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Aviation History
1944
1944 - 0254.PDF
CORRESPONDENCE .,, , .1 • .^verted fa« rnrrrtbmdents The names and addresses of the writers, The Editor does not hold WjjgHgg JSSX^fTSStCompany letters. JET PROPULSION FOR AIRCRAFT Alternative Application Suggested THREE years ago the Government asked for suggestions re ldefenJ from German bombers I wrote to them suggest in* Aires 20 oooft to 30,000ft. high to show up the bombers ogour nlght'Shters. The Government must have thought A rn^ood although the Germans must think it good. If we had hd X flares at'the time ot the blitzes we should have brought down a lot more Germans. " Now about the jet.aircraft In stead of he ets coming out of the tail, shape the aircraft hke an orange Pip and have several jets coming out of the shoulders, pre^TnTaiPrPagainSt and all round the fuselage, when the air craft will shoot forward twice as quickly on only halt the Pass this on if you think anything ^of rt. ^ ^ Two Efficiency Factors power. is of the order of ij cu. ft./sq. ft. of wing area per second, and it has been proposed to use a fan or a compressor to carry out the operation, but this entails extra weight, equipment and fuel When however, the slots are connected to the intake of a iet propulsion engine, the whole aspect of the proposition is changed and a new field of development is opened. Such an engine might use, say, 850 cu. ft. of air per second, which would successfully scavenge an area of 700 sq. ft. Furthermore, when the ducts or pipes connecting the open ings to the intake of the jet propulsion engine are arranged with a 30 degree elbow pointing backwards, a resultant reaction occurs on the outer wall of the bend, a component force of which is of the order of 600 lb. and acts as a propelling force on the aircraft. . . ,, , JLI.L This combination of high lift (which would almost be high enough to raise a fighter off the deck of an aircraft carrier), together with the primary and secondary propulsive forces. and the reduction in drag would improve the all-round per formance of the machine. The reduction in drag to the region of zero opens up the way to phenomenal speeds, and perhaps even ballistic velocities would eventually be attained. , When landing, the total weight would have been reduced t # the weight of fuel consumed during the journey, and landing would be a normal procedure. NE FRONTE CREDE. TYPHOON v. JUNGMANN is tne only criterion 01 tne relative einciency 01 uie two systems. The argument applies equally well in the extreme analogy of the batge mentioned in the article, although it must neces sarily employ equally extreme assumptions. What though the forward speed is 1 m.p.h. and the jet slip r.ooo m.p.h.—if that jet unit uses less fuel than the horse that normally tows the barge at 1 m.p.h., then it must be more efficient. Can I still go on reading the series, or is it back to the kindergarten and a paper kite for me? H. G. PUTTICK. Possibilities in Boundary-layer Control GERMAN views on assisted take-off, published in Flight on December 30th last, by no means exhaust the possible methods of attaining this end. Boundary layer control, by suction, applied to the air flowing over the cambered surfaces of the fuselage and wings is yet another method, which not only assists the take-off; it also presents a more normal solution without loose and detachable odds and ends. The scavenging of the boundary layer takes place through a number of openings or slots located on the fuselage or wings near the point where separation occurs and turbulence begins, and practically eliminates turbulent air flow with its enhanced drag; as a result the lift is considerably increased and the drag is reduced almost to vanishing point. The quantity of air to be removed in this*vay, at 200 m.p.h., are .peed 1st the -stance* -ours, .... in • •ill , . , "*" . ,. , -..-.-— *»©•-• «» —. ;xack o. a high-speed fighter, for there is a limit to how low the high speed fighter is able to fly in order that his guns may be teainei on to a dodging or really low-flying aircraft. In substantiation of these views, I may add that my duties include flying both the Typhoon and Taylorcraft Auster and when I have flown in mock-combat from the seat of either machine, I have been able to assess values to the conclusion that m defensive tactics, the low-speed " ultra-manoeuvrable " .aircraft is more than a match for the high-speed fighter. It further explains how on one occasion nine Messerschmitts set upon a lone Auster and failed to register a single hit, and also accounts for the extremely low losses suffered bv the Taylorcraft Auster throughout the Middle East campaigns. I am convinced that the Germans are not loth to fly low down under any conditions and that it is purely a question of manoeuvrability and the high degree of skill of the A.O.P. pilots which has given the Auster such outstanding success CHIEF TEST PILOT, Taylorcraft Aeroplanes (England), Ltd. I Gas Turbines and Jet Propulsion for Aircraft I [ By G. GEOFFREY SMITH, M.B.E. A second edition of the above booklet is now available from "Flight" publishing offices. The new work consists of ten chapters and includes many illustrations. Price 3/6 plus 3d. post. !
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