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Aviation History
1932
1932 - 0314.PDF
FLIGHT, APRIL 1, 1932 WING COM. ORLEBAR ON HIGHSPEED FLYING VP ING COM. A. H. ORLEBAK, A.F.C., read a paper on " High-Speed Flying " before the Royal United Service Institution on March 23. Air Marshal Sir Edward Ellington, K.C.B., C.M.G., C.B.E., was in the chair. The majority of what the late commanding officer of the High-Speed Flight had to say is already familiar to readers of FLIGHT, but the paper seemed to make a great impression on the members of the two older services in the audience, and to give them a great deal of information which surprised them very much. Wing Com. Orlebar started by saying that there were many ways of treating his subject. One might mention the number of cups of tea which could have been boiled by the heat generated by the engines, or one might go into very technical points. He proposed on that occasion to do neither, but to take a broad view of the subject and to discuss the use of high-speed flying. The connection of the service with high-speed flying dated from 1926, when the first High-Speed Flight was formed in order to compete for the 1927 contest. For practice purposes they found various machines such as the Bamel on floats and the Gloster III, which had been flown only by civilian pilots and were quite strange to R.A.F. pilots. Their speed was about 240 m.p.h., only just faster than the modern types of R.A.F. aeroplanes. The speed of service types then was not above 150 m.p.h. Also these old machines were far inferior in structure and aero dynamic qualities to the new ones which were produced for the 1927 contest, namely, the Gloster TV and the Supermarine S.5. The actual racers were only delivered to the Flight a short time before the contest, and directly after the contest the Flight was disbanded. The 1929 High-Speed Flight were more fortunate in having racers of the previous contest as training machines, and very good training machines they proved. He then explained the reason why the contest was held with seaplanes instead of landplanes. An increase of speed implied higher landing and taking-off speeds, and the extensive fairly level surface necessary for those high speeds could only be found on the water. Actually, he thought that unfaired wheels on landplanes set up worse drag than did the well streamlined floats of the seaplanes. Nearly all the pilots chosen for the High-Speed Flight came from landplanes, because the behaviour of the racing machines in the air resembled that of fighter landplanes more closely than it did that of normal seaplanes. But the take-off and landing were rather peculiar. When taking off the machine would veer to the left until it gained sufficient speed to make the rudder effective. In the early stage the spray prevented the pilot from seeing straight ahead. He could do nothing except keep his head down to prevent his goggles becoming covered with spray, start off to the right of the wind, hold the stick to the right and back, and be ready to take control as soon as the machine gained way. In the latter stages of the run the floats were subjected to enormous stresses, and there were no shock-absorbers other than the V shape of the floats. This made one realise the strength of the structure. It took over a mile to get off the water, and another half- mile" before the machine was climbing comfortably. Once when the engine cut out suddenly after just taking off, the machine covered three miles before it could be landed. From full throttle at a height of 200 ft. it took three miles to pull up. When landing, the pilot had to approach at 160 m.p.h. The speed dropped slowly. The machine touched the water at about 110 m.p.h. It touched very gently, but the deceleration was very rapid, and the pilot needed to brace his shoulders well back to prevent being thrown forward and breaking his goggles on the board. Good water was needed for a landing, but a glassy surface made it difficult to judge height. The take-off was the only real difficulty of high-speed flying. The floats had to travel at the speed of the world's record speed boat. They could not stand high waves, and usually when there were white horses on the waves (say a wind of 15 m.p.h.) it was too rough to take-off. High-speed machines presented problems for propeller designers. The drag of the floats was high, and the coarse pitch of the propellers would only just permit of accele ration. But in the air the machines were simple to fly. They had had one instance of tail flutter, but it had been completely cured. All the accidents which had occurred had been during taking-off and landing. Flying the speed course was not uncomfortable to the pilot. He had little sensation of speed unless he looked at objects near to him. It was the control of power which made high-speed flying exhilarating—and it was exhilarating. The pilot had no need of conscious concentration. The machine would fly itself at 330 m.p.h. with hands and feet off. The consumption was about 3 m.p.g. When turn'ng it was possible, but not necessary, to get unpleasant eifects. Sudden steep turns drew the blood from an artery which supplies the eye. The first effect was a feeling of tightness round the neck ; then a blurring of sight, and finally " blacking out." But familiarity with the machine allowed turns to be made with only the feeling of tightness round the neck. There were no after effects, and as soon as the machine was straightened out all such sensations vanished. It was inefficient to force the machine into a tight turn. On a course with long legs, where full speed could be regained between turns, it paid to do a gentle turn. One got the maximum benefit at 4G (when the pressure of the turn was four times the force of gravity). At 5G the " black-out " was normally felt, though pilots varied in this respect. It followed that what was best for the pilot was also best for the machine. The lessons thus learnt could apply to the case of fighters diving to attack bombers. If they dived underneath and suddenly zoomed, they might black-out. If they did a slower turn, they would be at a greater range from the bomber's guns at the dangerous moment of turning. In the High-Speed Flight, each pilot only got about 12 hr. high-speed flying. The pilot indulged in no special training, but it was a point of honour to confess if one felt unfit. An elastic belt had been tried, but it had not been a success. It was advisable to wear a loose collar. Of the 12 pilots who had been in High-Speed Flights, over 50 per cent, had been non-smokers and teetotallers. Without the stimulus of a Schneider Contest, it would have been impossible to get the co-operation of all the experts. The result was a freak machine, but the know ledge gained had been very useful. The cost was great, but the knowledge bad been cheap at the price. All pro gress levied a toll in cost and usually in lives ; but most of it was done in secret. He did not run down exploration, but he had noticed that one brief Antarctic expedition had cost two and a-half times the sum expended on the British Schneider effort. He submitted that the results of high-speed flying were as useful as those of polar exploration. Among the less concrete results was the effect on the human element. To members of the High-Speed Flight anything under 300 m.p.h. seemed slow. It was once said that motorists could not stand 60 m.p.h. He thought that Schneider machines pointed the way to higher speeds in commercial flying. Flying Boat Lands in Snow A SHORT time ago it became necessary to send a Dornier flying boat from Friedrichshafen to Munich, and as the Munich aerodrome was covered in snow it was decided to try the experiment of landing the machine on the snow. The boat, Dornier Wal D.1422, was piloted by Herr Wagner, the Dornier test pilot, and the landing was completely successful. No special preparations had been made at Munich beyond marking out a line with black ^paper streamers on sticks. These proved effective in enabling the pilot to judge his height in spite of the fact that the landing was made against the sun. So smooth was the landing that the engineer, who was inside the hull, was unaware of the exact moment of contact. As the machine taxied in a large curve to come to a standstill by the hangar it was not possible to measure the distance to pull up. The relatively flat bottom of the Wal and the wing stumps on the hull render this machine particularly suited to alight on snow or ice. Doubtless it could take off from snow just as readily once it had been broken loose. 290
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