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Aviation History
1914
1914 - 0560.PDF
mechanical flight from a dangerous undertaking into one of comparative safety. R.E. i, to which the lecturer referred, is not the first inherently stable aeroplane—to say that it is would be to disparage the work which has been carried out by con structors in this and other countries by such men as Dunne, Handley Page, D.F.W., &c.—but it is the result of long- continued and patient experiment with models at the National Physical Laboratory and with full-size machines at the Royal Aircraft Factory, that association of theory and practice—co-operation between engineers engaged in experimental work and those who design the machines— which has been repeatedly advocated in these columns. R.E. i is remarkable, and stands for what we believe it does—the commencement of a new era in aero nautical design—because it exhibits no radical departure from accepted lines of development, neither stabilising mechanism nor specialised construction being em ployed. In appearance, it resembles the later B.E's. excepting that the triangular fin in front of the rudder is of larger dimensions, the wing section has been improved, the body has somewhat finer lines, while there is only one pair of struts between the planes on each side. These are, however, details which are common to many machines, and have been introduced for the purpose of increasing the efficiency of the machine. The inherent stability of R.E. i is due only to the adoption of a dihedral between the planes of suitable magnitude, and correctly proportioning and locating the various surfaces—all of which have been calculated with infinite care—in accord ance with experimentally determined values. Hence there is no reason why every manufacturer should not be able to build machines possessing an equal degree of stability, as the methods employed can be adapted to the design of any aeroplane. The beneficial effect upon the pilot of such machines, especially on long distance flights, need only be mentioned as the reduced physical and mental strain involved in their control is readily apparent. It is not too much to say that the fact that an aeroplane of a standard type has been designed from data experimentally obtained in an aerodynamic labora tory has given to aerial transit a huge impetus; that the earnest desire of every serious student and believer in the future of aeronautics—the application of the aero plane to commercial purposes, the carrying of passengers, mails, &c.—is within measurable distance of consumma tion ; and the confidence which such an event inspires in the layman renders it possible that within a comparatively short time we may have services of aeroplanes in active operation in many parts of the world. • • <e» The much-belated Annual Technical Report Advisory °^ l^e Advisory Committee has at length Committee come to hand. We use the term " much- Report belated," not because it has been published eighteen months after its immediate pre decessor, but because an examination of the dates attached to the memoranda reveals the fact that, with the exception of Dr. Rosenheim's Report on Light Alloys (September, 1913), all were presented not later than March of last year, fifteen months ago !—many were prepared in 1912, and one by December, 1911. We are fully aware that work of this character, which is accepted without question the world over, requires thoroughly checking ; but if the dates count for anything, they should indicate the time at which the tests to which they refer were complete and had been verified, and if our assumption MAY 29, 1914. be correct we consider that this delay represents so much loss of time, which, at the present state of aeronautics, is much to be deplored. It is to be hoped that subsequent reports will be issued at a much earlier date or that means will be devised whereby manufacturers and others in terested in the experimental work conducted at the N.P.L. and rhe R.A.F. may be made acquainted with the results obtained at these establishments. The high standard of excellence obtained in the previous reports has been well maintained, and will prove equally, if not more, valuable to designers and others. Much new ground has been broken, notably in regard to aerofoils, wind forces and moments on parts of aeroplanes, stability, the calculation of stresses in wing spars and in the fabric, wind forces on hydroplane floats, and the properties of light alloys; while a considerable amount of other research has been carried to a further stage of completion. It will, therefore, be evident that the Report now under notice represents a most comprehensive examination of many of the more pressing problems that now await solution, and although some parts are highly technical in character, the greater part of the matter can be perused with profit and pleasure by the most casual reader. Much help in this respect is afforded by the large number of graphs presented, which form, as in previous volumes, an important portion of the work. Space precludes any possibility of dealing adequately with the subject-matter of this volume, and we shall therefore confine our comment, principally, to the covering letter to the First Lord of the Treasury, which is signed by the President of the Committee, Lord Rayleigh. With the exception of research on the determination of the lifting power of samples of hydrogen, the leakage of gas through, and the proofing of balloon fabrics, no experimental work in connection with airships is recorded ; although it is stated that some tests have been made on the resistance of airship models in the William Froude National Tank, which more immediately pressing questions have prevented from continuance. These experiments form an extension of the work carried on last year, and refer especially to the determination of the conversion factor when passing from the model to full scale results. The results obtained in the aerofoil experiments are of an extremely interesting character. Previous work, as is well known to readers of FLIGHT, has indicated that the efficiency of a wing is mainly determined by the camber of the top surface, the under surface being rela tively unimportant. In the present report the effect of varying the position of the maximum ordinate while keeping the camber constant is recorded; and as the lift curves of many wing sections drop rapidly when a certain angle of attack is reached, it was considered desirable to reduce this decrease in lift as much as pos sible, and to increase the angle at which it occurred to as large a value as possible. This, it has been found, can be effected with an aerofoil having a camber of 1 in 20, by changing the position of the maximum ordinate, the best position being at a distance from the leading edge of about three-eighths of the chord. In this position, the lift maxi mum extends, with little diminution, over a considerable angular range, although a slightly higher value of lift to drift was obtained when the position of the maximum ordinate was moved to about one-third of the chord from the leading edge, but with the attendant disadvantage that there was some possibility of re-introducing the sudden drop in lift. Further experiments conducted in this direction, had as their object to ascertain to what extent the aerofoil could
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