British Airships: Past, Present and FuturePart 3 out of 3permitted at the various patrol stations, having passed a balloon course and undergone a rudimentary training at various places. To conclude, the greatest of all difficulties was the shortage of money voted for airship development, and this was a disadvantage under which airships laboured even until the conclusion of hostilities. We have seen previously how the other difficulties were surmounted and how our airships were evolved, type by type, and the measure of success which attended them. It is interesting to recall that five years ago we only possessed three ships capable of flying, and that during the war we built upwards of two hundred, of which no fewer than 103 were actually in commission on the date of the signing of the Armistice. The work carried out by our airships during the war falls under three main headings: 1. Operations with the fleet or with various units. 2. Anti-submarine patrol and searching for mines. 3. Escort of shipping and examination duties. With regard to the first heading it is only permissible at present to say very little; certain manoeuvres were carried out in connection with the fleet, but the slow development of our rigid airships prohibited anything on a large scale being attempted. The Germans, on the other hand, made the fullest use of their Zeppelins for scouting purposes with the high seas fleet. 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 country. The main function of the Zeppelin airship was to act as an aerial scout, and it carried out these duties with the utmost efficiency during the war. It is acknowledged that the German fleet owed its escape after the Battle of Jutland to the information received from their airships, while again the Zeppelin was instrumental in effecting the escape of the flotilla which bombarded Scarborough in 1916. Very probably, also, the large airship was responsible for the success which attended the U boats during their attack on the cruisers Nottingham and Falmouth, and also at the Hogue disaster. Various experiments were carried out in towing airships by cruisers, in refuelling while in tow and changing crews, all of which would have borne good fruit had the war lasted longer. An exceedingly interesting experiment was carried out during the closing stages of the war by an airship of the S.S. Zero type. At this period the German submarines were gradually extending their operations at a greater distance from our coasts, 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 distances. 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 purposes, to replenish gas, and change her crew. To test the feasibility of this idea S.S. Z 57 carried out landing experiments on the deck of H.M.S. Furious, which had been adapted as an aeroplane carrier. S.S. Z 57 came over the deck and dropped her trail rope, which was passed through a block secured to the deck, and was hauled down without difficulty. These experiments were continued while the ship was under weigh and were highly successful. No great difficulty was encountered in making fast the trail rope, and the airship proved quite easy to handle. The car was also lowered into the hangar below the upper deck, the envelope only remaining on the upper level, and everything worked smoothly. If the war had continued there is no doubt that some attempt would have been made to test the practical efficiency of the problem. Anti-submarine patrol was the chief work of the airship during the war, and, like everything else, underwent most striking changes. Submarine hunting probably had more clever brains concentrated upon it than anything else in the war, and the part allotted to the airship in conjunction with the hunting flotillas of surface craft was carefully thought out. In the case of a suspected submarine in a certain spot, all surface and air craft were concentrated by means of wireless signals at the appointed rendezvous. It is in operations of this kind that the airship is so superior to the seaplane or aeroplane, as she can hover over a fixed point for an indefinite period with engines shut off. If the submarine was located from the air, signals were given and depth charges dropped in the position pointed out. Incidents of this kind were of frequent occurrence, and in them the value of the airship was fully recognized. The most monotonous and arduous of the airship's duties was the routine patrol. The ship would leave her shed before dawn and be at the appointed place many miles away from land. She then would carry out patrol, closely scanning the sea all round, and investigating any suspicious object. For hours this might last with nothing seen, and then in the gathering darkness the ship would make her way home often against a rising wind, and in the winter through hail and snow. Bombs were always carried, and on many occasions direct hits were observed on enemy submarines. A sharp look-out was always kept for mines, and many were destroyed, either by gunfire from the airship herself or through the agency of patrol boats in the vicinity. This was the chief work of the S.S. ships, and was brought to a high pitch of perfection by the S.S. Zero. These ships proved so handy that they could circle round an object without ever losing sight of it, and yet could be taken in and out of sheds in weather too bad to handle bigger ships. The hunting of the submarine has been likened to big-game hunting, and certainly no one ever set out to destroy a bigger quarry. It needs the same amount of patience and the same vigilance. Days may pass without the opportunity, and that will only be a fleeting one: the psychological moment must be seized and it will not brook a moment's delay. The eye must be trained to pick up the minutest detail, and must be capable of doing this for hour after hour. For those on submarine patrol in a small ship there is not one second's rest. As is well known, the submarine campaign reached its