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Aviation History
1950
1950 - 0044.PDF
2ft FLJGM2. 5 Jatvmpy 1959 CORRESPONDENCE The Editor of "Flight" does not hold himself responsible for the views expressed by correspondents in these columns, lhe names and addresses 0/ the writers, not necessarily for publication, must in ail cases accompany letters. "Reheat"P ATIENTLY I have waited for the pundits to pronounce on "afterburning" or "reheat." Like your correspondent Mr. J. Talbot (Flight, December 8th), I had noted the ambigu- ity of "reheat " and consider " afterburning " to be preferable. As a point of historical interest it may be mentioned that DugaJd Clerk, about 60 years ago, applied the term "afterburning" to his hypothesis that in the combustion of gas not all the heat was liberated by the time maximum pressure was reached, but that burning continued long after that point. If memory serves me aright, this was never substantiated. It has no currency to-day and therefore does not affect the issue. The American preference for " afterburning " is interesting, but their choice of words is not always so sound. For a turbojet unit with '' afterburning'' they have coined the word '' turbo- ramjet." In my opinion this is basically a contradiction. A ramjet is specifically a thermal duct which, by reason of its for- ward speed, effects compression of the air for combustion. It can, therefore, dispense with the mechanical compressor andy of course, the turbine which is required solely to drive it. To infer that a tailpipe afterburner is a ramjet because it receives the high-velocity turbine efflux is surely false. The working medium of a ramjet is atmospheric air; in an afterburner the air is contaminated by nitrogen, carbon dioxide and water vapour. No useful energy can be obtained from a ramjet while stationary on the ground or moving at low forward velocity; an afterburner, however, can materially augment the thrust of a turbojet when static or during take-off. Coventry. F. SINCLAIR. Safety Fuel? I SHALL be glad if one of yotrr technically minded readerscan tell me whether the following idea could have any scientific basis for development as a safety measure. With the introduction of gas turbines and the simplification of aircraft engines, is it possible to mix some substance with the paraffin so that it is non-inflammable in bulk when stored in the aircraft tanks? And would it then be possible to include a device (mechanical or chemical) to separate the substance from the paraffin just before it is burned? Chesham Bois, Bucks. N. H. MAPPERLEY. Jets—U.S. and British " I FEEL I must comment on your leader, "Jet Awakening,"in Flight of November 24th. To quote you: "Yet of all large post-war civil projects in this country, the Comet owes most to private enterprise and capital—though not, perhaps, to the extent of $25,000,000 to $30,000,000, the figure quoted by Capt. Eddie Rickenbacker for the development of a com- parable aircraft." Surely, the recent announcement in the public Press by the Minister of Supply to the effect that the Comet has so far cost the country ^4,000,000 (at pre-devalued £1 exchange rate 16,000,000 dollars) is not exactly private enterprise, or far out in equivalent U.S. costs quoted by Capt. Rickenbacker. Then again, do we really know what the American engine makers are doing? How is it the Shooting Star engines are running authorized overhaul lives in excess of our Meteor engines, to say nothing of the fact that one of their standard fully equipped fighters holds the world's air speed record ? Credit where credit is due, please, Mr. Editor, without too much complacency. Time will tell whether we shall sell our jet airliners abroad in any quantity; and please pep up our aircraft makers for the proposed New Zealand Air Race in 1951, because they had better not "lay on their oars" too much, for time aad American aircraft fly very fast Paisley. P. W. LAMBELL, A.S.Ae.S. [The statement by the Minister was obscure. The ^4,000,000 referred to breaks down as follows:—Development of the Ghost military turbojet for the Venom and for export (Saab J-29), ^2,000,000 (every sizeable civil transport to-day is powered by engines developed in the first place for military purposes, and this sum cannot fairly be charged against the Comet. Of the ,£2,000,000 remaining, about half the cost of three D.H.108 research aircraft can be charged