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Aviation History
1927
1927 - 0118.PDF
18 STTPPLEMSNT TO FLIGHT FEBKTTAKY 24. 1927 THE AIRCRAFT ENGINEER Rolling and yawing moments are to be measured on a 13-2 in. chord model at wind speeds up to 120 ft./sec, to determine the rate of change of these moments with scale. THE DIRECT MEASUREMENT OF THE ANGLE OF FLIGHT PATH OF AN AEROPLANE AS A MEANS OF ELIMINATING THE EFFECT OF AIR CURRENTS ON THE MEASUREMENT OF LIFT AND DRAG. By E. T. JONES, M.Eng., and H. L. STEVENS, B.A. Presented by the Director of Scientific Research. R. & M. No. 1049 (Ae. 235). (7 pages and 4 diagrams.) August, 1926. Price 9d. net. In making performance measurements there has always been some difficulty due to the up and down currents that are present in the atmosphere. These currents result in the scattering of the observations obtained during full-scale testing, and the elimination of their effect would largely increase the accuracy of such work-and also allow the work to be carried out in less settled weather. A suspended instrument to record the true angle of the flight path independently of atmospheric currents has been made and fitted to a Bristol Fighter. A number of glides have been carried out both by the standard method and with the instrument in use. The scattering of the observa- tions was considerably reduced with the aid of the instrument, and the results were also obtained more quickly. The flight path recorder will be used in all further work of this nature, and a lighter instrument, suitable for quick transference from one aeroplane to another, is being designed. The instrument will also be used to check the circulation theory by exploring the flow at various depths below the aeroplane. FULL SCALE AND MODEL MEASUREMENTS OF LIFT AND DRAG OF BRISTOL FIGHTER WITH R.A.F. 30 WINGS. PART I.—FULL SCALE. PART II.—MODEL EXPERIMENTS. PART III.—COMPARISON OF MODEL AND FULL SCALE RESULTS. By A. E. WOODWAED NTJTT, B.A., R. G. HARRIS, D.SC., and L. E. CAYGILL, B.SC, A.M.I.M.E. Presented by the Director of Scientific Research. R. & M. No. 1052 (Ae. 237). (6 pages and 9 diagrams.) August, 1926. Price M. net. A number of thick wing sections are being tested in flight and in a wind tunnel and recent experiments include tests on R.A.F. 30, 31,* and 32.f These are to be followed by tests on R.A.F. 34. The lift and drag of a Bristol Fighter with wings of R.A.F. 30 section have been determined for the full-scale aeroplane and for a l/10th scale model at speeds of 40, 60 and 90 ft./sec. The maximum lift coefficient is considerably higher for the full-scale aeroplane than for the model, the increase being larger than that of either R.A.F. 31, or R.A.F. 32 ; the two sets of values agree up to 10° incidence, but the full-scale lift reaches 0-60 at 20|° and the model only 0-42 at about 15° with a wind speed of 90 ft./sec. The drag coefficient is slightly lower for the full-scale than for the model throughout the range with minima of 0-031 on full-scale and 0-032 at 90 ft./sec. on the l/10th scale model. Elevator angles and forces have still to be measured full-scale to verify the C.P. position. * R. & M. 990. Full-scale and model measurements of lift and drag ofBristol Fighter with R.A.F. 31 wings.—B. D. Clark, B.Sc., and R. U. Harris, D.Sc. * R. & M. 105:"). Tests on Handley Page Aerofoil A.I. and R.A.F. 31.—Messrs. Handley Page, Ltd. t H. <fe M. 1006. Full-scale and model measurements of lift and drag ofBristol Fighter with R.A.F. 32 wings.—E. F. Anderson and L. E. t'aygill, R.A.E. SECOND REPORT ON FULL SCALE EXPERIENCE WITH THE SLOT AND AILERON CONTROL FITTED TO A BRISTOL FIGHTER. By H. L. STEVENS, B.A. Presented by the Director of Scientific Research. R. & M. No. 1051 (Ae. 236). (3 pages and 2 diagrams.) August, 1926. Price 4d. net. In March, 1926, a preliminary report No. T. 2254 (un- published) was issued, giving the experience obtained up t< that time on the slot and aileron control as fitted to botl planes of a Bristol Fighter aeroplane. It was concluded that the control had the features desired when the aeroplan; was stalled, but that the feel in normal flight was unpleasant The wind tunnel tests on this control are described in R. am! M. 1008. The present report describes the modifications carried out tt improve the control in this respect and the results obtained. In particular, the effect of fitting the control to the top plane only was investigated. With the control fitted to the top plane only, the bottom plane and ailerons being standard, and with the remaining slots having a 50 per cent, greater range of opening, the control is still adequate, and the feel is quite pleasant. The relative weakness of the rudder control is now very apparent and should be improved. The combination will probably considerably increase the aeroplane's fighting efficiency. It was recommended as a result of this work that the large fin and rudder reported on in R. & M. 972 be fitted and the aeroplane allotted to a service squadron for a further report. These Reports are published by His Majesty's Stationery Office, London, and may be purchased directly from H.M. Stationery Office at the following addresses : Adastral House, Kingsway, W.C. 2; 28, Abingdon Street, London, S.W.I; York Street, Manchester ; 1, St. Andrew's Crescent, Cardiff ; or 120, George Street, Edinburgh ; or through any book- seller. AMERICAN NATIONAL ADVISORY COMMITTEE REPORTS. The National Advisory Committee for Aeronautics in the United States of America corresponds to our own Aero- nautical Research Committee. Two distinct classes of reports are issued, the first being known as Technical Reports. These Technical Reports are printed, and are illustrated by photo- graphs and/or drawings. The second class are known as Technical Notes, and are issued in mimeographed form so as to enable them to be rapidly distributed to a somewhat smaller, but directly interested, circle of readers. Copies of the Reports and Notes may be obtained from the Superin- tendent of Documents, Government Printing Office, Wash- ington, D.C., U.S.A., but the American N.A.C.A. have a Technical Assistant in Europe, whose office is at 18, Rue Tilsitt, Paris, from whom copies can usually be obtained, thus saving a certain amount of time. The average price of the Technical Reports is 10 cents. which is, of course, remarkably cheap in view of the informa- tion contained, and in some instances the price is as low as 5 cents. Summaries of Technical Notes Published in 1926. (Continued from page 12.) PROPELLER DESIGN : EXTENSION OF TEST DATA ON A FAMILY OF MODEL PROPELLERS BY MEANS OF THE MODIFIED BLADE ELEMENT THEORY—II.—No. 236. By FEED E. WEICK, Langley Memorial Aeronautic;1.! Laboratory. This report is the second of a series of four on propeller design, and describes the method used to extend the data obtained from tests on a family of thirteen model propeller , to include all propellers of the same form likely to be m< i in practice. This necessitates the development of a meth< i of propeller analysis which when used to calculate the powe •> and efficiencies gives results which check the tests throughoi.: their range. Airfoil characteristics are derived from the mod 1 propeller tests themselves, and used in the single sectica method of analysis (given in the first of this series, N.A.C.* • Technical Note No. 235) to calculate the powers and efficien- cies for propellers outside of the test range. 100/
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