climax in April, 1917. In that month British and Allied shipping sustained its greatest losses. The value of the airship in combating this menace was now fully recognized, and with the big building programme of Zero airships approved, the housing accommodation again reached an acute stage. Shortage of steel and timber for shed building, and the lack of labour to erect these materials had they been available, rendered other methods necessary. It was resolved to try the experiment of mooring airships in clearings cut into belts of trees or small woods. A suitable site was selected and the trees were felled by service labour. The ships were then taken into the gaps thus formed and were moored by steel wires to the adjacent trees. Screens of brushwood were then built up between the trees, and the whole scheme proved so successful that even in winter, when the trees were stripped of their foliage, airships rode out gales of over 60 miles per hour. The personnel were housed either in tents or billeted in cottages or houses in the neighbourhood, and gas was supplied in tubes as in the earlier days of the stations before the gas plants had been erected. This method having succeeded beyond the most sanguine expectations, every station had one or more of these sub-stations based on it, the airships allocated to them making a periodical visit to the parent station for overhaul as required. Engineering repairs were effected by workshop lorries, provided that extensive work was not required. In this way a large fleet of small airships was maintained around our coasts, leaving the bigger types of ships on the parent stations, and the operations were enabled to be considerably extended. Of course, certain ships were wrecked when gales of unprecedented violence sprung up; but the output of envelopes, planes and cars was by this time so good that a ship could be replaced at a few hours' notice, and the cost compared with building of additional sheds was so small as to be negligible. From the month of April, 1917, the convoy system was introduced, by which all ships on entering the danger zones were collected at an appointed rendezvous and escorted by destroyers and patrolboats. The airship was singularly suitable to assist in these duties. Owing to her power of reducing her speed to whatever was required, she could keep her station ahead or abeam of the convoy as was necessary, and from her altitude was able to exercise an outlook for a far greater distance than was possible from the bridge of a destroyer. She could also sweep the surface ahead of the approaching convoy, and warn it by wireless or by flash-lamp of the presence of submarines or mines. By these timely warnings many vessels were saved. 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 Channel. In a similar manner, the main shipping routes on the east coast and also in the Irish Sea were under constant observation. The mail steamers between England and Ireland and transports between England and France were always escorted whenever flying conditions were possible. For escort duties involving long hours of flying, the Coastal and C Star types were peculiarly suitable, and at a later date the North Sea, which could accompany a convoy for the length of Scotland. Airships have often proved of value in summoning help to torpedoed vessels, and on occasions survivors in open boats have been rescued through the agency of patrolling airships. Examination duties are reckoned among the many obligations of the airship. Suspicious-looking vessels were always carefully scrutinized, and if unable to give a satisfactory answer to signals made, were reported to vessels of the auxiliary patrol for closer examination. Isolated fishing vessels always were kept under close observation, for one of the many ruses of the submarine was to adopt the disguise of a harmless fishing boat with masts and sails. The large transports, conveying American troops who passed through England on their way to France, were always provided with escorting airships whenever possible, and their officers have extolled their merits in most laudatory terms. Our rigid airships also contributed their share in convoy work, although their appearance as active units was delayed owing to slowness in construction. A disturbing feature to the advocate of the large airship, has been the destruction of raiding Zeppelins by heavier-than-air machines, 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 aeroplane. There is never any obstacle in this world that cannot be surmounted by some means or other. On the one hand there is helium, a non-inflammable gas which would render airships almost immune to such attacks. On the other hand, 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 defence, in the same way that the capital ship is escorted at sea by destroyers and torpedo boats. This latter idea has been even further developed by those who look into the future, and have conceived the possibility of a gigantic airship carrying its own aeroplanes for its protection. To test the possibility of this innovation, a small aeroplane was attached to one of our rigid airships beneath the keel. Attachments were made to the top of the wings and were carried to the main framework of the hull. The release gear was tested on the ground to preclude the possibility of any accident, and on the day appointed the airship was got ready for flight. While the airship was flying, the pilot of the aeroplane was in his position with his engine just ticking over. The bows of the airship were then inclined upwards and the release gear was put into operation. 