GB274167A - Improvements in under-carriages or landing gear for aircraft - Google Patents

Abstract

274,167. La Cierva, J. de. April 7, 1926. Wheels, runners, and skids; floats, arrangement and disposition of.-The landing elements of an aircraft of the type having freely-rotative wings or positively driven lifting screws are so arranged with relation to the centre of gravity of the machine that the machine may assume either of two positions of equilibrium, one for use when the aircraft is at rest or just about to land, in which the longitudinal axis of the machine is horizontal and the angle of incidence of the wings zero, and the other for use when taking off in which the tail-skid contacts with the ground and the incidence of the wings is positive. The invention is described as applied to aircraft with rotary wing-systems of the kind described in Specification 196,594. The axles D' of the main landing wheels D are disposed to the rear of the centre of gravity x when the longitudinal axis BB of the machine is horizontal and the wing incidence is zero, the aircraft being maintained in this position by one or more front wheels F. The machine may be displaced to rest on the wheels D and a tail-skid J, in which position the centre of gravity x is to the rear of the axles D<1> and the wing incidence is positive, by depressing the elevator to cause the propeller slip stream to tilt the fuselage. The front wheels F may be replaced by skids. In amphibian aircraft the main wheels and the front wheels or skids may be mounted upon floats or on the hull. In a modification, each skid H, Fig. 4, together with its main wheel D, is mounted to permit a restricted pivotal movement about a vertical axis M in advance of the centre of friction in order that the landing elements may set themselves parallel to the resultant line of advance when the aircraft lands with a lateral as well as a forward speed. Centralizing springs may be provided to maintain the skids normally parallel to the fuselage. An arrangement is described in the Provisional Specification in which skids are provided with small wheels or rollers at their rear ends, the skids being sufficiently long by themselves to support the machine with its longitudinal axis horizontal, whilst when the machine is tilted backwards the machine is supported partly by the skids and partly by the wheels or rollers.