and at the present day it has been arranged to collect air from the slip-stream of the propeller through a metal air scoop or blower-pipe and discharge it into an air duct which distributes it to the ballonets4 ,the following example will explain their functions3 ,an airship ascends from the ground full to #a1jjj feet4 ,the ballonets are empty1 and remain so throughout the ascent4 ,by the time the airship reaches #a1jjj feet it will have lost #a_/cjth of its volume of gas which will have escaped through the valves4 ,if the ship has a capacity of #cjj1jjj cubic feet it will have lost #aj1jjj cubic feet of gas4 ,the airship now commences to descend2 as it descends the gas within contracts and air is blown into the ballonets4 ,by the time the ground is reached #aj1jjj cubic feet of air will have been blown into the ballonets and the airship will have retained its shape and not be flabby4 ,on making a second ascent1 as the airship rises the air must be let out of the ballonet instead of gas from the envelope1 and by the time #a1jjj feet is reached the ballonets will be empty4 ,to ensure that this is always done the ballonet valves are set to open at less pressure than the gas valves4 ,it therefore follows in the example under consideration that it will not be necessary to lose gas during flight1 provided that an ascent is not made over #a1jjj feet4 ,valves are provided to prevent the pressure in the envelope from exceeding a certain determined maximum and are fitted both to ballonets and the gaschamber4 ,they are automatic in action1 and1 as we have said1 the gas valve is set to blow off at a pressure in excess of that for the air valve4 ,in rigid airships ballonets are not provided for the gasbags1 and as a consequence a long flight results in a considerable expenditure of gas4 ,if great heights are required to be reached1 it is obvious that the wastage of gas would be enormous1 and it is understood that the ,germans on starting for a raid on ,england1 where the highest altitudes were necessary1 commenced the flight with the gasbags only about #fj per cent full4 ,to stabilize the ship in flight1 fins or planes are fitted to the after end of the envelope or hull4 ,without the horizontal planes the ship will continually pitch up and down1 and without the vertical planes it will be found impossible to keep the ship on a straight course4 ,the planes are composed of a framework covered with fabric and are attached to the envelope by means of stay wires fixed to suitable points1 in the case of non-rigid ships skids being employed to prevent the edge of the plane forcing its way through the surface of the fabric4 ,the rudder and elevator flaps in modern practice are hinged to the after edges of the planes4 ,the airship car contains all instruments and controls required for navigating the ship and also provides a housing for the engines4 ,in the early days swivelling propellers were considered a great adjunct1 as with their upward and downward thrust they proved of great value in landing4 ,nowadays1 owing to greater experience1 landing does not possess the same difficulty as in the past1 and swivelling propellers have been abandoned except in rigid airships1 and even in the later types of these they have been dispensed with4 ,owing to the great range of an airship a thoroughly reliable engine is a paramount necessity4 ,the main requirements are--firstly1 that it must be capable of running for long periods without a breakdown2 secondly1 that it must be so arranged that minor repairs can be effected in the air2 and thirdly1 that economy of oil and fuel is of far greater importance to an airship than the initial weight of the engine itself4 ,,handling ,,and ,,flying ,,of ,,airships ,the arrangements made for handling airships on the ground and while landing1 and also for moving them in the open1 provide scope for great ingenuity4 ,an airship when about to land is brought over the aerodrome and is ballasted up so that she becomes considerably lighter than the air which she displaces4 ,the handling party needs considerable training1 as in gusty weather the safety of the ship depends to a great extent upon its skill in handling her4 ,the ship approaches the handling party head to wind and the trail rope is dropped2 it is taken by the handling party and led through a block secured to the ground and the ship is slowly hauled down4 ,when near the ground the handling party seize the guys which are attached to the ship at suitable points1 other detachments also support the car or cars1 as the case may be1 and the ship can then be taken into the shed4 ,in the case of large airships the size of the handling party has to be increased and mechanical traction is also at times employed4 ,as long as the airship is kept head to wind1 handling on the ground presents little difficulty2 on many occasions1 however1 unless the shed is revolving1 as is the case on certain stations in ,germany1 the wind will be found to be blowing across the entrance to the shed4 ,the ship will then have to be turned1 and during this operation1 unless great discretion is used1 serious trouble may be experienced4 ,many experiments have been and are still being conducted to determine the best method of mooring airships in the open4 ,these will be described and discussed at some length in the chapter devoted to the airship of the future4 ,during flight certain details require attention1 and carelessness on the pilot's part1 even on the calmest of days1 may lead to disaster4 ,the valves and especially the gas valves should be continually tested1 as on occasions they have been known to jam1 and the loss of gas has not been discovered until the ship had become unduly heavy4 ,pressure should be kept as constant as possible4 ,most airships work up to #cj millimetres as a maximum and #ae millimetres as a minimum flying pressure4 ,during a descent the pressure should be watched continuously1 as it may fall so low as to cause the nose to blow in4 ,this will right itself when the speed is reduced or the pressure is raised1 but there is always the danger of the envelope becoming punctured by the bow stiffeners when this occurs4 ,,housing ,,accommodation ,,for ,,airships1 ,,etc4 ,during the early days of the war1 when stations were being equipped1 the small type of airship was the only one we possessed4 ,the sheds to accommodate them were constructed of wood both for cheapness and speed of construction and erection4 ,these early sheds were all of very similar design1 and were composed of trestles with some ordinary form of roof-truss4 ,they were covered externally with corrugated sheeting4 ,the doors have always been a source of difficulty1 as they are compelled to open for the full width of the shed and have to stand alone without support4 ,they are fitted with wheels which run on guide rails1 and are opened by means of winches and winding gear4 ,the later sheds built to accommodate the rigid airship are of much greater dimensions1 and are constructed of steel1 but otherwise are of much the same design4 ,the sheds are always constructed with sliding doors at either end1 to enable the ship to be taken out of the lee end according to the direction of the wind4 ,it has been the practice in this country to erect windscreens in order to break the force of the wind at the mouth of the shed4 ,these screens are covered with corrugated sheeting1 but it is a debatable point as to whether the comparative shelter found at the actual opening of the shed is compensated for by the eddies and air currents which are found between the screens themselves4 ,experiments have been carried out to reduce these disturbances1 in some cases by removing alternate bays of the sheeting and in other cases by substituting expanded metal for the original corrugated sheets4 ,it must be acknowledged that where this has been done1 the airships have been found easier to handle4 ,at the outbreak of war1 with the exception of a silicol plant at ,kingsnorth1 now of obsolete type1 and a small electrolytic plant at ,farnborough1 there was no facility for the production of hydrogen in this country for the airship service4 ,when the new stations were being equipped1 small portable silicol plants were supplied capable of a small output of hydrogen4 ,these were replaced at a later date by larger plants of a fixed type1 and a permanent gas plant1 complete with gasholders and high pressure storage tanks was erected at each station1 the capacity being #e1jjj or #aj1jjj cubic feet per hour according to the needs of the station4 ,with the development of the rigid building programme1 and the consequent large requirements of gas1 it was necessary to reconsider the whole hydrogen situation1 and after preliminary experimental work it was decided to adopt the water gas contact process1 and plants of this kind with a large capacity of production were erected at most of the larger stations4 ,at others electrolytic plants were put down4 ,hydrogen was also found to be the bye-product of certain industries1 and considerable supplies were obtained from commercial firms1 the hydrogen being compressed into steel cylinders and dispatched to the various stations4 ,before concluding this chapter1 certain words must be written on parachutes4 ,a considerable controversy raged in the press and elsewhere a few months before the cessation of hostilities on the subject of equipping the aeroplane with parachutes as a life-saving device4 ,in the airship service this had been done for two years4 ,the best type of parachute available was selected1 and these were fitted according to circumstances in each type of ship4 ,the usual method is to insert the parachute1 properly folded for use1 in a containing case which is fastened either in the car or on the side of the envelope as is most convenient4 ,in a small ship the crew are all the time attached to their parachutes and in the event of the ship catching fire have only to jump overboard and possess an excellent chance of being saved4 ,in rigid airships where members of the crew have to move from one end of the ship to the other1 the harness is worn and parachutes are disposed in the keel and cars as are lifebuoys in seagoing vessels4 ,should an emergency arise1 the nearest parachute can be attached to the harness by means of a spring hook1 which is the work of a second1 and a descent can be made4 ,it is worthy of note that there has never been a fatal accident or any case of a parachute failing to open properly with a man attached4 ,the material embodied in this chapter1 brief and inadequate as it is1 should enable the process of the development of the airship to be easily followed4 ,much has been omitted that ought by right to have been included1 but1 on the other hand1 intricate calculations are apt to be tedious except to mathematicians1 and these have been avoided as far as possible in the following pages4 ,,chapter ,,ii ,,early ,,airships ,,and ,,their ,,development ,,to ,,the ,,present ,,day ,the science of ballooning had reached quite an advanced stage by the middle of the eighteenth century1 but the construction of an airship was at that time beyond the range of possibility4 ,discussions had taken place at various times as to the practicability of rendering a balloon navigable1 but no attempts had been made to put these points of argument to a practical test4 ,airship history may be said to date from ,january #bdth1 #aghd4 ,on that day ,brisson1 a member of the ,academy in ,paris1 read before that ,society a paper on airships and the methods to be utilized in propelling them4 ,he stated that the balloon1 or envelope as it is now called1 must be cylindrical in shape with conical ends1 the ratio of diameter to length should be one to five or one to six and that the smallest cross-sectional area should face the wind4 ,he proposed that the method of propulsion should be by oars1 although he appeared to be by no means sanguine if human strength would be sufficient to move them4 ,finally1 he referred to the use of different currents of the atmosphere lying one above the other4 ,this paper caused a great amount of interest to be taken in aeronautics1 with the result that various ,frenchmen turned their attention to airship design and production4 ,to ,france must be due the acknowledgment that she was the pioneer in airship construction and to her belongs the chief credit for early experiments4 ,at a later date ,germany entered the lists and tackled the problems presented with that thoroughness so characteristic of the nation4 ,it is just twenty-one years ago since ,count ,zeppelin1 regardless of public ridicule1 commenced building his rigid airships1 and in that time such enormous strides were made that ,germany1 at the outbreak of the war1 was ahead of any other country in building the large airship4 ,in #aijh ,italy joined the pioneers1 and as regards the semi-rigid is in that type still pre-eminent4 ,great ,britain1 it is rather sad to say1 adopted the policy of wait and see1 and1 with the exception of a few small ships described in the two succeeding chapters1 had produced nothing worthy of mention before the outbreak of the great ,european war4 ,she then bestirred herself1 and we shall see later that she has produced the largest fleet of airships built by any country and1 while pre-eminent with the non-rigid1 is seriously challenging ,germany for the right to say that she has now built the finest rigid airship4 ,,france ,to revert to early history1 in the same year in which ,brisson read his paper before the ,academy1 the ,duke of ,chartres gave the order for an airship to the brothers ,robert1 who were mechanics in ,paris4 ,this ship was shaped like a fish1 on the supposition that an airship would swim through the air like a fish through water4 ,the gas-chamber was provided with a double envelope1 in order that it might travel for a long distance without loss of gas4 ,the airship was built in ,st4 ,cloud ,park2 in length it was #eb feet with a diameter of #hb feet1 and was ellipsoidal in shape with a capacity of #cj1jjj cubic feet4 ,oars were provided to propel it through the air1 experiments having proved that with two oars of six feet diameter a back pressure of #ij lb4 was obtained and with four oars #adj lb4 ,on ,july #fth in the same year the first ascent was made from ,st4 ,cloud4 ,the passengers were the ,duke of ,chartres1 the two brothers ,robert and ,colin-,hulin4 ,no valves having been fitted1 there was no outlet for the expansion of gas and the envelope was on the point of bursting1 when the ,duke of ,chartres1 with great presence of mind1 seized a pole and forced an opening through both the envelopes4 ,the ship descended in the ,park of ,meudon4 ,on ,september #aith the airship made a second ascent with the same passengers as before1 with the exception of the ,duke4 ,according to the report of the brothers ,robert1 they succeeded in completing an ellipse and then travelled further in the direction of the wind without using the oars or steering arrangements4 ,they then deviated their course somewhat by the use of these implements and landed at ,bethune1 about #ahj miles distant from ,paris4 ,in those days it was considered possible that a balloon could be rendered navigable by oars1 wings1 millwheels1 etc41 and it was not until the last decades of the nineteenth century1 when light and powerful motors had been constructed1 that the problem became really practical of solution4 ,during the nineteenth century several airships were built in ,france and innumerable experiments were carried out1 but the vessels produced were of little real value except in so far as they stimulated their designers to make further efforts4 ,two of these only will be mentioned1 and that because the illustrations show how totally different they were from the airship of to-day4 ,in #ahcd the ,compte de ,lennox built an airship of #ih1gjj cubic feet capacity4 ,it was cylindrical in form with conical ends1 and is of interest because a small balloon or ballonet1 #g1jej cubic feet contents1 was placed inside the larger one for an air filling4 ,a car #ff feet in length was rigged beneath the envelope by means of ropes eighteen inches long4 ,above the car the envelope was provided with a long air cushion in connection with a valve4 ,the intention was by compression of the air in the cushion and the inner balloon1 to alter the height of the airship1 in order to travel with the most favourable air currents4 ,the motive power was #bj oar propellers worked by men4 ,this airship proved to be too heavy on completion to lift its own weight1 and was destroyed by the onlookers4 ,the next airship1 the ,dupuy de ,lome1 is of interest because the experiments were carried out at the cost of the ,state by the ,french ,government4 ,this ship consisted of a spindle-shaped balloon with a length of #aab feet1 diameter of #dh #a_/b feet and a volume of #aba1hjj cubic feet4 ,an inner air balloon of #f1jjj cubic feet volume was contained in the envelope4 ,the method of suspension was by means of diagonal ropes with a net covering4 ,a rudder in the form of a triangular sail was fitted beneath the envelope and at the after part of the ship4 ,the motive power was double-winged screws #bi feet #f inches diameter1 to be worked by four to eight men4 ,on her trials the ship became practically a free balloon1 an independent velocity of about six miles per hour being achieved and deviation from the direction of the wind of ten degrees4 ,at the close of the nineteenth century ,santos-,dumont turned his attention to airships4 ,the experiments which he carried out marked a new epoch and there arose the nucleus of the airship as we know it to-day4 ,between the years #ahih and #aije he had in all built fourteen airships1 and they were continually improved as each succeeding one made its appearance4 ,in the last one he made a circular flight2 starting from the aerodrome of the aero club1 he flew round the ,eiffel ,tower and back to the starting point in thirty-one minutes on ,october #aith1 #aijb4 ,for this feat the ,deutsch prize was awarded to him4 ,the envelopes he used were in design much nearer approach to a streamline form than those previously adopted1 but tapered to an extremely fine point both at the both and stem4 ,for rigging he employed a long nacelle1 in the centre of which was supported the car1 and unusually long suspensions distributed the weight throughout practically the entire length of the envelope4 ,to the name of ,santos-,dumont much credit is due4 ,he may be regarded as the originator of the airship for pleasure purposes1 and by his success did much to popularize them4 ,he also was responsible to a large extent for the development and expansion of the airship industry in ,paris4 ,at a little later date1 in #aijb to be precise1 the ,lebaudy brothers1 in conjunction with ,julliot1 an engineer1 and ,surcoup1 an aeronaut1 commenced building an airship of a new type4 ,this ship was a semirigid and was of a new shape1 the envelope resembling in external appearance a cigar4 ,in length it was #agh feet with a diameter of #cj feet and the total capacity was #fd1hjj cubic feet4 ,this envelope was attached to a rigid elliptical keel-shaped girder made of steel tubes1 which was about a third of the length of the ship4 ,the girder was covered with a shirting and intended to prevent the ship pitching and rolling while in flight4 ,a horizontal rudder was attached to the under side of this girder1 while right aft a large vertical rudder was fixed4 ,a small car was suspended by steel rods at a distance of #ag feet #i inches from the girder1 with a framework built up underneath to absorb the shock on landing4 ,a #ce horse-power ,daimler-,mercedes motor1 weighing some #hjj lb4 without cooling water and fuel1 drove two twin-bladed propellers on either side of the car4 ,in the year #aijc a number of experimental flights were made with this ship and various details in the construction were continually introduced4 ,the longest flight was #b hours #df minutes4 ,towards the end of that year1 while a voyage was being made from ,paris to ,chalais ,meudon1 the airship came in contact with a tree and the envelope was badly torn4 ,in the following year it was rebuilt1 and the volume was slightly increased with fixed and movable planes added to increase the stability4 ,after several trips had been made1 the airship again on landing came in contact with a tree and was burst4 ,the ship was rebuilt and after carrying out trials was purchased by the ,french ,army4 ,the ,lebaudy airship had at that time been a distinct success1 and in #aiaj one was purchased for the ,british ,government by the readers of the ,morning ,post4 ,in the ten-ton ,lebaudy the length of the keel framework was greatly extended1 and ran for very nearly the full length of the envelope4 ,the disadvantage of this ship was its slowness1 considering its size and power1 and was due to the enormous resistance offered by the framework and rigging4 ,airships known as the ,clement-,bayard were also built about this time4 ,they were manufactured by the ,astra ,company in conjunction with ,monsieur ,clement1 a motor engineer4 ,in later days vessels were built by the ,astra ,company of the peculiar design introduced by ,senor ,torres4 ,these ships1 some of which were of considerable size1 were highly successful1 and we became purchasers at a later date of several4 ,the ,zodiac ,company also constructed a number of small ships which were utilized during the war for anti-submarine patrol4 ,it cannot be said1 however1 that the ,french have fulfilled their early promise as airship designers1 the chief reason for this being that the airship is peculiarly suitable for work at sea and the ,french relied on us to maintain the commerce routes on the high seas and concentrated their main efforts on defeating the ,germans in the field1 in which as all the world acknowledges they were singularly successful and hold us under an eternal obligation4 ,,germany ,the progress and development of the airship in ,germany must now be considered2 it will be seen that1 although the production of satisfactory ships was in very few hands1 considerable success attended their efforts in the early days of the twentieth century4 ,in #ahab1 ,leppig built an airship at the cost of the ,state at ,woronzowo in ,russia4 ,this was of the shape of a fish with a rigid framework beginning at the height of the longitudinal axis4 ,the lower keel-shaped part of the same formed the car4 ,two fans were attached to the sides and a tail piece was provided behind to act as a rudder4 ,the ship was inflated1 but structural damage occurred during this operation and rendered it incapable of flight4 ,in #ahcf1 ,georg ,rebenstein1 of ,nurnburg1 was considering the use of the fall of inclined planes to obtain horizontal motion4 ,nothing of importance was produced until a much later date1 when in #ahhe ,m4 ,wolf constructed an envelope of #bf1ejj cubic feet4 ,an engine and propeller were fixed in a triangular framework in front of the airship1 supported by the steam pipe of a steam engine fixed under the body of the envelope4 ,the framework lacked rigidity1 and the envelope tore during inflation and the airship failed to ascend4 ,in the following year ,dr4 ,woelfert1 of ,berlin1 produced a cigar-shaped envelope1 to which was attached rigidly a long bamboo framework containing the car4 ,an #h horse-power benzine ,daimler motor drove a twin-bladed aluminium propeller1 and another propeller for vertical movement was provided beneath the car4 ,four trial flights were attempted1 but on each occasion the motor gave unsatisfactory results1 and ,woelfert sought to improve it with a benzine vaporizer of his own pattern4 ,this improvement was not a success1 as during the last flight an explosion took place and both ,woelfert and an aeronaut named ,knabe1 who was accompanying him1 were killed4 ,in #aijf1 ,major von ,parseval experimented1 in ,berlin1 with a non-rigid type of airship4 ,his first ship had a volume of #fe1bjj cubic feet1 but owing to his system of suspensions1 the car hung #bg feet #f inches below the envelope4 ,a ,daimler engine was used1 driving a four-bladed propeller4 ,owing to the great overall height of this ship1 experiments were made to determine a system of rigging1 enabling the car to be slung closer to the envelope1 and in later types the elliptical rigging girdle was adopted4 ,his later ships were of large dimensions and proved very satisfactory4 ,about the same time ,major ,gross also built airships for the ,german aeronautical battalion4 ,it is1 however1 the rigid airship that has made ,germany famous1 and we must now glance at the evolution of these ships with which we became so familiar during the war4 ,the first rigid airship bearing any resemblance to those of the present day was designed by ,david ,schwartz1 and was built in ,st4 ,petersburg in #ahic4 ,it was composed of aluminium plates riveted to an aluminium framework4 ,on inflation1 the frame-work collapsed and the ship was unusable4 ,in #ahie he designed a second rigid airship1 which was built in ,berlin by ,messrs4 ,weisspfennig and ,watzesch4 ,the hull framework was composed of aluminium and was #aee feet long1 elliptical in cross section1 giving a volume of #acj1ejj cubic feet4 ,it was pointed in front and rounded off aft4 ,the car1 also constructed of the same material1 was rigidly attached to the hull by a lattice framework1 and the whole hull structure was covered in with aluminium sheeting4 ,a #ab horse-power ,daimler benzine motor was installed in the car1 driving through the medium of a belt twin aluminium screw propellers2 no rudders were supplied1 the steering being arranged by means of a steering screw placed centrally to the ship above the top of the car4 ,inflation took place at the end of #ahig by a method of pressing out air-filled fabric cells which were previously introduced into the hull4 ,this operation took three and a half hours4 ,on the day of the first flight trials there was a fresh wind of about #ag miles per hour4 ,the airship ascended into the air1 but1 apparently1 could make little headway against the wind4 ,during the trip the driving-belt became disengaged from the propellers and the ship drifted at the mercy of the wind1 but sustained little damage on landing4 ,after being deflated1 the hull began to break up under the pressure of the wind and was completely destroyed by the vandalism of the spectators4 ,in #ahih ,graf ,f4 von ,zeppelin1 inspired by the example of ,schwartz1 and assisted by the engineers ,kober and ,kubler1 conceived the idea of constructing a rigid airship of considerable dimensions4 ,for this purpose a floating shed was built on ,lake ,constance1 near to ,friedrichshafen4 ,the hull was built of aluminium lattice-work girders1 and had the form of a prism of twenty-four surfaces with arch-shaped ends4 ,in length it was #dbj feet1 with a diameter of #ch feet #f inches1 and its capacity was #djj1jjj cubic feet4 ,the longitudinal framework was divided by a series of rings1 called transverse frames1 into seventeen compartments containing fabric gasbags4 ,the transverse frames were fitted with steel wire bracings1 both radial and chord1 and to strengthen the whole a triangular aluminium keel of lattice work was used4 ,a vertical and horizontal rudder were fitted to the forward portion of the ship1 and aft another vertical rudder4 ,the whole exterior of the ship was fitted with a fabric outer cover4 ,two aluminium cars1 each about #bj feet long1 were rigidly attached to the framework of the hull4 ,each car was furnished with a #af horse-power ,daimler engine1 driving two four-bladed screw propellers of aluminium sheeting4 ,these propellers were situated on the side of the hull at the centre of resistance4 ,the transmission was supplied by steel tubes with universal cross joints through the medium of bevel gears4 ,reversible driving arrangements were installed in the cars in order that the ship could be driven backwards and forwards4 ,electric bells1 telegraphs1 and speaking tubes were also fitted1 and it can be seen that for general arrangements this airship was a long way ahead of any built at that date4 ,the first flight was made on ,july #bnd1 #aijj4 ,the ship attained a speed of #ag per hour1 and the numerous technical details stood the tests well4 ,the stability was considered sufficient1 and the height of flight could be altered by the horizontal rudder4 ,the landing on the water was accomplished without difficulty1 and could be regarded as free from danger4 ,the faults requiring remedy were1 firstly1 the upper cross stays1 which buckled in flight owing to insufficient strength for the length of the hull2 secondly1 the gasbags were not sufficiently gastight and1 thirdly1 the power of the engines were not sufficient for such a heavy ship4 ,this airship was