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 him. The machine made a circuit of the aerodrome and landed in perfect safety, while no trouble was experienced in any way in the airship. Whether this satisfactory experiment will have any practical outcome the future alone can say, but this achievement would have been considered,beyond all the possibilities of attainment only a few years ago. Since the Armistice several notable endurance flights were accomplished by ships of the North Sea class, several voyages being made to the coast of Norway, and quite recently a trip was carried out all round the North Sea. The weather has ceased to be the deterrent of the early days. Many will no doubt remember seeing the North Sea airship over London on a day of squalls and snow showers, and R 34 encountered heavy snow storms on the occasion of one of her flight trials, which goes to prove that the airship is scarcely the fair-weather aircraft as maintained by her opponents. Throughout the war our airships flew for approximately 89,000 hours and covered a distance of upwards of two and a quarter million miles. The Germans attempted to win the war by the wholesale sinking of our merchant shipping, bringing supplies and food to these islands, and by torpedoing our transports and ships carrying guns and munitions of war. They were, perhaps, nearer to success than we thought at the time, but we were saved by the defeat of the submarine. In the victory won over the underseas craft the airship certainly played a prominent part and we, who never suffered the pinch of hunger, should gratefully remember those who never lost heart, but in spite of all difficulties and discouragement, designed, built, maintained and flew our fleet of airships. CHAPTER IX THE FUTURE OF AIRSHIPS With the signing of the Armistice on November 11th, 1918, 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 activity. 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 mines. "What is to be the future of the airship?" is the question which is agitating the minds of innumerable people at the present moment. During the war we have built the largest fleet of airships in the world, in non-rigids we have reached a stage in design which is unsurpassed by any country, and in rigid airships we are second only to the Germans, who have declared that, with the signing of the peace terms, their aircraft industry will be destroyed. Such is our position at the present moment, a position almost incredible if we look back to the closing days of the year 1914. Are we now to allow ourselves to drift gradually back to our old policy of supineness and negligence as existed before the war? Surely such a thought is inconceivable; as we have organized our airship production for the purposes of war, so shall we have to redouble our efforts for its development in peace, if we intend to maintain our supremacy in the air. Unless all war is from henceforth to cease, a most improbable supposition when the violence of human nature is considered, aircraft will be in the future almost the most important arm. Owing to its speed, there will not be that period of waiting for the concentration and marching of the armies of the past, but the nation resolved on war will be able to strike its blow, and that a very powerful and terrible one, within a few hours of the rupture of negotiations. Every nation to be prepared to counter such a blow must be possessed of adequate resources, and unless the enormous expense is incurred of maintaining in peace a huge establishment of aircraft and personnel, other methods must be adopted of possessing both of these available for war while employed in peace for other purposes. From the war two new methods of transportation have emerged--the aeroplane and the airship. To the business man neither of these is at the present juncture likely to commend itself on the basis of cost per ton mile. When, however, it is considered that the aeroplane is faster than the express train and the airship's speed is double that of the fastest merchant ship, it will be appreciated that for certain commercial purposes both these mediums for transport have their possibilities. The future may prove that in the time to come both the airship and the aeroplane will become self-supporting, but for the present, if assisted by the Government, a fair return may be given for the capital laid out, and a large fleet of aircraft together with the necessary personnel will always be available for military purposes should the emergency arise. 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 purposes, and it appears that a similar organization can be effected to reinforce our aerial navies in future times of danger. In discussions relative to the commercial possibilities of aircraft, a heated controversy always rages between advocates of the airship and those of the heavier-than-air machine, but into this it is not proposed to plunge the reader of this volume. The aeroplane is eminently adapted for certain purposes, and the greatest bigot in favour of the airship can hardly dispute the claims of this machine to remain predominant for short-distance travel, where high speed is essential and the load to be carried is light. For long distance voyages over the oceans or broken or unpopulated country, where large loads are to be carried, the airship should be found to be the more suitable. The demand for airships for commercial purposes falls under three main headings, which will be considered in some detail. It will be shown to what extent the present types will fill this demand, and how they can be developed in the future to render the proposed undertakings successful. 1. Pleasure. 2. A quick and safe means of transport for passengers. 3. A quick commercial service for delivering goods of reasonable weight from one country to another. 1. Pleasure.