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Aviation History
1944
1944 - 0080.PDF
4a FLIGHT JANUARY 13TH, 1944 A GREAT BRITISH ACHIEVEMENT tors, his outstanding qualities as a pilot resulting in an appointment as test pilot at Martlesham Heath. Flight Lieutenant Sayer left the R.A.F. on the completion of his five-year commission to join the Hawker Com pany, and was appointed as assistant to Group Captain P. W. S. Bulman. Here he was engaged in testing Harts, Furies, and other aircraft, and on the acquisi tion of the Gloster Aircraft Company by the Hawker Group, was appointed in 1935 chief test pilot of the Gioster Com pany. He has been described as a typical British test pilot, modest to a degree and disinclined to talk about his work. A tribute paid to him by Mr. Michael Daunt, one of his assistant test pilots, stated: " I have worked with ' Jerry ' for five- and-a-half years, and although he was virtually my boss he was the type of boss who was so much more a personal friend that one did every job of work as a piece of co-operation. As a test pilot he was one of the foremost in the country. He had a terrific ability of being able to fly extremely well and smoothly, but he had also the type of orderly brain that never misses a detail. When he landed after an important test, the information he gave would always be of value to the future of that aeroplane and of help to its designer.'' Canadian Broadcast On Friday afternoon last the Canadian Broadcasting Cor poration arranged a brief talk by Mr. Geoffrey Smith over the trans-Canada network on the subject of jet-propelled aircraft. This is the text: — " To-day one of the biggest secrets of the war in connection with aircraft was divulged by the Royal Air Force and the United States Army Air Corps. I refer to the disclosure that jet-propelled aircraft had been successfully flown and are now in production as fighters. To the man in the street the term jet propulsion will be somewhat mystifying, and a few words of simple explanation may serve to enlighten those interested in engineering progress. And let me here say that this new power unit is of. a revolutionary character and we owe it to a brilliant young British engineer-pilot in the R.A.F., Frank Whittle, who was promoted Group Captain a few months ago. In the case of jet-propelled aircraft the power unit consists essentially of an air compressor driven by a combustion gas turbine (not a steam turbine). This combined unit produces a stream of air and gas which is ejected at high velocity through a nozzle in the tail of the aircraft. The rearward thrust of this jet of heated air creates an opposite reactive thrust on'the machine and propels it forward. " But let me briefly outline the process from the beginning. A combined airscrew and jet-propulsion unit. A, centri fugal compressor ; B, air inlets ; C, annular air duct ; D, mixing chamber ; E, bulkhead ; F, fuel nozzles ; G, gas turbine ; H, discharge duct ; J, discharge flap ; K, effluent by-pass flap. Fcur suggested arrangements of power units on all-wing aircraft. A has four continuous-combustion turbine and axial compressor-type jet-propulsion units. B has two turbine-driven contra-rotating airscrews and two jet-propulsion units. In C two reciprocating engines drive contra-rotating airscrews, and there are two jet-propulsion units. D has the same power units, but airscrew pushers. The working medium is air drawn from the atmosphere, com- ^v pressed and passed into a combustion chamber. Here liquid fuel is sprayed in and continuously burned in order to heat and expand the air. From the combustion chamber this hot gas mixture expands through the turbine, thus imparting energy which is utilised to drive the compressor. Both the turbine and the compressor are on a common shaft and rotate at extremely high speed—certainly in excess of 10,000 r.p.m., but speed, of course, depends upon the size of the turbine adopted. From the turbine the gas /air stream is discharged to atmos phere as a high-velocity jet through the tail nozzle previously referred to. It seems fantastic that any aircraft propelled by reaction of a jet of air in this manner can improve upon exist ing performance and, at the same time, eliminate a great deal of complication in the power unit. What is amazing to those who have not studied the subject is that this revolutionary unit at certain altitudes makes- possible a speed higher than has been attained up to the present with orthodox types of air craft engines. In the upper atmosphere this particular form of turbine combination revels in its work. You may ask: 'What are the further advantages of jet propulsion now so-* enthusiastically appraised by. Britain and America? ' Here are some points: Apart from the elimination of the airscrew, which tended to become a limiting factor in ordinary engine development, the turbine compressor unit is of extremely con venient shape for installation. Rotary components are used exclusively and this, coupled with the high speeds attained, provides extremely smooth operation. The absence of an air screw enables the aircraft to be of exceptionally low build, as obviously there is no need of ground clearance for the rotating blades. No transmission or conversion mechanism is required so that cost, complication and man-hours in production are very much reduced with jet propulsion plants. " To some Canadians this idea of jet propulsion is not entirely new. Some years ago, having recognised the great promise of this new form of power unit, I wrote many articles on the subject, which were later published in book form. Copies found their way to my son, a Squadron Leader in the R.A.F. instructing in Canada at Bowden, Kingston and elsewhere, and he, too, became imbued with the enthusiasm I had exhibited for early projects in jet propulsion systems, and lectured on one or two occasions on the subject. "Following upon Group Captain Whittle's enterprise in per fecting jet propulsion plant over a period of years, it is good to know that the United States Army Air Corps at once recognised its potentialities and requested a sample, which was sent to the G.E.C. Company in the U.S.A. The two Allies are now working in close co-operation and one can be sure that their joint efforts will result in big new technical and operational developments in the not distant future. Many of us feel that in the turbine-compressor unit we have a strong competitor to the reciprocating engine, at least for certain services, and the adoption of such units will revolutionise the design of aircraft of the immediate future, and in the air transport world of the days of peace. It is pleasing that this pioneer work can be credited to British enterprise."
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