broken up in #aijb4 ,in #aije the second ship of the series was completed4 ,she was of nearly the same size as the previous ship1 but the workmanship was much superior4 ,increased engine-power was also supplied1 as in this instance two #he horse-power ,mercedes engines were fitted4 ,this ship was destroyed by a storm while landing during the next year4 ,the third ship1 which was completed in #aijf1 was the first ,zeppelin airship acquired by the ,government1 and lasted for a considerable time1 being rebuilt twice1 first in #aijh and again in #aiaa4 ,she was slightly larger than the previous two4 ,the building was continued1 and up to the outbreak of war no fewer than twenty-five had been completed4 ,it is impossible1 in the space at our disposal1 to trace the career of all of them4 ,several came to an untimely end1 but as the years went by each succeeding ship proved more efficient1 and the first ship which was delivered to the ,navy performed the notable flight of thirty-one hours4 ,to revert1 for a moment1 once more to the earlier ships--the fourth was wrecked and burned at ,echterdingen in the same year in which she was completed4 ,the fifth1 which was the second military airship1 was fitted with two #aaj horse-power engines and also came to a tragic end1 being destroyed by wind at ,weilberg in #aiaj1 and the following ship was burnt at ,baden in the same year4 ,the seventh ship was the first passenger airship of the series1 and was known as the ,deutschland4 ,by this time the capacity had increased to #ecf1jjj cubic feet1 and she was propelled by three #abj horse-power engines4 ,she also fell a victim to the wind1 and was wrecked in the ,teutoberg ,forest in #aiaj2 and yet another was destroyed in the following year at ,dusseldorf4 ,the tenth ship to be completed was the passenger ship ,schwaben2 her capacity was #fcf1ejj cubic feet1 and she had three #aej horse-power engines4 ,this ship carried out her first flight in ,june1 #aiaa1 and was followed four months later by the ,victoria ,luise4 ,the fourth passenger airship was known as the ,hansa4 ,these three ships were all in commission at the outbreak of war4 ,the first naval airship1 ,l #a1 mentioned above1 was larger than any of these4 ,the total length was #ebe feet1 diameter #ej feet1 and cubic contents #ggf1jjj cubic feet4 ,her hull framework in section formed a regular polygon of seventeen sides1 and was built up of triangular aluminium girders4 ,the gasbags were eighteen in number4 ,this ship was fitted with three #agj horse-power ,maybach engines1 which were disposed as follows--one in the forward car1 driving two two-bladed propellers2 two in the after car1 each driving a single four-bladed propeller4 ,for steering purposes she had six vertical and eight horizontal planes4 ,the total lift was #bg tons1 with a disposable lift of #g tons4 ,her speed was about #ej miles per hour1 and she could carry fuel for about #dh hours4 ,her normal crew consisted of fourteen persons1 including officers4 ,it will probably be remembered that the military ,zeppelin ,z ,,iii was compelled to make a forced landing in ,france4 ,this ship was of similar construction to ,l #a1 but of smaller volume1 her capacity being #fbj1jjj cubic feet4 ,a trial flight was being carried out1 and while above the clouds the crew lost their bearings4 ,descending they saw some ,french troops and rose again immediately4 ,after flying for four hours they thought they must be safely over the frontier and1 running short of petrol1 made a landing--not knowing that they were still in ,france until too late4 ,the airship was taken over by the ,french authorities4 ,until the year #aiaf the ,zeppelin may be considered to have passed through three stages of design4 ,of the twenty-five ships constructed before the war1 twenty-four were of the first type and one of the second4 ,each type possessed certain salient features1 which1 for simplicity1 will be set out in the form of a tabulated statement1 and may be useful for comparison when our own rigid airships are reviewed4 ,stage #a4 ,long parallel portion of hull with bluff nose and tail4 ,external keel with walking way4 ,box rudders and elevators4 ,two cars4 ,four wing propellers4 ,stage #b4 ,long parallel portion of hull with bluff nose1 tail portion finer than in ,stage ,i ,internal keel walking way4 ,box rudders and elevators4 ,three cars1 foremost for control only4 ,four wing propellers4 ,stage #c4 ,shorter parallel portion of hull framework1 bluff nose and tapering tail4 ,internal keel walking way4 ,balanced monoplane rudders and elevators4 ,three cars1 foremost for control only4 ,two foremost cars close together and connected by a canvas joint to look like one car4 ,four engines and four propellers4 ,one engine in forward car driving pusher propeller4 ,three engines in after car driving two wing and one pusher propeller4 ,to the second stage belongs naval airship ,l #b1 which was destroyed by fire a month after completion in #aiac4 ,in #aiaf a fourth stage made its appearance1 of which the first ship was ,l #cj1 completed in ,may1 and to which the ill-fated ,l #cc belonged4 ,this type is known as the super-,zeppelin1 and has been developed through various stage until ,l #gj1 the latest product before the armistice4 ,in this stage the following are its main features3 ,stage #d4 ,short parallel portion of hull1 long rounded bow and long tapering stern4 ,in all respects a good streamline shape4 ,internal keel walking way4 ,balanced monoplane rudders and elevators4 ,five cars4 ,two forward 7combined as in ,stage #c71 one aft1 and two amidships abreast4 ,six engines and six propellers4 ,the after one of the forecar and the sidecars each contain one engine driving direct a pusher propeller4 ,the after car contains three engines1 two of which drive two wing propellers2 the third1 placed aft1 drives direct a pusher propeller4 ,in this stage the type of girders was greatly altered4 ,a company known as the ,schutte-,lanz ,company was also responsible for the production of rigid airships4 ,they introduced a design1 which was a distinct departure from ,zeppelin or anyone else4 ,the hull framework was composed of wood1 the girders being built up of wooden sections4 ,the shape of these ships was much more of a true streamline than had been the ,zeppelin practice1 and it was on this model that the shape of the super-,zeppelin was based4 ,these ships proved of use and took part in raids on this country1 but the ,company was taken over by the ,government and the personnel was amalgamated with that engaged on ,zeppelin construction during the war4 ,,italy ,in #aijh1 ,italy1 stimulated by the progress made by other continental nations1 commenced experimental work4 ,three types were considered for a commencement1 the ,p type or ,piccolo was the first effort1 then followed the ,m type1 which signifies medium sized1 and also the semirigid ,forlanini4 ,in the ,forlanini type the envelope is divided into several compartments with an internal rigid keel and to-day these ships are of considerable size1 the most modern being over #fjj1jjj cubic feet capacity4 ,during the war1 ,italian airships were developed on entirely dissimilar lines to those in other countries4 ,both we and our ,allies1 and to a great extent the ,germans1 employed airships exclusively for naval operations2 on the other hand1 the ,italian ships were utilized for bombing raids in conjunction with military evolutions4 ,for this reason height was of primary importance and speed was quite a secondary consideration1 owing to the low velocity of prevailing winds in that country4 ,flights were never of long duration compared with those carried out by our airships4 ,height was always of the utmost importance1 as the ,italian ships were used for bombing enemy towns and must evade hostile gunfire4 ,for this reason weight was saved in every possible manner1 to increase the height of the ceiling4 ,in addition to the types already mentioned1 three other varieties have been constructed since the war--the ,usuelli ,d4,e4 type and ,g class4 ,the ,g class was a rigid design which has not been proceeded with1 and1 with this single exception1 all are of a semirigid type in which an essentially non-rigid envelope is reinforced by a metal keel4 ,in the ,forlanini and ,usuelli types the keel is completely rigid and assists in maintaining the shape of the envelopes1 and in the ,forlanini is enclosed within the envelope4 ,in the other types the keel is in reality a chain of rigid links similar to that of a bicycle4 ,the form of the envelope is maintained by the internal pressure and not by the keel1 but the resistance of the latter to compression enables a lower pressure to be maintained than would be possible in a purely non-rigid ship4 ,the ,m type ship is of considerable size1 the ,p smaller1 while the ,d4,e4 is a small ship comparable to our own ,s4,s4 design4 ,the review of these three countries brings the early history of airships to a conclusion4 ,little of importance was done elsewhere before the war1 though ,baldwin's airship is perhaps worthy of mention4 ,it was built in ,america in #aijh by ,charles ,baldwin for the ,american ,government4 ,the capacity of the envelope was #bj1jjj cubic feet1 she carried a crew of two1 and her speed was #af miles per hour4 ,she carried out her trial flight in ,august1 #aijh1 and was accepted by the ,american military authorities4 ,during the war both the naval and military authorities became greatly interested in airships1 and purchased several from the ,french and ,english4 ,in addition to this a ship in design closely resembling the ,s4,s4 was built in ,america1 but suffered from the same lack of experience which we did in the early days of airship construction4 ,we must now see what had been happening in this country in those fateful years before the bombshell of war exploded in our midst4 ,,chapter ,,iii ,,british ,,airships ,,built ,,by ,,private ,,firms ,it has been shown in the previous chapter that the development of the airship had been practically neglected in ,england prior to the twentieth century4 ,ballooning had been carried out both as a form of sport and also by the showman as a ,saturday afternoon's sensational entertainment1 with a parachute descent as the piece de resistance4 ,the experiments in adapting the balloon into the dirigible had1 however1 been left to the pioneers on the ,continent4 ,,partridge',s ,,airship ,it appears that in the nineteenth century only one airship was constructed in this country1 which proved to be capable of ascending into the air and being propelled by its own machinery4 ,this airship made its appearance in the year #ahdh1 and was built to the designs of a man named ,partridge4 ,very little information is available concerning this ship4 ,the envelope was cylindrical in shape1 tapering at each end1 and was composed of a light rigid framework covered with fabric4 ,the envelope itself was covered with a light wire net1 from which the car was suspended4 ,the envelope contained a single ballonet for regulating the pressure of the gas4 ,planes1 which in design more nearly resembled sails1 were used for steering purposes4 ,in the car1 at the after end1 were fitted three propellers which were driven by compressed air4 ,several trips of short duration were carried out in this airship1 but steering was never successfully accomplished owing to difficulties encountered with the planes1 and1 except in weather of the calmest description1 she may be said to have been practically uncontrollable4 ,,hugh ,,bell',s ,,airship ,in the same year1 #ahdh1 ,bell's airship was constructed4 ,the envelope of this ship was also cylindrical in shape1 tapering at each end to a point1 the length of which was #ef feet and the diameter #ba feet #d inches4 ,a keel composed of metal tubes was attached to the underside of the envelope from which the car was suspended4 ,on either side of the car screw propellers were fitted to be worked by hand4 ,a rudder was attached behind the car4 ,it was arranged that trials should be carried out in the ,vauxhall ,gardens in ,london1 but these proved fruitless4 ,,barton',s ,,airship ,in the closing years of the nineteenth century appeared the forerunners of airships as they are to-day1 and interest was aroused in this country by the performances of the ships designed by ,santos-,dumont and ,count ,zeppelin4 ,from now onwards we find various ,british firms turning their attention to the conquest of the air4 ,in #aijc ,dr4 ,barton commenced the construction of a large non-rigid airship4 ,the envelope was #agf feet long with a height of #dc feet and a capacity of #bce1jjj cubic feet2 it was cylindrical in shape1 tapering to a point at each end4 ,beneath the whole length of the cylindrical portion was suspended a bamboo framework which served as a car for the crew1 and a housing for the motors supplying the motive power of the ship4 ,this framework was suspended from the envelope by means of steel cables4 ,installed in the car were two #ej horse-power ,buchet engines which were mounted at the forward and after ends of the framework4 ,the propellers in themselves were of singular design1 as they consisted of three pairs of blades mounted one behind the other4 ,the were situated on each side of the car1 two forward and two aft4 ,the drive also include large friction clutches1 and each engine was under separate control4 ,to enable the ship to be trimmed horizontally1 water tanks were fitted at either end of the framework1 the water being transferred from one to the other as was found necessary4 ,a series of planes was mounted at intervals along the framework to control the elevation of the ship4 ,this ship was completed in #aije and was tried at the ,alexandra ,palace in the ,july of that year4 ,she1 unfortunately1 did not come up to expectations1 owing to the difficulty in controlling her1 and during the trial flight she drifted away and was destroyed in landing4 ,,willows ,no4 #a ,from the year #aije until the outbreak of war ,messrs4 ,willows ,co4 were engaged on the construction of airships of a small type1 and considerable success attended their efforts4 ,each succeeding ship was an improvement on its predecessor1 and flights were made which1 in their day1 created a considerable amount of interest4 ,in #aije their first ship was completed4 ,this was a very small non-rigid of only #ab1ejj cubic feet capacity4 ,the envelope was made of ,japanese silk1 cylindrical in shape1 with rather blunt conical ends4 ,a long nacelle or framework1 triangular in section and built up of light steel tubes1 was suspended beneath the envelope by means of diagonally crossed suspensions4 ,a #g horse-power ,peugeot engine was fitted at the after end of the nacelle which drove a #aj-;feet diameter propeller4 ,in front were a pair of swivelling tractor screws for steering the ship in the vertical and horizontal plane4 ,no elevators or rudders were fixed to the ship4 ,,willows ,no4 #b ,the second ship was practically a semi-rigid4 ,the envelope was over twice the capacity of the earlier ship1 being of #bi1jjj cubic feet capacity4 ,this envelope was attached to a keel of bamboo and steel1 from which was suspended by steel cables a small car4 ,at the after end of the keel was mounted a small rudder for the horizontal steering4 ,for steering in the vertical plane two propellers were mounted on each side of the car1 swivelling to give an upward or downward thrust4 ,a #cj horse-power ,j4,a4,p4 engine was fitted in this case4 ,several successful flights were carried out by this ship1 of which the most noteworthy was from ,cardiff to ,london4 ,,willows ,no4 #c ,no4 #b1 having been rebuilt and both enlarged and improved1 became known as ,no4 #c4 ,the capacity of the envelope1 which was composed of rubber and cotton1 was increased to #cb1jjj cubic feet1 and contained two ballonets4 ,the gross lift amounted to about half a ton4 ,as before1 a #cj horse-power ,j4,a4,p4 engine was installed1 driving the swivelling propellers4 ,these propellers were two-bladed with a diameter of #fa feet4 ,the maximum speed was supposed to be #be miles per hour1 but it is questionable if this was ever attained4 ,this ship flew from ,london to ,paris1 and was the first ,british-built airship to fly across the ,channel4 ,,willows ,no4 #d ,the fourth ship constructed by this firm was completed in #aiab1 and was slightly smaller than the two preceding ships4 ,the capacity of the envelope in this instance was reduced to #bd1jjj cubic feet1 but was a much better shape1 having a diameter of #bj feet1 which was gradually tapered towards the stern4 ,a different material was also used1 varnished silk being tried as an experiment4 ,the envelope was attached to a keel on which was mounted the engine1 a #ce horse-power ,anzani1 driving two swivelling four-bladed propellers4 ,from the keel was suspended a torpedo-shaped boat car in which a crew of two was accommodated4 ,originally a vertical fin and rudder were mounted at the stern end of the keel1 but these were later replaced by fins on the stern of the envelope4 ,this ship was purchased by the naval authorities1 and after purchase was more or less reconstructed1 but carried out little flying4 ,at the outbreak of war she was lying deflated in the shed at ,farnborough4 ,as will be seen later1 this was the envelope which was rigged to the original experimental ,s4,s4 airship in the early days of #aiae1 and is for this reason1 if for no other1 particularly interesting4 ,,willows ,no4 #e ,this ship was of similar design1 but of greater capacity4 ,the envelope1 which was composed of rubber-proofed fabric1 gave a volume of #ej1jjj cubic feet1 and contained two ballonets4 ,a #fj horsepower engine drove two swivelling propellers at an estimated speed of #ch miles per hour4 ,she was constructed at ,hendon1 from where she made several short trips4 ,,marshall ,,fox',s ,,airship ,in the early days of the war an airship was constructed by ,mr4 ,marshall ,fox which is worthy of mention1 although it never flew4 ,it was claimed that this ship was a rigid airship1 although from its construction it could only be looked upon as a non-rigid ship1 having a wooden net-work around its envelope4 ,the hull was composed of wooden transverse frames forming a polygon of sixteen sides1 with radial wiring fitted to each transverse frame4 ,the longitudinal members were spiral in form and were built up of three-ply lathes4 ,a keel of similar construction ran along the under side of the hull which carried the control position and compartments for two ,green engines1 one of #dj horse-power1 the other of #hj horse-power1 together with the petrol1 bombs1 etc4 ,in the hull were fitted fourteen gasbags giving a total capacity of #ajj1jjj cubic feet4 ,the propeller drive was obtained by means of a wire rope4 ,the gross lift of the ship was #d1bgf lb41 and the weight of the structure1 complete with engines1 exceeded this4 ,it became apparent that the ship could never fly1 and work was suspended4 ,she was afterwards used for carrying out certain experiments and at a later date was broken up4 ,apart from the various airships built under contract for the ,government there do not appear to be any other ships built by private firms which were completed and actually flew4 ,it is impossible to view this lack of enterprise with any other feelings than those of regret1 and it was entirely due to this want of foresight that ,great ,britain entered upon the ,world ,war worse equipped1 as regards airships1 than the ,central ,empires or any of the greater ,allied ,powers4 ,,chapter ,,iv ,,british ,,army ,,airships ,the ,french and ,german military authorities began to consider airships as an arm of the ,service in the closing years of the nineteenth century1 and devoted both time and considerable sums of money in the attempt to bring them to perfection4 ,their appearance in the ,british ,army was delayed for many years on account of the expense that would be incurred in carrying out experiments4 ,in #aijb1 ,colonel ,templer1 at that time head of the ,balloon ,section1 obtained the necessary sanction to commence experiments1 and two envelopes of gold-beaters skin of #ej1jjj cubic feet capacity were built4 ,with their completion the funds were exhausted1 and nothing further done until #aijg4 ,,nulli ,,secundus ,i ,in #aijg the first complete military airship in ,england was built1 which bore the grandiloquent title of ,nulli ,secundus4 ,one of the envelopes constructed by ,colonel ,templer was used3 it was cylindrical in shape with spherical ends4 ,suspended beneath the envelope by means of a net and four broad silk bands was a triangular steel framework or keel from which was slung a small car4 ,a #ej horsepower ,antoinette engine was situated in the forward part of the car which drove two metal-bladed propellers by belts4 ,at the after part of the keel were fitted a rudder and small elevators1 and two pairs of movable horizontal planes were also fitted forward4 ,it is remarkable that no stabilizing surfaces whatsoever were mounted4 ,the envelope was so exceedingly strong that a high pressure of gas could be sustained1 and ballonets were considered unnecessary1 but relief valves were employed4 ,the first flight took place in ,september and was fairly successful4 ,several were made afterwards1 and in ,october she was flown over ,london and landed at the ,crystal ,palace4 ,the flight lasted #c hours and #be minutes1 which constituted at the time a world's record4 ,three days later1 owing to heavy winds1 the ship had to be deflated and was taken back to ,farnborough4 ,,nulli ,,secundus ,,ii ,in #aijh the old ship was rebuilt with several modifications4 ,the envelope was increased in length and was united to the keel by means of a covering of silk fabric in place of the net1 four suspension bands being again used4 ,a large bow elevator was mounted which made the ship rather unstable4 ,a few flights were accomplished1 but the ship proved of little value and was broken up4 ,,baby ,this little airship made its first appearance in the spring of #aiji4 ,the envelope was fish-shaped and composed of gold-beater's skin1 with a volume of #ba1jjj cubic feet4 ,one ballonet was contained in the envelope which1 at first1 had three inflated fins to act as stabilizers4 ,these proved unsatisfactory as they lacked rigidity1 and were replaced after the first inflation by the ordinary type4 ,two #h horse-power #c-;cylinder ,berliet engines were mounted in a long car driving a simple propeller1 and at a later date were substituted by a ,r4,e4,p4 engine which proved most unsatisfactory4 ,during the autumn permission was obtained to enlarge the envelope and fit a more powerful engine4 ,,beta ,beta was completed in ,may1 #aiaj4 ,the envelope was that of the ,baby enlarged1 and now had a volume of #ce1jjj cubic feet4 ,the car was composed of a long frame1 having a centre compartment for the crew and engines1 which was the standard practice at that time for ships designed by the ,astra ,company4 ,a #ce horse-power ,green engine drove two wooden two-bladed propellers by chains4 ,the ship was fitted with an unbalanced rudder1 while the elevators were in the front of the frame4 ,this ship was successful1 and in ,june flew to ,london and back1 and in ,september took part in the ,army manoeuvres1 on one occasion being in the air for #g #c_/d hours without landing1 carrying a crew of three4 ,trouble was experienced in the steering1 the elevators being situated too near the centre of the ship to be really efficient and were altogether too small4 ,in #aiab1 ,beta1 having been employed regularly during the previous year1 was provided with a new car having a ,clerget engine of #de horse-power4 ,in #aiac she was inflated for over three months and made innumerable flights1 on one occasion carrying ,h4,r4,h4 the ,prince of ,wales as passenger4 ,she had at that time a maximum speed of #ce miles per hour1 and could carry fuel for about eight hours with a crew of three4 ,,gamma ,in #aiaj the ,gamma was also completed4 ,this was a much bigger ship with an envelope of #ge1jjj cubic feet capacity1 which1 though designed in ,england1 had been built by the ,astra ,company in ,paris4 ,the car1 as in ,beta1 was carried in a long framework suspended from the envelope4 ,this portion of the ship was manufactured in ,england1 together with the machinery4 ,this consisted of an #hj horse-power ,green engine driving swivelling propellers1 the gears and shafts of which were made by ,rolls ,royce4 ,the engine drove the propeller shafts direct1 one from each end of the crankshaft4 ,originally the envelope was fitted with inflated streamline stabilizers on either side1 but at a later date these were replaced by fixed stabilizing planes4 ,at the same time the ,green engine was removed and two ,iris engines of #de horse-power were installed1 each driving a single propeller4 ,there were two pairs of elevators1 each situated in the framework1 one forward1 the other aft4 ,in #aiab1 having been rigged to a new envelope of #aja1jjj cubic feet capacity1 the ship took part in the autumn manoeuvres1 and considerable use was made of wireless telegraphy4 ,in a height reconnaissance the pilot lost his way1 and running out of petrol drifted all night1 but was safely landed4 ,when returning to ,farnborough the rudder controls were broken and the ship was ripped4 ,in this operation the framework was considerably damaged4 ,when repairs were being carried out the elevators were removed from the car framework and attached to the stabilizing fins in accordance with the method in use to-day4 ,,clement-,,bayard ,in #aiaj it was arranged by a committee of ,members of ,parliament that the ,clement-,bayard firm should send over to ,england a large airship on approval1 with a view to its ultimate purchase by the ,war ,office1 and a shed was erected at ,wormwood ,scrubs for its accommodation4 ,this ship arrived safely in ,october1 but was very slow and difficult to control4 ,the envelope1 moreover1 was of exceedingly poor quality and consumed so much gas that it was decided to deflate it4 ,she was taken to pieces and never rebuilt4 ,,lebaudy ,about the same time1 interest having been aroused in this country by the success of airships on the ,continent1 the readers of the ,morning ,post subscribed a large sum to purchase an airship for presentation to the ,government4 ,this was a large ship of #cej1jjj cubic feet capacity and was of semi-rigid design1 a long framework being suspended from the envelope which supported the weight of the car4 ,it had two engines of #aej horse-power which developed a speed of about #cb miles per hour4 ,the ,war ,office built a shed at ,farnborough to house it1 and in accordance with dimensions given by the firm a clearance of #aj feet was allowed between the top of the ship and the roof of the shed4 ,inconceivable as it may sound1 the overall height of the ship was increased by practically #aj feet without the ,war ,office being informed4 ,the ship flew over and was landed safely1 but on being taken into the shed the envelope caught on the roof girders1 owing to lack of headroom1 and was ripped from end to end4 ,the ,government agreed to increase the height of the shed and the firm to rebuild the ship4 ,this was completed in ,march1 #aiaa1 and the ship was inflated again4 ,on carrying out a trial flight1 having made several circuits at #fjj feet1 she attempted to land1 but collided with a house and was completely wrecked4 ,this was the end of a most unfortunate ship1 and her loss was not regretted4 ,,delta ,towards the end ,of #aiaj the design was commenced of the ship to be known as the ,delta1 and in #aiaa the work was put in hand4 ,the first envelope was made of waterproofed silk4 ,this proved a failure1 as whenever the envelope was put up to pressure it invariably burst4 ,experiments were continued1 but no good resulting1 the idea was abandoned and a rubber-proofed fabric envelope was constructed of #agc1jjj cubic feet volume4 ,this ship was inflated in #aiab4 ,the first idea was to make the ship a semi-rigid by lacing two flat girders to the sides of the envelope to take the weight of the car4 ,this idea had to be abandoned1 as in practice1 when the weight of the car was applied1 the girders buckled4 ,the ship was then rigged as a non-rigid4 ,a novelty was introduced by attaching a rudder flap to the top stabilizing fin1 but as it worked somewhat stiffly it was later on removed4 ,this ship took part in the manoeuvres of #aiab and carried out several flights4 ,she proved to be exceedingly fast1 being capable of a speed of #dd miles per hour4 ,in #aiac she was completely re-rigged and exhibited at the ,aero ,show1 but the re-designed rigging revealed various faults and it was not until late in the year that she carried out her flight trials4 ,two rather interesting experiments were made