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Aviation History
1948
1948 - 0218.PDF
igo FLIGHT FEBRUARY 12TH, 1948 CORRESPONDENCE The Editor does not hold himself responsible for the views expressed by correspondents. Th: names and addresses of the writers, not necessarily for publication, must in all cases accompany letters. THE INFORMAL LIGHT AIRCRAFT COMMITTEE Importance of First-class Maintenance I WOULD like to endorse the remarks of W. J. Andrews,Chairman, the Society of Licensed Aircraft Engineers (Flight, January 29th) on the report of the Informal Light Aircraft Committee, particularly in so far as it affects that essential but oft-maligned individual the Licensed Aircraft Maintenance Engineer. On studying the report, it is painfully obvious that the committee have displayed a lack of appreciation of the absolute necessity of first-class maintenance and subsequent economic operation if they really consider the services of one qualified to hold the position of Chief Engineer are to be obtained at a salary of some ^500 per annum. It was, perhaps, a pity that the committee did not discuss the question of maintenance staff with the body best qualified to offer sound advice based on present-day conditions. Tnnbridge Wells. DAVID G. THORPE. •.-"•,••:;•:;.;—,• JET NOISE - -;;;.;,:.,.....,,,,,. A Question of Frequencies ' IT was with great interest that I read the two paragraphson Jet Noise on page 135 of Flight of January 29th.It states that most of the complaints of deafness come from personnel actually working on the engines. I believethat loss' of balance is one of the physical defects attributed to this so-called supersonic sickness; I think super-audiblesickness would be a more suitable name for it. The theory at present set forward for this loss of balance is as follows : — The high-frequency vibrations set up by a jet engine attack the nerve (8th nerve) running from the 120 deg "spirit level" in the ear to the brain, so that although the spirit level functions, no message is carried to the brain, and the person so affected does not realize he is leaning over until he falls. There has been a case here in Hendon of a lady of about65 years of age complaining of drumming noises in her ears. On checking up, it has been found that her attacks corre-spond with the times that de Havillands have been carrying out jet engine tests, 18 miles away, at Hatfield.As is common knowledge, H.F.s cannot travel far, and are hardly likely to have been the cause of the above case. Lowfrequencies, on the other hand, travel farther, but jets are not much troubled by them. -They do, however, producenoises of 100 db plus at the 10,000-30,000 c/s bands. The Goblin is very noisy around 2,000 c/s.Further, it is a common phenomenon for test-bed noises to be heard more easily at, say, 15-20 miles than close to.I hop» this information may be of some interest. Hendon, N.W.4. < GURNEY SMEED. AIR-CONDITIONING OF FLYING BOATS Standard Equipment in Large American Aircraft I SHOULD like to take the opportunity of expressing mysincere appreciation to Mr. J. Lankester Parker for hisinteresting letter published in your Correspondence page in Flight of October 23rd, 1947. Whilst I feel honoured that Great Britain's foremost testpilot of flying boats, and flying-boat research specialist, should be good enough to reply to the points I raised in my letterpublished in your journal on October 9th last, at the same time I do feel some of the reasons he puts forward are notentirely satisfactory for. my digestion, even though I can hardly call myself a qualified aeronautical engineer. His argument that uncomfortably high temperatures experi-enced in the tropics are just as applicable to other forms of transport, and even houses, 'cannot be taken as a logicalexcuse for the lack of solving "these problems" on flying boats and other large transport aircraft. Moreover, it is a well-known fact that Pullman-type motorcoaches and first-class railway carriages have been fitted with successful air-conditioning equipment for the past ten yearsat least—that is, of course, when they have been built for specific use in the tropics in many countries all over theivorld. So, too, have large numbers of public buildings, and even the private houses of the wealthy who can afford to havesuch equipment installed. Naturally, in producing such equipment, the manufacturershave