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Aviation History
1944
1944 - 0338.PDF
176 FLIGHT FEBRUARY 17TH. 1944 FLIC H T TESTING partial or " saw-tooth," climb tests. To determine the best climb performance i+ is necessary to know the best climbing speed at all heights from ground level to ceiling. The pro cedure found best when an observer is carried is to obtain steady climbing conditions at the chosen speed, and then to read a Kollsman altimeter at ten-second intervals over the selected height range. The required speed range should be covered systematically up and down,, i.e., the range 120-160 m.p.h A.S.I, should be covered in the order 120, 130, 140, 150, 160, level, 160, 150, 140, 130, 120. On fast-climbing single-seater fighters, an " automatic observer " is now being carried, which records the many data which the pilot cannot possibly note during the tests. Partial climbs with one or more engines " dead " follow much the same procedure a:i with all engines working, but it may l>e necessary to continue each run for a longer period of time. Having determined, for all heights, the speeds which give the maximum rate of climb, the climb to ceiling is made, using the maximum climb power and the best climbing speeds. Before a range flight can be made, accurate measurements are required of the fuel flow over a wide range of power and flight conditions. From these results, suitably corrected to standard conditions, the specific range in air miles per gallon at each of a large number of combinations of the factors involved is obtained. From this, in.turn, the optimum con ditions can be selected and the maximum operating ranges in still air determined. An actual range flight is then required as a practical check on the ideal range. Fuel flow is measured by the Kent flowmeter, which comprises two units, a trans mitter installed in the last fuel pipe to the carburettor, and a receiving unit in the cockpit. The actual range tests vary with aircraft types, but, in general, a series of runs is made in each supercharger gear at a height slightly below the full-throttle height for maximum weak-mixture cruising conditions. Fuel flow and speed are Aircraft of the Fighting Powers, Vol. IV. Compiled by H. J. Cooper and O. G. Thetford, and edited by D. A. Russell. Harborough, £1 is. T HIS attractively presented book fives up to the standard set by its forerunners and forms another annual instalment in what is virtually a chronological record of military aviation during World War No. 2. It deals with 16 British, one Cana dian, 47 American, 10 German, one Russian and one Japanese aircraft, according the same amount of space to every one. In spite of present-day obstacles (of which "security" is not the least) this book gives a surprising amount of information and achieves a laudable degree of accuracy. "Pathfinders," by Cecil Lewis. Peter Davies, Ltd. 9s. Gd. IN this book the author of Sagittarius Rising, for two decades unrivalled in its particular field, has written another classic, which takes up a complementary position by the side of its subjective companion. There is no question of rivalry; each is self-sufficient, self-contained, and of its temporal kind.perfect. In Pathfinders, Lewis has exercised his gift of character drawing to such effect that it is with a sense of shock one continually is drawn back by an unrelenting mind to the in escapable fact that these men are dead. Yet they live; you live with them; you cannot help experiencing coevally with them their various lives, their hopes, fears, despondencies, and struggles. The author's powers of description, abstract and concrete, are wielded with so sure a touch that the habit of one's own existence is put aside and donned again only with reluctance. An aura of authenticity illuminates these pages, and the pen pictures delineated conjure in the mind a personal association that mocks the vicariousness of the feeling experienced. The treatment of this book is beautifully simple. You are introduced, at their Station, to the six men who form the crew, of the Wellington, "P" for Pathfinder; you are briefed, climb aboard with them and take off. During the flight to Kiel you raise the curtain that shrouds the privacy of these men, one by one, and live with them their tiny lives. So rarely is it that a man, who, being fastidious in his tastes for reading and having with th*t quality an impatience for technical inaccuracies, can be really satisfied with a book that has a setting indissolubly wedded to technicalities. So rare, and yet Cecil Lewis writes of Italy, Canada, Hampstead, New measured at all combinations of r.p.m. and boost in steps of, say, 100 r.p.m. and 1 Ib./sq. in. boost. Tests are mainly made using weak mixture, but a few are made with rich so as to decide the losses incurred by the use of rich mixtures, the consumption under combat conditions, etc. The results are then plotted in the form of air miles per gallon against an A.S.I. " grid." Tests of the cooling of engines have occupied more flying time at the A. and A.E.E. than other tests because definite requirements have to be met in definite conditions of flight. The effectiveness is determined from observations of tem peratures. - That part of the lecture which dealt with the determination of flight characteristics, or, in other words, " behaviour," cannot usefully be summarised, but the following tribute, paid by the lecturer to our test pilots, deserves to be placed on record: '' All the world knows of the excellence of some of our types operating to-day, and I am happy to have this opportunity of suggesting that a large slice of the credit should be given to the test pilots of the past." Mr. Jones expressed the view that the test pilot still plays a large part in the assessment of the behaviour of new types, and in the accuracy of many of the performance results. His influence over the latter would be reduced by the more extensive use of recording equipment, but over the former it would remain and even increase. If we were to keep up the present excellent all-round standards, the test pilot's know ledge and experience must keep pace with designers. As a first step towards ensuring this, a school for test pilots had been founded at the A. and A.E.E. The aircraft on which these pilots will be required to maL-ff certain tests will be fitted with special instruments. A modern aircraft in which the fin area and the wing-tip dihedral could be varied in flight would be of immense help in making possible a study of the interaction of lateral and directional stability in actual flight. . Two items of equipment which would be a boon were the Desyn system of remote indication of control-surface angle-s and forces, and the electrical resistance strain gauge for the measurement of steady stresses in structures. Zealand and a London slum with a facile ease that is never at variance with the accuracy of his Service and flying descrip- 'tions. More, he knows the sea; there is a personal touch about the Pacific hurricane that verifies the written word. Viewed collaterally. Pathfinder is not in the same sphere with contemporary literature dealing with the Royal Air Force, its work, or personnel. It is a constellation with its own orbit. The fact that the unifying conditions are those of a bombing force pathfinder is supplementary in importance to the main theme, yet that quality alone places the book ahead of any thing yet written on the same foundation. The Birth of the Royal Air Force. By Air Commodore J. A. Chamier, C.B., C.M.G., D.S.O., O.B.E. Pitman) 15s, net. ™ A IR COMMODORE CHAMIER explains in a note that he became impressed with the fact that the official history of the first world war in six volumes was only suitable for serious students, and that there was room for a more concise history. He was certainly right. He has, however, not been content merely to record facts in an abridged form; he has ventured on criticisms of how the R.A.F. and R.N.A.S. were used in the war. He has no good word to say for the Admiralty in its handling of the R.N.A.S., and he is equally frank, though his words* are more restrained, in criticising the strategic and the tactical handling of the R.F.C. He himself might be criticised as being wise after the event, but he makes the reader share his surprise that many things were not done differently. All through the book Air Cmdre. Chamier preaches the prin ciple of concentration of effort, and shows by innumerable examples how this was persistently ignored throughout the last war. As a result he concludes '' that there is no direct evidence that all our bombing and all our ground attacks between 1914 and igi8 altered by a hairsbreadth the course of the war on the ground." It will be observed that air recon naissance is not included in this condemnation. Also, he makes an exception of Palestine, where aircraft destroyed an army in a defile. . Of the air fighting policy he writes: "The doctrine of tbe offensive, associated for ever with the name of Trenchard, w?ps the correct one from the point of view of morale as well as of materia] results, but an active offensive iu the air at all time* and places regardless of need or object pras a stupidity for which we paid dearly in lives." HOOK REVIEWS
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