--In the past, men have kept mechanically-driven means of transport such as yachts, motor cars, and motor boats for their amusement, and to a limited extent have taken recreation in the air by means of balloons. For short cruises about this country and round the coast a small airship, somewhat similar to the S.S. Zero, would be an ideal craft. In cost it would be considerably less than a small yacht, and as it would only be required in the summer months, 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 incurred. For longer distances, a ship of 150,000 cubic feet capacity, with a covered-in car and driven by two engines, would have an endurance of 25 hours at a cruising speed of 45 miles per hour. With such a ship voyages could easily be made from the south coast to the Riviera or Spain, and mooring out would still be possible under the lee of a small wood or to a buoy on the water. Possibilities also exist for an enterprising firm to start a series of short pleasure trips at various fashionable seaside resorts, and until the novelty had worn off the demand for such excursions will probably be far in excess of the supply. 2. Passenger transport.--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 before. This country is largely bound up with the United States of America in business interests which necessitate continual visits between the two countries. The time occupied by steamer in completing this journey is at present about five days. If this time can be cut down to two and a half days, no doubt a large number of passengers will be only too anxious to avail themselves of this means of travel, providing that it will be accomplished in reasonable safety and comfort. 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 conditions. The transatlantic service if successful could then be extended until regular passenger routes are established encircling the globe. 3. Quick commercial service for certain types of goods.-- Certain mails and parcels are largely enhanced in value by the rapidity of transport, and here, as in the passenger service outlined above, the airship offers undoubted facilities. As we have said before, it is mainly over long distances that the airship will score, and for long distances on the amount carried the success of the enterprise will be secured. For this purpose the rigid airship will be essential. There are certain instances in which the non-rigid may possibly be profitably utilized, and one such is suggested by a mail service between this country and Scandinavia. A service is feasible between Newcastle and Norway by airships of a capacity of the S.S. Twin type. These ships would carry 700 lb. of mails each trip at about 4d. per ounce, which would reduce the time of delivering letters from about two and a half to three days to twenty-four hours. A commercial airship company is regarded in this country as a new and highly hazardous undertaking, and it seems to be somewhat overlooked that it is not quite the novel idea so many people imagine. Before the war, in the years 1910 to 1914, the Deutsche Luftfahrt Actien Gesellschaft successfully ran a commercial Zeppelin service in which four airships were used, namely, Schwaben, Victoria Luise, Hansa and Sachsan. During this period over 17,000 passengers were carried a total distance of over 100,000 miles without incurring a single fatal accident. Numerous English people made trips in these airships, including Viscount Jellicoe, but the success of the company has apparently been forgotten. We have endeavoured to show that the non-rigid airship has potentialities even for commercial purposes, but there is no doubt whatever that the future of the airship in the commercial world rests entirely with the rigid type, and the airships of this type moreover must be of infinitely greater capacity than those at present in existence, if a return is to be expected for the capital invested in them. General Sykes stated, in the paper which he read before the London Chamber of Commerce, "that for commercial purposes the airship is eminently adapted for long-distance journeys involving non-stop flights. It has this inherent advantage over the aeroplane, that while there appears to be a limit to the range of the aeroplane as at present constructed, there is practically no limit whatever to that of the airship, as this can be overcome by merely increasing the size. It thus appears that for such journeys as crossing the Atlantic, or crossing the Pacific from the west coast of America to Australia or Japan, the airship will be peculiarly suitable." He also remarked that, "it having been conceded that the scope of the airship is long-distance travel, the only type which need be considered for this purpose is the rigid. The rigid airship is still in an embryonic state, but sufficient has already been accomplished in this country, and more particularly in Germany, to show that with increased capacity there is no reason why, within a few years' time, 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 proposition." The report of the Civil Aerial Transport Committee also states that, "airships are the most suitable aircraft for the carrying of passengers where safety, comfort and reliability are essential." When we consider the rapid development of the rigid airship since 1914, it should not be insuperable to construct an airship with the capabilities suggested by General Sykes. In 1914, the average endurance of the Zeppelin at cruising speed was under one day and the maximum full speed about 50 miles per hour. In 1918, the German L 70, which is of 2,195,000 cubic feet capacity, the endurance at 45 miles per hour has risen to 7.4 days and the maximum full speed to 77 miles per hour. The "ceiling" has correspondingly increased from 6,000 feet to 23,000 feet. The British R 38 class, at present building, with a capacity of approximately 2 3/4 million cubic feet has an estimated endurance at 45 miles per hour of 211 hours or 8.8 days, which is 34 hours greater than the German L 70 class. It is evident that for a ship of this calibre the crossing of the Atlantic will possess no difficulty, 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 remarkable. This airship in the autumn of 1917 left the station at Jamboli to carry twelve tons of ammunition for the relief of a force operating in German East Africa. Having crossed the Mediterranean, she proceeded up the course of the Nile until she had reached