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Aviation History
1950
1950 - 1358.PDF
86 FLIGHT, 13 July 1950 CORRESPONDENCE The Editor of "Flight" does not hold himself responsible for tlie views expressed by correspondents in these columns. The names and addresses of the writers, not necessarily for publication. nius>- in all cases accompany letter;. Deck Landing Longer Ago HPHE iirst British arrester gear trials were not, as stated•*• by Sqn. Ldr Bunn in your issue of June 29th last, made with a Fairey .Flycatcher on H.M.S. Courageous in 1930- Soine eailier ones, and I doubt if they were the frrst, weremade with a Sopwith Pup on the aft flying deck of H.M.S. Furious in 1918, a couple of wars ago Not many of these were highly successful—which is notto be wondered at, in view of the gossamer-like wing loadings of that epoch and the turbulent mass of hot gases emittedfrom the midship funnel C. B COLLINS. Croydon, Surrey Consumption, Temperature and Speed IN the article about the jet transport conference in Flight ofJune 15th-it was stated that airlines will need lorecasts fpr upper air temperature accurate to within 5 deg C. Noreasons are given for the need for this accuracy and to the writer it seems questionable. The major criterions for airline operation would appear to betotal fuel consumption and true air speed for the journey If we compare the results obtained with an aircraft flyingat a certain altitude under different temperature conditions, we see that the effect of the lower temperature is to require anincrease in engine fuel consumption, so as to fly the aircraft at the same true air speed. Alternatively, if the fuel con-sumption is maintained constant the aircraft speed will be reduced. This is because horsepower is very nearly propor-tional to fuel consumption, while the drag of the aircraft is mainly a function of Mach number (for a given all-up weight). Considering now some figures to indicate the extent of thiseffect it may be said that a change in temperature of 5 deg C results, for a given Mach number, in a change in aircraft speedof less than 5 m.p.h. for a mean aircraft speed of 400 m.p.h. However, that is not all. if the aircraft were to increasealtitude slightly it would be possible to continue at the original speed without appreciably increasing the fuel con-sumption ; this would be possible because the air density would increase due to the temperature drop. If the aircraft were to increase its height to a level where theair density was equal to the original density before the tem- perature change (about 500 feet for a change of 5 deg C in theregion of 30,000-35,000 feet) then the drag would, in fact, increase due to a Mach number increase. This, however, wouldbe offset to a large extent by an improvement in the engine cycle efficiency. It seems to the writer theretore that this high degree ofaccmacy in temperature forecasting is not essential. As for the iorecasts of wind velocities, surely some of thebenefit of high cruising speeds is the relative independence of met. wind forecasts in that they sink into relative insignih-cance. 1 can think of no other excuse for the abandonment of the very comfortable flying-boat transatlantic B.O.A.C.service for the high speed Constellation service—which, how- ever, requires quite all the hours saved to recover from itsafter effects. Similar feelings, 1 am sure would be expressed with regard to any of the modern, fast landplane services. G. A. LEWIS Acocks Green,Birmingham 27. Safe and Practicable IN Flight of June 8th there appeared a report on the I.A.T.A.Technical Conference held at Asbury Park, N.J., last May. It was noted that the "Communications Working Group"had discussed the merits of R/T versus W/T, and had found the former was entirely "Safe and practicable" for air-to-ground communication. If such a statement refers to aerodrome, or even area, control,their findings could be accepted. However, if they also in- clude oceank control, then the Working Group has surelybeen misinformed of the real facts. Only last week an aircrait (not British) flying across theNorth Atlantic did not contact an aeronautical ground station for over two hours Something had gone wrong with the"Safe and Practicable " radio-telephone. Perhaps led astray by I.A.T.A 's confidence, this aircraft was not carrying aradio officer and therefore was not able to advise oceanic control by radio-telegraph that all was well. As a conse-quence, an "Alert" was broadcast. Other aircraft making a similar flight but able to communicate on W/T had nodifficulty in maintaining continuous contact with either side of the ocean as appropriate. This is not an isolated incidentwhere, in W/T versus R/T, the latter has been found sadly unreliable. The Working Group go on to say that I.C.A.O. has beenasked to expand the use of R/T as a primary means of com- munication on long international routes. It is humbly suggested that the Working Group get to workimmediately, contact representative aircrew organizations in Britain—and find out from those who really know by practical.experience what goes on along the airways. Bristol. 9. A. R. PARTRIDGE. • PARENTS at PANSHANGER STUDENTS of the de Havilland Aeronautical TechnicalSchool, their parents and friends, enjoyed a most pleasant afternoon on Saturday, July 1st, at Panshanger, the head-quarters of the London Aeroplane Club and No. 1 Reserve Flying School. It was a delightful event with the unflurried,leisurely atmosphere of a family party—-which, indeed, in a sense it was. Highlight of the afternoon was the presentation to the Club of its first Chipmunk. Pat Fillinghain flew it from Hatfield, and then Sir Geoffrey de Havilland formally handed over the aircraft and documents to F/L. CatHer, the C.F.I, of the Club. •Following this ceremony, No. 1 R.F.S. Tiger Moths aud Chipmunks demonstrated some air drill, after which Chris Beaumont showed an appreciative audience wfaat re-heat meant to a Vampire. He finished with a high-speed run across the field at about 3,000ft, thence pulling up into a 30-deg climb until he vanished from sight at about 15,000ft. Geoffrey Pike, who made the first flights ofboth Dove and Heron, showed off the later machine, which has now completed some 60hours' flying. The Heron was, admittedly, flying light, but the shortness of its take-offand landing runs were revealing, nevertheless. The afternoon's demonstration flying waswound up by John Derry, who gave one of bis unrivalled expositions of a Vampire 5. Hisveil-known '' vertical reverse '' manoeuvre was particularly appreciated. Following the dis-play. No. 1 Reserve School then resumed its normal flying programme. Sir Geoffrey de Havilland (extreme left) withF/L Cather and members of the D.H. Edu- cation Board, after the presentation of theLondon Aeroplane Club's first Chipmunk.
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