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Aviation History
1913
1913 - 0327.PDF
mmmm MARCH 22, 1013. [fuGim SOME AUTOMATIC STABILITY AEROPLANE PATENTS. By ERNEST WHILE the question of the stability of aeroplanes, as obtained by the shape and curvature of the wing surfaces, apart from auxiliary attachments such as pendulum devices, &c., is so much before the public, it might be of service to consider a few of the many patent obtained in this country relating to the subject. The success of the Dunne, Handle - Page, Etrich and Lohner aeroplanes, to mention just a few names of the type of machine, is certain to produce a host of others working on the same or similar lines, and designed to produce the same results. When examining the various patents, it must be borne in mind that the force of gravity must in some way or other be used to ensure the correct attitude of the aeroplane with relation to the ground. Any device that claims to keep an aeroplane in a fixed attitude without reference to gravity is foredoomed to failure. Patentees of the various devices such as are described in this article are in many cases very loose in expounding their theories, and in certain cases appear to consider that with suitable shaped wings the aeroplane will always remain in a horizontal position irrespective of the action of wind gusts. Although certain shapes of wing surfaces are undoubtedly much less influenced by wind disturbances than others, it is quite impossible to believe that conditions will not arise when horisontality will not be maintained, and unless the force of gravity or the control of the pilot is called in to provide a restoring couple, the aeroplane must lose its equilibrium. In practically no instance can the inventor's theory be put into a form concise enough to include in this short article, and it is more than probable that the theory as set out in the specification is far from being a complete statement of the case, or is even adequate to explain the undoubted success of certain of the inventions. In the descriptions of the various inventions, the theory is not given, but those who may be interested are advised to refer to a copy of the specification. It is somewhat curious to note that patents standing in the names of well-known experimenters in the quest of automatic stability are not so numerous as one might fancy, and this will to a certain extent explain the reason why no patents covering several well- known machines are mentioned in this article, which sets out to discuss the patents on automatic stability machines which have actually flown. One of the earliest experimenters was Weias. his patent, No. 17150/08, showing a tailless machine having more or less crescent- shaped wings, the side portions being almost flat, and the rear portions quite flexible. The curvature of the plane in longitudinal section decreases from the centre to the sides ; horizontal planes are used for steering. As a model glider and a? a man-carrying glider, the Weiss machine proved a success, having a large amount of inherent stability, but as a power-driven machine it did not do so well, perhaps owing to difficulties of construction. It is to be noted that in the later experiments a tail was fitted. Another pioneer, Dunne, has several patents on the subject. The main patent appears to be No. 8188/09. This shows the typical Dunne V-shaped wings, the angle of incidence decreasing from the centre to the lips, and in some cases forming a negative angle. Horizontal flaps are used for steering. In his patent specification No. 11021/09, Dunne describes an improvement on his previous patent. In this case the invention is applicable to biplanes and multiplanes, the variation of incidence of the upper plane being greater than that of the lower plane, so that the tips of the upper plane are inclined forwards in relation to those of the lower plane. In Dunne's specification No. 26441/09, an improvement on his two prior specifications, the V is described as not being so pronounced, an additional plane surface being provided, preferably situated in front of the main planes. An earlier patent of Dunne, No. 2808/08, is also of interest. Etrich's patent specification No. 14204/10 (datedunder convention, * F. M. Rogers and Co., Patent Agents, »i, Finsbury Pavtment, E.C. ® ® ROYAL FLYING CORPS. THE following appointments were announced in the London Gazette of the 14th inst. :— Special Reserve of Officers.—K.F.C.—Military Wing.— The undermentioned to be second lieutenants (on probation). Dated March 15, 1913 : Hon. Capt. Gilbert Braithwaite Rickards and Hugh Clarence Fuller. The following appointments were announced by the Admiralty on the 17th inst. :— Lieuts. R. A. Wilson, W. R. Crocker, and W. C. Hicks to the " Actseon," additional, for training in airship work. M. GREEN/ September, 1909) describes an aeroplane in which the main planes are provided with rearwardly projecting extensions. The central portion of the main planes has a substantially laifblM curvature in the direction of flight; the extensions have a negative angle and are flexible, being used for warp control. An interesting patent is that of Hragg-Smith, No. 27812 08. which shows a biplane of the "Canard'*' type in which lateral stability is obtained by curving up the lower plane ai it.- ««nti-r end* to or towards the upper plane, or the same result may be obtained by employing a series of plane sections. The upptr plane is set at a dihedral angle. ' As a model this invention has had a large degree of success, and it is to lie hoped that a full-sited power-driven machine will be constructed in the near future in order more fully to lest the merit* of the invention. ounnt <w*M*a DRAGG-dniTn CH5IS/CVS WCIdS. IWXVOft. -^CP^ MtWl (iVVViU CTRKrt I4204yto Fowsm. no6,Ad. Somewhat similar to Bragg Smith's patent is that of Sloan of "Bicurve" fame, No. 7303/11 (dated under convention, March, 1910). In this, the upper and lower planes converge at their outer ends and are curved laterally. At the outer ends openings are provided so as to allow for the escape of air imprisoned between the two planes. In Fokker's specification No. 596/13, just recently published, stability is obtained by inclining the planes upwards as well as in a rearward direction, and distributing the weight so that the centre of gravity is disposed above the centre line of the vertical force. No provision is made for warping or for balancing flaps. it is to be noted that the fin effects of the lxxty and tail have been cut down to a minimum in order to make the rudder act very quickly. The above-mentioned patents must only be considered as a few of the many patents on the subject, although it is hoped that the more important ones are included. %> ® Flying at Montrose. SOME fine work was carried out by the squadron of the R.F.C. at Montrose on Monday. The conditions appeared good in the morning, and Capt. Becke went up on a BE 2 for a cross-country trip. He had not, however, been long in the air before a blizzard swept over the district, and it was only with difficulty that he was able to effect a landing. Capt, Longcroft on another ISE and Lieut. Waldron on a M. Farman also had exciting times. They had been up for three-quarters of an hour when they were caught in a windstorm, and Capt. Longcroft came down about two miles north of the aerodrome while Lieut. Waldron landed at Cuthlie, three mi'es west of Arbroath. 333
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