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Aviation History
1947
1947 - 0119.PDF
JANUARY 23RD, 1947 . FLIGHT OPERATI ONAL TRAINER bomber, or "baby Battle" as it was mistakenly dubbed. After clearance at the A. & A.E.E., Boscombe Down, the Trainer, in charge of Mr. Menzies, set out for the Ad- vanced Flying School, R.N.A.S. Hinstock; the Navy's Operational Flying School at Lossiemouth ; the Deck-Land- ing Training and Deck-Landing Control Officer Training Station at Milltown ; and the School of Naval Warfare at St. Merryn. In France the machine was flown by French test pilots at Les Mureaux, and in Holland by pilots of the Netherlands Navy at the Operational Flying School, Valkenborg. Mr. Menzies confirmed on his travels that a relatively high percentage of mishaps occur as a result of incorrect handling, on or near the ground, by pupils unaccustomed to the "feel" of modern high-performance fighters with relatively high wing loadings. An average pupil may need four hours or more to familiarize himself with a modernfighter, and expensive accidents are not infrequent. The Firefly Trainer differs essentially from the Mk Ifighter-reconnaissance machine in having the reaT cockpit raised i2in above the normal position and in having two,instead of four, 20-mm British Hispano guns. This arma- ment, of course, is adequate for gunnery training. It ispossible to carry R.P.s or bombs as on the first-line aircraft, and dive-bombing and R.P. firing results should certainlybenefit as the instructor is able to note the manner in which the pupil brings his sight to bear. Apart from offering instruction in instrument-flying, theFirefly seems to provide an ideal means of making periodic checks on instrument-flying proficiency. In air-to-air com-bat, as in R.P. firing and bombing, the instructor can aid in perfecting the pupil's technique of approach and break-away. Finally, having the full deck-landing equipment carried by the operational Firefly, the Trainer enablesinstruction to be given in carrier approach and landing technique. " Indicator " Discusses Topics of the Day y To-morrow is Not Another Day Some Implications of Really High-speed Air Travel • Structure and Passenger Loadings : End of the Quess and Qod Technique SLOWLY but surely—and just as Einstein's andBohr's theories of matter and space eventuallyreached the ordinary person in somewhat garbled form—some of the facts and difficulties of high-speed airtravel are beginning to leak out. In a year or two, and probably when the technicians find that they really have,after all, solved most of the problems, the knowledgeable chap in the local will have reached the point of discus-sing gust loadings, bump conditions at high levels and the faults of radio approach systems. That is how italways has been. In the meantime, I feel that the worst might well beunderstood now so that too much will not be expected too quickly and the eventual achievement involved in the safeand regular operation of a 500-m.p.h. air service will be fully appreciated. As Dr. Spiiffing recently remarked, itwill be necessary for passengers to hold on to their hats very tightly when passing the speed of sound ; further-more, it will be necessary for these hats—and the passen- gers' bowels—to be held even more tightly at very muchlower speeds unless the greatest care is exercised in flight- planning. And the stresses on the hats and bowels will,all the time, be repeated jn the aircraft's structure. I have certain very powerful recollections of the physi-cal meaning even of a mere 450 m.p.h. in an aircraft which is passing through mildly rough patches of air.With everything stowed safely and while wearing a Sutton harness pulled down as tightly as it was possible to do so,fche effects were little short of frightening. Having con- vinced oneself of the improbability that one would actuallypart company with the aircraft, it was still quite impos- sible to feel convinced that the wings wouldn't part com-pany with the fuselage. Meanwhile, an otherwise direc- tionally stable machine might start a rhythmic weavingmotion, which it was impossible to combat with accuracy, and one wondered about the strength of the back parts. When the particular cubic area of roughness had beenfinally passed, one rejoiced not so much in the skill of the designer, the care of the constructor and the reliability ofaerodynamicist's guessings as in the essential flexibility of structures in general. I won't go into the gust-loadingsituation—even if I was capable of such an erudite exposi- tion—but it is obvious that the faster the aircraft the moresudden and violent are the changes in the air forces in- volved. As a matter of interest, I believe that the record- breaking Meteor, even in conditions which would be con-sidered to be quite smooth by normal standards, was suffering accelerations of the order of 6G during some ofits practice runs. In the earlier attempt at Herne Bay the pilots waited week after week for smooth air, andwere very lucky to find such conditions as soon as they did. At speeds over 500 m.p.h. even the faint ripplescaused by a gentle off-shore wind were quite shattering in their effects. Of course, the obvious answer to all this is that thesehigh-speed long-range transports must fly really high. But bumps are met even at 30,000ft over to tops ofcumulus and, in any case, the aircraft cannot actually start its flight at operating height. There is, indeed, nopositive proof that rough air will not be met at very much greater heights ; we are only guessing that it is alwayssmooth at 50,000ft. Fortunately, the temperature of the atmosphere appears to remain more or less constant overabout 36,000ft, so that, subject to the successful pressur- ization and conditioning of the interior and to the satis-factory operation of jet units at high levels, there are no reasonable Mach number limits to the altitude at which anaircraft can fly above this figure. Even so, at 36,000ft an aircraft flying at a true speed of 500 m.p.h. is facingMach number conditions expressed by the figure 0.75— which is quite high enough from the design point of view.It would be necessary for the aircraft concerned to have good flying and handling characteristics at a Mach num-ber very much higher than this in order to be on the safe side. Long Range Short Duration There are other parallel considerations, too. Any purejet high-speed transport will have a long range only at this high speed—its actual endurance will be comparativelylimited. Consequently, if it is to have a safe reserve of miles in hand there can be no loitering during the climb,while passing through bumpy air, or, perhaps, while being forced to fly at comparatively low levels under interme-diate levels which may be icing too heavily for a climb to be possible. The flight-plan will need to be rigidly held,or the schedule abandoned. There is one good feature here. If an Atlantic crossingcan be made, say, in five hours, the meteorological fore- casts over such a short period are likely to be accurate and
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