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Aviation History
1946
1946 - 1108.PDF
568 FLIGHT JUNE 6TH, 1946 CORRESPONDENCE The Editor does 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. FLIGHT OF BIRDS The Strongest Leads the FormationI N answer to your correspondent's question about the " V "- formation flight of birds Flight, May 9th), observation has confirmed the fact that the reason for this formation is aero- dynamic. The leader of the "V" is the strongest bird, and the arms of the "V" contain birds that become progressively weaker towards the ends. The geese, or whatever they are, appear to be in some way aided by the slipstream of the bird ahead, and the weaker birds gravitate automatically to the easiest positions, i.e., at the tails of the "V." Incidentally, observers should beware of applying too much orthodox fixed- wing theory to ornithoptic flight. In connection with previous letters to your magazine, it may safely be said that no healthy bird will spin for more than one turn unless it intends to; the degree of control is far greater than on anv fixed-wing aircraft. 'A. R. FORREST. AN ACCESSIBILITY DANGER Hinged Leading Edges as "Potential Accidents" ON reading the description of the Bristol Wayfarer I amshocked to see that a new design should have a potential accident built into it. I am willing to bet that the Wayfarer will, sooner or later, fail to unstick or take-off through the accidental opening of a leading-edge inspection panel, and as long as such wing panels exist and are arranged to open outwards the danger will always be there. In my own small experience I have known the following to happen: Wellingtons have failed to unstick with the refuel- ling covers open; Bostons and Blenheims have failed when fully loaded with the gills left open; I have known a Lancaster refuse to leave the ground when the leading edge lifted; and a Defiant crashed when the landing light panel blew out. So long as quick-release panels are built into the top surface of a wing they must occasionally blow out. Cannot we learn from the past and screw them down? The Chinese say that it is " better to save one life than to build a seven-storey Pagoda." HAPPY TAKE OFFS. [Although we agree with our correspondent that such a danger does exist, it would seem that the many advantages of a hinged centie-section leading edge outweighs any risks involved It is unlikely that the leading edges either of the Wayfarer or the Dove could possibly blow open when properly fastened, but the greatest possible attention must obviously be paid to means by which the ground staff can be " drilled " in the need for check and countercheck in such matters. Some- thing on the lines oi a wing-folding warning device, or of the usual undercarriage and pitot-head cover " flags," could easily be arranged to deal with the situation. Any such warning system should, of course, be planned so that neither ground nor air crew could possibly overlook it. Certainly, the results of leading-edge distortion or displacement can be catastrophic. Even the departure of the tiny "man-hole" cover in the Spitfire fillet could be unpleasant, and the blowing-in of a Beaufighter landing-light cover was a deal worse than that. Yet gun-panels, further aft, could leave without appreciable results.—ED.] THE JAMESON AIRCRAFT ENGINE Very Creditable Figures ObtainedI HAVE read with considerable interest your excellent de- scription of the Jameson engine, which is a fine piece of design and evidences some very careful and ingenious drawing office work. The figures are good, but bearing in mind the layout, I doubt whether engineers generally would go so far as to confirm your rather forthright statement that as a re- sult of this design " the reciprocating type of I.C. unit will be given a completely new lease of life." The hypotheses, and the explanation of what occurs in the induction system seem also somewhat debatable, particularly in the absence of data regarding the valve timing. The pro- gressive variation in mixture strength per charge, may or may not be obtained as per your diagram, and in all four cylinders, but the induction pipe length and its proximity to the hot cylinders is certainly a factor in the ability to burn lean mix- tures. The reason adduced for absence of wear generally, particu- larly on bearings and gears, may be to some extent questioned, as the horizontally opposed layout running on lean mixtures^ should have an inherently high durability. However, it may very properly be contended that it is results that count rather than premises or speculations as to their causes, and the figures obtained are certainly very credit- able. . "M.I.A.E." " [We would point out that the "forthright statement" quoted (in part only) by our correspondent began with the words: ' 'If the practical application of the Jameson induction system can be extended to piston engines generally . . . "— ED.] LANDING THE HUDSON Divergence of Opinion Among Instructors " TNDICATOR" should be congratulated on yet another -1- excellent article—this time about the Hudson and Ven- tura (Flight, May i6ch). As an ex-Silloth instructor, how- ever, I feel I must set him right as to the landing procedure which really was used at this O.T.U. There was always a divergence of personal opinion between instructors as to the relative merits of " wheelers " and " three- < pointers" : the ruling generally laid down, however, was that "wheelers" should be taught at night and in cross-wind con- ditions, whilst "three-pointers" should be encouraged at all other times. If a pupil showed a tendency to cope nicely with one particular form of landing, no effort was made to force him into the other before solo-ing, though often, indeed, it was quite difficult to tell just what sort of landing was being attempted. A knowledge of both methods was desirable, as three-pointers'' were highly dangerous in a serious cross- wind, and "wheelers" unsatisfactory in no-wind conditions on the many very short runways then in use. The approach speeds recommended varied between 80 kts in zero wind to 95 kts in a bad cross-wind. The stick was cer- tainly pushed forward after making a wheel landing, but not right against the panel. The extreme form of approach land- ing described by "Indicator" was normally not used at all (except, we used to claim, by squadron-trained pilots who had never had the advantage of a Silloth course !). "Indicator" is quite right about the difficulty of going round again with full flap lowered; success could only be achieved by opening up to the maximum available power of 45in—and even then it was quite an exciting performance. D. I. C. More Pros and ConsI VERY much enjoyed reading "Indicator's" article on Hudsons, as I have many happy memories of conveying the poor unfortunates who had to travel around Aden Com- mand. I recall that, having received an hour's "dual" on a single-control aircraft, and arrived at my first destination (Riyan) in the rain, I only just repressed an inclination to ask if any of the passengers would like to try it, but thereafter I had many happy landings and I do think some of "Indi- cator's" criticisms a little harsh. Starting (in a warm climate) was reasonably simple sing handed, without the necessity, as on Ansons, Blenheims, Bothas, of having an assistant inside the engine, whilst, pro- vided that one remembered the correct rudder technique of wing lifting, take off, even on desert landing-grounds, was reasonably safe. One nasty trick it did have was that, if much engine was used to correct landing swing, that half of the aircraft would imme- diately become air-borne, and I can still see my "second's" fingerprints round his eyes when we found this out! It was quite common practice on just adequate runways to run up to about 2,200 r.p.m. against the brakes, let them off, and simultaneously finish opening the throttles, which does show that the take-off was not so bad. It is also possible, into wind, to perform at least one out of two landings with no use of brakes, provided that the tail was dropped gradually, and rudder used to the full. Much of the adverse criticism received by the Hudson was due to just plain old age, the accumulation of many coats cf dope, and failure to fly on "Hudson" rule; In any case I should like to thank "Indicator" for ;:" interesting article, and I look forward to more—what about "A Spot of Botha"? " SAD-BUT-NOT- SORRY."
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