during these flights4 ,in one a parachute descent was successfully accomplished2 and in another the equivalent weight of a man was picked up from the ground without assistance or landing the ship4 ,,eta ,the ,eta was somewhat smaller than the ,delta1 containing only #aah1jjj cubic feet of hydrogen1 and was first inflated in #aiac4 ,the envelope was composed of rubber-proofed fabric and a long tapering car was suspended1 this being in the nature of a compromise between the short car of the1 ,delta and the long framework gear of the ,gamma4 ,her engines were two #hj horse-power ,canton-,unne1 each driving one propeller by a chain4 ,this ship proved to be a good design and completed an eight-hour trial flight in ,september4 ,on her fourth trial she succeeded in towing the disabled naval airship ,no4 #b a distance of fifteen miles4 ,her speed was #db miles per hour1 and she could carry a crew of five with fuel for ten hours4 ,on ,january #ast1 #aiad1 the ,army disbanded their ,airship ,section1 and the airships ,beta1 ,gamma1 ,delta and ,eta were handed over to the ,navy together with a number of officers and men4 ,,chapter ,v ,,early ,,days ,,of ,,the ,,naval ,,airship ,,section--,,parseval ,,airships1 ,,astra-,,torres ,,type1 ,,etc4 ,the rapid development of the rigid airships in ,germany began to create a considerable amount of interest in official circles4 ,it was realized that those large airships in the future would be invaluable to a fleet for scouting purposes4 ,it was manifest that our fleet1 in the event of war1 would be gravely handicapped by the absence of such aerial scouts1 and that ,germany would hold an enormous advantage if her fleet went to sea preceded by a squadron of ,zeppelin airships4 ,the ,imperial ,committee1 therefore1 decided that the development of the rigid airship should be allotted to the ,navy1 and a design for ,rigid ,airship ,no4 #a was prepared by ,messrs4 ,vickers in conjunction with certain naval officers in the early part of #aiji4 ,as will be seen later this ship was completed in #aiaa1 but broke in two in ,september of that year and nothing more was done with her4 ,in ,february1 #aiab1 the construction of rigid airships was discontinued1 and in ,march the ,naval ,airship section was disbanded4 ,in ,september1 #aiab1 the ,naval ,airship section was once more reconstituted and was stationed at ,farnborough4 ,the first requirements were airships1 and owing to the fact that airship construction was so behindhand in this country1 in comparison with the ,continent1 it was determined that purchases should be made abroad until sufficient experience had been gained by ,british firms to enable them to compete with any chance of success against foreign rivals4 ,first a small non-rigid1 built by ,messrs4 ,willows1 was bought by the ,navy to be used for the training of airship pilots4 ,in addition an ,astra-,torres airship was ordered from ,france4 ,this was a ship of #bbi1dej cubic feet capacity and was driven by twin ,chenu engines of #baj horse-power each4 ,she carried a crew of six1 and was equipped with wireless and machine guns4 ,the car could be moved fore and aft for trimming purposes1 either by power or by hand4 ,this was1 however1 not satisfactory1 and was abandoned4 ,in ,april #aiah1 ,messrs4 ,vickers were asked to forward proposals for a rigid airship which afterwards became e known as ,no4 #i4 ,full details of the vicissitudes connected with this ship will be given in the chapter devoted to ,rigid ,airships4 ,in ,july1 approval was granted for the construction of six non-rigid ships4 ,three of these were to be of the ,german design of ,major von ,parseval and three of the ,forlanini type1 which was a semi-rigid design manufactured in ,italy4 ,the order for the ,parsevals was placed with ,messrs4 ,vickers and for the ,forlaninis with ,messrs4 ,armstrong4 ,the ,parseval airship was delivered to this country and became known as ,no4 #d2 a second ship of the same type was also building when war broke out2 needless to say this ship was never delivered4 ,at a later date ,messrs4 ,vickers1 who had obtained the patent rights of the ,parseval envelope1 completed the other two ships of the order4 ,the ,forlanini ship was completing in ,italy on the declaration of war and was taken over by the ,italians2 ,messrs4 ,armstrong had not commenced work on the other two4 ,these ships1 although allocated numbers1 never actually came into being4 ,,parseval ,,airship ,no4 #d ,this airship deserves special consideration for two reasons2 firstly1 on account of the active-service flying carried out by it during the first three years of the war1 and1 secondly1 for its great value in training of the officers and men who later on became the captains and crews of rigid airships4 ,the ,parseval envelope is of streamline shape which tapers to a point at the tail1 and in this ship was of #cjj1jjj cubic feet capacity4 ,the system of rigging being patented1 can only be described in very general terms4 ,the suspensions carrying the car are attached to a large elliptical rigging band which is formed under the central portion of the envelope4 ,to this rigging band are attached the trajectory bands which pass up the sides and over the top of the envelope1 sloping away from the centre at the bottom towards the nose and tail at the top4 ,the object of this is to distribute the load fore and aft over the envelope4 ,these bands1 particularly at the after end of the ship1 follow a curved path1 so that they become more nearly vertical as they approach the upper surface of the envelope4 ,this has the effect of bringing the vertical load on the top of the envelope2 but a greater portion of the compressive force comes on the lower half1 where it helps to resist the bending moment due to the unusually short suspensions4 ,a single rudder plane and the ordinary elevator planes were fitted to the envelope4 ,a roomy open car was provided for this ship1 composed of a duralumin framework and covered with duralumin sheeting4 ,two #agj horse-power ,maybach engines were mounted at the after end of the car1 which drove two metal-bladed reversible propellers4 ,these propellers were later replaced by standard four-bladed wooden ones and a notable increase of speed was obtained4 ,two officers and a crew of seven men were carried1 together with a wireless installation and armament4 ,this airship1 together with ,no4 #c1 took part in the great naval review at ,spithead1 shortly before the commencement of the war1 and in addition to the duties performed by her in the autumn of #aiad1 which are mentioned later1 carried out long hours of patrol duty from an east coast station in the summer of #aiag4 ,in all respects she must be accounted a most valuable purchase4 ,,parseval ,,airships #e1 #f and #g ,parseval ,no4 #e was not delivered by ,germany owing to the war1 so three envelopes and two cars were built by ,messrs4 ,vickers on the design of the original ship4 ,these were delivered somewhat late in the war1 and on account of the production of the ,north ,sea airship with its greater speed were not persevered with4 ,the dimensions of the envelopes were somewhat increased1 giving a cubic capacity of #cbe1jjj cubic feet4 ,twin ,maybach engines driving swivelling propellers were installed in the car1 which was completely covered in1 but these ships were slow in comparison with later designs1 and were only used for the instruction of officers and men destined for the crews of rigid airships then building4 ,an experimental ship was made in #aiag which was known as ,parseval #e2 a car of a modified coastal pattern with two #bdj horse-power ,renault engines was rigged to one of envelopes4 ,during a speed trial1 this ship was calculated to have a ground speed of #ej to #ec miles per hour4 ,the envelope1 however1 consumed an enormous amount gas and for this reason the ship was deflated and struck off the list of active ships4 ,this digression on ,parseval airships has anticipated events somewhat1 and a return must now be made to earlier days4 ,two more ,astra-,torres were ordered from ,france1 one known as ,no4 #h1 being a large ship of #d1jj1jjj cubic feet capacity4 ,she was fitted with two ,chenu engines of #bdj horse-power1 driving swivelling propellers4 ,this ship was delivered towards the end of the year #aiad4 ,the second ,astra was of smaller capacity and was delivered1 but as will be seen later1 was never rigged1 the envelope being used for the original coastal ship and the car slung to the envelope of the ex-army airship ,eta4 ,on ,january #ast1 #aiad1 an important event took place3 the ,army disbanded their airship service1 and the military ships together with certain officers and men were transferred to the ,naval ,air ,service4 ,before proceeding further1 it may be helpful to explain the system by which the naval airships have been given numbers4 ,these craft are always known by the numbers which they bear1 and the public is completely mystified as to their significance whenever they fly over ,london or any large town4 ,it must be admitted that the method is extremely confusing1 but the table which follows should help to elucidate the matter4 ,the original intention was to designate each airship owned by the ,navy by a successive number4 ,the original airship1 the rigid ,mayfly1 was known as ,no4 #a1 the ,willows airship ,no4 #b1 and so on4 ,these numbers were allocated regardless of type and as each airship was ordered1 consequently some of these ships1 for example the ,forlaninis1 never existed4 ,that did not matter1 however1 and these numbers were not utilized for ships which actually were commissioned4 ,on the transfer of the army airships1 four of these1 the ,beta1 ,gamma1 ,delta and ,eta1 were given their numbers as they were taken over1 together with two ships of the ,epsilon class which were ordered from ,messrs4 ,rolls ,royce1 but never completed4 ,in this way it will be seen that numbers #a to #bb are accounted for4 ,in #aiae it was decided to build a large number of small ships for anti-submarine patrol1 which were called ,s4,s4's or ,submarine ,scouts4 ,it was felt that it would only make confusion worse confounded if these ships bore the original system of successive numbering and were mixed up with those of later classes which it was known would be produced as soon as the designs were completed4 ,each of these ships was accordingly numbered in its own class1 ,s4,s41 ,s4,s4,p41 ,s4,s4 ,zero1 ,coastal1 ,c ,star and ,north ,sea1 from #a onwards as they were completed4 ,in the case of the rigids1 however1 for some occult reason the old system of numbering was persisted in4 ,the letter ,r is prefixed before the number to show that the ship is a rigid4 ,hence we have ,no4 #a a rigid1 the second rigid constructed is ,no4 #i1 or ,r #i1 and the third becomes ,r #bc4 ,from this number onwards all are rigids and are numbered in sequence as they are ordered1 with the exception of the last on the list1 which is a ship in a class of itself4 ,this ship the authorities1 in their wisdom1 have called ,r #hj--why1 nobody knows4 ,with this somewhat lengthy and tedious explanation the following table may be understood3 ,no4 ,type4 ,remarks4 #a4 ,rigid ,wrecked1 ,sept4 #bd1 #aiaa4 #b4 ,willows ,became ,s4,s4 #a4 #c4 ,astra-,torres ,deleted1 ,may #aiaf4 #d4 ,parseval ,deleted1 ,july1 #aiag4 #e4 ,parseval ,never delivered from ,germany4 7,substitute ship built by ,messrs4 ,vickers74 #f4 ,parseval ,built by ,messrs4 ,vickers4 #g4 ,parseval ,built by ,messrs4 ,vickers4 #h4 ,astra-,torres ,deleted1 ,may1 #aiaf4 #i4 ,rigid ,deleted1 ,june1 #aiah4 #aj4 ,astra-,torres ,envelope used for ,c #a4 #aa4 ,forlanini ,never delivered owing to war4 #ab4 ,forlanini ,never delivered owing to war4 #ac4 ,forlanini ,never delivered owing to war4 #ad4 ,rigid ,never built4 #ae4 ,rigid ,never built4 #af4 ,astra-,torres ,see ,no4 #h4 #ag4 ,beta ,transferred from ,army4 ,deleted1 ,may1 #aiaf4 #ah4 ,gamma ,deleted1 ,may1 #aiaf4 #ai4 ,delta ,deleted1 ,may1 #aiaf4 #bj4 ,eta ,transferred from the ,army4 ,fitted with car from ,no4 #aj4 ,deleted ,may1 #aiaf4 #ba4 ,epsilon ,construction cancelled ,may1 #aiaf4 #bb4 ,epsilon ,construction cancelled ,may1 #aiaf4 #bc4 ,rigid #bc ,class4 #bd4 ,rigid #bc ,class4 #be4 ,rigid #bc ,class4 #bf4 ,rigid #bc ,class4 #bg4 ,rigid #bcx ,class4 #bh4 ,rigid #bcx ,class4 ,never completed4 #bi4 ,rigid #bcx ,class4 #cj4 ,rigid #bcx ,class4 ,never completed4 #ca4 ,rigid #ca ,class4 #cb4 ,rigid #ca ,class1 building4 #cc4 ,rigid #cc ,class4 #cd4 ,rigid #cc ,class4 #ce4 ,rigid ,cancelled4 #cf4 ,rigid ,building4 #cg4 ,rigid ,building4 #ch4 ,rigid ,building4 #ci4 ,rigid ,building4 #dj4 ,rigid ,building4 #hj4 ,rigid ,building4 ,in ,august1 #aiad1 ,europe1 which had been in a state of diplomatic tension for several years1 was plunged into the world war4 ,the naval airship service at the time was in possession of two stations1 ,farnborough and ,kingsnorth1 the latter in a half-finished condition4 ,seven airships were possessed1 ,nos4 #b1 #c and #d1 and the four ex-army ships--,beta1 ,gamma1 ,delta and ,eta--and of these only three1 ,nos4 #c1 #d and the ,beta1 were in any condition for flying4 ,notwithstanding this1 the utmost use was made of the ships which were available4 ,on the very first night of the war1 ,nos4 #c and #d carried out a reconnaissance flight over the southern portion of the ,north ,sea1 and ,no4 #d came under the fire of territorial detachments at the mouth of the ,thames on her return to her station4 ,these zealous soldiers imagined that she was a ,german ship bent on observation of the dockyard at ,chatham4 ,no4 #c and ,no4 #d rendered most noteworthy service in escorting the original ,expeditionary ,force across the ,channel1 and in addition to this ,no4 #d carried out long patrols over the channel throughout the following winter4 ,no4 #ag 7,beta7 also saw active service1 as she was based for a short period early in #aiae at ,dunkirk1 and was employed in spotting duties with the ,belgian artillery near ,ostend4 ,the ,gamma and the ,delta were both lying deflated at ,farnborough at the outbreak of the war1 and in the case of the latter the car was found to be beyond repair1 and she was accordingly deleted4 ,the ,gamma was inflated in ,january1 #aiae1 and was used for mooring experiments4 ,the ,eta1 having been inflated and deflated several times owing to the poor quality of the envelope1 attempted to fly to ,dunkirk in ,november1 #aiad4 ,she encountered a snowstorm near ,redhill and was compelled to make a forced landing4 ,in doing this she was so badly damaged as to be incapable of repair1 and at a later date was deleted4 ,no4 #h1 which was delivered towards the end of #aiad1 was also moored out in the open for a short time near ,dunkirk1 and carried out patrol in the war zone of the ,belgian coast4 ,so ends the story of the ,naval ,airship ,service before the war4 ,with the submarine campaign ruthlessly waged by the ,germans from the spring of #aiae and onwards1 came the airship's opportunity1 and the authorities grasped the fact that1 with development1 here was the weapon to defeat the most dangerous enemy of the ,empire4 ,the method of development and the success attending it the following chapters will show4 ,,chapter ,,vi ,,naval ,,airships4--,,the ,,non-,,rigids--,s4,s4 ,,type ,the development of the ,british airships of to-day may be said to date from ,february #bhth1 #aiae4 ,on that day approval was given for the construction of the original ,s4,s4 airship4 ,at this time the ,germans had embarked upon their submarine campaign1 realizing1 with the failure of their great assaults on the ,british troops in ,flanders1 that their main hope of victory lay in starving ,great ,britain into surrender4 ,there is no doubt that the wholesale sinking of our merchant shipping was sufficient to cause grave alarm1 and the authorities were much concerned to devise means of minimizing1 even if they could not completely eliminate the danger4 ,one proposal which was adopted1 and which chiefly concerns the interests of this book1 was the establishment of airship stations round the coasts of ,great ,britain4 ,these stations were to be equipped with airships capable of patrolling the main shipping routes1 whose functions were to search for submarines and mines and to escort shipping through the danger zones in conjunction with surface craft4 ,airship construction in this country at the time was1 practically speaking1 non-existent4 ,there was no time to be wasted in carrying out long and expensive experiments1 for the demand for airships which could fulfil these requirements was terribly urgent1 and speed of construction was of primary importance4 ,the non-rigid design having been selected for simplicity in construction1 the expedient was tried of slinging the fuselage of an ordinary ,b4,e4 #b;,c aeroplane1 minus the wings1 rudder and elevators and one or two other minor fittings1 beneath an envelope with tangential suspensions1 as considerable experience had been gained already in a design of this type4 ,for this purpose the envelope of airship ,no4 #b1 which was lying deflated in the shed at ,farnborough1 was rushed post haste to ,kingsnorth1 inflated and rigged to the fuselage prepared for it4 ,the work was completed with such despatch that the airship carried out her trial flight in less than a fortnight from approval being granted to the scheme4 ,the trials were in every way most satisfactory1 and a large number of ships of this design was ordered immediately4 ,at the same time two private firms were invited to submit designs of their own to fulfil the ,admiralty requirements4 ,one firm's design1 ,s4,s4 #b1 did not fulfil the conditions laid down and was put out of commission2 the other1 designed by ,messrs4 ,armstrong1 was sufficiently successful for them to receive further orders4 ,in addition to these a car was designed by ,messrs4 ,airships ,ltd41 which somewhat resembled a ,maurice ,farman aeroplane body1 and as it appeared to be suitable for the purpose1 a certain number of these was also ordered4 ,about this period the station at ,farnborough was abandoned by the ,naval ,airship ,service to make room for the expansion of the military aeroplane squadrons4 ,the personnel and airships were transferred to ,kingsnorth1 which became the airship headquarters4 ,the greatest energy was displayed in preparing the new stations1 which were selected as bases for the airships building for this anti-submarine patrol4 ,small sheds1 composed of wood1 were erected with almost incredible rapidity1 additional personnel was recruited1 stores were collected1 huts built for their accommodation and that of the men1 and by the end of the summer the organization was so complete that operations were enabled to commence4 ,the ,s4,s41 or submarine scout1 airship proved itself a great success4 ,beginning originally with a small programme the type passed through various developments until1 at the conclusion of the war1 no fewer than #aej ships of various kinds had been constructed4 ,the alterations which took place and the improvements effected thereby will be considered at some length in the following pages4 ,s4,s4,b4,e4 #b;,c ,the envelope of the experimental ship ,s4,s4 #a was only of #bj1ejj cubic feet capacity2 for the active-service ships1 envelopes of similar shape of #fj1jjj cubic feet capacity were built4 ,the shape was streamline1 that is to say1 somewhat blunt at the nose and tapering towards the tail1 the total length being #adc feet #f inches1 with a maximum diameter of #bg feet #i inches4 ,the gross lift of these ships with #ih pure gas at a temperature of #fj degrees ,fahrenheit and barometer #cj inches1 is #d1ahj lb4 ,the net lift available for crew1 fuel1 ballast1 armament1 etc41 #a1dcd lb41 and the disposable lift still remaining with crew of two on board and full tanks1 #fei lb4 ,the theoretical endurance at full speed as regards petrol consumption is a little over #h hours1 but in practice it is probable that the oil would run short before this time had been reached4 ,at cruising speed1 running the engine at #a1bej revolutions1 the consumption is at the rate of #c4f gallons per hour1 which corresponds to an endurance of #af #a_/b hours4 ,with the engine running at #a1hjj revolutions1 a speed of #ej4f miles per hour has been reached by one of these ships1 but actually very few attained a greater speed than #dj miles per hour4 ,the envelopes of ,s4,s4 airships are composed of rubber-proofed fabric1 two fabrics being used with rubber interposed between and also on the inner or gas surface4 ,to render them completely gastight and as impervious to the action of the weather1 sun1 etc41 as possible1 five coats of dope are applied externally1 two coats of ,delta dope1 two of aluminium dope and one of aluminium varnish applied in that order4 ,one ripping panel is fitted1 which is situated on the top of the envelope towards the nose4 ,it has a length of #ad feet #e inches and a breadth of about #h inches4 ,the actual fabric which has to be torn away overlaps the edge of the opening on each side4 ,this overlap is sewn and taped on to the envelope and forms a seam as strong and gastight as any other portion of the envelope4 ,stuck on this fabric is a length of biased fabric #h #a_/d inches wide4 ,these two strips overlap the opening at the forward end by about three feet4 ,at this end the two strips are loose and have a toggle inserted at the end to which the ripping cord is tied4 ,the ripping cord is operated from the car4 ,it is led aft from the ripping panel to a pulley fixed centrally over the centre of the car1 from the pulley the cord passes round the side of the envelope and through a gland immediately below the pulley4 ,the nose of the envelope is stiffened to prevent it blowing in4 ,for this purpose #bd canes are fitted in fabric pockets around the nose and meet at a point #b #a_/d inches in front of the nose4 ,an aluminium conical cap is fitted over the canes and a fabric nose cap over the whole4 ,two ballonets are provided1 one forward and one aft1 the capacity of each being #f1cge cubic feet4 ,the supply of air for filling these is taken from the propeller draught by a slanting aluminium tube to the underside of the envelope1 where it meets a longitudinal fabric hose which connects the two ballonet air inlets4 ,non-return fabric valves known as crab-pots are fitted in this fabric hose on either side of their junction with the air scoop4 ,two automatic air valves are fitted to the underside of the envelope1 one for each ballonet4 ,the air pressure tends to open the valve instead of keeping it shut and to counteract this the spring of the valve is inside the envelope4 ,the springs are set to open at a pressure of #be to #bh mm4 ,two gas valves are also fitted1 one on the top of the envelope1 the other at the bottom4 ,the bottom gas valve spring is set to open at #cj to #ce mm4 pressure1 the top valve is hand controlled only4 ,these valves are all very similar in design4 ,they consist of two wooden rings1 between which the envelope is gripped1 and which are secured to each other by studs and butterfly nuts4 ,the valve disc1 or moving portion of the valve1 is made of aluminium and takes a seating on a thin india rubber ring stretched between a metal rod bent into a circle of smaller diameter than the valve opening and the wooden ring of the valve4 ,when it passes over the wooden ring it is in contact with the envelope fabric and makes the junction gastight4 ,the disc is held against the rubber by a compressed spring4 ,the valve cords are led to the pilot's seat through eyes attached to the envelope4 ,the system of rigging or car suspension is simplicity itself and is tangential to the envelope4 ,on either side there are six main suspensions of #be cwt4 stranded steel cable known as ,c suspensions4 ,each ,c cable branches into two halves known as the ,b bridles1 which in turn are supported at each end by the bridles known as ,a4 ,the ends of the ,a bridles are attached to the envelope by means of ,eta patches4 ,these consist of a metal ,d-shaped fitting round which the rigging is spliced and through which a number of webbing bands are passed which are spread out fanwise and solutioned to the envelope4 ,it will thus be seen that the total load on each main suspension is proportionally taken up by each of the four ,a bridles1 and that the whole weight of the car is equally distributed over the greater part of the length of the envelope4 ,four handling guys for manoeuvering the ship on the ground are provided under the bow and under the stem4 ,a group of four ,eta patches are placed close together1 which form the point of attachment for two guys in each case4 ,the forward of these groups of ,eta patches forms the anchoring point4 ,the bridle1 consisting of #be cwt4 steel cable1 is attached here and connected to the forepart of the skids of the car4 ,the junction of this bridle with the two cables from the skids forms the mooring point and there the main trail rope is attached4 ,this is #abj feet long and composed of #b-;inch manilla4 ,this is attached1 properly coiled1 to the side of the car and is dropped by a release gear4 ,it is so designed that when the airship is held in a wind by the trail rope the strain is evenly divided between the envelope and the car4 ,the grapnel carried is fitted to a short length of rope4 ,the other end of the rope has an eye1 and is fitted to slide down the main trail rope and catch on a knot at the end4 ,for steering and stabilizing purposes the ,s4,s4 airship was originally designed with four fins and rudders1 which were to be set exactly radial to the envelope4 ,in some cases the two lower fins and rudders were abandoned1 and a single vertical fin and rudder fitted centrally under the envelope were substituted4 ,the three planes are identical in size and measure #af feet by #h feet #f inches1 having a gross stabilizing area of #djb #a_/b square feet4 ,they are composed of spruce and aluminium and steel tubing braced with wire and covered by linen doped and varnished when in position4 ,the original rudders measured #c feet by #h feet #f inches4 ,in the case1 however1 of the single plane being fitted1 #d-;feet rudders are invariably employed4 ,two kingposts of steel tube are fitted to each plane and braced with wire to stiffen the whole structure4 ,the planes are attached to the envelope by means of skids and stay wires4 ,the skids1 composed of spruce1 are fastened to the envelope by eight lacing patches4 ,the car1 it will be remembered1 is a ,b4,e4 #b;,c fuselage stripped of its wings1 rudders and elevators1 with certain other fittings added to render it suitable for airship work4 ,the undercarriage is formed of two ash skids1 each supported by three struts4 ,the aeroplane landing wheels1 axle and suspensions are abandoned4 ,in the forward end of the fuselage was installed a #ge horse-power air cooled ,renault engine driving a single four-bladed tractor propeller through a reduction gear of #b to #a4 ,the engine is of the #h-;cylinder ,v type1 weighing #dch lb4 with a bore of #if mm4 and a stroke of #abj mm4 ,the ,claudel-,hobson type of carburettor is employed with this engine4 ,the type of magneto used is the ,bosch ,d4,v4#d1 there being one magneto for each line of cylinders4 ,in the older ,french ,renaults the ,bosch ,h4,l4#h is used1 one magneto supplying the current to all the plugs4 ,petrol is carried in three tanks1 a gravity and intermediate tank as fitted to the original aeroplane1 and a bottom tank placed underneath the front seat of the car4 ,the petrol is forced by air pressure from the two lower tanks into the gravity tank and is obtained by a hand pump fitted outside the car alongside the pilot's seat4 ,the oil tank is fitted inside the car in front of the observer4 ,the observer's seat is fitted abaft the engine and the pilot's seat is aft of the observer4 ,the observer1 who is also the wireless operator1 has the wireless apparatus fitted about his seat4 ,this consists of a receiver and transmitter fitted inside the car1 which derives power from accumulator batteries4 ,the aerial reel is fitted outside the car4 ,during patrols signals can be sent and received up to and between #ej and #fj miles4 ,the pilot is responsible for the steering and the running of the engine1 and the controls utilized are the fittings supplied with the aeroplane4 ,steering is operated by the feet and elevating by a vertical wheel mounted in a fore and aft direction across the seat4 ,the control wires are led aft inside the fairing of the fuselage to the extreme end1 whence they pass to the elevators and rudders4 ,the instrument board is mounted in front of the pilot4 ,the instruments comprise a watch1 an air-speed indicator graduated in knots1 an aneroid reading to #aj1jjj feet1 an ,elliott revolution counter1 a ,clift inclinometer reading up to #bj degrees