GB514798A - Improvements in or relating to landing gear for aircraft - Google Patents

Abstract

514,798. Retractable alighting gear for aircraft. SOC. D'INVENTIONS AERONAUTIQUES ET MECANIQUES S.I.A.M, May 16, 1938, No. 14594. Convention date, May 31, 1937. (Class 4] A retractable landing gear, particularly a tail wheel gear, comprises a pivoted leg the position of which is controlled by means comprising a link pivotally connected to the leg and to a further link pivotally connected to the aircraft structure, the links in the operative position of the landing gear being parallel to each other and the distance between their points of attachment to leg and structure respectively being equal to the difference in length of the links. A leg 2, Fig. 1, carrying a tail wheel 1 is pivoted at 3 to a fixed part of the aeroplane A and the position thereof is controlled by elements 4, 5 interconnected at 6 and pivoted to leg 2 at 7 and structure A at 8, respectively. Element 4 is provided with a lever arm 12 to which is pivotally connected the ram of a hydraulic jack C pivotally mounted at 9 on element 5. Extension of the jack causes the angle between elements 4, 5 to close, element 5 pivoting upwardly about axis 8 in the direction f until points 3, 7, 6 are in line (upper dotted position) thereafter pivot 6 moves in the direction f<1> to the lower dotted position wherein element 4 lies parallel to element 5 and in which reactions between wheel 1 and the ground produce no force on the jack, Fig. 3. The hydraulic jack may be substituted by a mechanical, pneumatic or electrical device. The two part leg 4, 5 may be duplicated as shown in Fig. 4, one jack C only being employed.