the upper waters of this river. Information was then received by wireless of the surrender of the force, and that its commander, Von Lettow, was a fugitive in the bush. She thereupon set out for home and reached her station in safety, having been in the air 96 hours, or four days, without landing. It is therefore patent that in R 33 and R 34 we possess two airships which can cross to America to-morrow as far as actual distance is concerned, but various other conditions are necessary before such voyages can be undertaken with any prospects of commercial success. The distance between England and America must be roughly taken as 3,000 miles. It is not reasonable for airship stations to be situated either in the inaccessible extreme west of Ireland or among the prevailing fogs of Newfoundland. Weather conditions must also be taken into account; head winds may prevail, rendering the forward speed of the ship to be small even with the engines running full out. In calculations it is considered that the following assumptions should be made: 1. At least 75 per cent additional petrol to be carried as would be necessary for the passage in calm air, should unfavourable weather conditions be met. This amount could be reduced to 50 per cent in future airships with a speed of upwards of 80 miles per hour. 2. 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 proposition. We will consider the commercial loads that can be carried by the German airship L 70 and our airships R 33 and R 38 under the conditions given above. Two speeds will be taken for the purposes of this comparison: normal full speed, or about 60 miles per hour, and cruising speed of 45 miles per hour. L 70.--At 60 miles per hour a distance of 3,000 miles will be accomplished in 50 hours. Fuel consumption about 13 tons + 9.75 tons (additional for safety) = 22.75 tons. Available lift for fuel and freight = 27.8 tons. Fuel carried = 22.75 " ------------ Balance for freight = 5 " about. ----------- At 45 miles per hour, distance will be accomplished in 66.6 hours. Fuel consumption about 10 tons + 7.5 tons additional = 17.5 tons. Available lift = 27.8 tons Fuel carried = 17.5 " ------------ Balance for freight = 10 " about. ------------ R. 33.--At 60 miles per hour. Fuel consumption 14.25 tons + 10.68 tons additional = 24.93 tons. Lift available for fuel and freight = 21.5 tons. Fuel carried = 24.93 " ------------ Minus balance = 3. 43 " ------------ At 45 miles per hour. Fuel consumption 9.66 tons + 7.23 tons (17 tons approx.) Lift available for fuel and freight = 21.5 tons. Fuel carried = 17 " ------------ Balance for freight = 4.5 " ------------ R. 38.-Estimated only. At 60 miles per hour. Fuel consumption 20 tons + 15 tons additional = 35 tons. Lift available for fuel and freight = 42 tons. Fuel carried = 35 " ------------ Balance for freight = 7 " ------------ At 45 miles per hour. Fuel consumption 12 tons + 9 tons additional = 21 tons. Lift available for fuel and freight = 42 " Fuel carried = 21 " ------------ Balance for freight = 21 " ------------ It will thus be seen that at the faster speed small commercial loads can be carried by L 70 and R 38 and not at all in the case of R 33, that is assuming, of course, that the extra fuel is carried, of which 75 per cent of the total does not appear at all excessive in view of the weather continually experienced over the Atlantic. At the cruising speed the loads naturally increase but still, in L 70, and more particularly in R 33, they are too small to be considered commercially. In R 38, however, the load that can be carried at cruising speed is sufficient to become a commercial proposition. From this short statement it is evident that, by a comparatively small increase in volume, the lifting capacity of an airship is enormously increased, and it is in this subject that the airship possesses such undoubted advantage over the aeroplane. In the heavier-than-air machine there is no automatic improvement in efficiency resulting from greater dimensions. In the airship, however, this automatic improvement takes place in a very marked degree; for example, an airship of 10,000,000 cubic feet capacity has five times the lift of the present 2,000,000 cubic feet capacity rigid, but the length of the former is only 1.7 times greater, and therefore the weight of the structure only five times greater (1.7); that is, the weight of the structure is directly proportional to the total lift. Having seen that the total lift varies as the cube of the linear dimensions while air resistance, B.H.P.--other things being equal--vary as the square of the linear dimensions,it follows that the ratio "weight of machinery/total lift" decreases automatically. In comparing the different methods of transport for efficiency, the resistance or thrust required is compared as a percentage of the total weight. The result obtained is known as the "co-efficient of tractive resistance." Experiments have shown that as the size of the airship increases, the co-efficient of tractive resistance decreases to a marked extent; with a proportionate increase in horse-power it is proportionally more economical for a 10,000,000 cubic feet capacity rigid to fly at 80 miles per hour than for a 2,000,000 cubic feet capacity to fly at 60 miles per hour. As the ratio "weight structure/total lift" is in airships fairly constant, it follows that the ratio "disposable lift/total lift" increases with the dimensions. It is therefore obvious that increased benefits are obtained by building airships of a larger size, and that the bigger the ship the greater will be its efficiency, providing, of course, that it is kept within such limits that it can be handled on the ground and manoeuvred in the air. The proportion of the useful lift in a large rigid, that is the lift available for fuel, crew, passengers, and merchandise, is well over 50 per cent when compared with the gross lift. 