THE AIRWAYS

Evening Star, Issue 21931, 18 January 1935, Page 12

THE AIRWAYS

SPEEDING THEM DP A PUBLIC DEMAND AMERICAN EXAMPLE Sir Philip Sassoon, Under-Secretary of State for Air, writing in ‘ Flight;’ says that the performance of the American machines in the race to Australia has served a useful purpose. It has brought home to the British public the fact that there are air transport lines flying in the United. States at an average speed of'some 160 miles per hour. Even though the general average of all the American companies is only some 130 miles per hour, and even though this is achieved at a cost to the United States Post Office of between £4,000,000 and £5,000,000 a year, with petrol at something like 7d per gallon only, it is all to the good that the British public should be taught to look for higher speeds. We are going to get them.

The plans which are now under consideration, writes Major F. A. De V. Robertson, in the * Manchester Guardian,’ are for a service to Australia, taking about seven and a-quarter days, and it is understood that the K.L.M. (Royal Dutch Air Line) does not consider it possible to work to less than a seven-day schedule to Melbourne. It seems clear that the public, stirred up by the performances in the Macßobertson race, are demanding an increase of speed by Imperial Airways, and the prospect held out by the Government ought to satisfy that demand. It is well to remember, however, that speed costs money. It appears that the taxpayers in England and in the dominions and colonies traversed by Imperial Airways will have to find that money. A speeding up will necessarily postpone the time when Imperial Airways will become self-supporting and able to carry on without a subsidy. It is to be hoped that in due time the increase of Empire business due to this speed-up will repay the taxpayers, indirectly if not directly. SPEED AND PETROL PRICE. In the United States speed was from the beginning an indispensable element in an air mail service. The railways there are good, and if the airways were to attract any business at all they had to beat the rail by a substantial margin. The Government thought it worth while to spend the money which made that speed possible. The air transport companies in the TJnited States had many advantages which can never be shared by any company which flies across the British Empire. Chief among them is the cheapness of petrol, and high-grade petrol at that. Sir Eric Geddes said_ in his recent speech at the annual meeting of Imperial Airways: “ The price we have to pay for fuel has been, and still is, the most powerful deterrent to high speed with which we have to contend.” In the United States the companies fly over a homogeneous country with no political difficulties, no passport worries, and no language problems. All these things go to simplify their task. The natural result has been that the United States designers have produced commercial aeroplanes which maintain a high average speed. Hitherto there has been no call for British firms to product aircraft of that class, but it should_ be remembered that whenever our designers have been called upon to design for a certain purpose—to win the Schneider trophy, to establish records for speed, altitude, and range, and to win the race to Melbourne—they have always shown themselves able to rise to the occasion. PETROL LOAD. The Douglas D.C.2 and the Boeing 247 D Transport are two of the types which have done most to bring American air transport to its present high speed. Both took part in th© race to Australia., Aerodynamically there is

nlucb that is common to both of them and also to the Comet. All three are low-wing cantilever monoplanes with two engines, variable-pitch propellers, retractile undercarriages, and wheel brakes. In engine power the differences are marked, for tne Douglas has two Wright radial Cyclones of 715 horsepower each, the Boeing two Pratt and Whitney radial Wasps of 550 horsepower each, while the Comet has only two six-cylinder in-line Gipsies of 225 horse-power each. All are air cooled. It should be noted that the Comet could carry enough petrol to reach Bagdad without overloading, while neither of the American machines could carry enough to feed their powerful engines for the 2.530 miles without breaking the international regulations for airworthiness. It may also be remarked that the United States has not signed the international agreement under which these rules have force. , It was a case in which the smaller engines could carry_ a greater “ disposable ” load at a.liighcr speed than the larger ones could do. For passenger traffic, however, it is not economical to carry a heavy load of petrol. It is more profitable to carry more passengers and to refuel more often. That is why the Atlantic presents such a difficult problem. THE MONOPLANE. All these machines realise ambitions after which the early pioneers hankered in vain. The rivalry between monoplane and biplane dates from the days of the first exploits of Bleriot and Farman. The monoplane, and particularly the cantilever monoplane, offers less resistance to the air, but to get the same amount of wing area it needs a greater span than the biplane, and at first it unplied heavier construction. Methods of construction have improved —the monospar is one example—and now the fashion is tending more and more towards the use of the monoplane. The low-wing monoplane is also a fairly recent fashion, and it has led the way to the retractile undercarriage. Wheels and struts are useless when in the air, and they cause a heavy drag. It is no gain to raise them unless they can be hidden away inside the fuselage or the wings and faired off. The monoplane usually has a high-lift wing of thick section, and_ so, when the lowwing arrangement is adopted, it is possible to retract the wheels into slots- in the lower side of the wings. This was not the arrangement on the Comet, where the wheels were raised up behind the engines, and the mudguards rose with them and faired them off. PROPELLER PITCH, The variable-pitch propeller is another development which has been keenly desired for years past, yet it is; only recently that practicable forms of. it have been developing in America and France. Wbeu talking off, a fine pitch is desirable, with the engine “ full out,” but when the machine is in the air and the engine throttled down to the revolutions at which it has been decided to fly, then the coarser pitch gives better drive for the power expended. Both the Douglas and the Boeing use the Hamilton V.P. propeller, for which the De Haviland Company holds the British rights; but owing to lack of time the Comet had to use French Hatier V.-P. propellers in the race. Views on high lending speed have had to be modified of late. It is permissible on a large specially-prepared aerodrome, and consequently if forced landings could be eliminated there would he small need to aim at low landing speeds. Aero engines have become very reliable, and when a multi-eneined machine can maintain height with one engine out of action the danger from forced landings is much reduced. Air brakes of various descriptions reduce landing speed, and wheel brakes are now so efficient that fast-landing machines can be pulled up in a smaller space than was once possible. Sir Alan Cobb am recently landed at Malta with his wheels retracted, and the machine was hardly damaged.