not been handicapped so much by the question of weight, power plants and the rigid utility that such air-conditioningequipment would require in the case of large transport aircraft. In front of me I have details of American "portable" air-conditioning equipment which is proving itself quite satis- factory in such well-known U.S. transport aircraft as theConstellation (model 6/749), the Douglas DC-6,.and the newer Boeing Strathocruiser (yet to go into airline service) : suchequipment is capable of operating when these aircraft are on the ground in temperatures of 100 deg. F upward. Surely if our American friends have made such presearch into "these problems" and have produced equipment to overcome them (incidentally it should be notedthat this air-conditioning equipment is fitted as "standard" on all three of the types mentioned, i.e., not as an expensive"extra" as suggested in Mr. Parker's letter), it certainly is up to British aircraft engineers, with their refrigeratorspecialist colleagues, to design and produce air-conditioning equipment as our American friends have done, and not towait until such an important ancillary is in use for several years in American airliners before British manufacturers decideto adopt it for bur big transport aircraft. Cairo, Egypt. DENNIS M. POWELL. PARACHUTES FOR CLUB FLYING Scarcely a Worthwhile PrecautionY OUR correspondent, Terence L. Kelly (Flight, January29th) raises the question of the use of parachutes in club aircraft. I think that, if he studies the statistics of two decades, orborrows from the recollections of those whose experience covers a similarly long period, he will find that accidents to clubaircraft involving structural failure, or collision at a consider- able height, where parachutes might have saved lives, havebeen so rare as to make the wearing of a crash helmet in a saloon car appear a much more worthwhile precaution. Having made this point in the interests of perspective, Imust add that I am in complete agreement with Mr. Kelly. Parachutes should be provided for those who require them,and it may interest your readers to know that the Derby Aero Club has two parachutes regularly maintained for the useof its flying members. ' R. L. PORTEOUS, Derby Aero Club. Chief Instructor and Secretary. FORTHCOMING EVENTS Feb. 12th.—Royal Aeronautical Society : " The Aerodynamics of the Gas Turbine." A. R. Howell. Feb. I4tn.—Fair Oaks Aero Club : St. Valentine's Day Dance. Feb. 18th.—Royal United Service Institution : "The Strategic Offensiv- Against Germany." Air Chief Marshall Sir Norman BottO'fflfb> ley. K.C.B., C.I.E., D.S.O., A.F.C. ^ Feb. 23rd.—R.Ae.S. (Bristol): "Accidents and Their Investigation." Air Commodore Vernon Brown, C.B., S.B.E., M.A., F.R.Ae.S. Feb. 25th.—Royal United Service Institution : " The Home Fleet in the War." Vice-Admiral Sir Patrick Brind, K.C.B., C.B.E. Feb. 25th.—R.Ae.S. (Graduates and Students) : " Suction Aerofoils." B. Thwaites. Feb. 26th.—Royal Aeronautical Society : " Evolution of the Design of an Aeroplane." Prof. R. L. Lickley, B.Sc, D.I.C., F.R.Ae.S. Feb. 26th.—R.Ae.S. (Manchester) : " Naval Aircraft." Capt. Fancourt, R.N. Mar. 3rd.—R.Ae.S. (Bristol) : Prize-winning Papers by Junior Members. Mar. 4th.—R.Ae.S. (Gloucester and Cheltenham) : " Ths Development of the A.S. Type Gas Turbine Engine," W. H. Lindsey, M.A., A.F.R.Ae.S. Mar. 10th.—-Royal United Service Institution : " Progress fn Aircraft Design," B. N. Wallis, C.B.E., F.R.S. Mar. 12th.—Institute of Navigation : " Air Sextants." P. F. Everitt, B.Sc. Mar. 18th.—Royal Aeronautical Society : " Flight Testing at High Sub- sonic Speeds." H. Davies, B.A., M.Sc., A.F.R.Ae.S. Mar. 22nd.—R.Ae.S. (Bristol) : " Operation of Civil Transport Air- craft." N. E. Rowe, C.B.E., F.R.Ae.S. Mar. 31st.—Royal United Service Institution : " Atomic Energy." Prof. H. S. W. Massey, F.R.S. Apr. 1st.—R.Ae.S. (Manchester) : " Flight Refuelling." C. H. Latimer Need ham. Apr. 3rd.—Royal Aeronautical Society : Full Day Discussion on Safety in Civil Aviation. Speakers : A. V-M. D. C. T. Bennett, C.B., D.S.O., F.R.Ae.S. ; Prof. A. A. Hall, M.Sc., M.A., F.R.Ae.S. ; Dr. K. G. Bergin, M.A., M.D., M.B. Apr. 14th— R.Ae.S. (Graduates and Students) : " The influence of the Recent Civil Airworthiness Requirements on Civil Aircraft Design." W. Tye, B.Sc., F.R.Ae.S.
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