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 carried. Capacity in Gross Lift Length Diameter cubic feet in tons in feet in feet 2,000,000 60.7 643 79 3,000,000 91.1 736 90.4 4,000,000 121.4 810 99.5 5,000,000 151.8 872 107.2 6,000,000 182.2 927 113.9 7,000,000 212.5 976 119.9 8,000,000 242.8 1,021 125.5 9,000,000 273.3 1,061 130.4 10,000,000 303.6 1,100 135.1 In airships of their present capacity, in order to obtain the greatest amount of lift possible, lightness of construction has been of paramount importance. With this object in view duralumin has been used, and complicated girders built up to obtain strength without increase of weight. In a large ship with a considerable gain in lift, steel will probably be employed with a simpler form of girder work. In that way cheapness of construction will be effected together with increased rapidity of output, and in addition the strength of the whole structure should be increased. The rigid airship of 10,000,000 cubic feet capacity will have a disposable lift of over 200 tons available for fuel, crew, passengers, and merchandise in such proportions as are desired. The endurance of such a ship at a cruising speed of 45 miles per hour will be in the neighbourhood of three weeks, with a maximum speed of 70 to 80 miles per hour, and a "ceiling" of some 30,000 feet can be reached. This will give a range of over 20,000 miles, or very nearly a complete circuit of the globe. For commercial purposes the possibilities of such a craft are enormous, and the uses to which it could be put are manifestly of great importance. Urgent mails and passengers could be transported from England to America in under half the time at present taken by the steamship routes, and any city in the world could be reached from London in a fortnight. In the event of war in the future, which may be waged with a nation situated at a greater distance from this country than was Germany, aircraft Of long endurance will be necessary both for scouting in conjunction with our fleets and convoy duties. The British Empire is widely scattered, and large tracts of ocean lie between the various colonies, all of which will require protection for the safe-guarding of our merchant shipping. The provision of a force of these large airships will greatly add to the security of our out-lying dominions. We have now reached a point where it is incumbent on us to face certain difficulties which beset the airship of large dimensions, and which are always magnified by its detractors. Firstly, there is the expense of sheds in which to house it; secondly, the large number of trained personnel to assist in landing and handling it when on the ground; thirdly, the risks attendant on the weather-- for the airship is still considered the general public as a fair-weather craft; and fourthly, though this is principally in connection with its efficiency for military purposes, its vulnerability. We will deal with the four difficulties enumerated under these headings seriatim, and endeavour to show to what extent they may be surmounted if not entirely removed. The solution of the first two problems may be summed up in two words: "mooring out"; on the success of this it is considered that the whole future of airships for commercial purposes rests. It will be essential that in every country which the airship visits on its voyages, one large central station is established for housing and repairs. The position of such a station is dependent on good weather conditions and the best railway facilities possible. In all respects this station will be comparable to a dry dock for surface vessels. The airship will be taken into the shed for overhaul of hull structure, renewing of gasbags or outer cover, and in short to undergo a periodical refit. The cost of a shed capable of housing two rigid airships, even at the present time, should not greatly exceed L500,000. This sum, though considerable, is but a small item compared with the cost of constructing docks to accommodate the Atlantic liner, 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 dock. Apart from these occasional visits to a shed, the airship, in the ordinary way at the end of a voyage, will pick up its moorings as does the big steamer, and land its passengers and cargo, at the same time replenishing its supplies of fuel, gas, provisions, etc., while minor repairs to the machinery can be carried out as she rides in the air. A completely satisfactory solution of the mooring problem for the rigid airship has yet to reach its consummation. We saw in the previous chapter how, in the case of small non-rigids, they were sheltered in berths cut into woods or belts of trees, but for the rigid airship something more secure and less at the mercy of the elements is required. At the present moment three systems of mooring are in an experimental stage: one, known as "the single-wire system," is now practically acknowledged to fall short of perfection; the second, "the three-wire system," and the third, "mooring to a mast," both have their champions, but it is probable that the last will be the one finally chosen, and when thoroughly tried out with its imperfections eliminated will satisfy the most exacting critics. The single-wire system is at the same time the simplest and most obvious method which suggests itself, 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 ground. It has been found that an airship secured in this way requires constant attention, and that steering is always necessary to render her steady in the air. Considerable improvement is obtained if a dragging weight is added to the wire, as it tends to check to a considerable extent lateral motion of the bow of the ship. The three-wire system is an adaptation and an improvement on the one previously mentioned. In this case the mooring point of the ship is attached to three long wire cables, which, when raised in the air, form a pyramid to the head of which the ship is attached. These wires are led to bollards which form in plan an equilateral triangle. The lift of