FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1935
1935 - 0926.PDF
>44<> FLIGHT. APRIL 25, 1935. A PRIZE and a PUZZLE The Air Ministry's £25,000 Award : A High-performance " General-purpose " Tjype Aimed at : Is the Specification on the Right Lines? WHEREVER aeronautical folk foregathered during last week, there was but one topic of conversa tion : the Air Ministry's ^25,000 prize. It seems that the Air Ministry issued a sort of tentative specification to form a basis for discussion, and from talking the matter over with a number of interested people we gather that on the whole the draft specification has not met with universal approval. While full details are, some what naturally, not available for the present, it is gathered that, briefly, the aim of the specification has been to call lor a machine with a range of at least 800 miles, to carry not less than twelve passengers and a crew of three, and to have a payload (including passengers, of course) of at least 4,000 lb. If one assumes that the machine is intended to be suitable for use on inland and continental air routes, it would appear that the size has not been too well chosen. For inland air routes, and for such continental services as are likely to be operated by British firms, a range of 800 miles and a payioad of 4,000 lb. both seem excessive. Granting that the machines which may be built for the competition wiil not be ready for more than one year, and that, therefore, one must look ahead, it still seems unlikely that the growth of internal and Conti nental air transport will be so rapid as to require an aircraft of such capacity unless " capital-to-capital " services are contem plated. In that case Oslo, Copenhagen, Berlin, Prague, Vienna, Paris and Madrid would be within non-stop range of London, but Rome would be about 100 miles beyond range, and Stockholm nearly 200 miles. On the other hand, as a link in the Empire air routes, if such was in the minds of those who drew up the specification, 800 miles' range is in sufficient to give the possibility of " all-red route ' operation. Twelve Passengers As far as can be gathered the draft specification definitely calls for at least twelve passengers, and not their equivalent in other payload, so that it does not appear to be permissible to add materially to the range by sacrificing a proportion of the payload. It is difficult to see the need for 800 miles range on any possible internal air routes within the British Isles, and unless the designer be permitted to exchange fuel for pay- load for internal air-route work, the type of machine visualised is scarcely likely to have a wide appeal. Some weeks ago Flight suggested that the competition might be divided into two: one for the "best" specification, and one, the larger of the two, for the "best" aeroplane built to the selected specification. From what we can gather the draft specification does not show obvious signs of having been discussed with people who have practical experience of inland transport. One cannot help feeling that, if the draft specification has been correctly interpreted by those who have seen it, it falls between two stools by calling for a machine which is too large for internal and European work and not large enough for Empire air routes. If the new large flying boats on order for Imperial Airways are to be taken as an indication of the type of aircraft which that company considers suitable for the Empire routes, the type which would be created by this new specification must be a good deal too small, apart from prob ably being unsuitable in other directions. From the technical aspect there are obvious difficulties in meeting the specification. This is in no way a serious criti cism, as one would not expect the Air Ministry to expend the taxpayer's money on anything which was too easy ' It is very right and proper that the specification should ' aim high," and that those who decide to enter the competition should be compelled 10 incorporate in the design every refine ment which modern knowledge can suggest, such as slots, flaps, retractable undercarriages, variable-pitch airscrew, and so forth. And on first examination the draft specification does not sound unduly difficult. A range of 800 miles, carrying a payload of 4,000 lb., cruis ing at about 180 m.p h. is not, in modern times, an unattain able combination. The famous Douglas D.C.2 almost achieves- it. When carrying fourteen passengers and 2,160 lb. of fuel it has a total payload, of 3,400 lb., with a range of 865 miles. The ratio of gross to tare weight of the Douglas is 18,000: 11,875=1.515, which is by no means an exceptionally good figure, the average of a large number of types being about 1.65, British designers should be able to achieve this ratio for the competition machine. The Douglas carries fourteen passen gers, which is two more than the minimum specified, but it carries a crew of but two as against the crew of three de manded of the British machine. There is thus in hand for the Douglas the equivalent of one passenger, or 200 lb., so that the payload falls short of the minimum stipulated by but 400 lb. The Engine Problem. The standard power plant of the Douglas is two Wright " Cyclone " radial air-cooled engines rated at about 710 b.h.p. at 1,900 r.p.m. and 7,000 ft. altitude. At present there is not available to British designers a very wide choice of engines of this power suitable for commercial aviation. This is on the assumption that but two engines are installed. Ap parently the draft specification contains a clause prohibiting the use of three engines. It is not very obvious why this clause should be inserted. It would seem that those who drew up the specification were guided by a desire to avoid placing the engine in the nose of the fuselage, presumably in order to keep down the level of noise in the cabin. It might be suggested that a third engine has been known to be fitted elsewhere than in the nose, and it does appear that by ruling out the third engine a number of suitable British engines are debarred from being used. If one thinks in terms of a four-engined machine the posi tion is little better. A total engine power of 1,500-1,600 b.h.p. will probably be required, and most of the British engine types available either fall rather short of the 400 h.p. or exceed it by too large a margin. The choice of a machine in the 18,000-20,000 lb. class has, apart from its somewhat problematic utility for inland and European air routes, the drawback that it is sufficiently large to be rather expensive to build, and the number of firms which can afford, as a pure speculation, to put down some thing like £50,000 or /6o,ooo for such a machine is not likely to be large. This must, unfortunately, mean that instead of getting a large number of brains to concentrate on the prob lem, we shall get but relatively few. The True Ideal We cannot help feeling that if we have properly understood the main points of the specification, as discussed everywhere in aviation circles, the specification rather '' misses the boat. To us it seems that something a little less ambitious, prob ably a good deal faster, and giving a really wide choice of engine combinations, would be more likely to find favour with a much greater number of operators. For example, a smaller machine, with about 500 miles range and cruising at 200 m.p.h , would be able to make the double journey be tween London and Scotland twice in a day—in the summer at any rate—and to many of the provincial centres three double journeys a day or even four, could be made. In view of Capt. de Havilland's recent assertion that ton-miles per gallon operational economy does not depend very much on cruising speed, 200 m.p.h. should not be too high to aim, and a machine with this speed should, on quite a number of routes, be capable of such intensive operation that its use would be attractive to operators and the public alike. The Soviet Season On May 5 the summer services open on Soviet air lines. A non-stop service between Moscow and Sverdlovsk, a pas senger line from Moscow to Kharkov and a mail service between Moscow and Leningrad will be opened or re-opened. A direct service will also be operated between Moscow and Tashkent. The U.S.S.R. planners expect to carry 100,000 passengers this year as against 70,000 in 1934.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
