GB520994A - Improvements relating to retractable undercarriages for aircraft - Google Patents

Abstract

520,994. Retractable undercarriages for aircraft. DOWTY, G. H. Sept. 17, 1938, No. 27188. [Class 4] A retractable undercarriage for aircraft consists of a self-contained structure embodying retraction motor means (e.g., a jack) and also a source of energy (e.g., a compressed air container) for operating such motor means. Compressed air may be supplied to the container by a pump operated by movements of a shock-absorber, or by rotation of a landing- wheel. In the form shown in Fig. 1, a tubular undercarriage member 1 is pivoted at 4 to a spar 3, and is provided with a two-part jointed strut 5 and with a double-acting retraction jack 10, which is fitted at the pivot 4 with an actuating-valve controlled by a lever 14 and cable 15. The space 12 in the member 1 constitutes a pressure container, and is supplied with compressed air, for operating the jack, by a pump, the piston 30 of which is actuated through a shock-absorber 23, 24 pivoted to a lever 20 carrying the landing-wheel 21. As a modification, a part of the shock-absorber may constitute the pump, a relief valve in the shock-absorber cylinder being connected to the compressed-air reservoir. In another construction, the rotation of the landing-wheel operates the pump by means of a cam groove, on the internal periphery of the wheel, engaging rollers on each end of a stem carrying the piston, the compressed air being delivered through a passage in the axle and through a pipe to a two-way valve by which it is admitted to the reservoir or to exhaust. Specification 520,995 is referred to.