426 



NATURE 



[January 30, 19 19 



a useful load of something' like 2 tons of mer- 

 chandise. This in itself is very encouraging, but 

 . is no doubt that attempts will lie made to 

 increase the carrying capacity to double or treble 

 this amount in the near future. There is appa- 

 rently no very great difficulty in doing this from 

 the point of view of the aerodynamic design of 

 'the machine, though the provision of sufficiently 

 light controls may give considerable trouble. It is 

 also fairly certain that engines of greater output 

 will soon be available. The greatest difficulty- 

 besetting the large aeroplane would seem to be 

 the landing- problem, experience having shown 

 that the larger the machine the more difficult it 

 is to land, especially on a bad ground or in a poor 

 light. Moreover, the landing speed cannot be 

 reduced without sacrifice of maximum flying speed, 

 which is the aeroplane's greatest commercial 

 asset. In this connection Mr. Curtiss, the well- 

 known American builder, prophesies the more 

 rapid development of the large seaplane, since 

 the landing difficulties are considerably less than 

 with the aeroplane, and the provision of suitable 

 landing-grounds is not necessary, a large area of 

 still water being almost always available. Mr. 

 Curtiss is at present building a flying-boat of 

 126-ft. span, and considers that it will be able 

 to accomplish the Atlantic flight during the 

 coming summer. He gives a second reason for 

 the more rapid development of seaplanes, stating 

 that the advantage to be gained is greater than 

 in the case of over-land machines, since the speed 

 of ocean liners is so much less than that of 

 express trains. While this reasoning may be 

 quite correct, there is no doubt that in England 

 the main attention will be devoted to the land 

 machine, most of the useful European and Asiatic 

 routes being over-land. 



While considering the possibilities of the giant 

 aeroplane in the commercial world, we must not 

 lose sight of the rigid airship as a means for the 

 transport of merchandise. The speed of the air- 

 ship is lower than that of the aeroplane, it is true, 

 but the airship has at present far greater capa- 

 bilities as regards endurance, and might well prove 

 the more useful machine for reaching distant 

 points in a journey of one stage when the utmost 

 limit of speed is not essential. It may here be 

 mentioned that an airship nearly 700 ft. in length, 

 and with a gas capacity of 2,750,000 cu. ft., is 

 already under construction. Announcement was 

 made on December 19 that this ship would have a 

 useful capacity of about 50 tons, a range of 9000 

 miles, and an endurance of more than eight days. 

 Such a ship, if successful, could be used for com- 

 mercial eni prises for which any present-day- 

 aeroplane wmi: he useless. A rigid airship of 

 10,000,000 cu. ft., with a useful lift of 200 tons, 

 is said to be under consideration, but it would 

 appear that this is too great an advance to make 

 in a single step, and that the wiser course would 

 be to await the experience gained on the 50-ton 

 ship, and to advance by gentle stages to the colos- 

 sus of 200 tons. One greal disadvantage of the 

 NO. 2570, VOL. I02~] 



rigid airship is its inability to cope with rough 

 weather, and it is not easy to see how this diffi- 

 culty is to be overcome, as it must be overcome if 

 such craft are to undertake continuous com- 

 mercial work. A further disadvantage lies in the 

 fact that an airship can only land in places where 

 a large gang of men is available to handle the 

 ship when upon the ground. 



To return to the large aeroplane, it is possible 

 that inventors will try to solve the landing diffi- 

 culty by the use of the helicopter, or direct-lift 

 principle. There does not appear to be very much 

 hope in this direction, as will be evident when it 

 is stated that with helicopters of reasonable dia- 

 meter the horse-power required for every thou- 

 sand pounds lift is in the neighbourhood of 

 100, while an aeroplane can fly at 60 m.p.h. 

 with only about 22 h.p. per thousand pounds of 

 weight. This consideration, together with the 

 great mechanical difficulties of construction, seems 

 completely to discredit the helicopter, at any rate 

 for the present. 



Reference may here be made to a very lucid 

 article by Mr. Handley Page which appears in 

 the January number of the Fortnightly Review 

 under the title of "Air Transport." The author 

 traces the gradual increase in the speed of transit 

 of goods from the early days of history to the 

 present time, and shows that the rate of transit 

 is simply a question of weight per horse-poyver. 

 As the weight per horse-power of the available 

 "engines" has decreased, so has the rate of 

 transit increased. Flying was only rendered pos- 

 sible at all by the development of the petrol 

 engine, the weight of yvhich per horse-power was 

 very much lower than that of the best steam- 

 engine previously available. Even at the present 

 time improvement in the efficiency of flight is 

 much more likely to come from improvement in 

 the engine than from any increase in aerodynamic 

 efficiency. Mr. Handley Page gives his opinion 

 that, even with existing machines, it will be pos- 

 sible to convey passengers at threepence per mile 

 — first-class railway fare — and letters at a penny 

 per ounce. He considers that to realise the ad- 

 vantages of the high speed of aircraft, the stages 

 flown should not be less than 400 miles each. 



To summarise the foregoing notes, it would 

 appear that aeroplanes of the largest size built, 

 such as the latest Handley Page machine, form 

 the best basis on which to start commercial 

 schemes of aviation, and that the carrying of 

 mails and limited numbers of passengers should 

 be the first problems attacked. As experience is 

 gained, the size of machines should be gradually 

 increased, and greater loads carried, the difficul- 

 ties of design and use of the larger machines 

 being thus overcome by degrees. Too much 

 emphasis cannot be laid on the danger of prema- 

 ture attempts to build colossal aeroplanes. To 

 endeavour to build a machine of 50 tons gross 

 weight at the present time yvould be to court 

 almost certain failure, and to throw discredit upon 

 the large aeroplane, whereas if a machine of this 