depression or elevation1 a map case with celluloid front4 ,there are in addition an oil pressure gauge1 a petrol pressure gauge1 a glass petrol level and two concentric glass pressure gauges for gas pressure4 ,the steering compass is mounted on a small wooden pedestal on the floor between the pilot's legs4 ,the water-ballast tank is situated immediately behind the pilot's seat and contains #ad gallons of water weighing #adj lbs4 ,the armament consists of a ,lewis gun and bombs4 ,the bombs are carried in frames suspended about the centre of the undercarriage4 ,the bomb sight is fitted near the bomb releasing gear outside the car on the starboard side adjacent to the pilot's seat4 ,the ,lewis gun1 although not always carried on the early ,s4,s4 airships1 was mounted on a post alongside the pilot's seat4 ,s4,s4 ,,maurice ,,farman ,for this type of ,s4,s4 the cars were built by ,messrs4 ,airships ,ltd4 ,in general appearance they resemble the ,maurice ,farman aeroplane and were of the pusher type2 #fj1jjj and in later cases #gj1jjj cubic feet envelopes were rigged to these ships1 which proved to be slightly slower than the ,b4,e4 #b;,c type1 but this was compensated for owing to the increased comfort provided for the crew1 the cars being more roomy and suitable for airship work in every way4 ,the system of rigging to all intents and purposes is the same in all types of ,s4,s4 ships1 the suspensions being adjusted to suit the different makes of car4 ,in these ships the pilot sits in front1 and behind him is the wireless telegraphy operator2 in several cases a third seat was fitted to accommodate a passenger or engineer2 dual rudder and elevator controls are provided for the pilot and observer4 ,the engine is mounted aft1 driving a four-bladed pusher propeller1 with the petrol tanks situated in front feeding the carburettors by gravity4 ,the engines used are ,rolls ,royce ,renaults1 although in one instance a #ge horse-power ,rolls ,royce ,hawk engine was fitted1 which assisted in making an exceedingly useful ship4 ,s4,s4 ,,armstrong ,,whitworth ,the car designed by ,messrs4 ,armstrong ,whitworth is of the tractor type and is in all ways generally similar to the ,b4,e4 #b;,c4 ,the single-skid landing chassis with buffers is the outstanding difference4 ,these cars had to be rigged to #gj1jjj cubic feet envelopes otherwise the margin of lift was decidedly small4 ,a water-cooled #ajj horse-power ,green engine propelled the ship1 and a new feature was the disposition of petrol1 which was carried in two aluminium tanks slung from the envelope and fed through flexible pipes to a two-way cock and thence to the carburettors4 ,these tanks1 which were supported in a fabric sling1 showed a saving in weight of #ajj lb4 compared with those fitted in the ,b4,e4 #b;,c4 ,for over two years these three types of ,s4,s4 ships performed a great part of our airship patrol and gave most excellent results4 ,owing to the constant patrol which was maintained whenever weather conditions were suitable1 the hostile submarine hardly dared to show her periscope in the waters which were under observation4 ,in addition to this1 practically the whole of the airship personnel now filling the higher positions1 such as ,captains of ,rigids and ,north ,seas1 graduated as pilots in this type of airship4 ,from these they passed to the ,coastal and onwards to the larger vessels4 ,as far as is known the height record for a ,british airship is still held by an ,s4,s4,b4,e4 #b;,c1 one of these ships reaching the altitude of #aj1cjj feet in the summer of #aiaf4 ,the ,maurice ,farman previously mentioned as being fitted with the ,hawk engine1 carried out a patrol one day of #ah hours #bj minutes4 ,in the summer of #aiaf one of the ,armstrong ships was rigged to an envelope doped black and sent over to ,france4 ,while there she carried out certain operations at night which were attended with success1 proving that under certain circumstances the airship can be of value in operating with the military forces over land4 ,s4,s4,p4 ,in #aiaf the design was commenced for an ,s4,s4 ship which should have a more comfortable car and be not merely an adaptation of an aeroplane body4 ,these cars1 which were of rectangular shape with a blunt nose1 were fitted with a single landing skid aft1 and contained seats for three persons4 ,the engine1 a #ajj horse-power water-cooled ,green1 was mounted on bearers aft and drove a four-bladed pusher propeller4 ,the petrol was carried in aluminium tanks attached by fabric slings to the axis of the envelope4 ,six of these ships were completed in the spring of #aiag and were quite satisfactory1 but owing to the success achieved by the experimental ,s4,s4 ,zero it was decided to make this the standard type of ,s4,s4 ship1 and with the completion of the sixth the programme of the ,s4,s4,p's was brought to a close4 ,these ships enjoyed more than1 perhaps1 was a fair share of misfortune1 one was wrecked on proceeding to its patrol station and was found to be beyond repair1 and another was lost in a snowstorm in the far north4 ,the remainder1 fitted at a later date with #ge horse-power ,rolls ,royce engines1 proved to be a most valuable asset to our fleet of small airships4 ,s4,s4 ,,zero ,the original ,s4,s4 ,zero was built at a south-coast station by ,air ,service labour1 and to the design of three officers stationed there4 ,the design of the car shows a radical departure from anything that had been previously attempted1 and as a model an ordinary boat was taken4 ,in shape it is as nearly streamline as is practicable1 having a keel and ribs of wood with curved longitudinal members1 the strut ends being housed in steel sockets4 ,the whole frame is braced with piano wire set diagonally between the struts4 ,the car is floored from end to end1 and the sides are enclosed with #h-ply wood covered with fabric4 ,accommodation is provided for a wireless telegraphy operator1 who is also a gunner1 his compartment being situated forward1 amidships is the pilot and abaft this seat is a compartment for the engineer4 ,the engine selected was the #ge horse-power water-cooled ,rolls ,royce1 it being considered to be the most efficient for the purpose4 ,the engine is mounted upon bearers above the level of the top of the car1 and drives a four-bladed pusher propeller4 ,the car is suspended from an envelope of #gj1jjj cubic feet capacity1 and the system of rigging is similar to that in use on all ,s4,s4 ships4 ,the petrol is carried in aluminium tanks slung on the axis of the envelope1 identically with the system in use on the ,s4,s4,p's4 ,the usual elevator planes are adopted with a single long rudder plane4 ,the speed of the ,zero is about #de miles per hour and the ship has a theoretical endurance of seventeen hours2 but this has been largely exceeded in practice4 ,the original ship proved an immediate success1 and a large number was shortly afterwards ordered4 ,as time went on the stations expanded and sub-stations were added1 while the ,zero airship was turned out as fast as it could be built1 until upwards of seventy had been commissioned4 ,the work these ships were capable of exceeded the most sanguine expectations4 ,owing to their greater stability in flight and longer hours of endurance1 they flew in weather never previously attempted by the earlier ships4 ,with experience gained it was shown that a large fleet of airships of comparatively small capacity is of far more value for an anti-submarine campaign than a lesser fleet of ships of infinitely greater capacity4 ,the average length of patrol was eight hours1 but some wonderful duration flights were accomplished in the summer of #aiah1 as the following figures will show4 ,the record is held by ,s4,s4,z4 #ci1 with #ej hours #ee minutes2 another is #cj hours #bj minutes2 while three more vary from #be #a_/b hours to #bf #a_/d4 ,although small1 the ,zero airship has been one of the successes of the war1 and we can claim proudly that she is entirely a ,british product4 ,s4,s4 ,,twin ,during the year #aiag1 designs were submitted for a twin-engined ,s4,s4 airship1 the idea being to render the small type of airship less liable to loss from engine failure4 ,the first design proved to be a failure1 but the second was considered more promising1 and several were built4 ,its capacity is #ajj1jjj cubic feet1 with a length of #afd feet #f inches1 and the greatest diameter #cb feet4 ,the car is built to carry five1 with the engines disposed on gantries on the port and starboard side1 driving pusher propellers4 ,this type1 although in the experimental stage1 is being persevered with1 and the intention is that it will gradually supplant the other ,s4,s4 classes4 ,it is calculated that it will equal if not surpass the ,c ,star ship in endurance1 besides being easier to handle and certainly cheaper to build4 ,,coastal ,,and ,c ,,star ,,airships ,the urgent need for a non-rigid airship to carry out anti-submarine patrol having been satisfied for the time with the production of the ,s4,s4 ,b4,e4 #b;,c type1 the airship designers of the ,royal ,naval ,air ,service turned their attention to the production of an airship which would have greater lift and speed than the ,s4,s4 type1 and1 consequently1 an augmented radius of action1 together with a higher degree of reliability4 ,as the name ,coastal or ,coast ,patrol implies1 this ship was intended to carry out extended sea patrols4 ,to obtain these main requirements the capacity of the envelope for this type was fixed at #agj1jjj cubic feet1 as compared with the #fj1jjj cubic feet and1 later1 the #gj1jjj cubic feet envelopes adopted for the ,s4,s4 ships4 ,greater speed was aimed at by fitting two engines of #aej horse-power each1 and it was hoped that the chances of loss owing to engine failure would be considerably minimized4 ,the ,astra-,torres type of envelope1 with its system of internal rigging1 was selected for this class of airship2 in the original ship the envelope used was that manufactured by the ,french ,astra-,torres ,company1 and to which it had been intended to rig a small enclosed car4 ,the ship in question was to be known as ,no4 #aj4 ,this plan was1 however1 departed from1 and the car was subsequently rigged to the envelope of the ,eta1 and a special car was designed and constructed for the original ,coastal4 ,coastal airship ,no4 #a was commissioned towards the end of #aiae and was retained solely for experimental and training purposes4 ,approximately thirty of these airships were constructed during the year #aiaf1 and were allocated to the various stations for patrol duties4 ,the work carried out by these ships during the two and a half years in which they were in commission1 is worthy of the highest commendation4 ,before the advent of later and more reliable ships1 the bulk of anti-submarine patrol on the east coast and south-west coast of ,england was maintained by the ,coastal4 ,on the east coast1 with the prevailing westerly and south-westerly winds1 these airships had many long and arduous voyages on their return from patrol1 and in the bitterness of winter their difficulties were increased ten-fold4 ,to the whole-hearted efforts of ,coastal pilots and crews is due1 to a great extent1 the recognition which somewhat tardily was granted to the ,airship ,service4 ,the envelope of the ,coastal airship has been shown to be of #agj1jjj cubic feet capacity4 ,it is trilobe in section to employ the ,astra-,torres system of internal and external rigging4 ,the great feature of this principle is that it enables the car to be slung much closer to the envelope than would be possible with the tangential system on an envelope of this size4 ,as a natural consequence there is far less head resistance1 owing to the much shorter rigging1 between the envelope and the car4 ,the shape of the envelope is not all that could have been desired1 for it is by no means a true streamline1 but has the same cross section for the greater part of its length1 which tapers at either end to a point which is slightly more accentuated aft4 ,owing to the shape1 these ships1 in the early days until experience had been gained1 were extremely difficult to handle1 both on the landing ground and also in the air4 ,they were extremely unstable both in a vertical and horizontal plane1 and were slow in answering to their rudders and elevators4 ,the envelope is composed of rubber-proofed fabric doped to hold the gas and resist the effects of weather4 ,four ballonets are situated in the envelope1 two in each of the lower lobes1 air being conveyed to them by means of a fabric air duct1 which is parallel to the longitudinal centre line of the envelope1 with transverse ducts connecting each pair of ballonets4 ,in earlier types of the ,coastal1 the air scoop supplying air to the air duct was fitted in the slip stream of the forward engine1 but later this was fitted aft of the after engine4 ,six valves in all are used1 four air valves1 one fitted to each ballonet1 and two gas valves4 ,these are situated well aft1 one to each of the lower lobes1 and are fitted on either side of the rudder plane4 ,a top valve is dispensed with because in practice when an ,astra-,torres envelope loses shape1 the tendency is for the tail to be pulled upwards by the rigging1 with the result that the two gas valves always remain operative4 ,crabpots and non-return valves are employed in a similar manner to ,s4,s4 airships4 ,the ,astra-,torres system of internal rigging must now be described in some detail4 ,the envelope is made up of three longitudinal lobes1 one above and two below1 which when viewed end on gives it a trefoil appearance4 ,the internal rigging is attached to the ridges formed on either side of the upper lobe1 where it meets the two side lobes4 ,from here it forms a ,v1 when viewed cross sectionally1 converging at he ridge formed by the two lobes on the underside of the envelope which is known as the lower ridge4 ,to the whole length of the top ridges are attached the internal rigging girdles and also the lacing girdles to which are secured the top and side curtains4 ,these curtains are composed of ordinary unproofed fabric and their object is to make the envelope keep its trilobe shape4 ,they do not1 however1 divide the ship into separate gas compartments4 ,the rigging girdle consists of a number of fabric scallops through which run strands of ,italian hemp4 ,these strands1 of which there are a large number1 are led towards the bottom ridge1 where they are drawn together and secured to a rigging sector4 ,to these sectors the main external rigging cables are attached4 ,the diagram shows better than any description this rigging system4 ,ten main suspensions are incorporated in the ,coastal envelope1 of which three take the handling guys1 the remaining seven support the weight of the car4 ,the horizontal fins with the elevator flaps1 and the vertical fin with the rudder flap1 are fixed to the ridges of the envelope4 ,the car was evolved in the first instance by cutting away the tail portion of two ,avro seaplane fuselages and joining the forward portions end on1 the resulting car1 therefore1 had engines at either end with seating accommodation for four4 ,the landing chassis were altered1 single skids being substituted for the wider landing chassis employed in the seaplane4 ,the car consists of four longerons with struts vertical and cross1 and stiffened with vertical and cross bracing wires4 ,the sides are covered with fabric and the flooring and fairing on the top of the car are composed of three-ply wood4 ,in the later cars five seats were provided to enable a second officer to be carried4 ,the engines are mounted on bearers at each end of the car1 and the petrol and oil tanks were originally placed adjoining the engines in the car4 ,at a later date various methods of carrying the petrol tanks were adopted1 in some cases they were slung from the envelope and in others mounted on bearers above the engines4 ,wireless telegraphy is fitted as is the case with all airships4 ,in the ,coastal a gun is mounted on the top of the envelope1 which is reached by a climbing shaft passing through the envelope1 another mounting being provided on the car itself4 ,bombs are also carried on frames attached to the car4 ,sunbeam engines originally supplied the motive power1 but at a later date a #bbj horse-power ,renault was fitted aft and a #ajj horse-power1 ,berliet forward4 ,with the greater engine power the ship's capabilities were considerably increased4 ,exceedingly long flights were achieved by this type of ship1 and those exceeding ten hours are far too numerous to mention4 ,the most noteworthy of all gave a total of #bd #a_/d hours1 which1 at the time1 had only once been surpassed by any ,british airship4 ,towards the end of #aiag1 these ships1 having been in commission for over two years1 were in many cases in need of a complete refit4 ,several were put in order1 but it was decided that this policy should not be continued1 and that as each ship was no longer fit for flying it should be replaced by the more modern ,coastal known as the ,c ,star4 ,the record of one of these ships so deleted is surely worthy of special mention4 ,she was in commission for #b years #ge days1 and averaged for each day of this period #c hours #f minutes flying4 ,during this time she covered upwards of #ff1jjj miles4 ,from this it will be seen that she did not pass her life by any means in idleness4 ,c ,,star ,,airship ,after considerable experience had been gained with the ,coastal1 it became obvious that a ship was required of greater capabilities to maintain the long hours of escort duty and also anti-submarine patrols4 ,to meet these requirements it was felt that a ship could be constructed1 not departing to any extent from the ,coastal1 with which many pilots were now quite familiar1 but which would show appreciable improvement over its predecessor4 ,the design which was ultimately adopted was known as the ,c ,star1 and provided an envelope of #baj1jjj cubic feet1 which secured an extra ton and a quarter in lifting capacity4 ,this envelope1 although of the ,astra-,torres type1 was of streamline form1 and in that respect was a great advance on the early shape as used in the ,coastal4 ,it is to all intents and purposes the same envelope as is used on the ,north ,sea ships1 but on a smaller scale4 ,an entirely new type of fabric was employed for this purpose4 ,the same model of car was employed1 but was made more comfortable1 the canvas covering for the sides being replaced by three-ply wood4 ,in all other details the car remained entirely the same4 ,the standard power units were a #ajj horse-power ,berliet forward and a ,fiat of #bfj horse-power aft4 ,the petrol tanks in this design were carried inside the envelope1 which was quite a new departure4 ,these airships may be considered to have been successful1 though not perhaps to the extent which was expected by their most ardent admirers4 ,with the advent of the ,s4,s4 ,twin it was resolved not to embark on a large constructional programme1 and when the numbers reached double figures they were no longer proceeded with4 ,notwithstanding this the ships which were commissioned carried out most valuable work1 and1 like their prototypes1 many fine flights were recorded to their credit4 ,thirty-four and a half hours was the record flight for this type of ship1 and another but little inferior was thirty hours ten minutes4 ,these flights speak well for the endurance of the crews1 as it must be borne in mind that no sleeping accommodation is possible in so small a car4 ,the ,coastal airship played no small part in the defeat of the submarine1 but its task was onerous and the enemy and the elements unfortunately exacted a heavy toll4 ,a ,german wireless message received in this country testified to the valiant manner in which one of these ships met with destruction4 ,,the ,,north ,,sea ,,airship ,the ,north ,sea or ,n4,s4 airship was originally designed to act as a substitute for the ,rigid1 which1 in #aiaf1 was still a long way from being available for work of practical utility4 ,from experience gained at this time with airships of the ,coastal type it was thought possible to construct a large ,non-,rigid capable of carrying out flights of twenty-four hours' duration1 with a speed of #ee to #fj knots1 with sufficient accommodation for a double crew4 ,the main requirements fall under four headings3 #a4 ,capability to carry out flights of considerable duration4 #b4 ,great reliability4 #c4 ,the necessary lift to carry an ample supply of fuel4 #d4 ,adequate arrangements to accommodate the crew in comfort4 ,if these could be fulfilled the authorities were satisfied that ships possessing these qualifications would be of value to the ,fleet and would prove efficient substitutes until rigid airships were available4 ,the ,north ,sea1 as may be gathered from its name1 was intended to operate on the east coasts of these islands4 ,the first ship1 when completed and put through her trials1 was voted a success1 and the others building were rapidly pushed on with4 ,when several were finished and experience had been gained1 after long flights had been carried out1 the ,north ,sea airship suffered a partial eclipse and people were inclined to reconsider their favourable opinion4 ,thus it was that for many months the ,north ,sea airship was decidedly unpopular1 and it was quite a common matter to hear her described as a complete failure4 ,the main cause of the prejudice was the unsatisfactory design of the propelling machinery1 which it will be seen later was modified altogether1 and coupled with other improvements turned a ship of doubtful value into one that can only be commended4 ,the envelope is of #cfj1jjj cubic feet capacity1 and is designed on the ,astra-,torres principle for the same reasons as held good in the cases of the ,coastal and ,c ,star4 ,all the improvements which had been suggested by the ships of that class were incorporated in the new design1 which was of streamline shape throughout1 and looked at in elevation resembled in shape that of the ,s4,s4 airship4 ,six ballonets are fitted1 of which the total capacity is #abh1jjj cubic feet1 equivalent to #ce4e per cent of the total volume4 ,they are fitted with crabpots and non-return valves in the usual manner4 ,the rigging is of the ,astra-,torres system1 and in no way differs from that explained in the previous chapter4 ,nine fans of the internal rigging support the main suspensions of the car1 while similar fans both fore and aft provide attachment for the handling guys4 ,auxiliary fans on the same principle support the petrol tanks and ballast bag4 ,four gas and six air valves in all are fitted1 all of which are automatic4 ,two ripping panels are embodied in the top lobe of the envelope4 ,the ,n4,s4 ship carries four fins1 to three of which are attached the elevator and rudder flaps4 ,the fourth1 the top fin1 is merely for stabilizing purposes1 the other three being identical in design1 and are fitted with the ordinary system of wiring and kingposts to prevent warping4 ,the petrol was originally carried in aluminium tanks disposed above the top ridges of the envelope1 but this system was abandoned owing to the aluminium supply pipes becoming fractured as the envelope changed shape at different pressures4 ,they were then placed inside the envelope1 and this rearrangement has given every satisfaction4 ,to the envelope of the ,n4,s4 is rigged a long covered-in car4 ,the framework of this is built up of light steel tubes1 the rectangular transverse frames of which are connected by longitudinal tubes1 the whole structure being braced by diagonal wires4 ,the car1 which tapers towards the stern1 has a length of #he feet1 with a height of #f feet4 ,the forward portion is covered with duralumin sheeting1 and the remainder with fabric laced to the framework4 ,windows and portholes afford the crew both light and space to see all that is required4 ,in the forward portion of the car are disposed all the controls and navigating instruments1 together with engine-telegraphs and voice pipes4 ,aft is the wireless telegraphy cabin and sleeping accommodation for the crew4 ,a complete electrical installation is carried of two dynamos and batteries for lights1 signalling lamps1 telephones1 etc4 ,the engines are mounted in a power unit structure separate from the car and reached by a wooden gangway supported by wire cables4 ,this structure consists of two ,v-shaped frameworks connected by a central frame and by an under-structure to which floats are attached4 ,the mechanics' compartment is built upon the central frame1 and the engine controls are operated from this cabin4 ,in the original power units two #bej horse-power ,rolls ,royce engines were fitted1 driving propellers on independent shafts through an elaborate system of transmission4 ,this proved to be a great source of weakness1 as continual trouble was experienced with this method1 and a fracture sooner or later occurred at the universal joint nearest to the propeller4 ,when the modified form of ship was built the whole system of transmission was changed1 and the propellers were fitted directly on to the engine crankshafts4 ,at a later date #bdj horse-power ,fiat engines were installed1 and the engineers' cabin was modified and an auxiliary blower was fitted to supply air to the ballonets for use if the engines are not running4 ,in the ,n4,s4 ship as modified the car has been raised to the same level as the engineers' cabin1 and all excrescences on the envelope were placed inside4 ,this1 added to the improvement effected by the abolition of the transmission shafts1 increased the reliability and speed of the ship1 and also caused a reduction in weight4 ,the leading dimensions of the ship are as follows3 length1 #bfb feet2 width1 #ef feet #i inches2 height1 #fi feet #c inches4 ,the gross lift is #bd1cjj lb42 the disposable lift1 without crew1 petrol1 oil1 and ballast1 #h1ejj lb4 ,the normal crew carried when on patrol is ten1 which includes officers4 ,as in the case of the ,coastal1 a gun is mounted on the top of the envelope1 which is approached by a similar climbing shaft1 and guns and bombs are carried on the car4 ,these ships have become notorious for breaking all flying records for non-rigid airships4 ,even the first ship of the class1 despite the unsatisfactory power units1 so long ago as in the summer of #aiag completed a flight of #di hours #bb minutes1 which at the time was the record flight of any ,british airship4 ,since that date numerous flights of quite unprecedented duration have been achieved1 one of #fa #a_/b hours being particularly noteworthy1 and those of upwards of #cj hours have become quite commonplace4 ,since the ,armistice one of these ships completed the unparalleled total of #aja hours1 which at that date was the world's record flight1 and afforded considerable evidence as to the utility of the non-rigid type for overseas patrol1 and even opens up the possibility of employing ships of similar or slightly greater dimensions for commercial purposes4 ,n4,s4 #f appeared several times over ,london in the summer months of #aiah1 and one could not help being struck by the ease with which she was steered and her power to remain almost stationary over such a small area as ,trafalgar ,square for a quite considerable period4 ,the flights referred to above were not in any way stunt performances to pile up a handsome aggregate of hours1 but were the ordinary flying routine of the station to which the ships were attached1 and most of the hours were spent in escorting convoys and hunting for submarines4 ,in addition to these duties1 manoeuvres were carried out on occasions with the ,fleet or units thereof4 ,from the foregoing observations it must be manifest that this type of ship1 in its present modified state1 is a signal success1 and is probably the best large non-rigid airship that has been produced in any country4 ,for the purposes of comparison it will be interesting to tabulate the performances of the standard types of non-rigid airships4 ,the leading dimensions are also included in this summary3 ,type ,s4,s4 ,zero ,s4,s4 ,twin ,coastal ,north ,star ,sea ,length #adc' #j #afe' #j #bah' #j #bfb' #j ,overall width #cb' #j #ce' #f #di' #c #ef' #i ,overall height #df' #j #di' #j #eg' #f #fi' #c ,hydrogen capacity 7cubic feet7 #gj1jjj #ajj1jjj #baj1jjj #cfj1jjj ,gross lift 7lb47 #d1ijj #g1jjj #ad1ejj #bd1cjj ,disposable lift 7lb47 #a1hej #b1bjj #d1hej #h1ejj ,crew #c #d #e #aj ,lift available for fuel and freight 7lb47 #a1cgj #a1edj #d1jej #f1ijj ,petrol consumption at full speed 7lb4 per hour7 #c4f #g4b #ah4d #bi4h ,gals4 per hour #j4cf #j4gb #b4je #c ,,chapter ,,vii ,,naval ,,airships4--,,the ,,rigids--,,rigid ,,airship ,no4 #a ,the responsibility for the development the ,rigid airship having been allotted to the ,navy1 with