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Aviation History
1910
1910 - 0268.PDF
\fiMH APRIL 9, 1910. ANOTHER ALL-BRITISH BIPLANE. DETAILS OF THE DE HAVILLAND MACHINE. UNFORTUNATELY, the actual machine with which we are concerned in the present article was one that proved to have a very short life, although it is none the less interesting on that account, for two distinct reasons. On the one hand, it is now being replaced by a second machine designed and constructed in the light of the knowledge gained from it; and in the second place, there is much to be learned from the mere fact that this initial attempt at aeroplane building resulted somewhat disastrously. Fortunately for the British industry, Mr. G. de Havilland, its designer and builder, is a man of the type whose enthusiasm and determination is apt to increase rather than diminish after any preliminary set back ; while equally fortunate is it for readers of FLIGHT that he should be willing to place much of the experience that he has just gained at the disposal of fellow British workers in the interests of the aeronautic movement. The machine of which we are, by his courtesy, now enabled to give a fully illustrated description, was built "Havilland No. I" completed and ready for trial. Note the bevel-driven propellers and the hinged wing-tips. entirely by himself and by his assistant, Mr. F. T. Hearle. And they it is who are now alone busily engaged with an exceedingly promising "Havilland No. II," although possibly, for the sake of accelerating matters, Mr. de Havilland would feel disposed to consider the advisability of arranging for some other would-be pioneer to join him if the right man were to come forward to help him bear the burden of the undertaking. Needless to say, the expense of building preliminary machines like these is considerable if the task is shouldered, as it has been in Mr. de Havilland's case up till now, by one man only. Briefly stated the machine in question was a 36-ft. span biplane, having a front mono-elevator, an adjustable mono-tail, a rear vertical rudder, and hinged wing-tips mounted near the extremities of the upper main planes. It was supported on three wheels—one beneath the tail —and was provided with an additional front wheel beneath the elevator, as well as with skids below the ends of the lower main planes. Also it should be mentioned in advance that it was propelled by a pair of bevel-driven screws situated behind and between the main planes on either side of the central girder. And then it should be added that the past tense has advisably been used in the foregoing paragraph, inasmuch as the first free flight of the machine terminated in almost complete wreckage. The first time that it left the ground it did so after travelling some 40 yards on a downward slope under its own power; it then rose at rather a steep angle, which was corrected by the pilot; and almost immediately afterwards—about 35 yards from the take-off—the left main plane doubled up, causing the machine to fall heavily forward and to the left. Luckily, Mr. de Havilland himself was not hurt, but it will be observed from some of the photographs which we repro duce that the machine as such, apart from the propelling mechanism, the rudder, and the tail, was, for all practical purposes, virtually annihilated by the fall. As will be observed from what now follows, some important and original features are embodied in this machine, although in general principles there is no radical departure from systems that have proved suc cessful in other cases HBMMBHHHHHBHHJHHI hitherto. Also, the student ot details would do well to bear in mind that this particular ma chine showed itself to be insufficiently strong for its purpose, thereby, by the way, indicating not only the inadequacy of the cross sections employed, but also the great difficulty that there is in selecting suitable woods for aeroplane con struction. To a large extent a form of Ameri can whitewood was chosen by Mr. de Havil land, chiefly in order to obtain a good straight grain, but the subsequent fractures indicate an internal softness which was not apparent previously, and we understand that the very much stronger machine now in hand will have silver spruce, ash and hickory in place of the whitewood. Referring to the special features of Mr. de Havilland's design, it should briefly be mentioned here that these include a neat form of bevel drive for the two propellers in conjunction with the 4-cylinder horizontal opposed engine that also owes its origin to this same designer; while even the propellers themselves are unlike those on other flyers, inasmuch as the aluminium blades are adjustable as to pitch, and as to twist. Our Illustrations. Concerning the photographs that we reproduce herewith, it will be observed that one of these only shows the " Havilland No. I " complete and prior to the accident, while two others were taken from the wreck. The first of these is sufficiently clear to be self-explanatory in very large measure, while the other two repay inspection for the light that they throw upon the whole matter. The remaining photograph includes two views of the propeller, and demonstrates the manner and extent to which the 266
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