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Aviation History
1911
1911 - 0340.PDF
1/PCHfl totally abandon, any member which diminishes the stability of normal flight, even though such member may, as is the case with this elevator plane, slightly increase stability under certain conditions, for example, when it is tipped up and heavily loaded on the occasion of checking a gliding flight. 6y. Class S Aeroplanes.—In view of the above results one is naturally tempted to examine another type of machine, especially one where a plane in the position of the elevator plane is an essential feature. In the left-hand top corner of Fig. 17 an S type aero plane is shown diagrammatically. The distribution of loading is such that the small plane in front is set at an angle of 5' S°. *-*M it is more heavily loaded per square foot than the main planes, which, being much larger, carry more total weight at a less angle, namely, 4°. The result is a Vee fore and aft. 68. First assume, that owing to a puff of wind, or some other accidental circumstance, the aeroplane as a whole becomes cabrt1, i.e., pitches upwards 20. As before, the increased angle of incidence of the air on the front plane increases its lift in the same ratio as the angle is increased, namely, as $• 5 is to 7*5, while the lift of the back plane is increased by a larger percentage, namely, from 40 to 6°. Accordingly, the centre of pressure travels towards the back plane, thereby tending to counteract the upward pitch, that is, it throws the machine back to the normal position. To draw the curves it was necessary to determine the position of the centre of gravity (from the weight distribution of an ordinary machine), while the centre of pressure which must come in the vertical over the centre of gravity during horizontal flight in homogeneous air, must also be correctly given by the distances from the two planes and their total load. 69. It is worth while noticing that when the condition of the aeroplane indicated in the left-hand bottom corner exists, APRIL 15, 1911. namely, the commencement of a downward pitching move ment, a much more rapid increase of the righting couple with angular deviation exists than at the corresponding com mencement of an upward pitching movement. So greatly does this couple increase, that it is reasonable to say that an unintentional dive or header with this type of machine is difficult. Stability similar to this in all direc tions is what we want. 70. In spite of this, a well-known machine which would commonly be described as of this type, succeeded some time ago in taking a header and so meeting with a serious accidenL There is in my mind little doubt but that when this occurred the front plane (which in this case is not fixed but is hand- controlled like an elevator) was carrying but little load per square foot compared to the back one. This at once gave an inverted Vee between the planes and removed the machine from the S Class. Accordingly, the taking of a dive was the natural and proper thing for it to do, just as a pyramid must totter if it were stood on its point. The only doubt was whether it should move head first or tail first. Since that date this designer has shown that the lesson was learnt. The cure for diving, unexpectedly enough, is to put the weight farther forward, and this has been done by him, and there is now probably no better machine for steady gliding, or what is called " vol plane-ing " (a horrible and unnecessary hybrid). 71. I have not dealt with lateral stability in this paper, and therefore I do not touch on the effect of rising and falling upon such lateral stability as is afforded by a Vee between the wings, by the use of fins, the boxing of the ends of biplanes, or the provision of flexible trailing edges and other such devices. I should none the less be very glad if the discussion were to produce expression of opinion from persons like Mr. Lanchester, Mr. Handley Page, Mr, Clarke, Mr. Dunne and others on this point. (To be cone hided.) MANVILLE £500 PRIZE AND BROOKLANDS, MAJOR LINDSAY LLOYD, the Brooklands Clerk of the Course, writes us in regard to the regulations of the Manville £500 Prize just announced, and points out that the conditions for this prize are somewhat similar to the conditions for the prizes offered by the Brooklands Club at various race meetings, and that a good many of the days on which the Manville Prize can be competed for coincide with the days of these meetings. Major Lloyd continues as follows :— "The differences between the conditions of the Manville Prize and our prizes are, that in the former, the competitor and aeroplane must be all British and a passenger must be carried, whereas in our competitions anyone can compete, and also, in the Manville Prize the competition can commence at 10 a.m., whereas the competition for the Brooklands prizes commences at 2 p.m., and continues for a little longer than in the case of the Manville competition. " In order to ensure that a proper timekeeper is in attendance on the days of the Manville competition, should an aviator wish to compete at Brooklands, I will arrange for the presence of a time keeper from 10 a.m. on each of the days on which the Manville competition will be held. M Some competitors may wish to compete both for the Manville Prize and for the Brooklands prizes, and any performance put up on the Brooklands race days for the Manville Prize will count towards the Brookland prizes, and the conditions for the Brooklands prizes would be varied to this extent—that at 2 p.m., should an aviator be in the air, it will not be necessary for him to descend and make a fresh ascent to count towards the Brooklands prizes, but the time to count for the latter prizes will be taken as from 2 p.m. "Further, as the conditions of the Manville Prize, in so far that a passenger is to be carried, are more onerous than those imposed on competitors for the Brooklands prizes, my Committee will offer on each Brooklands race meeting day a special prize of ^10, to be awarded for the best performance under the Manville Prize com petition over and above the prizes offered for the Brooklands competitions. " I shall be pleased to receive intimations from those wishing to compete for the Brooklands prizes on April 17th as soon as possible, in order that their names may appear in the programme ; and in the case of those entering for the Manville Prize, an intimation to that effect, as I propose to make a note in the programme of those com petitors who are taking part in both competitions. " The Royal Aero Club condidons for the Manville Prize do not state whose certificate is necessary as to whether Rules 6 and 7 (with regard to nationality of aviators and machines) are complied with, but that the decision of the Royal Aero Club shall be final. I take it that the Royal Aero Club Secretary will arrange with intending competitors as to the examination of their machines." ARMY OFFICERS VISIT "BRISTOL" AEROPLANE WORKS. THE close attention which officers in the Army are paying to the question of the use of aeroplanes for military purposes was exemplified on Friday afternoon last week, when a large party of officers from the depot of the Gloucestershire Regiment visited the Filton works of the British and Colonial Aeroplane Co., Ltd. The party included Col. G. W. Hacket-Pain, C B., Commanding No. 7 District; Major G. F. Gardiner, Commanding Depot, Gloucestershire Regiment; Captains W. A. M. Temple, J. E. Ruck, P. S. Vassall; Lieuts. W. P. S. Foord, H. F. L. Hilton Green, W. Wilkins, Quarter master Gloucestershire Regiment. Col. Hacket-Pain has taken a very great interest in the military aspect of aviation, and has written important articles on the subject, in which he expresses his great belief in the future of aviation from a military point of view. The party of officers were received at the works by Mr. H. White Smith, the secretary of the Company ; Mr. G. H. Challenger, the Company's engineer; and Mr. Herbert Thomas, who conducted them over the works. The officers evinced the greatest interest in the process of the manufacture of the machines which was going on, and special interest was evoked by the two Bristol Military biplanes which have been completed to the order of the British War Office, and which are at present awaiting delivery. Mr. Maurice Tabuteau was prepared to give an exhibition flight, but the wind was blowing at so great a velocity that it was unsafe for him to venture. A further occasion will be afforded, however, for demonstrating to the officers of the Gloucestershire Regiment the possibilities of the famous Bristol machines. Mr. Henry M. Jullerot, who has just returned from India, where he has been carrying on experiments with the Bristol Military biplane in connection with the Indian Army Manoeuvres, was present and had a long interview with Col. Pain, who was keenly interested in the recital of the aviator's experience in India. 342
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