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Aviation History
1936
1936 - 0098.PDF
48 FLIGHT. JANUARY 9, 1936. it is necessary to know something about the assumptions on which it is based. The number of passengers carried is the number which can be carried on ordinary air-line work when the aeroplane is also equipped with luggage and lava tory accommodation. Top speed is used in preference to cruising speed, because it is a definite quantity, whereas cruising speed is interpreted in so many different ways, and can be varied (within limits) to suit the conditions. A high cruising speed, for example, can be obtained by running the engines at a high proportion of their maxi mum output, but this necessitates more frequent overhaul and a shorter life for the engines. The horse-power is the total rated output of the engines in the aeroplane. Obtaining the Comparison In the table shown I have included only those aeroplanes of which I have been able to find out the price, because the total value of the Commercial Efficiency depends on this as well as the other factors. In cases where the price is not known it is possible to compare different aeroplanes, using the first term of the formula only; and, as this term forms a big proportion of the total, it will give a reason ably good comparison, unless the price of the aeroplane is exceptionally high or low. One of the most noticeable things about the aeroplane, compared with other means of transport, is its speed, and so many people are inclined to judge aeroplanes by that alone. In my opinion, Commercial Efficiency is a much fairer basis of comparison for transport aeroplanes, and the table I have given shows the relative merits of the aeroplanes in an order very different from the popular esti mate based on speed alone. Finally, let me say that this article is not intended as a defence of the slow aeroplane. I am not one of those who believe that high-speed transport must necessarily and inevitably cost far more than medium speed. And calcu lations on some other aeroplanes will show that a low cruising speed does not necessarily mean high Commercial Efficiency. Although the British aeroplanes quoted are not quite so fast as the Americans, they cannot be called slow, and there are being built in this country at the present time several really fast transport aeroplanes, which will prob ably show just as good figures of Commercial Efficiency as the existing aeroplanes. Aeroplane. D.H.86 (4 Gipsy VI) AIRSPEED ENVOY (2 Lvnx IVc) LOCKHEED EI.ECTRA (2 Hornets) D.H.8B (2 Gipsy VI) DOUGLAS D.C.2 (2 Cyclones) AVRO 652 (2 Cheetah VI) BOEING 247.D (2 Wasps) Total H.P. 7C0 446 900 380 1,420 580 1,100 - Price. JCA.OOO £5,115 £10,100 £4,500 £17,000 £6,250 £12,500* Top Speed m.p.h. (V) 173 174 207 160 210 195 200 No. of Pass. (P) 12 6 10 0 14 6 10 H.P. per Pass. 63.3 74.3 eo.o 76.0 101.5 96.7 110.0 PxV HP 2.730 2.340 2.300 2.105 2.071 2.015 1.818 P — £ 1.333 1.173 0.990 1.111 0.986 0.960 0.800 Com mercial Effici ency. 4.063 3.513 3.290 3.216 3.057 2.975 2.618 * The price of the relative to the Douglas, Boeing is an estimate based on the size of the aeroplane which is of similar general layout. A COMET'S DESCENDANT PERHAPS it may be remembered that in a lecture given shortly after the England-Australia Race, Capt. G. de Havilland referred to the possibility of building a " scaled- up " Comet, which could be made into a very efficient com mercial aeroplane It was almost a foregone conclusion that sooner or later the De Havilland Company would design and build such a machine as that foreshadowed by Capt. de Havil land. Work on the design of a new high-speed transport aeroplane has now begun at Hatfield, and although it some what resembles the Comet, the new type differs in very many respects, apart from size, from the famous winner of the England-Australia Race. For one thing, the new monoplane will have four engines instead of the Comet's two. The engines themselves will be of a new type, and it seems likely that they will be inverted vee air-cooled, with twelve cylinders. In view of the great success attained with the Gipsy Six engine, it is, perhaps, not unnatural to assume that the new engine will have similar cylinders. As the Gipsy Six delivers at least 200 h.p., it may be estimated that the new engine will be of some where in the neighbourhood of twice that power at least. It may also be taken for granted that gearing and the ability to take controllable-pitch airscrews will be incorporated in the design. NEW YEAR HONOURS The following names, which occur in the list of New Year Honours, will be of special interest to readers of Flight:— VISCOUNT TRENCHARD, MARSHAL OF THE ROYAL AIR FORCE HUGH MONTAGUE, BARON, G.C.B., G.C.V.O., D.S.O., D.C.L., LL.D., lately Commissioner of Metropolitan Police. KNIGHT BACHELOR SHELMERDINE, LIEUTENANT-COLONEL FRANCIS CLAUDE, CLE., O.B.E., F.R.Ae.S., Director- General of Civil Aviation, Air Ministry. K.C.B. (Military Division) BOWHILL, AIR MARSHAL FREDERICK WILLIAM, C.B., C.M.G., D.S.O., Royal Air Force. BURNETT, AIR MARSHAL CHARLES STUART, C.B., CB.E, D.S.O., Royal Air Force. C.B. (Military Division) CAVE-BROWN-CAVE, AIR VICE MARSHAL HENRY MEYRICK, D.S.O., D.F.C., Royal Air Force. GILL, AIR COMMODORE NAPIER JOHN, C.B.E., M.C., Royal Air Force. C.B.E. (Military Division) HOWE, GROUP CAPTAIN THOMAS EDWARD BARHAM, A.F.C., Royal Air Force. O.B.E. (Civil Division) STEVENS, HERBERT LAWRENCE, Esq., F.R.Ae.S., Principal Scientific Officer, Air Ministry. M.B.E. (Civil Division) BARRACLOUGH, CAPTAIN SYDNEY, Education Officer, Grade III, Air Ministry. WHITE, WILLIAM ARTHUR JOHN, Esq., Super intendent, Headquarters, Royal Air Force, India.
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