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Aviation History
1946
1946 - 1312.PDF
FLIGHT JULY 1946 CORRESPONDENCE The Editor does not hold himseij responsible Jor the views expressed by correspondents. The names and addresses of the writers, not necessarily for publication, must in all cases accompany letters. ALTITUDE COUGH CURE Decompression a Cheaper WayI HAVE on many occasions recently seen articles in the Press regarding air-borne cures for whooping cough, and I now note that your distinguished journal has published a reference to this subject. If, as seems reasonable, there is a certain amount of justifica- tion to believe that an air trip to a certain altitude produces the right effect to cure or alleviate this illness, surely a more economical method of achieving the same result would be to use simply constructed pressure chambers in which the effects of altitude flying could easily be synthesized. I have seen such apparatus at R.A.E. Farnborough, but, of course, such elaborate equipment would not be required for the purpose suggested above. An apparatus on these lines could easily be installed in every town, and by simple control, any height or change of altitude could be simulated—in fact, as you suggest, another few thou- sand feet may have made all the difference in the experiments you quote. With pressure apparatus, patients could be taken up till they bust! R.J.SULLIVAN. [As mentioned in the article, "Altitude Research," else- where in this issue, respiratory complaints have been treated in Germany by the use of the decompression chamber.—ED.] SPEED AND. THRUST Some Simple Answers to Vexed Questions WITH reference to your correspondent's letter [Flight, June20th] on the question ol jet and piston engine capabili- ties, perhaps the following remarks may be of help to him:— (i) The airscrew derives its thrust by imparting backward momentum to a stream of fluid. At the same time, rotational motion is imparted, but the work done in imparting angular momentum is wasted. The question of airscrew efficiencies precludes the use of thrust as a measure of piston-engine capa- bility, the airscrew efficiency varying widely with different con- ditions. The only true measure foi any given set of conditions is a b.h.p. measurement obtained by dynamometer. (ii) In the case of the jet engine we have no intermediate device for imparting backward momentum to the fluid stream (i.e., no airscrew). We cannot obtain a measurement of b.h.p. on the test bench by means of the usual types of dynamometer, but we can readily measure the static thrust. (iii) With the jet engine there is no need for angular momeii- tum to be imparted to the fluid stream. It should be remem- bered that the turbine-compressor unit is not a fundamental part of the jet engine. Compression before combustion can, for example, be obtained purely by means of ram effect. (iv) The two engines are not equivalent to each other. To obtain a true comparison of capabilities under given flight con- ditions an imaginary airscrew efficiency must be included in the calculation of equivalent jet horse-power. (v) For level flight at constant speed, Thrust = Drag. This still holds good at zero speed. In this case either we have no thrust (i.e., engines stopped) and no drag in the line of thrust, or else our thrust is countered by various reaction forces, such as those set up by chocks and brakes and by ground friction. " A. E. O." NOT SO SIMPLE Practical Experiences of Strip Casualties in Burma /CONGRATULATIONS to "Indicator" on his "Not soys Simple " article. Referring to the training of wartime pilots in cross-windlandings, in my own case these were practically non-existent. During E.F.T.S. days I had one single dual on :'cross-winds,"and solo practice was "not permitted." At S.F.T.S., my log book shows two hours' dual, and three solo on Harvard IIA'Sand Master Us. From S.F.T.S. until I joined my squadron at Imphal Main, I flew 53 hours 25 min at an O.T.U. in theMiddle East on Hurricanes. During eleven months in Burma, all the strips were singleclearings (with the exception of Meiktila Main), made from "paddy" fields with the bunkers knocked out. Flying fromthese strips entailed taking off in one direction and landing in the opposite direction. The strips were cut where the terrain made them physically possible and prevailing winds could never be considered. The strip which stands most clearly in my mind is Imphal, where terrific cross-winds were a daily occurrence, and in the latter days of 1944 it became a graveyard of Dakotas and Com- mando C.46S. At one period the crashes were on an average of one a day, and in our own squadron two new pilots who^* «.,.• joined us ended up on the opposite side of the Manipur Road •', amidst the undergrowth. The aircraft which I found most unpleasant to land in heavy cross-winds on those, muddy Burma strips was the Harvard IIA. After the first few attempts at "three pointers," and a nasty scare during one attempt, " wheelers " became universal. Neither Spitfires nor Hurricanes gave us much trouble in cross-winds after a few hours' flying under those conditions, 3'et from Imphal to Rangoon the strips all took their quota of Dakotas. Agreeing with "Indicator," I also believe that no future pilot can be really proficient if he is taught on anything but the "hard" lines. I can't see why people wish to eliminate one of the three controls, for on many occasions I have prayed that the cockpit contained a few more! JOHN INGRAM, Ex-XI Squadron, S.E.A.A.F. IN THE AIR Suggested Continuation with Light Civil Types ''THANKS, "Indicator," for those very interesting "In the -*- Air" series of articles dealing with the war's outstanding military aircraft. I am sure that many readers would welcome a series on post-war light civil aircraft. C. F. PENHALIGON. R.A.JP. TRADESMEN Treatment Skilled Men Resent AS a sergeant fitter, with ten years' service, may I say a fewwords on why the R.A.F. is having difficulty in retaining its skilled men? The difficulty of " settling down " in Service life is undoubt- edly a bugbear, but it is mitigated to some extent by the airman's realization that he can be more or less content on any normal station, providing he is what he likes to call "let alone," and it is this business of not being "let alone" that is the cause of the skilled men's flight from the Service and the grievous discontent of those compelled to continue in the R.A.F. The tradesman may be called upon to work long hours, and a great deal of unpaid overtime, perhaps, at his trade, and this he will do fairly cheerfully. But the trouble begins when work at his particular trade is slack and he finds himself at anybody's mercy. A short list of the jobs he may find himself doing includes coal fatigues, incinerator duties, the collection of dead leaves, cleaning out and scrubbing odd buildings, polishing various floors, digging and filling in holes, moving lumber about, and quite a few other tasks. All these tasks are carried out under the supervision of non-technical N.C.O.s or "trades- men," and the Service police—a very sore point. These tasks faithfully performed, he is then permitted to work overtime at his trade again, with the cheerful knowledge K that when the aircraft are serviced he may once again be-/fc\ handed over to the camp commandant or S.W.O. for further fatigues. Add to this, guard duties, etc., ceaseless changing of billets at the whims of the powers-that-be, etc., and compare it with the civilian tradesman's lot, and y.ou will see which is more likely to attract. The solution is, of course, to treat the skilled tradesman in such a fashion as to dignify himself and his job in his own eyes. (The trade union looks after the civilian.) You say "a good craftsman is worth good pay;" quite right, and it should be obvious that he is also worth decent treatment. It is clear that a little imagination and organization could enable the odd duties referred to, so demoralizing to the trades- man, to be carried out by special unskilled parties ; but whether these reforms will be carried out in my lifetime I sadly doubt. Petty irritation to the point of infuriation appears to be the motto. " SGT."
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