this object in view1 in the years #aijh and #aiji a design was prepared by ,messrs4 ,vickers ,ltd41 in conjunction with certain naval officers1 for a purely experimental airship which should be as cheap as possible4 ,the ship was to be known as ,naval ,airship ,no4 #a1 and though popularly called the ,mayfly1 this title was in no way official4 ,in design the following main objects were aimed at3 #a4 ,the airship was to be capable of carrying out the duties of an aerial scout4 #b4 ,she was to be able to maintain a speed of #dj knots for twenty-four hours1 if possible4 #c4 ,she was to be so designed that mooring to a mast on the water was to be feasible1 to enable her to be independent of her shed except for docking purposes1 as in the case with surface vessels4 #d4 ,she was to be fitted with wireless telegraphy4 #e4 ,arrangements were to be made for the accommodation of the crew in reasonable comfort4 #f4 ,she was to be capable of ascending to a height of not less than #a1ejj feet4 ,these conditions rendered it necessary that the airship should be of greater dimensions than any built at the time1 together with larger horse-power1 etc4 ,these stipulations having been settled by the ,admiralty1 the ,admiralty officials1 in conjunction with ,messrs4 ,vickers ,ltd41 determined the size1 shape1 and materials for the airship required4 ,the length of the ship was fixed at approximately #ejj feet1 with a diameter of #dh feet4 ,various shapes were considered1 and the one adopted was that recommended by an ,american professor named ,zahm4 ,in this shape1 a great proportion of the longitudinal huff framework is parallel sided with curved bow and stern portions1 the radius of these curved portions being1 in the case of the bow1 twice the diameter of the hull1 and in the case of the stern nine times the same diameter4 ,experiments proved that the resistance of a ship of this shape was only two-fifths of the resistance of a ship of the same dimensions1 having the #a #a_/b calibre bow and stern of the ,zeppelin airships at that time constructed4 ,a considerable difference of opinion existed as to the material to be chosen for the construction of the hull4 ,bamboo1 wood1 aluminium1 or one of its alloys1 were all considered4 ,the first was rejected as unreliable4 ,the second would have been much stronger than aluminium1 and was urged by ,messrs4 ,vickers4 ,the ,admiralty1 however1 considered that there was a certainty of better alloys being produced1 and as the ship was regarded as an experiment and its value would be largely negatived if later ships were constructed of a totally different material1 aluminium or an alloy was selected4 ,the various alloys then in existence showed little advantage over the pure metal1 so pure aluminium was specified and ordered4 ,this metal was expected to have a strength of ten tons per square inch1 but that which arrived was found to be very unreliable1 and many sections had1 on test1 only half the strength required4 ,the aluminium wire intended for the mesh wiring of the framework was also found to be extremely brittle4 ,a section of the framework was1 however1 erected1 and also one of wood1 as a test for providing comparisons4 ,in the tests1 the wooden sections proved1 beyond all comparison1 the better1 but the ,admiralty persisted in their decision to adopt the metal4 ,towards the end of #aiji a new aluminium alloy was discovered1 known as duralumin4 ,tests were made which proved that this new metal possessed a strength of twenty-five tons per square inch1 which was over twice as strong as the nominal strength of aluminium1 and in practice was really five times stronger4 ,the specific gravity of the new metal varied from #b4ge to #b4hf1 as opposed to the #b4ef of aluminium4 ,as the weights were not much different it was possible to double the strength of the ship and save one ton in weight4 ,duralumin was therefore at once adopted4 ,the hull structure was composed of twelve longitudinal duralumin girders which ran fore and aft the length of the ship and followed the external shape4 ,the girders were secured to a steel nose-piece at the bow and a pointed stern-piece aft4 ,these girders1 built of duralumin sections1 were additionally braced wherever the greatest weights occurred4 ,to support these girders in a thwartship direction a series of transverse frames were placed at #ab feet #f inches centres throughout the length of the ship1 and formed1 when viewed cross-sectionally1 a universal polygon of twelve sides4 ,for bracing purposes mesh wiring stiffened each bay longitudinally1 so formed by the junction of the running girder and the transverse frames1 while the transverse frames between the gasbags were stiffened with radial wiring which formed structure similar to a wheel with its spokes4 ,the frames where the gondolas occurred were strengthened to take the addition weight1 while the longitudinals were also stiffened at the bow and stern4 ,communication was provided between the gondolas by means of an external keel which was suspended from extra keel longitudinals4 ,in this design the keel was provided for accommodation purposes only1 and in no way increased the structural stability of the ship as in ,no4 #i and later ships4 ,this keel1 triangular in section1 widened out amidships to form a space for a cabin and the wireless compartment4 ,the fins and rudders1 which were adopted1 were based entirely on submarine experience1 and the ,zeppelin method was ignored4 ,the fins were fitted at the stern of the ship only1 and comprised port and starboard horizontal fins1 which followed approximately the shape of the hull1 and an upper and lower vertical fin4 ,attached to these fins were box rudders and elevators1 instead of the balanced rudders first proposed4 ,auxiliary rudders were also fitted in case of a breakdown of the main steering gear abaft the after gondola4 ,elevators and rudders were controlled from the forward gondola and the auxiliary rudders from the after gondola4 ,the gasbags were seventeen in number and were twelve-sided in section1 giving approximately a volume of #ffc1jjj cubic feet when completely full4 ,continental fabric1 as in use on the ,zeppelin airships1 was adopted1 although the original intention was to use gold-beater's skin1 but this was abandoned owing to shortage of material4 ,these bags were fitted with the ,parseval type of valve1 which is situated at the top1 contrary to the current ,zeppelin practice1 which had automatic valves at the bottom of the bags1 and hand-operated valves on the top of a few bags for control purposes4 ,nets were laced to the framework to prevent the bags bulging through the girders4 ,the whole exterior of the hull was fitted with an outer cover2 ,zeppelin at this time used a plain light rubber-proofed fabric1 but this was not considered suitable for a ship which was required to be moored in the open1 as in wet weather the material would get saturated and water-logged4 ,various experiments were carried out with cotton1 silk and ramie1 and1 as a result1 silk treated with ,ioco was finally selected4 ,this cover was laced with cords to the girder work1 and cover-strips rendered the whole impervious to wet4 ,fire-proofed fabric was fitted in wake of the gondolas for safety from the heat of the engines4 ,two gondolas1 each comprising a control compartment and engine-room1 were suspended from the main framework of the hull4 ,they were shaped to afford the least resistance possible to the air1 and were made of ,honduras mahogany1 three-ply where the ballast tanks occurred1 and two-ply elsewhere4 ,the plies were sewn together with copper wire4 ,the gondolas were designed to have sufficient strength to withstand the strain of alighting on the water4 ,they were suspended from the hull by wooden struts streamline in shape1 and fitted with internal steel-wire ropes2 additional wire suspensions were also fitted to distribute the load over a greater length of the ship4 ,the engines were carried in the gondolas on four hollow wooden struts1 also fitted internally with wire4 ,the wires were intended to support the gondolas in the event of the struts being broken in making a heavy landing4 ,two engines were mounted1 one in each gondola1 the type used being the #h-;cylinder vertical water-cooled ,wolseley developing a horse-power of #afj4 ,the forward engine drove two wing propellers through the medium of bevel gearing1 while the after engine drove a single large propeller aft through #d gear box to reduce the propeller revolutions to half that of the engine4 ,the estimated speed of the ship was calculated to be #db miles per hour1 petrol was carried in tanks1 fitted in the keel1 and the water ballast tanks were placed close to the keel and connected together by means of a pipe4 ,no4 #a was completed in ,may1 #aiaa4 ,she had been built at ,barrow in a shed erected on the edge of ,cavendish ,dock4 ,arrangements were made that she should be towed out of the shed to test her efficiency at a mooring post which had been prepared in the middle of the dock4 ,she was launched on ,may #bbnd in a flat calm and was warped out of the shed and hauled to the post where she was secured without incident4 ,the ship rode at the mooring post in a steady wind1 which at one time increased to #cf miles per hour1 until the afternoon of ,may #beth1 and sustained no damage whatever4 ,various engine trials were carried out1 but no attempt was made to fly1 as owing to various reasons the ship was short of lift4 ,valuable information was1 however1 gained in handling the ship1 and much was learnt of her behaviour at the mast4 ,more trouble was experienced in getting her back into the shed1 but she was eventually housed without sustaining any damage of importance4 ,owing to the lack of disposable lift1 the bags were deflated and various modifications were carried out to lighten the ship1 of which the principal were the removal of the keel and cabin entirely1 and the removal of the water-trimming services4 ,other minor alterations were made which gave the ship1 on completion1 a disposable lift of #c4ba tons4 ,the transverse frames between the gasbags were strengthened1 and a number of broken wires were replaced4 ,on ,september #bbnd the ship was again completed1 and on the #bdth she was again to be taken out and tested at the mooring post4 ,unfortunately1 while being hauled across the dock1 the framework of the ship collapsed1 and she was got back into the shed the same day4 ,examination showed that it was hopeless to attempt to reconstruct her1 and she was broken up at a later date4 ,the failure of this ship was a most regrettable incident1 and increased the prejudice against the rigid airship to such an extent that for some time the ,navy refused to entertain any idea of attempting a second experiment4 ,,rigid ,,airship ,no4 #i ,rigid ,airship ,no4 #a having met with such a calamitous end1 the authorities became rather dubious as to the wisdom of continuing such costly experiments4 ,most unfortunately1 as the future showed and as was the opinion of many at the time1 rigid construction in the following year #aiab was ordered to be discontinued4 ,this decision coincided with the disbanding of the ,naval ,air ,service1 and for a time rigid airships in this country were consigned to the limbo of forgetfulness4 ,after the ,naval ,air ,service had been reconstituted1 the success which attended the ,zeppelin airships in ,germany could no longer be overlooked1 and it was decided to make another attempt to build a rigid airship in conformity with existing ,zeppelin construction4 ,the first proposals were put forward in #aiac1 and1 finally1 after eleven months delay1 the contract was signed4 ,this airship1 it has been seen1 was designated ,no4 #i4 ,no4 #i experienced numerous vicissitudes1 during the process of design and later when construction was in progress4 ,the contract having been signed in ,march1 #aiad1 work on the ship was suspended in the following ,february1 and was not recommenced until ,july of the same year4 ,from that date onwards construction was carried forward2 but so many alterations were made that it was fully eighteen months before the ship was completed and finally accepted by the ,admiralty4 ,the ship as designed was intended to be generally in conformity with existing ,zeppelin construction1 with the following main requirements stipulated for in the specification3 #a4 ,she was to attain a speed of at least #de miles per hour at the full power of the engines4 #b4 ,a minimum disposable lift of five tons was to be available for movable weights4 #c4 ,she was to be capable of rising to a height of #b1jjj feet during flight4 ,the design of this ship was prepared by ,messrs4 ,vickers1 ,ltd41 and as it was considered likely that owing to inexperience the ship would probably be roughly handled and that heavy landings might be made1 it was considered that the keel structure and also the cars should be made very strong in case of accidents occurring4 ,this1 while materially increasing the strength of the ship1 added to its weight1 and coupled with the fact that modifications were made in the design1 rendered the lift somewhat disappointing4 ,the hull structure was of the ,zahm shape as in ,no4 #a1 a considerable portion being parallel sided1 while in transverse section it formed a #ag-sided polygon4 ,in length it was #ebf feet with a maximum diameter of #ec feet4 ,the hull framework was composed of triangular duralumin girders1 both in the longitudinal and transverse frames1 while the bracing was carried out by means of high tensile steel wires and duralumin tubes4 ,attached to the hull was a ,v-shaped keel composed of tubes with suitable wire bracings1 and in it a greater part of the strength of the structure lay4 ,it was designed to withstand the vertical forces and bending moments which resulted from the lift given by the gasbags and the weights of the car and the cabin4 ,the keel also provided the walking way from end to end of the ship1 and amidships was widened out to form a cabin and wireless compartment4 ,the wiring of the transverse frames was radial and performed similar functions to the spokes of a bicycle wheel4 ,these wires could be tightened up at the centre at a steel ring through which they were threaded and secured by nuts4 ,in addition to the radial wires were the lift wires1 which were led to the two points on the transverse frames which were attached to the keel2 on the inflation of the gasbags1 the bags themselves pressed upon the longitudinal girders on the top of the ship1 which pressure was transferred to the transverse frames and thence by means of the several lift wires to the keel4 ,in this way all the stresses set up by the gas were brought finally to the keel in which we have already said lay the main strength of the ship4 ,the hull was divided by the transverse frames into seventeen compartments each containing a single gasbag4 ,the bags were composed of rubber-proofed fabric lined with gold-beater's skin to reduce permeability1 and when completely full gave a total volume of #hij1jjj cubic feet4 ,two types of valve were fitted to each bag1 one the ,parseval type of valve with the pressure cone as fitted in ,no4 #a1 the other automatic but also controlled by hand4 ,to distribute the pressure evenly throughout the upper longitudinal frames1 and also to prevent the gasbags bulging between the girders1 nets were fitted throughout the whole structure of the hull4 ,the whole exterior of the ship was fitted with an outer cover1 to protect the gasbags and hull framework from weather and to render the outer surface of the ship symmetrical and reduce skin friction and resistance to the air to a minimum4 ,to enable this cover to be easily removed it was made in two sections1 a port and starboard side for each gasbag4 ,the covers were laced to the hull framework and the connections were covered over with sealing strips to render the whole weathertight4 ,the system of fins for stabilizing purposes on ,no4 #i were two--vertical and horizontal4 ,the vertical fin was composed of two parts1 one above and the other below the centre line of the ship4 ,they were constructed of a framework of duralumin girders1 covered over with fabric4 ,the fins were attached on one edge to the hull structure and wire braced from the other edge to various positions on the hull4 ,the horizontal fins were of similar design and attached in a like manner to the hull4 ,triplane rudders and biplane elevators of the box type were fitted in accordance with the ,german practice of the time4 ,auxiliary biplane rudders were fitted originally abaft the after car1 but during the first two trial flights they proved so very unsatisfactory that it was decided to remove them4 ,two cars or gondolas were provided to act as navigating compartments and a housing for the engines1 and in design were calculated to offer the least amount of head resistance to the wind4 ,the cars were composed of duralumin girders1 which formed a flooring1 a main girder running the full length of the car with a series of transverse girders spaced in accordance with the main loads4 ,from each of these transverse girders vertical standards with a connecting piece on top were taken and the whole exterior was covered with duralumin plating4 ,the cars were suspended in the following manner4 ,two steel tubes fitting into a junction piece at each end were bolted to brackets at the floor level at each end of the transverse girders4 ,they met at an apex above the roof level and were connected to the tubing of the keel4 ,in addition1 to distribute the weight and prevent the cars from rocking1 steel wire suspensions were led to certain fixed points in the hull4 ,each car was divided into two parts by a bulkhead1 the forward portion being the control compartment in which were disposed all instruments1 valve and ballast controls1 and all the steering and elevating arrangements4 ,engine-room telegraphs1 voice pipes and telephones were fitted up for communication from one part of the ship to the other4 ,the keel could be reached by a ladder from each car1 thus providing with the climbing shaft through the hull access to all parts of the ship4 ,the original engine equipment of ,no4 #i was composed of four ,wolseley-,maybach engines of #ahj horse-power each1 two being installed in the forward car and two in the after car4 ,as the ship was deficient in lift after the initial flight trials had been carried out1 it was decided to remove the two engines from the after car and replace them with a single engine of #bej horse-power2 secondly1 to remove the swivelling propeller gear from the after car and substitute one directly-driven propeller astern of the car4 ,this as anticipated reduced the weight very considerably and in no way lessened the speed of the ship4 ,the forward engines drove two four-bladed swivelling propellers through gear boxes and transmission shafts1 the whole system being somewhat complicated1 and was opposed to the ,zeppelin practice at the time which employed fixed propellers4 ,the after engine drove a large two-bladed propeller direct off the main shaft4 ,the petrol and water ballast were carried in tanks situated in the keel and the oil was carried in tanks beneath the floors of the cars4 ,the wireless cabin was situated as before mentioned in a cabin in the keel of the ship1 and the plant comprised a main transmitter1 an auxiliary transmitter and receiver and the necessary aerial for radiating and receiving4 ,no4 #i was inflated in the closing days of #aiaf1 and the disposal lift was found to be #b4a tons under the specification conditions1 namely1 barometer #bi4e inches and temperature #ee degrees ,fahrenheit4 ,the contract requirements had been dropped to #c4a tons1 which showed that the ship was short by one ton of the lift demanded4 ,the flight trials were1 however1 carried out1 which showed that the ship had a speed of about #db #a_/b miles per hour4 ,the alterations previously mentioned were afterwards made1 the bags of the ship were changed and another lift and trim trial was held in ,march1 #aiag1 when it was found that these had had the satisfactory result of increasing the disposable lift to #c4h tons or 4#g ton above the contract requirements1 and with the bags #ajj per cent full gave a total disposable lift of #e4a tons4 ,additional trials were then carried out1 which showed that the speed of the ship had not been impaired4 ,for reference purposes the performances of the ship are tabulated below4 ,speed3 ,full #de miles per hour ,normal #b_/c #ch ,cruising #a_/c #cb ,endurance3 ,full #ah hours #hjj miles ,normal #bf #a1jjj ,cruising #ej #a1fjj ,no4 #i having finished her trials was accepted by the ,admiralty in ,mar4 #aiag1 and left ,barrow1 where she had been built1 for a patrol station4 ,in many ways she was an excellent ship1 for it must be remembered that when completed she was some years out-of-date judged by ,zeppelin standards4 ,apart from the patrol and convoy work which she accomplished1 she proved simply invaluable for the training of officers and men selected to be the crews of future rigid airships4 ,many of these received their initial training in her1 and there were few officers or men in the airship service who were not filled with regret when orders were issued that she was to be broken up4 ,the general feeling was that she should have been preserved as a lasting exhibition of the infancy of the airship service1 but unfortunately rigid airships occupy so much space that there is no museum in the country which could have accommodated her4 ,so she passed1 and1 except for minor trophies1 remains merely a recollection4 ,,rigid ,,airship ,no4 #bc ,,class ,after the decision had been made in #aiae that work on ,no4 #i should be restarted1 the ,admiralty determined that a programme of rigid airships should be embarked upon1 and design was commenced4 ,several ships of the same class were1 ordered1 and the type was to be known as the #bc class4 ,progress on these ships1 although slow1 was more rapid than had been the case with ,no4 #i1 and by the end of #aiag three were completed and a fourth was rapidly approaching that state4 ,the specification1 always ambitious1 laid down the following main stipulations4 7#a7 ,the ship is to attain a speed of at least #ee miles per hour for the main power of the engines4 7#b7 ,a minimum of #h tons is to be available for disposable weights when full4 7#c7 ,the ship must be capable of rising at an average rate of not less than #a1jjj feet per minute1 through a height of #c1jjj feet starting from nearly sea level4 ,as will be seen later this class of ship1 although marking a certain advance on ,no4 #i both as regards workmanship and design1 proved on the whole somewhat disappointing1 and it became more evident every day that we had allowed the ,germans to obtain such a start in the race of airship construction as we could ill afford to concede4 ,we may here state that all of the ships of this class which had been ordered were not completed1 the later numbers being modified into what was known as the #bc ,x class2 four in all of the #bc class were built1 of which two--,nos4 #bc and #bf--were built by ,messrs4 ,vickers1 ,ltd41 at ,barrow1 ,no4 #bd by ,messrs4 ,wm4 ,beardmore and ,co41 at ,glasgow1 and ,no4 #be by ,messrs4 ,armstrong1 ,whitworth and ,co41 at ,selby1 ,yorkshire4 ,in many respects the closest similarity of design exists between ,no4 #i and ,no4 #bc1 especially in the hull1 but it will be of interest to mention the salient differences between the two ships4 ,the length of the hull1 which in ,no4 #i was #ebj feet1 was increased in ,no4 #bc to #ece feet1 and the number of gasbags from seventeen to eighteen4 ,this gave a total volume of #iig1ejj cubic feet compared with #hij1jjj cubic feet in ,no4 #i1 with a disposable lift under specification conditions of #e4g tons as opposed to #c4h tons4 ,the longitudinal shape of ,no4 #bc is a modified form of ,zahm shape1 the radius of the bow portion being twice the diameter of the parallel portion1 while the stern radius is three times the same diameter4 ,in design the hull framework is almost a repetition of ,no4 #i1 particularly in the parallel portion1 the same longitudinal and transverse frames dividing the hull into compartments1 with tubes completely encircling the section between each main transverse frame4 ,the system of wiring the hull is precisely the same in both the ships1 and nets are employed in the same way4 ,the triangular section of keel is adhered to1 but its functions in ,no4 #bc are somewhat different4 ,in ,no4 #i it was intended to be sufficiently strong to support all the main vertical bending moments and shearing forces1 but in ,no4 #bc it was primarily intended to support the distributed weights of water ballast1 petrol tanks1 etc41 between the main transverse frames4 ,unlike ,no4 #i1 the keel is attached to the main transverse frames only4 ,the cabin and wireless cabin are disposed in the keel in the same manner1 and it also furnishes a walking way for the total length of the ship4 ,the stabilizing fins1 both vertical and horizontal1 are similar to those attached to ,no4 #i1 but the system of rudders and elevators is totally different4 ,in place of the box rudders and elevators in ,no4 #i1 single balanced rudders and elevators are attached to the fins2 they have their bearing on the outboard side on the external girders of the fins1 which are extended for the purpose4 ,the elevators and rudders are composed of a duralumin framework1 stiffened by a kingpost on either side with bracing wires4 ,the bags1 eighteen in number1 are made of rubber-proofed fabric lined with gold-beater's skin4 ,it is interesting to note that the number of skins used for the bags of a ship of this class is approximately #cej1jjj4 ,the system of valves is entirely different from that in ,no4 #i4 ,the ,parseval type of valve with the pressure cone at the bottom of the bag is omitted1 and in the place of the two top valves in the former ship are a side valve of the ,zeppelin type entirely automatic and a top valve entirely hand controlled4 ,the side valve is set to blow off at a pressure of from #c to #e millimetres4 ,the outer cover was fitted in the same manner as in ,no4 #i4 ,two cars or gondolas1 one forward1 the other aft1 each carry one engine provided with swivelling propellers and gears4 ,they are enclosed with sides and a fireproof roof1 and are divided into two compartments1 one the navigating compartment1 the other the engine room4 ,the cars are in all respects very similar to those of ,no4 #i1 and are suspended from the hull in a similar manner4 ,the remaining two engines are carried in a small streamline car situated amidships1 which has just sufficient room in it for the mechanics to attend to them4 ,originally this car was open at the top1 but it was found that the engineers suffered from exposure1 and it was afterwards roofed in4 ,the engine arrangements in this ship were totally different to those of ,no4 #i1 four #bej horse-power ,rolls ,royce engines being installed in the following order4 ,single engines are fitted in both the forward and after cars1 each driving two swivelling four-bladed propellers4 ,in the centre car two similar engines are placed transversely1 which drive single fixed propellers mounted on steel tube outriggers through suitable gearing4 ,the engines are the standard #ab cylinder ,v-type ,rolls ,royce which will develop over #cjj brake horse-power at full throttle opening4 ,the engine is water cooled1 and in the case of those in the forward and after cars the original system consisted of an internal radiator supplied by an auxiliary water tank carried in the keel4 ,it was found on the flight trials that the cooling was insufficient1 and external radiators were fitted1 the internal radiator and fan being removed4 ,in the case of the centre car no alteration was necessary1 as external radiators were fitted in the first instance4 ,the engines are supported by two steel tubes held by four brackets bolted to the crank case1 these being carried by twelve duralumin tubes bolted to the bearers and transverse frames of the car respectively4 ,the drive from the engine is transmitted through a universal joint to a short longitudinal shaft1 running on ball bearings4 ,this shaft gears into two transverse shafts1 which drive the propellers through the medium of a gear box to the propeller shafts1 making five shafts in all4 ,the engines in the centre car being placed transversely the transmission is more direct1 the engines driving the propellers through two gear wheels only4 ,the propeller gear box is supported by steel tube outriggers attached by brackets to the framework of the car4 ,the petrol is carried in a series of tanks situated beneath the keel walking way1 and are interconnected so that any tank either forward or aft