against the Comet and the other naif against military aircraft to come. In addition, the whole cost of two Comets bought at ordinary commercial price, plus a very small advance m connection with testing, is represented in the sum. The M.o.S. requirement for two high-speed, four-jet research aircraft has no direct connection with Comet development. Any direct contribution towards the Comet airliner, other than encouragement and advice, is thus fairly insignificant. The J-33 overhaul period is 300 hr, while that of the Der- •went 5 is at present 200 hr and may very shortly be 250 b. The J-33 is a direct development of early Power Jets designs and has been operated on a large scale for a number of years (Over 1,400 Shooting Stars have been built). The overhaul period of the Goblins in service is 600 hr. The amount of day- to-day squadron maintenance between overhauls is ignored in this argument.—ED.] Wheels-up Landings A PILOT attempting a crash-landing will often choose to leave **• his undercarriage retracted, this being the only way, at present, of landing an aircraft on rough ground. A flying-boat forced down on to rough ground fares better as a rule, due to the design and strength of the hall, which is admirably suited to "glider" landings Why not, therefore, make crash-landings provision on land- planes, using reinforced fuselage bottoms, or, better still, ar- ranging for a retracting skid or emergency landing wheel ? One landing-wheel or skid, centrally placed, would be better taan nothing in the advent of •undercarriage failure. Lateral control can be maintained at speeds considerably less than flying speed; thus, with a central balancing-point of some kiad, an aircraft could lose a great deal of its speed before a wing-tip hit the ground. Also, consideration should be given to the possibility of lock- ing an undercarriage at, or about, the half-retracted position, which would keep the aircraft's fuselage clear of the ground whilst minimizing the tendency to dig in which occurs with a fully extended undercarriage on contacting rough ground. Furthermore, is it really necessary for an aircraft to fly around for hours simply to use up petrol before attempting a crash landing ? A jettison valve can be fitted, widen couid be farther arranged to ensure a small reserve of fuel with which to make the final nm-na. Congratulations to yon <m the production at a fine journal. FEBTUKBED DESIGN DRAUGHTSMAN. ! Southampton. ' FORTHCOMING EVENTS '»«. 7. British Interplanetary Society : "The Circum-lunar Rocket," by K. W. Gatland and A. E. Dixoti. Jaa. II. R-Ae.S. (Weybridge) : Brains Trust. •• Jan. II. Royal United Service Institution : " Higher Defence Organi- zation," by Lt.-Gen. Sir Lestie C. Hollis, K.B.E., C.B., R.M. J»n. 14. British Interplanetary Society (Manchester) : " Space Stations," by E. Burgess. Jan. 13. Royal United Service Institution : " Airfields in a War of Movement," by A. Cdre. T. G. Pike, C.B., C.B.E., D.F.C. Jan. 19. R.Ae.S. Section Lectures : " Acoustical Aspects of Recent Aerodynamic Research " (joint symposium with Acoustics Group of the Physical Society). Jan 20. Institute of Physics (Manchester): " Temperature Measure- ment," by J. A. Hall. Jan. 20. London Aeroplane Club : Annual Dinner Dance. Jan. 24. R.Ae.C. : " Air Travel through the U.S.A." film by William Courteray, M.M. (At Londonderry House.) Jan. 31. R.Ae.S. Section Lecture : " Further Problems of Aircraft Stressing," by J. H. Argyrhs, A.F.R.Ae.S. Feb. I. Royal United Service Institution: *" Aircrartt for Army Uses," 4»K Lt.-Gen. R. N. Gate, C.B., D.S.O., O.B.E., «£. fiefc. 4. British Interplanetary Society : Discussion—"Effects of • Interplanetary flight."* fefe. 8. R. Ae.S. (Brought "Rocket Propulsion and InserJPIanBrar* Right,- fey A. V. Cleaver, A. R. Ae. S. Feb. 9. R.Ae.S. : " ^reducing a Prototype Ainreb," by C T. Wilkms. AJFJRJteS. Pet). 13. Institute of Transport : Brancker Memorial Lectunt—A.V.-M. D. C. T. Bennett, C.B., CS.E., O.S.O. Feb. 14. R.Ae.S. Section Lecture : "Prototype Testing," by D. &. M. Dickinson, A.F.R.AcS. feb. 17. Institute of Navigation : " Air Traffn: Control," a symposium orf papers. fob. 21. *.Ae.S. f&tfihm.) : "Strength-testiinj of Aircraft," by Dr. P. B. Walker, M.A., Ph.D., F.R.Ae.S. Feb. 21. R.Ae.S. Section Lecture* " Air-lntakt Design for Htg-h-speed Aircraft," fcy Dr. J. Seddon, B.Sc.
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