the ship raises these wires off the ground, and if the ship is trimmed up by the bows she will be found to resist the action of the wind. A rigid airship moored out by this method remained in the open for a considerable time and rendered the future of this experiment most hopeful. It was resolved to continue these experiments by adding a subsidiary system of wires with running blocks, the whole wiring to form a polygon revolving round a fixed centre. The disadvantages of this method appear to be rather serious. It seems that great difficulty will always be found in picking up these moorings in a high wind, and though this also applies to the method with the mast, the initial obstacles do not appear to be so great. A powerful engine driving a winch will be necessary to raise these heavy wires from the ground, although of course the lift of the airship will assist in this. Secondly, the lowering of passengers and cargo will not be easy as the ship will not be rigidly secured. This, however, can probably be managed when experiments have reached a further stage, and at present the system may be said to present distinct possibilities. The third system, that of mooring to a mast, possesses several features peculiar to itself, and not embraced by the other two, which should secure it prolonged investigations. The system is by no means new and has been tried from time to time for several years, but since the question of mooring in the open has been so ventilated and is now considered of such vital importance, these experiments have been continued, and in less spasmodic fashion than in the past. In a trial with a small non-rigid airship some months ago a signal success was achieved. 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 year. During this period two men only were required to look after the ship, which experienced gales in which the force of the wind rose to 52 miles per hour, and not the slightest damage was sustained. Two or three methods of attaching the airship to the mast have been proposed, but the one which appears to be most practical is to attach the extreme bow point of the ship to some form of cap, in which the nose of the ship will fit, and will revolve round the top of the mast in accordance with the direction of the wind. For large airships, employed as passenger and commerce carriers, we can imagine the mast advanced a stage further, and transformed into a tower with a revolving head. Incorporated in this tower will be a lift for passengers and luggage, pipes also will be led to the summit through which both gas and water can be pumped into the ship. With the airship rigidly held at the head of such a structure all the difficulties of changing crews, embarking and disembarking passengers, shipping and discharging cargo and also refuelling, vanish at once. Assuming the mooring problem solved with success, and we feel correct in this assumption, the first two of our difficulties automatically disappear. Sheds will only be necessary as repair depots and will not be extensively required, all intermediate stopping places being provided with masts and necessary arrangements for taking in gas, etc. At these intermediate stations the number of men employed will be comparatively speaking few. At the depots or repair stations the number must, of course, be considerably increased, but the provision of an enormous handling party will not be necessary. 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 shed; when these conditions prevail the airship will, unless compelled by accident or other unforeseen circumstances, remain moored out in the open until the direction of the wind has changed. Mechanical traction will also help effectually in handling airships on the ground, and the difficulty of taking them in and out of sheds has always been unduly magnified. The provision of track rails and travellers to which the guys of the ship can be attached, as is the practice in Germany, will tend to eliminate the source of trouble. We must now consider the effect that weather will have on the big airship. In the past it has been a great handicap owing to the short hours of endurance, with the resulting probability of the ship having to land before the wind dropped and being wrecked in consequence. Bad weather will not endanger the big airship in flight, and its endurance will be such that, should it encounter bad weather, it will be able to wait for a lull to land. Meteorological forecasts have now reached a high state of efficiency, and it should be possible for ample warnings to be received of depressions to be met with during a voyage, and these will be avoided by the airship flying round them. In the northern hemisphere, 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 east. Going west, the airship would fly to the north of a depression to take advantage of the wind circulating round the edge, and going east the southern course would be taken. Lastly, the vulnerability of the airship must be taken into account. Hydrogen is, as everyone knows, most highly inflammable when mixed with air. The public still feels uncomfortable misgivings at the close proximity of an immense volume of gas to a number of running engines. It may be said that the danger of disaster due to the gas catching fire is for peace flying to all intents and purposes negligible. At the risk of being thought hackneyed we must point out a fact which has appeared in every discussion of the kind, namely, that British airships flew during the war some 21 million miles, and there is only one case of an airship catching fire in the air. This was during a trial flight in a purely experimental ship, and the cause which was afterwards discovered has been completely eliminated. For airships employed for military purposes this danger, due to the use of incendiary bullets, rockets and various other munitions evolved for their destruction, still exists. Owing to its ceiling, rate of climb and speed, which we take to be