can supply any engine1 by this means affording assistance for the trimming of the ship4 ,four-bladed propellers are used throughout the ship4 ,water ballast is carried in fabric bags also situated beneath the keel walking way1 and a certain amount is also carried beneath the floor of the car4 ,engine-room telegraphs1 swivelling propeller telegraphs1 speaking tubes and telephones1 with a lighting set for the illumination of the cars and keel1 were all fitted in accordance with the practice standard in all rigid airships4 ,the lift and trim trials taken before the initial flight trials showed that the ship possessed a disposable lift under standard conditions of #e4g tons4 ,the original disposable lift demanded by the specification was #c tons but this was reduced by #b tons owing to the machinery weights being #b tons in excess of the estimate4 ,since then these weights had been increased by another half-ton1 making a total of #b #a_/b tons over the original estimate4 ,it was evident that with so small a margin of lift these ships would never be of real use1 and it was decided to remove various weights to increase the lift and to substitute a wing car of a similar type to those manufactured for the ,r #cc class for the heavy after car at present in use4 ,r #bc carried out her trials without the alteration to the car1 which was effected at a later date1 and the same procedure was adopted with ,r #bd and ,r #be4 ,in the case of ,r #bf1 however1 she had not reached the same stage of completion as the other two ships1 and the alterations proposed for them were embodied in her during construction4 ,the gasbags were of lighter composition1 all cabin furniture was omitted and the wing car was fitted in place of the original after car4 ,this wing car is of streamline shape with a rounded bow and tapered stern4 ,the lower portion is plated with duralumin sheets and the upper part is covered with canvas attached to light wooden battens to give the necessary shape4 ,this effected a very considerable reduction in weight4 ,the original #bej horse-power ,rolls ,royce engine was installed1 now driving a single large two-bladed propeller astern4 ,a test having been taken1 it was found that the disposable lift under standard conditions was #f4bh tons4 ,it was therefore decided that all the ships of the class should be modified to this design when circumstances permitted4 ,speed trials were carried out under various conditions of running1 when it was found that the ship possessed a speed of #ed #a_/d miles per hour with the engines running full out4 ,to summarize the performances of these ships as we did in the case of ,no4 #i1 we find3 ,speed3 ,full #ed miles per hour ,normal #b_/c #dh ,cruising #a_/c #cc ,endurance3 ,full #ah hours #a1jjj miles ,normal #bf #a1bej ,cruising #ej #a1ijj ,the production of the rigid airship during the war was always surrounded with a cloak of impenetrable mystery4 ,few people1 except those employed on their construction or who happened to live in the immediate vicinity of where they were built1 even knew of their existence1 and such ignorance prevailed concerning airships of every description that the man in the street hailed a small non-rigid as the ,british ,zeppelin or admired the appearance of ,r #bc as the ,silver ,queen4 ,the authorities no doubt knew their own business in fostering this ignorance1 although for many reasons it was unfortunate that public interest was not stimulated to a greater degree4 ,in the summer months of #aiah1 however1 they relented to a certain extent1 and ,r #bc and one of her sister ships were permitted to make several flights over ,london to the intense delight of thousands of its inhabitants1 and a certain amount of descriptive matter appeared in the ,press4 ,from that time onwards these large airships have completely captured the popular imagination1 and many absurd rumours and exaggerations have been circulated regarding their capabilities4 ,it has been gravely stated that these airships could accomplish the circuit of the globe and perform other feats of the imagination4 ,it must be confessed that their merits do not warrant these extravagant assertions4 ,the fact remains1 however1 that ,r #bc and her sister ship ,r #bf have each carried out patrols of upwards of #dj hours duration and that1 similarly to ,no4 #i1 they have proved of the greatest value for training airship crews and providing experience and data for the building programme of the future4 ,at the present time highly interesting experiments are being carried out with them to determine the most efficient system of mooring in the open1 which will be discussed at some length in the chapter dealing with the airship of the future4 ,,rigid ,,airship #bc ,x ,,class ,during the early days of building the airships of the #bc class1 further information was obtained relating to rigid airship construction in ,germany1 which caused our designers to modify their views4 ,it was considered a wrong policy to continue the production of a fleet of ships the design of which was becoming obsolete1 and accordingly within ten months of placing the order for this class a decision was reached that the last four ships were to be altered to a modified design known as the #bc ,x class4 ,as was the case with the ships of the preceding class when nearing completion1 they were realized to be out of date1 and special efforts being required to complete the ships of the #cc class and to release building space for additional larger ships1 the construction of the second pair was abandoned4 ,the main modification in design was the abolition of the external keel1 and in this the later ,zeppelin principles were adopted4 ,this secured a very considerable reduction in structural weight with a corresponding large expansion of the effective capabilities of the ship4 ,it has been seen that the purpose of the keel in ,no4 #i was to provide a structure sufficiently strong to support all the main vertical bending moments and shearing forces1 and that in ,no4 #bc this principle was somewhat different1 in that the keel in this ship was primarily intended to support the distributed weights of petrol1 water1 ballast1 etc41 between the transverse frames4 ,in this later design1 namely1 the #bc ,x class1 it was considered that the weights could be concentrated and suspended from the radial wiring of the transverse frames and that the keel1 incorporated in the design of the former ships1 could be dispensed with4 ,for all practical purposes1 apart from the absence of the keel1 the #bc ,x class of airship may be regarded as a slightly varied model of the #bc class4 ,the main dimensions are nearly the same1 and the general arrangement of the ship is but little changed4 ,the loss of space owing to the introduction of the internal corridor is compensated by a modification of the shape of the bow1 which was redesigned with a deeper curve4 ,the hull structure was also strengthened by utilizing a stronger type of girder wherever the greatest weights occur4 ,in these strengthened transverse frames the girders1 while still remaining of the triangular section1 familiar in the other ships1 are placed the opposite way round1 that is1 with the apex pointing outwards4 ,the walking way is situated at the base of the hull passing through the gas chambers1 which are specially shaped for the purpose4 ,the corridor is formed of a light construction of hollow wooden struts and duralumin arches covered with netting4 ,in all other leading features the design of the #bc class is adhered to2 the gasbags are the same1 except for the alteration due to the internal corridor1 and the system of valves and the various controls are all highly similar4 ,the arrangement of gondolas and the fitting of engines in all ways corresponds to the original arrangement of ,r #bc1 with the exception that they were suspended closer to the hull owing to the absence of the external keel4 ,the substitution of the wing car of the #cc class for the original after gondola1 carried out in the modifications undergone by the ships of the #bc class1 was not adopted in these ships1 as the wireless compartment installed in the keel in the former was fitted in the after gondola in the latter4 ,the disposable lift of these ships under standard conditions is #g #a_/b tons1 which shows considerable improvement on the ships of the former classes4 ,summarizing as before1 the performances appear as under-- ,speed3 ,full #ef #a_/b miles per hour ,normal #ec ,cruising #de ,endurance3 ,normal #ai hours #a1jae miles ,cruising #bc #a_/b #a1jej ,the two ships of this class1 which were commissioned1 must be regarded within certain limits as most satisfactory1 and are the most successful of those that appeared and were employed during the war4 ,escort of convoys and extended anti-submarine patrols were carried out1 and certain valuable experiments will be attempted now that peace has arrived4 ,in spite of the grave misgivings of many critics1 the structure without the keel has proved amply strong1 and no mishap attended this radical departure on the part of the designers4 ,,rigid ,,airship ,no4 #ca ,,class ,the airship known as ,r #ha was a complete deviation from any rigid airship previously built in this country4 ,in this case the experiment was tried of constructing it in wood in accordance with the practice adopted by the ,schutte-,lanz ,company in ,germany4 ,it must be frankly acknowledged that this experiment resulted in failure4 ,the ship when completed showed great improvement both in shape1 speed and lifting capacity over any airship commissioned in this country1 and as a whole the workmanship exhibited in her construction was exquisite4 ,unfortunately1 under the conditions to which it was subjected1 the hull structure did not prove durable1 and to those conditions the failure is attributed4 ,under different circumstances it may be hoped that the second ship1 when completed1 will prove more fortunate4 ,in length ,r #ca was #fae feet1 with a diameter of #ff feet1 and the capacity was #a #a_/b million cubic feet4 ,in shape the hull was similar to the later types of ,zeppelin1 having a rounded bow and a long1 tapering stern4 ,the longitudinal and transverse frames were composed of girders built up of three-ply wood1 the whole structure being braced in the usual manner with wire bracings4 ,it had been found in practice with rigid airships that1 if for any reason one gasbag becomes much less inflated than those adjacent to it1 there is considerable pressure having the effect of forcing the radial wires of the transverse frames towards the empty bag4 ,the tension resulting in these wires may produce very serious compressive strain in the members of the transverse frames1 and to counteract this action an axial wire is led along the axis of the ship and secured to the centre point of the radial wiring4 ,this method1 now current practice in rigid airship construction1 was introduced for the first time in this ship4 ,as will be seen from the photograph1 the control and navigating compartment of the ship is contained in the hull1 the cars in each case being merely small engine rooms4 ,these small cars were beautifully made of wood of a shape to afford the least resistance to the air1 and in number were five1 each housing a single #bej horse-power ,rolls ,royce engine driving a single fixed propeller4 ,here we see another decided departure from our previous methods of rigid airship construction1 in that for the first time swivelling propellers were abandoned4 ,r #ca when completed carried out her trials1 and it was evident that she was much faster than previous ships4 ,the trials were on the whole satisfactory and1 except for a few minor accidents to the hull framework and fins1 nothing untoward occurred4 ,at a later date the whole ship was through fortuitous circumstances exposed to certain disadvantageous conditions which rendered her incapable of further use4 ,r #cc ,,class ,september #bdth1 #aiaf1 is one of the most important days in the history of rigid airship design in this country2 on this date the ,german ,zeppelin airship ,l #cc was damaged by gunfire over ,london1 and being hit in the after gasbags attempted to return to ,germany4 ,owing to lack of buoyancy she was forced to land at ,little ,wigborough1 in ,essex1 where the crew1 having set fire to the ship1 gave themselves up4 ,although practically the entire fabric of the ship was destroyed1 the hull structure most fortunately remained to all intents and purposes intact1 and was of inestimable value to the design staff of the ,admiralty1 who measured up the whole ship and made working drawings of every part available4 ,during this year other ,german rigid airships had been brought down1 namely ,l #ae1 which was destroyed at the mouth of the ,thames in ,april1 but which was of an old type1 and from which little useful information was obtained2 and also the ,army airship ,l4,z4 #he1 which was destroyed at ,salonica in the month of ,may4 ,a ,schutte-,lanz airship was also brought down at ,cuffley1 on ,september #bnd1 and afforded certain valuable details4 ,all these ships were1 however1 becoming out of date2 but ,l #cc was of the latest design1 familiarly called the super-,zeppelin1 and had only been completed about six weeks before she encountered disaster4 ,in view of the fact that the rigid airships building in this country at this date1 with the exception of the wooden ,schutte-,lanz ships were all based on pre-war designs of ,zeppelin airships1 it can be readily understood that this latest capture revolutionized all previous ideas1 and to a greater extent than might be imagined1 owing to the immense advance1 both in design and construction1 which had taken place in ,germany since #aiad4 ,all possible information having been obtained1 both from the wreck of the airship itself and from interrogation of the captured crew1 approval was obtained1 in ,november of the same year1 for two ships of the ,l #cc design to be built2 and in ,january1 #aiag1 this number was increased to five4 ,it was intended originally that these ships should be an exact facsimile of ,l #cc2 but owing to the length of time occupied in construction later information was obtained before they were completed1 both from ships of a more modern design1 which were subsequently brought down1 and also from other sources4 ,acting on this information1 various improvements were embodied in ,r #cc and ,r #cd1 which were in a more advanced state2 but in the case of the three other ships the size was increased1 and the ships1 when completed1 will bear resemblance to a later type altogether4 ,as a comment on the slowness of construction before mentioned1 the fact that while we in this country were building two ships on two slips1 ,germany had constructed no fewer than thirty on four slips1 certainly affords considerable food for reflection4 ,the two airships of this class having only just reached a state of completion1 a detailed description cannot be given without making public much information which must necessarily remain secret for the present4 ,various descriptions have1 however1 been given in the daily and weekly ,press1 but it is not intended in the present edition of this book to attempt to elaborate on anything which has not been already revealed through these channels4 ,it is regrettable that so much that would be of the utmost interest has to be omitted2 but the particulars which follow will at any rate give sonic idea of the magnitude of the ship and show that it marks a decided departure from previous experiments and a great advance on any airship before constructed in ,great ,britain4 ,it is also a matter for regret that these two ships were not completed before the termination of hostilities1 as their capabilities would appear to be sufficient to warrant the expectations which have been based on their practical utility as scouting agents for the ,grand ,fleet4 ,in all its main features the hull structure of ,r #cc and ,r #cd follows the design of the wrecked ,german ,zeppelin airship ,l #cc4 ,the hull follows more nearly a true streamline shape than in the previous ships constructed of duralumin1 in which a great proportion of the total length was parallel-sided4 ,the ,germans adopted this new shape from the ,schutte-,lanz design and have not departed from this practice4 ,this consists of a short parallel body with a long rounded bow and a long tapering stem culminating in a point4 ,the overall length of the ship is #fdc feet with a diameter of #gi feet and an extreme height of #ib feet4 ,the type of girders in this class has been much altered from those in previous ships4 ,the hull is fitted with an internal triangular keel throughout practically the entire length4 ,this forms the main corridor of the ship1 and is fitted with a footway down the centre for its entire length4 ,it contains water ballast and petrol tanks1 bomb stowage and crew accommodation and the various control wires1 petrol pipes and electric leads are carried along the lower part4 ,throughout this internal corridor runs a bridge girder1 from which the petrol and water ballast tanks are supported4 ,these tanks are so arranged that they can be dropped clear of the ship4 ,amidships is the cabin space with sufficient room for a crew of twenty-five4 ,hammocks can be slung from the bridge girder before mentioned4 ,in accordance with the latest ,zeppelin practice1 monoplane rudders and elevators are fitted to the horizontal and vertical fins4 ,the ship is supported in the air by nineteen gasbags which give a total capacity of approximately two million cubic feet of gas4 ,the gross lift works out at approximately #ei #a_/b tons1 of which the total fixed weight is #cc tons1 giving a disposable lift of #bf #a_/b tons4 ,the arrangement of cars is as follows3 ,at the forward end the control car is slung1 which contains all navigating instruments and the various controls4 ,adjoining this is the wireless cabin1 which is also fitted for wireless telephony4 ,immediately aft of this is the forward power car containing one engine1 which gives the appearance that the whole is one large car4 ,amidships are two wing cars each containing a single engine4 ,these are small and just accommodate the engine with sufficient room for mechanics to attend to them4 ,further aft is another larger car which contains an auxiliary control position and two engines4 ,it will thus be seen that five engines are installed in the ship2 these are all of the same type and horse-power1 namely1 #bej horse-power ,sunbeam4 ,r #cc was constructed by ,messrs4 ,armstrong ,whitworth ,ltd41 while her sister ship ,r #cd was built by ,messrs4 ,beardmore on the ,clyde4 ,in the spring of #aiah1 ,r #cc and ,r #cd carried out several flight trials1 and though various difficulties were encountered both with the engines and also with the elevator and rudder controls1 it was evident that1 with these defects remedied1 each of these ships would prove to be singularly reliable4 ,on one of these trials made by ,r #cd1 exceedingly bad weather was encountered1 and the airship passed through several blinding snowstorms2 nevertheless the proposed flight of some seventeen hours was completed1 and though at times progress was practically nil owing to the extreme force of the wind1 the station was reached in safety and the ship landed without any contretemps4 ,this trial run having been accomplished in weather such as would never have been chosen in the earlier days of rigid trial flights1 those connected with the airship felt that their confidence in the vessel's capabilities was by no means exaggerated4 ,the lift of the ship warranted a greater supply of petrol being carried than there was accommodation for1 and the engines by now had been tuned up to a high standard of efficiency4 ,accordingly it was considered that the ship possessed the necessary qualifications for a transatlantic flight4 ,it was1 moreover1 the opinion of the leading officers of the airship service that such an enterprise would be of inestimable value to the airship itself1 as demonstrating its utility in the future for commercial purposes4 ,efforts were made to obtain permission for the flight to be attempted1 and although at first the naval authorities were disinclined to risk such a valuable ship on what appeared to be an adventure of doubtful outcome1 eventually all opposition was overcome and it was agreed that for the purposes of this voyage the ship was to be taken over by the ,air ,ministry from the ,admiralty4 ,work was started immediately to fit out the ship for a journey of this description4 ,extra petrol tanks were disposed in the hull structure to enable a greater supply of fuel to be carried1 a new and improved type of outer cover was fitted1 and by ,may #bith1 ,r #cd was completed to the satisfaction of the ,admiralty and was accepted4 ,on the evening of the same day she left for her station1 ,east ,fortune1 on the ,firth of ,forth4 ,this short passage from the ,clyde to the ,forth was not devoid of incident1 as soon after leaving the ground a low-lying fog enveloped the whole country and it was found impossible to land with any degree of safety4 ,it having been resolved not to land until the fog lifted1 the airship cruised about the north-east coast of ,england and even came as far south as ,york4 ,returning to ,scotland1 she found the fog had cleared1 and was landed safely1 having been in the air for #ba hours4 ,the original intention was that the ,atlantic flight should be made at the beginning of ,june1 but the apparent unwillingness of the ,germans to sign the ,peace ,treaty caused the ,admiralty to retain the ship for a time and commission her on a war footing4 ,during this period she went for an extended cruise over ,denmark1 along the north coast of ,germany and over the ,baltic4 ,this flight was accomplished in #ef hours1 during which extremely bad weather conditions were experienced at times4 ,on its conclusion captain and crew of the ship expressed their opinion that the crossing of the ,atlantic was with ordinary luck a moral certainty4 ,peace having been signed1 the ship was overhauled once more and made ready for the flight1 and the day selected some three weeks before was ,july #bnd4 ,a selected party of air-service ratings1 together with two officers1 were sent over to ,america to make all the necessary arrangements1 and the ,american authorities afforded every conceivable facility to render the flight successful4 ,as there is no shed in ,america capable of housing a big rigid1 there was no alternative but to moor her out in the open1 replenish supplies of gas and fuel and make the return journey as quickly as possible4 ,on ,july #bnd1 at #b4ch a4m4 7,british summer time71 ,r #cd left the ground at ,east ,fortune1 carrying a total number of #cj persons4 ,the route followed was a somewhat northerly one1 the north coast of ,ireland being skirted and a more or less direct course was kept to ,newfoundland4 ,from thence the south-east coast of ,nova ,scotia was followed and the mainland was picked up near ,cape ,cod4 ,from ,cape ,cod the airship proceeded to ,mineola1 the landing place on ,long ,island4 ,all went well until ,newfoundland was reached4 ,over this island fog was encountered1 and later electrical storms became a disturbing element when over ,nova ,scotia and the ,bay of ,fundy4 ,the course had to be altered to avoid these storms1 and owing to this the petrol began to run short4 ,no anxiety was occasioned until on ,saturday1 ,july #eth1 a wireless signal was sent at #c4ei p4m4 asking for assistance1 and destroyers were dispatched immediately to the scene4 ,later messages were received indicating that the position was very acute1 as head winds were being encountered and petrol was running short4 ,the airship1 however1 struggled on1 and though at one time the possibility of landing at ,montauk1 at the northern end of ,long ,island1 was considered1 she managed after a night of considerable anxiety to reach ,mineola and land there in safety on ,july #fth at #i4ee a4m4 7,british summer time74 ,the total duration of the outward voyage was #ajh hours #ab minutes1 and during this time some #c1acf sea miles were covered4 ,r #cd remained at ,mineola until midnight of ,july #ith according to ,american time4 ,during the four days in which she was moored out variable weather was experienced1 and in a gale of wind the mooring point was torn out1 but fortunately1 another trail rope was dropped and made fast1 and the airship did not break away4 ,it was intended that the return should be delayed until daylight1 in order that spectators in ,new ,york should obtain a good view of the airship1 but an approaching storm was reported and the preparations were advanced for her immediate departure4 ,during the last half-hour great difficulty was experienced in holding the ship while gassing was completed4 ,at #e4eg a4m4 7,british summer time7 ,r #cd set out on her return voyage1 steering for ,new ,york1 to fly over the city before heading out into the ,atlantic4 ,she was picked up by the searchlights and was distinctly visible to an enormous concourse of spectators4 ,during the early part of the flight a strong following wind was of great assistance1 and for a short period an air speed of #hc miles per hour was attained4 ,on the morning of ,july #aath the foremost of the two engines in the after car broke down and was found to be beyond repair4 ,the remainder of the voyage was accomplished without further incident4 ,on ,july #abth at noon1 a signal was sent telling ,r #cd to proceed to the airship station at ,pulham in ,norfolk as the weather was unfavourable for landing in ,scotland4 ,on the same day at #h4be p4m41 land was first sighted and the coast line was crossed near ,clifden1 county ,galway1 at #i p4m4 ,on the following morning1 ,july #acth1 at #g4eg a4m4 7,british summer time71 the long voyage was completed and ,r #cd was safely housed in the shed1 having been in the air #ge hours #c minutes4 ,thus a most remarkable undertaking was brought to a successful conclusion4 ,the weather experienced was by no means abnormally good4 ,this was not an opportunity waited for for weeks and then hurriedly snatched1 but on the preordained date the flight was commenced4 ,the airship enthusiast had always declared that the crossing of the ,atlantic presented no insuperable difficulty1 and when the moment arrived the sceptics found that he was correct4 ,we may therefore assume that this flight is a very important landmark in the history of aerial transport1 and has demonstrated that the airship is to be the medium for long-distance travel4 ,we may rest assured that such flights1 although creating universal wonder to-day1 will of a surety be accepted as everyday occurrences before the world is many years older4 ,,chapter ,,viii ,,the ,,work ,,of ,,the ,,airship ,,in ,,the ,,world ,,war ,the outbreak of war found us1 as we have seen1 practically without airships of any military value4 ,for this unfortunate circumstance there were many contributory causes4 ,the development of aeronautics generally in this country was behind that of the ,continent1 and the airship had suffered to a greater extent than either the seaplane or the aeroplane4 ,our attitude in fact towards the air had not altered so very greatly from that of the man who remarked1 on reading in his paper that some pioneer of aviation had met with destruction1 ,if we had been meant to fly1 ,god would have given us wings4 ,absurd as this sounds nowadays1 it was the opinion of most people in this country1 with the exception of a few enthusiasts1 until only a few years before we were plunged into war4 ,the year #aiji saw the vindication of the enthusiasts1 for in this summer ,bleriot crossed the ,channel in an aeroplane1 and the first passenger-carrying ,zeppelin airship was completed4 ,those who had previously scoffed came to the conclusion that flying was not only possible but an accomplished fact1 and the next two years with their great aerial cross-country circuits revealed the vast potentialities of aircraft in assisting in military operations4 ,we1 therefore1 began to study aeronautics as the science of the future1 and aircraft as an adjunct to the sea and land forces of the empire4 ,the airship1 unfortunately1 suffered for many reasons from the lack of encouragement afforded generally to the development of aeronautics4 ,the airship undoubtedly is expensive1 and one airship of size costs more to build than many aeroplanes4 ,in addition1 everything connected with the airship is a source of considerable outlay4 ,the shed to house an airship is a most costly undertaking1 and takes time and an expenditure of material to erect1 and bears no comparison with the cheap hangar which can be run up in a moment to accommodate the aeroplane4 ,the gas to lift the airship is by no means a cheap commodity4 ,if it is to be made on the station where the airship is based1 it necessitates the provision of an expensive and elaborate plant4 ,if1 on the other hand1 it is to be manufactured at a factory1 the question of transport comes in1 which is a further source of expense with costly hydrogen tubes for its conveyance4 ,another drawback is the large tract of ground required for an aerodrome1 and the big airship needs a large number of highly-trained personnel to handle it4 ,a further point always1 raised when the policy of developing the airship was mooted is its vulnerability4 ,it cannot be denied that it presents a large target to artillery or to the aeroplane attacking it1 and owing to the highly inflammable nature of hydrogen when mixed with air there can be no escape if the gas containers are pierced by incendiary bullets or shells4 ,another contributing factor to the slow development of the airship was the lack of private enterprise4 ,rivalry existed between private firms for aeroplane contracts which consequently produced improvements in design2 airships could not be produced in this way owing to the high initial cost1 and if the resulting ships ended in failure1 as many were bound to do1 there would be no return for a large outlay of capital4 ,the only way by which private firms could be encouraged to embark on airship building was by subsidies from the ,government1 and at this time the prevalent idea of the doubtful value of the airship was too strong for money to be voted for this purpose4 ,to strengthen this argument no demand had either been made from those in command of the ,fleet or from commanders of our ,armies for airships to act as auxiliaries to our forces4 ,the disasters experienced by all early airships and most particularly by the ,zeppelins were always seized upon by those who desired to convince the country what unstable craft they were1 and however safe in the air they might be were always liable to be wrecked when landing in anything but fine weather4 ,those who might have sunk their money in airship building thereupon patted themselves upon the back and rejoiced that they had been so far-seeing as to avoid being engaged upon such a profitless industry4 ,finally1 all in authority were agreed to adopt the policy of letting other countries buy their experience and to profit from it at a later date4 ,had the war been postponed for another twenty years all might have been well1 and we should have reaped the benefit1 but most calamitously for ourselves it arrived when we were utterly unprepared1 and having1 as we repeat1 only three airships of any military value4 ,with these three ships1 ,astra-,torres 7,no4 #c71 ,parseval 7,no4 #d7 and ,beta1 the ,navy did all that was possible4 ,at the very outbreak of war scouting trips were made out into the ,north ,sea beyond the mouth of the ,thames by the ,astra and ,parseval1 and both these ships patrolled the ,channel during the passage of the ,expeditionary ,force4 ,the ,astra was also employed off the ,belgian coast to assist the naval landing party at ,ostend1 and together with the ,parseval assisted in patrolling the ,channel during the first winter of the war4 ,the ,beta was also sent over to ,dunkirk to assist in spotting for artillery fire and locating ,german batteries on the ,belgian coast4 ,our airships were also employed for aerial inspection of ,london and other large towns by night to examine the effects of lighting restrictions and obtain information for our anti-aircraft batteries4 ,with the single exception of the ,s4,s4 ship1 which carried out certain manoeuvres in ,france in the summer of #aiaf1 our airships were confined to operations over the sea2 but if we had possessed ships of greater reliability in the early days of the war1 it is conceivable that they would have been of value for certain purposes to the ,army4 ,the ,germans employed their ,zeppelins at the bombardment of ,antwerp1 ,warsaw1 ,nancy and ,libau1 and their raids on ,england are too well remembered to need description4 ,the ,french also used airships for the observation of troops mobilizing and for the destruction of railway depots4 ,the ,italians relied entirely at the beginning of the war on airships1 constructed to fly at great heights1 for the bombing of ,austrian troops and territory1 and met with a considerable measure of success4 ,when it was decided1 early in #aiae1 to develop the airship for anti-submarine work difficulties which appeared almost insuperable were encountered at first4 ,to begin with1 there were practically no firms in the country capable of airship production4 ,the construction of envelopes was a great problem2 as rubber-proofed fabric had been found by experiment to yield the best results for the holding of gas1 various waterproofing firms were invited to make envelopes1 and by whole-hearted efforts and untiring industry they at last provided very excellent samples4 ,fins1 rudder planes1 and cars were also entrusted to firms which had had no previous experience of this class of work1 and it is rather curious to reflect that envelopes were produced by the makers of mackintoshes and that cars and planes were constructed by a shop-window furnisher4 ,this was a sure sign that all classes of the community were pulling together for the good of the common cause4 ,among other difficulties was the shortage of hydrogen tubes1 plants1 and the silicol for making gas4 ,sufficient sheds and aerodromes were also lacking1 and the airships themselves were completed more quickly than the sheds which were to house them4 ,the lack of airship personnel to meet the expansion of the service presented a further obstacle4 ,to overcome this the system of direct entry into the ,r4,n4,a4,s4 was instituted1 which enabled pilots to be enrolled from civil life in addition to the midshipmen who were drafted from the ,fleet4 ,the majority of the ratings were recruited from civil life and given instruction in rigging and aero-engines as quickly as possible1 while technical officers were nearly all civilians and granted commissions in the ,r4,n4,v4,r4 ,a tremendous drawback was the absence of rigid airships and the lack of duralumin with which to construct them4 ,few men were also experienced in airship work at this time1 and there was no central airship training establishment as was afterwards instituted4 ,pilots were instructed as occasion permitted at the various patrol stations1 having passed a balloon course and undergone a rudimentary training at various places4 ,to conclude1 the greatest of all difficulties was the shortage of money voted for airship development1 and this was a disadvantage under which airships laboured even until the conclusion of hostilities4 ,we have seen previously how the other difficulties were surmounted and how our airships were evolved1 type by type1 and the measure of success which attended them4 ,it is interesting to recall that five years ago we only possessed three ships capable of flying1 and that during the war we built upwards of two hundred1 of which no fewer than #ajc were actually in commission on the date of the signing of the ,armistice4 ,the work carried out by our airships during the war falls under three main headings3 #a4 ,operations with the fleet or with various units4 #b4 ,anti-submarine patrol and searching for mines4 #c4 ,escort of shipping and examination duties4 ,with regard to the first heading it is only permissible at present to say very little2 certain manoeuvres were carried out in connection with the fleet1 but the slow development of our rigid airships prohibited anything on a large scale being attempted4 ,the ,germans1 on the other hand1 made the fullest use of their ,zeppelins for scouting purposes with the high seas fleet4 ,responsible people were guilty of a grave mistake when speaking in public in denouncing the ,zeppelin as a useless monster every time one was destroyed in a raid on this country4 ,the main function of the ,zeppelin airship was to act as an aerial scout1 and it carried out these duties with the utmost efficiency during the war4 ,it is acknowledged that the ,german fleet owed its escape after the ,battle of ,jutland to the information received from their airships1 while again the ,zeppelin was instrumental in effecting the escape of the flotilla which bombarded ,scarborough in #aiaf4 ,very probably1 also1 the large airship was responsible for the success which attended the ,u boats during their attack on the cruisers ,nottingham and ,falmouth1 and also at the ,hogue disaster4 ,various experiments were carried out in towing airships by cruisers1 in refuelling while in tow and changing crews1 all of which would have borne good fruit had the war lasted longer4 ,an exceedingly interesting experiment was carried out during the closing stages of the war by an airship of the ,s4,s4 ,zero type4 ,at this period the ,german submarines were gradually extending their operations at a greater distance from our coasts1 and the authorities became concerned at the prospect that the small type of airship would not possess sufficient endurance to carry out patrol over these increased distances4 ,the possibility was considered of carrying a small airship on board a ship which should carry out patrol and return to the ship for refuelling purposes1 to replenish gas1 and change her crew4 ,to test the feasibility of this idea ,s4,s4 ,z #eg carried out landing experiments on the deck of ,h4,m4,s4 ,furious1 which had been adapted as an aeroplane carrier4 ,s4,s4 ,z #eg came over the deck and dropped her trail rope1 which was passed through a block secured to the deck1 and was hauled down without difficulty4 ,these experiments were continued while the ship was under weigh and were highly successful4 ,no great difficulty was encountered in making fast the trail rope1 and the airship proved quite easy to handle4 ,the car was also lowered into the hangar below the upper deck1 the envelope only remaining on the upper level1 and everything worked smoothly4 ,if the war had continued there is no doubt that some attempt would have been made to test the practical efficiency of the problem4 ,anti-submarine patrol was the chief work of the airship during the war1 and1 like everything else1 underwent most striking changes4 ,submarine hunting probably had more clever brains concentrated upon it than anything else in the war1 and the part allotted to the airship in conjunction with the hunting flotillas of surface craft was carefully thought out4 ,in the case of a suspected submarine in a certain spot1 all surface and air craft were concentrated by means of wireless signals at the appointed rendezvous4 ,it is in operations of this kind that the airship is so superior to the seaplane or aeroplane1 as she can hover over a fixed point for an indefinite period with engines shut off4 ,if the submarine was located from the air1 signals were given and depth charges dropped in the position pointed out4 ,incidents of this kind were of frequent occurrence1 and in them the value of the airship was fully recognized4 ,the most monotonous and arduous of the airship's duties was the routine patrol4 ,the ship would leave her shed before dawn and be at the appointed place many miles away from land4 ,she then would carry out patrol1 closely scanning the sea all round1 and investigating any suspicious object4 ,for hours this might last with nothing seen1 and then in the gathering darkness the ship would make her way home often against a rising wind1 and in the winter through hail and snow4 ,bombs were always carried1 and on many occasions direct hits were observed on enemy submarines4 ,a sharp look-out was always kept for mines1 and many were destroyed1 either by gunfire from the airship herself or through the agency of patrol boats in the vicinity4 ,this was the chief work of the ,s4,s4 ships1 and was brought to a high pitch of perfection by the ,s4,s4 ,zero4 ,these ships proved so handy that they could circle round an object without ever losing sight of it1 and yet could be taken in and out of sheds in weather too bad to handle bigger ships4 ,the hunting of the submarine has been likened to big-game hunting1 and certainly no one ever set out to destroy a bigger quarry4 ,it needs the same amount of patience and the same vigilance4 ,days may pass without the opportunity1 and that will only be a fleeting one3 the psychological moment must be seized and it will not brook a moment's delay4 ,the eye must be trained to pick up the minutest detail1 and must be capable of doing this for hour after hour4 ,for those on submarine patrol in a small ship there is not one second's rest4 ,as is well known1 the submarine campaign reached its climax in ,april1 #aiag4 ,in that month ,british and ,allied shipping sustained its greatest losses4 ,the value of the airship in combating this menace was now fully recognized1 and with the big building programme of ,zero airships approved1 the housing accommodation again reached an acute stage4 ,shortage of steel and timber for shed building1 and the lack of labour to erect these materials had they been available1 rendered other methods necessary4 ,it was resolved to try the experiment of mooring airships in clearings cut into belts of trees or small woods4 ,a suitable site was selected and the trees were felled by service labour4 ,the ships were then taken into the gaps thus formed and were moored by steel wires to the adjacent trees4 ,screens of brushwood were then built up between the trees1 and the whole scheme proved so successful that even in winter1 when the trees were stripped of their foliage1 airships rode out gales of over #fj miles per hour4 ,the personnel were housed either in tents or billeted in cottages or houses in the neighbourhood1 and gas was supplied in tubes as in the earlier days of the stations before the gas plants had been erected4 ,this method having succeeded beyond the most sanguine expectations1 every station had one or more of these sub-stations based on it1 the airships allocated to them making a periodical visit to the parent station for overhaul as required4 ,engineering repairs were effected by workshop lorries1 provided that extensive work was not required4 ,in this way a large fleet of small airships was maintained around our coasts1 leaving the bigger types of ships on the parent stations1 and the operations were enabled to be considerably extended4 ,of course1 certain ships were wrecked when gales of unprecedented violence sprung up2 but the output of envelopes1 planes and cars was by this time so good that a ship could be replaced at a few hours' notice1 and the cost compared with building of additional sheds was so small as to be negligible4 ,from the month of ,april1 #aiag1 the convoy system was introduced1 by which all ships on entering the danger zones were collected at an appointed rendezvous and escorted by destroyers and patrolboats4 ,the airship was singularly suitable to assist in these duties4 ,owing to her power of reducing her speed to whatever was required1 she could keep her station ahead or abeam of the convoy as was necessary1 and from her altitude was able to exercise an outlook for a far greater distance than was possible from the bridge of a destroyer4 ,she could also sweep the surface ahead of the approaching convoy1 and warn it by wireless or by flash-lamp of the presence of submarines or mines4 ,by these timely warnings many vessels were saved4 ,owing to the position of the stations it was possible for a convoy to be met by airships west of the ,scilly ,isles and escorted by the airships of the succeeding stations right up the ,channel4 ,in a similar manner1 the main shipping routes on the east coast and also in the ,irish ,sea were under constant observation4 ,the mail steamers between ,england and ,ireland and transports between ,england and ,france were always escorted whenever flying conditions were possible4 ,for escort duties involving long hours of flying1 the ,coastal and ,c ,star types were peculiarly suitable1 and at a later date the ,north ,sea1 which could accompany a convoy for the length of ,scotland4 ,airships have often proved of value in summoning help to torpedoed vessels1 and on occasions survivors in open boats have been rescued through the agency of patrolling airships4 ,examination duties are reckoned among the many obligations of the airship4 ,suspicious-looking vessels were always carefully scrutinized1 and if unable to give a satisfactory answer to signals made1 were reported to vessels of the auxiliary patrol for closer examination4 ,isolated fishing vessels always were kept under close observation1 for one of the many ruses of the submarine was to adopt the disguise of a harmless fishing boat with masts and sails4 ,the large transports1 conveying ,american troops who passed through ,england on their way to ,france1 were always provided with escorting airships whenever possible1 and their officers have extolled their merits in most laudatory terms4 ,our rigid airships also contributed their share in convoy work1 although their appearance as active units was delayed owing to slowness in construction4 ,a disturbing feature to the advocate of the large airship1 has been the destruction of raiding ,zeppelins by heavier-than-air machines1 and the ,jeremiahs have not lost this opportunity of declaring that for war purposes the huge rigid is now useless and will always be at the complete mercy of the fast scouting aeroplane4 ,there is never any obstacle in this world that cannot be surmounted by some means or other4 ,on the one hand there is helium1 a non-inflammable gas which would render airships almost immune to such attacks4 ,on the other hand1 one opinion of thought is that the rigid airship in the future will proceed to sea escorted by a squadron of scouting aeroplanes for its defence1 in the same way that the capital ship is escorted at sea by destroyers and torpedo boats4 ,this latter idea has been even further developed by those who look into the future1 and have conceived the possibility of a gigantic airship carrying its own aeroplanes for its protection4 ,to test the possibility of this innovation1 a small aeroplane was attached to one of our rigid airships beneath the keel4 ,attachments were made to the top of the wings and were carried to the main framework of the hull4 ,the release gear was tested on the ground to preclude the possibility of any accident1 and on the day appointed the airship was got ready for flight4 ,while the airship was flying1 the pilot of the aeroplane was in his position with his engine just ticking over4 ,the bows of the airship were then inclined upwards and the release gear was put into operation4 ,the pilot afterwards said that he had no notion that anything had been done until he noticed that the airship was some considerable height above him4 ,the machine made a circuit of the aerodrome and landed in perfect safety1 while no trouble was experienced in any way in the airship4 ,whether this satisfactory experiment will have any practical outcome the future alone can say1 but this achievement would have been considered1 beyond all the possibilities of attainment only a few years ago4 ,since the ,armistice several notable endurance flights were accomplished by ships of the ,north ,sea class1 several voyages being made to the coast of ,norway1 and quite recently a trip was carried out all round the ,north ,sea4 ,the weather has ceased to be the deterrent of the early days4 ,many will no doubt remember seeing the ,north ,sea airship over ,london on a day of squalls and snow showers1 and ,r #cd encountered heavy snow storms on the occasion of one of her flight trials1 which goes to prove that the airship is scarcely the fair-weather aircraft as maintained by her opponents4 ,throughout the war our airships flew for approximately #hi1jjj hours and covered a distance of upwards of two and a quarter million miles4 ,the ,germans attempted to win the war by the wholesale sinking of our merchant shipping1 bringing supplies and food to these islands1 and by torpedoing our transports and ships carrying guns and munitions of war4 ,they were1 perhaps1 nearer to success than we thought at the time1 but we were saved by the defeat of the submarine4 ,in the victory won over the underseas craft the airship certainly played a prominent part and we1 who never suffered the pinch of hunger1 should gratefully remember those who never lost heart1 but in spite of all difficulties and discouragement1 designed1 built1 maintained and flew our fleet of airships4 ,,chapter ,,ix ,,the ,,future ,,of ,,airships ,with the signing of the ,armistice on ,november #aath1 #aiah1 the airship's work in the war was practically completed and peace reigned on the stations which for so many months had been centres of feverish activity4 ,the enemy submarines were withdrawn from our shipping routes and merchant ships could traverse the sea in safety except for the occasional danger of drifting mines4 ,what is to be the future of the airship8 is the question which is agitating the minds of innumerable people at the present moment4 ,during the war we have built the largest fleet of airships in the world1 in non-rigids we have reached a stage in design which is unsurpassed by any country1 and in rigid airships we are second only to the ,germans1 who have declared that1 with the signing of the peace terms1 their aircraft industry will be destroyed4 ,such is our position at the present moment1 a position almost incredible if we look back to the closing days of the year #aiad4 ,are we now to allow ourselves to drift gradually back to our old policy of supineness and negligence as existed before the war8 ,surely such a thought is inconceivable2 as we have organized our airship production for the purposes of war1 so shall we have to redouble our efforts for its development in peace1 if we intend to maintain our supremacy in the air4 ,unless all war is from henceforth to cease1 a most improbable supposition when the violence of human nature is considered1 aircraft will be in the future almost the most important arm4 ,owing to its speed1 there will not be that period of waiting for the concentration and marching of the armies of the past1 but the nation resolved on war will be able to strike its blow1 and that a very powerful and terrible one1 within a few hours of the rupture of negotiations4 ,every nation to be prepared to counter such a blow must be possessed of adequate resources1 and unless the enormous expense is incurred of maintaining in peace a huge establishment of aircraft and personnel1 other methods must be adopted of possessing both of these available for war while employed in peace for other purposes4 ,from the war two new methods of transportation have emerged--the aeroplane and the airship4 ,to the business man neither of these is at the present juncture likely to commend itself on the basis of cost per ton mile4 ,when1 however1 it is considered that the aeroplane is faster than the express train and the airship's speed is double that of the fastest merchant ship1 it will be appreciated that for certain commercial purposes both these mediums for transport have their possibilities4 ,the future may prove that in the time to come both the airship and the aeroplane will become self-supporting1 but for the present1 if assisted by the ,government1 a fair return may be given for the capital laid out1 and a large fleet of aircraft together with the necessary personnel will always be available for military purposes should the emergency arise4 ,the present war has shown that the merchant service provided a valuable addition both of highly-trained personnel and of vessels readily adapted for war purposes1 and it appears that a similar organization can be effected to reinforce our aerial navies in future times of danger4 ,in discussions relative to the commercial possibilities of aircraft1 a heated controversy always rages between advocates of the airship and those of the heavier-than-air machine1 but into this it is not proposed to plunge the reader of this volume4 ,the aeroplane is eminently adapted for certain purposes1 and the greatest bigot in favour of the airship can hardly dispute the claims of this machine to remain predominant for short-distance travel1 where high speed is essential and the load to be carried is light4 ,for long distance voyages over the oceans or broken or unpopulated country1 where large loads are to be carried1 the airship should be found to be the more suitable4 ,the demand for airships for commercial purposes falls under three main headings1 which will be considered in some detail4 ,it will be shown to what extent the present types will fill this demand1 and how they can be developed in the future to render the proposed undertakings successful4 #a4 ,pleasure4 #b4 ,a quick and safe means of transport for passengers4 #c4 ,a quick commercial service for delivering goods of reasonable weight from one country to another4 #a4 ,pleasure4--,in the past1 men have kept mechanically-driven means of transport such as yachts1 motor cars1 and motor boats for their amusement1 and to a limited extent have taken recreation in the air by means of balloons4 ,for short cruises about this country and round the coast a small airship1 somewhat similar to the ,s4,s4 ,zero1 would be an ideal craft4 ,in cost it would be considerably less than a small yacht1 and as it would only be required in the summer months1 it would be inflated and moored out in the open in a park or grounds and the expense of providing a shed need not be incurred4 ,for longer distances1 a ship of #aej1jjj cubic feet capacity1 with a covered-in car and driven by two engines1 would have an endurance of #be hours at a cruising speed of #de miles per hour4 ,with such a ship voyages could easily be made from the south coast to the ,riviera or ,spain1 and mooring out would still be possible under the lee of a small wood or to a buoy on the water4 ,possibilities also exist for an enterprising firm to start a series of short pleasure trips at various fashionable seaside resorts1 and until the novelty had worn off the demand for such excursions will probably be far in excess of the supply4 #b4 ,passenger transport4--,in the re-organization of the world after this devastating war the business man's time will be of even more value than it was before4 ,this country is largely bound up with the ,united ,states of ,america in business interests which necessitate continual visits between the two countries4 ,the time occupied by steamer in completing this journey is at present about five days4 ,if this time can be cut down to two and a half days1 no doubt a large number of passengers will be only too anxious to avail themselves of this means of travel1 providing that it will be accomplished in reasonable safety and comfort4 ,the requirements for this purpose are an aerial liner capable of carrying a hundred passengers with a certain quantity of luggage and sufficient provisions for a voyage which may be extended over the specified time owing to weather conditions4 ,the transatlantic service if successful could then be extended until regular passenger routes are established encircling the globe4 #c4 ,quick commercial service for certain types of goods4--,certain mails and parcels are largely enhanced in value by the rapidity of transport1 and here1 as in the passenger service outlined above1 the airship offers undoubted facilities4 ,as we have said before1 it is mainly over long distances that the airship will score1 and for long distances on the amount carried the success of the enterprise will be secured4 ,for this purpose the rigid airship will be essential4 ,there are certain instances in which the non-rigid may possibly be profitably utilized1 and one such is suggested by a mail service between this country and ,scandinavia4 ,a service is feasible between ,newcastle and ,norway by airships of a capacity of the ,s4,s4 ,twin type4 ,these ships would carry #gjj lb4 of mails each trip at about #d;d4 per ounce1 which would reduce the time of delivering letters from about two and a half to three days to twenty-four hours4 ,a commercial airship company is regarded in this country as a new and highly hazardous undertaking1 and it seems to be somewhat overlooked that it is not quite the novel idea so many people imagine4 ,before the war1 in the years #aiaj to #aiad1 the ,deutsche ,luftfahrt ,actien ,gesellschaft successfully ran a commercial ,zeppelin service in which four airships were used1 namely1 ,schwaben1 ,victoria ,luise1 ,hansa and ,sachsan4 ,during this period over #ag1jjj passengers were carried a total distance of over #ajj1jjj miles without incurring a single fatal accident4 ,numerous ,english people made trips in these airships1 including ,viscount ,jellicoe1 but the success of the company has apparently been