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Aviation History
1945
1945 - 1821.PDF
294 FLIGHT SEPTEMBER 13TK, 19.35 The Editor docs not hold himself responsible, for the views expressed by correspondents. The names and addresses of the writers, not necessarily for publication, must in all cases accompany letters. mention, ,:,oin Sir Roy Feddim. • . • ; GAS TURBINE DEVELOPMENT " . . A Valuable Contribution Overlooked TURING the last year or two many references have beer, jJ made in Flight in regard to historical associations in con- >,ecti«i with jet engines and gas turbines. "\Vhen preparing the text for .my Wilbur Wright lecture in y-.i, 1 made a considerable search in regard to pioneer v.-ork luVhis subject, both in this country and abroad. Ko mention 'owever, has been made of a valuable British contribution which has recently !,ecn brought to my notice. I nave just returned from a special technical mission to Germany lasting ..bout a mouth, which I had the honour to lead on behalf of the Minister of Air- crafi Production. Attached to our group was Mr. W. J. Stern, of the M.A.P., who acted as interpreter in the many interro- gations that were held. One of the subjects that we were in- vestigating was jet engines, and early on 1 was impressed with the grasp that Mr. Stern had of the whole subject and the assistance that he gave me in these investigations. On my return, I dis- covered that he had been.employed on therrnodynamic investigations at the Air .Ministry laboratory as early as 1920, and I have dug up and read with great interest an official publication entitled " The Internal Combustion Turbine " "(Engine Sub-Committee Report .No. 54, dated September 20th, 1020, published by the Director of Research), compiled by Mr. stern when he was serving at the Air Ministry laboratory at South Kensington. This is a most interesting review 01 87 pages with a number of illustrations and diagrams. It sets forth the state of the art of the piston aircraft engine at the time (viz., 1920) in relation to the possibilities of the gas turbine, and I cannot understand why it has been, missed as I think it is a document oi considerable merit and value. I thought therefore that you would be interested for me to call your attention to this report when this subject is so much in the limelight, as I cer- tainly think Mr. Stern should be given credit for having made a valuable contribution to the problem a long time ago. ROY FEDDEN. CENTRIFUGAL FORCE No More Contributions, PLEASE ! rTHE letter from Fit. Lt. Cohen in •*• our August 16th issue has brought a flood of replies. It is gratifying that so many readers have shown their willingness to help a puzzled reader out 0/ his centrifugal torment, but it is quite impossible: to find space for the many letters, and we can only tliank our many contributors; the centrifugal force they generated nearly threw us out of our revolving chair. ' THE EDITOR. WAR SECRETS A Somewhat Half-hearted Experiment TN Flight, July 19th, in "Here and There," there is a para- •*• graph headed " Another War Secret," in which is described an experiment made in November, 1940, with a form of aerial mine attached by a length of piano wire to a parachute and dropped in the path of invading bombers. I submitted just this scheme to the Air Ministry in June,: 939, and was then told that it was an old idea which "did R. and M. 1933: On the Drag of Circular Cylinders at High Speeds. By A. E. Knowlei, M.Sc, Ph.D., and F. W. Pmden, oi the Aerodynamics Division, N.P.L 10 pp., 19 diag, Feb. J&th, 1944. zs. 6d. net. - Measurements have been made of the drag of circular cylinders of -fc to lin. diameter-at speeds up to M=o.S5 by means of the electrical balance in the Circular High-speed Tunnel and by pressure, plotting round cylinders of gin. and S"ln- diameter in the Rectangular High-speed Tunnel. The measurements were annfincd in the main to cylinders which "id not show the usual critical drop in CD at a Reynolds cumber near 0.25x10". The value of CD started to rise at arxnrt M = o.35, after which it rose at an increasing rate to a 7this was succeeded by a minimum .75 and asharp rise at M = o.85. The speeds at which ••ne maxima and minima of the curves occurred for cylinders °' various diameters were used to correct for tunnel interference not add to their existing knowledge," and that there was in fact nothing secret about it. In January, 1941. I again raised the question and was told (in March) that there was nothing to be added to the reply I had received in June, 1939. What is surprising in the account now published is that it is described as " a desperate defensive measure," that the Trial was confined to four obsolete Harrows carrying a total 01 0,1'iy 720 mines, and that in spite of this at least three enemy bombers were definitely brought down. Apparently as " only ' three were known to have beer, destroyed the idea- was abandoned and operation Mutton was quite dead. On the face of it, this seems to have been a somewhat half-hearted experi- ment, and the conclusion reached entirely at variance with the comparative succesb attained. One wonders—in view of the punish- ment our cities were then taking frqm the German bombers — what the results would have been if a sizeable force oi the Wellingtons then available had beea used with this weapon, in conjunction with radio and searchlight control, on the bomber lanes. There seems to be something wrong somewhere. K. E. CARROLL, [The item, as it appeared in Flight, was taken from an official Air Ministry news bulletin.—ED.] 35 whc niaximurn at about M=o.7; fit M=o.7 a'shar rise n i BOMBERS OR ROCKETS Were the Atomic Bombs Necessary ? X~N his article in your issue of September 6th, entitled"Bombers or Rockets," Mr. A. V. Cleaver quotes from a previous article oi mine, in which I questioned the effect of bombing in driving a nation to surrender. The words which he quotes were: " We have yet to see if the late of Japan will afiord any evidence." On this Mr. Cleaver comments: "Xow indeed we have seen; within ten days oi the dropping of two atomic bombs on Hiroshima and Nagasaki, Japan surren- : dered." I agree that at first I believed that it was the effect of those two bombs, followed by the Russian declaration of war, which induced the. Japanese to surrender. But in T'te Times of September 6th it is reported that a senior official of the Domei Kews Agency told correspondents that the Emperor had de- cided as early as June 22nd that Japan must surrender, and told his Cabinet Ministers and Elder Statesmen of his decision. The Emperor, according to this account, did not carry his ;ioint at first, and subsequent meetings were held. But he asserted his authority at a final Cabinet meeting on August, 14th, and announced that he would broadcast to the people. If the Domei Agency is believed, it appears that the atomic bombs were not the deciding factor; and, indeed, the position of Japan was already so hopeless that surrender was the only sensible thing. ' F. A. I>E V. ROBERTSON. in the circular tunnel. Photographs were taken of the shock wave system in the Rectangular Tunnel at various speeds. R. and M. 1951 : The Measurement of Tailplane Stiffness. By J. Taylor, B.A., Communicated .by the Director of Scientific Research, Ministry of Aircraft Production. 7 pp., 3 diag., July, 1939. is. 6d net In view of the possible necessity for a stiffness requirement for tailplanes and to assist research work on tailplane flutter, static tests have been made of a number of tailplanes to provide typical stiffness data. As the section to which the require- ments would apply has still to De denned, tests were made at two sections suitably positioned to allow of estimation of the stiffness over a considerable span of the tailplane. A method has been evolved from the tests which should be satisfactory for routine use on all types of tailplanc design. An appendix deals with the design of the wooden frames used to apply the loading.
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