from 70 to 80 miles per hour in the airship of the future, the airship may be regarded as comparatively safe against attack from the ordinary type of seaplane. The chief danger to be apprehended is attack from small scouting seaplanes, possessing great speed and the power to climb to a great height, or from aeroplanes launched from the decks of ships. If, however, the airship is fitted to carry several small scout aeroplanes of high efficiency in the manner described in the previous chapter, it will probably be able to defend itself sufficiently to enable it to climb to a great height and thus make good its escape. The airship, moreover, will be more or less immune from such dangers if the non-inflamable gas, known as "C" gas, becomes sufficiently cheap to be used for inflating airships. In the past the expense of this gas has rendered its use absolutely prohibitive, but it is believed that it can be produced in the United States for such a figure as will make it compare favourably with hydrogen. The navigation of an airship during these long voyages proposed will present no difficulty whatever. The airship, as opposed to the aeroplane, is reasonably steady in the air and the ordinary naval instruments can be used. In addition, "directional" wireless telegraphy will prove of immense assistance. The method at present in use is to call up simultaneously two land stations which, knowing their own distance apart, and reading the direction of the call, plot a triangle on a chart which fixes the position of the airship. This position is then transmitted by wireless to the airship. In the future the airship itself will carry its own directional apparatus, 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 chart. We have so far confined our attention to the utilization of airships for transport of passengers, mails and goods, but there appear to be other fields of activity which can be exploited in times of peace. 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 country. Photography of broken country and vast tracks of forest can be much more easily undertaken from an airship than an aeroplane, on account of its power to hover for prolonged periods over any given area and its greater powers of endurance. For exploring the unmapped regions of the Amazon or the upper reaches of the Chinese rivers the airship offers unbounded facilities. Another scope suggested by the above is searching for pearl-oyster beds, sunken treasure, and assisting in salvage operations. Owing to the clearness of the water in tropical regions, objects can be located at a great depth when viewed from the air, and it is imagined that an airship will be of great assistance in searching for likely places. Sponges and coral are also obtained by diving, and here the airship's co-operation will be of value. Small ships such as the S.S. Zero would be ideal craft for these and similar operations. The mine patrol, as maintained by airships during the war, encourages the opinion that a systematic search for icebergs in the northern Atlantic might be carried out by airships during certain months of the year. As is well known, icebergs are a source of great danger to shipping in these waters during the late spring and summer; 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 voyage. The proposal put forward is that during these months as continuous a patrol as possible should be carried out over these waters. The airship employed could be based in Newfoundland and the method of working would be very similar to anti-submarine patrol. Fixes could be obtained from D.F. stations and warnings issued by wireless telegraphy. Ice is chiefly found within five hundred miles of the coast of Newfoundland, so that this work would come within the scope of the N.S. airship. 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 liners, and would also relieve the shipping companies and the public of great anxiety. 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 Soudan. The merits of all of these will doubtless be considered in due course and there for the present we must leave them. Finally, a few words must be written regarding the means to be adopted in introducing the airship into the realms of commerce. 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 men. Airships are very costly and are still in their infancy, which means that the premiums demanded for their insurance must of necessity be enormous. 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 companies. Another suggestion is that the Government should make arrangements to subsidize commercial airships. The subsidy might take the form of insuring them. If the burden of insurance is taken off their shoulders, it is considered feasible to promote companies which will give an adequate return for capital invested. The Government could also give a financial guarantee if mails are carried, in the same manner as is done by shipping companies. 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 commission. By this means the Government will have a large number of highly-trained and efficient personnel to call upon when the emergency arises, in the same way as the fleet can call upon the R.N.R. This system appears to be the best in every respect, and it cannot be denied that in the long run it would be the most economical for the country. The airship has now arrived at the parting of the ways, and at this point we must leave it. The flying in war has been concluded, the flying in peace has not yet commenced. It seems a far cry to the dark days of 1914, when we only possessed two airships of utility, the one manufactured in France, the other in Germany, while to-day we have built the mighty airship which can fly to America and back. We are now at the dawn of a new period of reconstruction and progress, and during this period many wonderful things will happen. Not the least of these will be the development of the airship.
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