forgotten4 ,we have endeavoured to show that the non-rigid airship has potentialities even for commercial purposes1 but there is no doubt whatever that the future of the airship in the commercial world rests entirely with the rigid type1 and the airships of this type moreover must be of infinitely greater capacity than those at present in existence1 if a return is to be expected for the capital invested in them4 ,general ,sykes stated1 in the paper which he read before the ,london ,chamber of ,commerce1 that for commercial purposes the airship is eminently adapted for long-distance journeys involving non-stop flights4 ,it has this inherent advantage over the aeroplane1 that while there appears to be a limit to the range of the aeroplane as at present constructed1 there is practically no limit whatever to that of the airship1 as this can be overcome by merely increasing the size4 ,it thus appears that for such journeys as crossing the ,atlantic1 or crossing the ,pacific from the west coast of ,america to ,australia or ,japan1 the airship will be peculiarly suitable4 ,he also remarked that1 it having been conceded that the scope of the airship is long-distance travel1 the only type which need be considered for this purpose is the rigid4 ,the rigid airship is still in an embryonic state1 but sufficient has already been accomplished in this country1 and more particularly in ,germany1 to show that with increased capacity there is no reason why1 within a few years' time1 airships should not be built capable of completing the circuit of the globe and of conveying sufficient passengers and merchandise to render such an undertaking a paying proposition4 ,the report of the ,civil ,aerial ,transport ,committee also states that1 airships are the most suitable aircraft for the carrying of passengers where safety1 comfort and reliability are essential4 ,when we consider the rapid development of the rigid airship since #aiad1 it should not be insuperable to construct an airship with the capabilities suggested by ,general ,sykes4 ,in #aiad1 the average endurance of the ,zeppelin at cruising speed was under one day and the maximum full speed about #ej miles per hour4 ,in #aiah1 the ,german ,l #gj1 which is of #b1aie1jjj cubic feet capacity1 the endurance at #de miles per hour has risen to #g4d days and the maximum full speed to #gg miles per hour4 ,the ceiling has correspondingly increased from #f1jjj feet to #bc1jjj feet4 ,the ,british ,r #ch class1 at present building1 with a capacity of approximately #b #c_/d million cubic feet has an estimated endurance at #de miles per hour of #baa hours or #h4h days1 which is #cd hours greater than the ,german ,l #gj class4 ,it is evident that for a ship of this calibre the crossing of the ,atlantic will possess no difficulty1 and as an instance of what has already been accomplished in the way of a long-distance flight the exploit of a ,zeppelin airship based in ,bulgaria during the war is sufficiently remarkable4 ,this airship in the autumn of #aiag left the station at ,jamboli to carry twelve tons of ammunition for the relief of a force operating in ,german ,east ,africa4 ,having crossed the ,mediterranean1 she proceeded up the course of the ,nile until she had reached the upper waters of this river4 ,information was then received by wireless of the surrender of the force1 and that its commander1 ,von ,lettow1 was a fugitive in the bush4 ,she thereupon set out for home and reached her station in safety1 having been in the air #if hours1 or four days1 without landing4 ,it is therefore patent that in ,r #cc and ,r #cd we possess two airships which can cross to ,america to-morrow as far as actual distance is concerned1 but various other conditions are necessary before such voyages can be undertaken with any prospects of commercial success4 ,the distance between ,england and ,america must be roughly taken as #c1jjj miles4 ,it is not reasonable for airship stations to be situated either in the inaccessible extreme west of ,ireland or among the prevailing fogs of ,newfoundland4 ,weather conditions must also be taken into account2 head winds may prevail1 rendering the forward speed of the ship to be small even with the engines running full out4 ,in calculations it is considered that the following assumptions should be made3 #a4 ,at least #ge per cent additional petrol to be carried as would be necessary for the passage in calm air1 should unfavourable weather conditions be met4 ,this amount could be reduced to #ej per cent in future airships with a speed of upwards of #hj miles per hour4 #b4 ,about a quarter of the total discharge able lift of the ship should be in the form of merchandise or passengers to render the project a reasonable commercial proposition4 ,we will consider the commercial loads that can be carried by the ,german airship ,l #gj and our airships ,r #cc and ,r #ch under the conditions given above4 ,two speeds will be taken for the purposes of this comparison3 normal full speed1 or about #fj miles per hour1 and cruising speed of #de miles per hour4 ,l #gj4--;,at #fj miles per hour a distance of #c1jjj miles will be accomplished in #ej hours4 ,fuel consumption about #ac tons #i4ge tons 7additional for safety7 #bb4ge tons4 ,available lift for fuel and freight #bg4h tons4 ,fuel carried #bb4ge ------------ ,balance for freight #e about4 ----------- ,at #de miles per hour1 distance will be accomplished in #ff4f hours4 ,fuel consumption about #aj tons #g4e tons additional #ag4e tons4 ,available lift #bg4h tons ,fuel carried #ag4e ------------ ,balance for freight #aj about4 ------------ ,r4 #cc4--;,at #fj miles per hour4 ,fuel consumption #ad4be tons #aj4fh tons additional #bd4ic tons4 ,lift available for fuel and freight #ba4e tons4 ,fuel carried #bd4ic ------------ ,minus balance #c4 #dc ------------ ,at #de miles per hour4 ,fuel consumption #i4ff tons #g4bc tons 7#ag tons approx47 ,lift available for fuel and freight #ba4e tons4 ,fuel carried #ag ------------ ,balance for freight #d4e ------------ ,r4 #ch4-;,estimated only4 ,at #fj miles per hour4 ,fuel consumption #bj tons #ae tons additional #ce tons4 ,lift available for fuel and freight #db tons4 ,fuel carried #ce ------------ ,balance for freight #g ------------ ,at #de miles per hour4 ,fuel consumption #ab tons #i tons additional #ba tons4 ,lift available for fuel and freight #db ,fuel carried #ba ------------ ,balance for freight #ba ------------ ,it will thus be seen that at the faster speed small commercial loads can be carried by ,l #gj and ,r #ch and not at all in the case of ,r #cc1 that is assuming1 of course1 that the extra fuel is carried1 of which #ge per cent of the total does not appear at all excessive in view of the weather continually experienced over the ,atlantic4 ,at the cruising speed the loads naturally increase but still1 in ,l #gj1 and more particularly in ,r #cc1 they are too small to be considered commercially4 ,in ,r #ch1 however1 the load that can be carried at cruising speed is sufficient to become a commercial proposition4 ,from this short statement it is evident that1 by a comparatively small increase in volume1 the lifting capacity of an airship is enormously increased1 and it is in this subject that the airship possesses such undoubted advantage over the aeroplane4 ,in the heavier-than-air machine there is no automatic improvement in efficiency resulting from greater dimensions4 ,in the airship1 however1 this automatic improvement takes place in a very marked degree2 for example1 an airship of #aj1jjj1jjj cubic feet capacity has five times the lift of the present #b1jjj1jjj cubic feet capacity rigid1 but the length of the former is only #a4g times greater1 and therefore the weight of the structure only five times greater 7#a4g72 that is1 the weight of the structure is directly proportional to the total lift4 ,having seen that the total lift varies as the cube of the linear dimensions while air resistance1 ,b4,h4,p4--other things being equal--vary as the square of the linear dimensions1 it follows that the ratio weight of machinery_/total lift decreases automatically4 ,in comparing the different methods of transport for efficiency1 the resistance or thrust required is compared as a percentage of the total weight4 ,the result obtained is known as the co-efficient of tractive resistance4 ,experiments have shown that as the size of the airship increases1 the co-efficient of tractive resistance decreases to a marked extent2 with a proportionate increase in horse-power it is proportionally more economical for a #aj1jjj1jjj cubic feet capacity rigid to fly at #hj miles per hour than for a #b1jjj1jjj cubic feet capacity to fly at #fj miles per hour4 ,as the ratio weight structure_/total lift is in airships fairly constant1 it follows that the ratio disposable lift_/total lift increases with the dimensions4 ,it is therefore obvious that increased benefits are obtained by building airships of a larger size1 and that the bigger the ship the greater will be its efficiency1 providing1 of course1 that it is kept within such limits that it can be handled on the ground and manoeuvred in the air4 ,the proportion of the useful lift in a large rigid1 that is the lift available for fuel1 crew1 passengers1 and merchandise1 is well over #ej per cent when compared with the gross lift4 ,when the accompanying table is studied it will be seen that with airships of large capacity the available lift will be such that considerable weights of merchandise or passengers can be carried4 ,capacity in ,gross ,lift ,length ,diameter cubic feet in tons in feet in feet #b1jjj1jjj #fj4g #fdc #gi #c1jjj1jjj #ia4a #gcf #ij4d #d1jjj1jjj #aba4d #haj #ii4e #e1jjj1jjj #aea4h #hgb #ajg4b #f1jjj1jjj #ahb4b #ibg #aac4i #g1jjj1jjj #bab4e #igf #aai4i #h1jjj1jjj #bdb4h #a1jba #abe4e #i1jjj1jjj #bgc4c #a1jfa #acj4d #aj1jjj1jjj #cjc4f #a1ajj #ace4a ,in airships of their present capacity1 in order to obtain the greatest amount of lift possible1 lightness of construction has been of paramount importance4 ,with this object in view duralumin has been used1 and complicated girders built up to obtain strength without increase of weight4 ,in a large ship with a considerable gain in lift1 steel will probably be employed with a simpler form of girder work4 ,in that way cheapness of construction will be effected together with increased rapidity of output1 and in addition the strength of the whole structure should be increased4 ,the rigid airship of #aj1jjj1jjj cubic feet capacity will have a disposable lift of over #bjj tons available for fuel1 crew1 passengers1 and merchandise in such proportions as are desired4 ,the endurance of such a ship at a cruising speed of #de miles per hour will be in the neighbourhood of three weeks1 with a maximum speed of #gj to #hj miles per hour1 and a ceiling of some #cj1jjj feet can be reached4 ,this will give a range of over #bj1jjj miles1 or very nearly a complete circuit of the globe4 ,for commercial purposes the possibilities of such a craft are enormous1 and the uses to which it could be put are manifestly of great importance4 ,urgent mails and passengers could be transported from ,england to ,america in under half the time at present taken by the steamship routes1 and any city in the world could be reached from ,london in a fortnight4 ,in the event of war in the future1 which may be waged with a nation situated at a greater distance from this country than was ,germany1 aircraft ,of long endurance will be necessary both for scouting in conjunction with our fleets and convoy duties4 ,the ,british ,empire is widely scattered1 and large tracts of ocean lie between the various colonies1 all of which will require protection for the safe-guarding of our merchant shipping4 ,the provision of a force of these large airships will greatly add to the security of our out-lying dominions4 ,we have now reached a point where it is incumbent on us to face certain difficulties which beset the airship of large dimensions1 and which are always magnified by its detractors4 ,firstly1 there is the expense of sheds in which to house it2 secondly1 the large number of trained personnel to assist in landing and handling it when on the ground2 thirdly1 the risks attendant on the weather--for the airship is still considered the general public as a fair-weather craft2 and fourthly1 though this is principally in connection with its efficiency for military purposes1 its vulnerability4 ,we will deal with the four difficulties enumerated under these headings seriatim1 and endeavour to show to what extent they may be surmounted if not entirely removed4 ,the solution of the first two problems may be summed up in two words3 mooring out2 on the success of this it is considered that the whole future of airships for commercial purposes rests4 ,it will be essential that in every country which the airship visits on its voyages1 one large central station is established for housing and repairs4 ,the position of such a station is dependent on good weather conditions and the best railway facilities possible4 ,in all respects this station will be comparable to a dry dock for surface vessels4 ,the airship will be taken into the shed for overhaul of hull structure1 renewing of gasbags or outer cover1 and in short to undergo a periodical refit4 ,the cost of a shed capable of housing two rigid airships1 even at the present time1 should not greatly exceed ,l#ejj1jjj4 ,this sum1 though considerable1 is but a small item compared with the cost of constructing docks to accommodate the ,atlantic liner1 and when once completed the cost of maintenance is small when weighed against the amount annually expended in dredging and making good the wear and tear of a dock4 ,apart from these occasional visits to a shed1 the airship1 in the ordinary way at the end of a voyage1 will pick up its moorings as does the big steamer1 and land its passengers and cargo1 at the same time replenishing its supplies of fuel1 gas1 provisions1 etc41 while minor repairs to the machinery can be carried out as she rides in the air4 ,a completely satisfactory solution of the mooring problem for the rigid airship has yet to reach its consummation4 ,we saw in the previous chapter how1 in the case of small non-rigids1 they were sheltered in berths cut into woods or belts of trees1 but for the rigid airship something more secure and less at the mercy of the elements is required4 ,at the present moment three systems of mooring are in an experimental stage3 one1 known as the single-wire system1 is now practically acknowledged to fall short of perfection2 the second1 the three-wire system1 and the third1 mooring to a mast1 both have their champions1 but it is probable that the last will be the one finally chosen1 and when thoroughly tried out with its imperfections eliminated will satisfy the most exacting critics4 ,the single-wire system is at the same time the simplest and most obvious method which suggests itself1 and means that the ship is secured by a wire cable attached to a suitable point in the ship and led to some fixed point on the ground4 ,it has been found that an airship secured in this way requires constant attention1 and that steering is always necessary to render her steady in the air4 ,considerable improvement is obtained if a dragging weight is added to the wire1 as it tends to check to a considerable extent lateral motion of the bow of the ship4 ,the three-wire system is an adaptation and an improvement on the one previously mentioned4 ,in this case the mooring point of the ship is attached to three long wire cables1 which1 when raised in the air1 form a pyramid to the head of which the ship is attached4 ,these wires are led to bollards which form in plan an equilateral triangle4 ,the lift of the ship raises these wires off the ground1 and if the ship is trimmed up by the bows she will be found to resist the action of the wind4 ,a rigid airship moored out by this method remained in the open for a considerable time and rendered the future of this experiment most hopeful4 ,it was resolved to continue these experiments by adding a subsidiary system of wires with running blocks1 the whole wiring to form a polygon revolving round a fixed centre4 ,the disadvantages of this method appear to be rather serious4 ,it seems that great difficulty will always be found in picking up these moorings in a high wind1 and though this also applies to the method with the mast1 the initial obstacles do not appear to be so great4 ,a powerful engine driving a winch will be necessary to raise these heavy wires from the ground1 although of course the lift of the airship will assist in this4 ,secondly1 the lowering of passengers and cargo will not be easy as the ship will not be rigidly secured4 ,this1 however1 can probably be managed when experiments have reached a further stage1 and at present the system may be said to present distinct possibilities4 ,the third system1 that of mooring to a mast1 possesses several features peculiar to itself1 and not embraced by the other two1 which should secure it prolonged investigations4 ,the system is by no means new and has been tried from time to time for several years1 but since the question of mooring in the open has been so ventilated and is now considered of such vital importance1 these experiments have been continued1 and in less spasmodic fashion than in the past4 ,in a trial with a small non-rigid airship some months ago a signal success was achieved4 ,the ship remained attached to a mast in open country with no protection whatsoever for six weeks in two of the worst months of the year4 ,during this period two men only were required to look after the ship1 which experienced gales in which the force of the wind rose to #eb miles per hour1 and not the slightest damage was sustained4 ,two or three methods of attaching the airship to the mast have been proposed1 but the one which appears to be most practical is to attach the extreme bow point of the ship to some form of cap1 in which the nose of the ship will fit1 and will revolve round the top of the mast in accordance with the direction of the wind4 ,for large airships1 employed as passenger and commerce carriers1 we can imagine the mast advanced a stage further1 and transformed into a tower with a revolving head4 ,incorporated in this tower will be a lift for passengers and luggage1 pipes also will be led to the summit through which both gas and water can be pumped into the ship4 ,with the airship rigidly held at the head of such a structure all the difficulties of changing crews1 embarking and disembarking passengers1 shipping and discharging cargo and also refuelling1 vanish at once4 ,assuming the mooring problem solved with success1 and we feel correct in this assumption1 the first two of our difficulties automatically disappear4 ,sheds will only be necessary as repair depots and will not be extensively required1 all intermediate stopping places being provided with masts and necessary arrangements for taking in gas1 etc4 ,at these intermediate stations the number of men employed will be comparatively speaking few4 ,at the depots or repair stations the number must1 of course1 be considerably increased1 but the provision of an enormous handling party will not be necessary4 ,at present large numbers of men are only required to take a large airship in or out of a shed when the wind is blowing in a direction across the shed2 when these conditions prevail the airship will1 unless compelled by accident or other unforeseen circumstances1 remain moored out in the open until the direction of the wind has changed4 ,mechanical traction will also help effectually in handling airships on the ground1 and the difficulty of taking them in and out of sheds has always been unduly magnified4 ,the provision of track rails and travellers to which the guys of the ship can be attached1 as is the practice in ,germany1 will tend to eliminate the source of trouble4 ,we must now consider the effect that weather will have on the big airship4 ,in the past it has been a great handicap owing to the short hours of endurance1 with the resulting probability of the ship having to land before the wind dropped and being wrecked in consequence4 ,bad weather will not endanger the big airship in flight1 and its endurance will be such that1 should it encounter bad weather1 it will be able to wait for a lull to land4 ,meteorological forecasts have now reached a high state of efficiency1 and it should be possible for ample warnings to be received of depressions to be met with during a voyage1 and these will be avoided by the airship flying round them4 ,in the northern hemisphere1 depressions generally travel from west to east and invariably rotate in a counter-clockwise direction with the wind on the south side blowing from the west and on the north side blowing from the east4 ,going west1 the airship would fly to the north of a depression to take advantage of the wind circulating round the edge1 and going east the southern course would be taken4 ,lastly1 the vulnerability of the airship must be taken into account4 ,hydrogen is1 as everyone knows1 most highly inflammable when mixed with air4 ,the public still feels uncomfortable misgivings at the close proximity of an immense volume of gas to a number of running engines4 ,it may be said that the danger of disaster due to the gas catching fire is for peace flying to all intents and purposes negligible4 ,at the risk of being thought hackneyed we must point out a fact which has appeared in every discussion of the kind1 namely1 that ,british airships flew during the war some #ba million miles1 and there is only one case of an airship catching fire in the air4 ,this was during a trial flight in a purely experimental ship1 and the cause which was afterwards discovered has been completely eliminated4 ,for airships employed for military purposes this danger1 due to the use of incendiary bullets1 rockets and various other munitions evolved for their destruction1 still exists4 ,owing to its ceiling1 rate of climb and speed1 which we take to be from #gj to #hj miles per hour in the airship of the future1 the airship may be regarded as comparatively safe against attack from the ordinary type of seaplane4 ,the chief danger to be apprehended is attack from small scouting seaplanes1 possessing great speed and the power to climb to a great height1 or from aeroplanes launched from the decks of ships4 ,if1 however1 the airship is fitted to carry several small scout aeroplanes of high efficiency in the manner described in the previous chapter1 it will probably be able to defend itself sufficiently to enable it to climb to a great height and thus make good its escape4 ,the airship1 moreover1 will be more or less immune from such dangers if the non-inflamable gas1 known as ,c gas1 becomes sufficiently cheap to be used for inflating airships4 ,in the past the expense of this gas has rendered its use absolutely prohibitive1 but it is believed that it can be produced in the ,united ,states for such a figure as will make it compare favourably with hydrogen4 ,the navigation of an airship during these long voyages proposed will present no difficulty whatever4 ,the airship1 as opposed to the aeroplane1 is reasonably steady in the air and the ordinary naval instruments can be used4 ,in addition1 directional wireless telegraphy will prove of immense assistance4 ,the method at present in use is to call up simultaneously two land stations which1 knowing their own distance apart1 and reading the direction of the call1 plot a triangle on a chart which fixes the position of the airship4 ,this position is then transmitted by wireless to the airship4 ,in the future the airship itself will carry its own directional apparatus1 with which it will be able to judge the direction of a call received from a single land station and plot its own position on a chart4 ,we have so far confined our attention to the utilization of airships for transport of passengers1 mails and goods1 but there appear to be other fields of activity which can be exploited in times of peace4 ,the photographic work carried out by aeroplanes during the war on the western front and in ,syria and ,mesopotamia has shown the value of aerial photography for map making and preliminary surveys of virgin country4 ,photography of broken country and vast tracks of forest can be much more easily undertaken from an airship than an aeroplane1 on account of its power to hover for prolonged periods over any given area and its greater powers of endurance4 ,for exploring the unmapped regions of the ,amazon or the upper reaches of the ,chinese rivers the airship offers unbounded facilities4 ,another scope suggested by the above is searching for pearl-oyster beds1 sunken treasure1 and assisting in salvage operations4 ,owing to the clearness of the water in tropical regions1 objects can be located at a great depth when viewed from the air1 and it is imagined that an airship will be of great assistance in searching for likely places4 ,sponges and coral are also obtained by diving1 and here the airship's co-operation will be of value4 ,small ships such as the ,s4,s4 ,zero would be ideal craft for these and similar operations4 ,the mine patrol1 as maintained by airships during the war1 encourages the opinion that a systematic search for icebergs in the northern ,atlantic might be carried out by airships during certain months of the year4 ,as is well known1 icebergs are a source of great danger to shipping in these waters during the late spring and summer2 if the situation becomes bad the main shipping routes are altered and a southerly course is taken which adds considerably to the length of the voyage4 ,the proposal put forward is that during these months as continuous a patrol as possible should be carried out over these waters4 ,the airship employed could be based in ,newfoundland and the method of working would be very similar to anti-submarine patrol4 ,fixes could be obtained from ,d4,f4 stations and warnings issued by wireless telegraphy4 ,ice is chiefly found within five hundred miles of the coast of ,newfoundland1 so that this work would come within the scope of the ,n4,s4 airship4 ,the knowledge that reliable information concerning the presence of ice will always be to hand would prove of inestimable value to the captains of ,atlantic liners1 and would also relieve the shipping companies and the public of great anxiety4 ,there are possibly many other uses to which airships can be put such as the policing of wide stretches of desert country as in ,arabia and the ,soudan4 ,the merits of all of these will doubtless be considered in due course and there for the present we must leave them4 ,finally1 a few words must be written regarding the means to be adopted in introducing the airship into the realms of commerce4 ,as we said at the beginning of the chapter it is not likely that the formation of a company to exploit airships only will at the present moment appeal to business men4 ,airships are very costly and are still in their infancy1 which means that the premiums demanded for their insurance must of necessity be enormous4 ,one suggestion is to place a reasonable scheme before the great shipping companies in case they will care to find the necessary capital and form subsidiary companies4 ,another suggestion is that the ,government should make arrangements to subsidize commercial airships4 ,the subsidy might take the form of insuring them4 ,if the burden of insurance is taken off their shoulders1 it is considered feasible to promote companies which will give an adequate return for capital invested4 ,the ,government could also give a financial guarantee if mails are carried1 in the same manner as is done by shipping companies4 ,in return for this the ,government could at the outbreak of hostilities commandeer all or any of the airships for war purposes and so save the number to be kept in commission4 ,by this means the ,government will have a large number of highly-trained and efficient personnel to call upon when the emergency arises1 in the same way as the fleet can call upon the ,r4,n4,r4 ,this system appears to be the best in every respect1 and it cannot be denied that in the long run it would be the most economical for the country4 ,the airship has now arrived at the parting of the ways1 and at this point we must leave it4 ,the flying in war has been concluded1 the flying in peace has not yet commenced4 ,it seems a far cry to the dark days of #aiad1 when we only possessed two airships of utility1 the one manufactured in ,france1 the other in ,germany1 while to-day we have built the mighty airship which can fly to ,america and back4 ,we are now at the dawn of a new period of reconstruction and progress1 and during this period many wonderful things will happen4 ,not the least of these will be the development of the airship4