Patent GB-463401-A (GB)
Title: Improvements relating to aeroplane landing gear
IPC: B64C25/50
Filed: 1935-07-23
Abstract: 463,401. Aircraft alighting - gear. COWEY, L. E., EUGSTER, E. J. P. July 23, 1935, Nos. 20900/35 and 763/36. [Class 4] An aircraft having fixed wing and tail surfaces and fitted with two or more main landing wheels situated in front of the centre of gravity of the aircraft and a further landing wheel or skid situated usually beneath the tail is additionally provided with an auxiliary landing wheel or skid pivotally connected with the fuselage and connected therewith in a resilient manner, the auxiliary landing wheel or skid being situated at the rear of the main landing wheels and depending downwardly to such an extent as to support the tail of the aircraft when the latter has made contact with the ground on landing in a position approximating to that assumed during normal level flight, the wheel or skid being retractable when not in use. In one form, Fig. 2, an aeroplane 1 having a conventional undercarriage 2 and tail skid 4 is provided with an auxiliary landing wheel 5, carried by triangulated tubes 6 pivotally connected to the fuselage at 7. The wheel fork is rotatably mounted in a bearing member 8 connected to the lower end of a compression strut 9 of which the upper end is pivoted to a triangulated structure 10, 11 within the fuselage. Compression strut 9 may consist of a piston operating within a cylinder and acting against the pressure of air and oil. The resistance offered by the compression strut may be just sufficient to maintain the tail in its raised position during landing but not sufficient to prevent the tail being lowered during the landing run by raising the elevators. When the auxiliary gear is fitted the main landing wheels may be placed somewhat further forward to permit of more effective braking and in such case the auxiliary gear may be lowered to assist take-off. In a modification a pivoted drop skid may be employed which is retractable preferably into the contour of the fuselage. The skid may be normally maintained in its retracted position by a spring and be moved into and maintained in, operative position by means comprising a piston and a cylinder adapted to be put into communication with the intake manifold of the engine. Alternatively the spring means may be employed for extending and piston and cylinder means for retracting the skid. In this case the piston may be loaded during flight by exhaust gas pressure, or by air from a compressed air bottle or other source of pressure fluid. In a still further modification the skid could be operated by a ratchet drum device incorporating a buffer spring. The braking pressure on the main wheels may be made dependent upon the load carried by the auxiliary landing device. In one such arrangement, Figs. 2 and 3, fluid pressure brakes are controlled by a hand lever 12 actuating a piston 13 working in a cylinder 14 which communicates by a non-return valve and pipe 15 with a reservoir and by pipe 16 with the brake mechanism on the main wheels and, if fitted, on the auxiliary wheel. Lever 12 carries a bell-crank lever 17 the upper arm 18 of which engages piston 13 and the other arm 20 of which is connected by cable 21 with structure 6 in such manner that lever 12 can.only be moved when cable 21 is slack. The second Provisional Specification describes other means for causing release of the wheel brakes when the machine tends to nose-over, these means comprise the use of a pendulum control or of a pilot wheel or skid pivoted about the axis of the landing wheels and connected to the brakes in such manner as to make the degree of application dependent upon the attitude of the machine.