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Aviation History
1912
1912 - 0962.PDF
I/OGHT OCTOBER 26, 1912. THE HANDLEY PAGE MONOPLANE. AMONG the disappointments of the Military Trials was the limited opportunity that they afforded for appreciating the proper merit of the Handley Page monoplane. The machine entered therein was one specially built to satisfy the conditions, as the firm's standard model, which had been flying quite well before the trials, was not suited to the requirements laid down by the tests. The trials machine, however, was unfortunately delayed in construction, and when at length it "got going" towards the end of the trials, a forced landing down wind damaged a wing, which put it out of action again for the few remaining days of the event. We thought then, and we think now, that it was particularly unfortunate that the machine in question was thus prevented, by a series of natural handicaps that are incidental to business of this sort, from performing in public and especially under the eye of the military observer, for although we have no cause to express an opinion one way or the other as to the probable military qualities of the machine, the fact remains that Mr. Handley Page has been bold enough to design on lines that are out of the ordinary, and has had the courage of his convictions to keep at work on the same main principle from the day that he first went into the industry. Moreover, that principle is related to the problem of stability inherent in design, and the question of natural security in the air is one of even greater importance to aviation at large than is the evolution of a military aeroplane to the nation in particular. For these reasons, therefore, we consider that there is good cause to regard the virtual absence of the H.P. monoplane from the military trials both as a disappointment and a misfortune. Since that event, however, the latest machine, which we illustrate by a series of photographs, sketches, and scale drawings, has been doing extremely good work gX Hendon, whither the firm has trans- fered its flying headquarters from the secluded aerodrome at Barking where the pioneer days were spent. Probably all our readers are aware, and if they were not hitherto aware they will at least have observed already from a mere glance at the pictures, that the characteristic feature of the Handley Page monoplane is the crescent- shaped plan form of the leading edge of its wings. The crescent plan form is, however, not everything, for there are two other characteristics less easily illustrated in general views, which are of even greater importance to the stability, that it is the object of the design to obtain. One of these is the reversal of curvature of the wing section as it approaches the trailing edge, and the other is the graded camber from shoulder to tip, whereby the wing section measures some seven or eight inches deep where it is adjacent to the body, while the positive camber is entirely washed out at the upturned extremities. These features—the crescent entering edge, the reversed curvature of the trailing edge, and the graded camber of the wing section from shoulder to tip—are all associated with the general problem of con ferring on this machine a degree of inherent stability, which is its whole object and raison d'etre. The reversed curvature of the trailing edge introduces the principle of the fore and aft dihedral on a very short base ; that is to say, while it tends to neutralise the retrogression of the centre of pressure, its lack of fore and aft length probably handicaps it in damping out any oscillation that has once commenced. Although it is claimed that the plane, as such, is naturally stable, the Handley Page monoplane in particular is fitted with a tail in order to enhance the natural damping tendency and to provide the pilot with adequate means of exaggerating the effect when necessary. The lateral stability of the machine is associated with the graded loading and the retreated tip, and on this point Mr. Handley Page has a theory of his own, which we explained in FLIGHT some time ago, but of which we give another brief outline now for the benefit of our readers who have not studied the question previously. His argument is that the graded loading tends to produce a diagonally outward flow of the relative air stream under the wing tips. The effect of a side gust, according to the designer, is to change this diagonal outflow into a flow parallel to the body and so to diminish the relative velocity as illustrated by the vector thus produced in the triangle of velocities. Thus, Mr. Page argues that instead of increasing the relative velocity on the near wing that it is, in fact, reduced by a side gust, and that in consequence the near wing does not tend to tilt up. The subject of lateral inherent stability and the theories properly to be associated with designs like the Handley Page is one that lends itself to extensive discussion, and some of our readers might with advantage take the matter up in our correspondence columns, for we feel sure that they would derive much interest therefrom. We are none too certain that a satisfactory explanation of the true theory in this matter has yet been advanced, and it is indeed unlikely that it should be until we know more about the nature and dimensions of a gust. For the time being, however, it is good mental exercise to picture possible effects on a broad scale, and to devise simple theories to suit the cases. Mr. Handley Page's theory belongs to this category, and should serve as a basis on which to open a discussion. Particularly, for example, would it be T-L u JI D "Flight" Copyright The Handley Page monoplane, showing, on the left, general view of the chassis, &c; top right, diagrammatic view of the fuselage; and, beneath, diagram of controls, the rudder bar not being shown. 962
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