GB809949A - Improvements in or relating to aircraft undercarriages - Google Patents

Abstract

809,949. Aircraft undercarriages. BRITISH MESSIER Ltd. April 3, 1957 [April 6, 1956], No. 10636/56. Class 4. An aircraft bogie undercarriage comprises a main leg 11 pivoted at its upper end to the aircraft, a trailing link 13 pivoted at its forward end to the lower end of the leg, a bogie frame 14 pivoted between its ends at 16 to the rear end of the trailing link and carrying land wheels 17, 18 (preferably in transverse pairs) fore and aft of its pivot, and a telescopic shock absorber 19 adjacent the leg and pivoted at its upper end to the leg and at its lower end to the bogie frame or to the link rearwardly of the pivot between the link and the leg, whereby raising and lowering of the bogie on the link with respect to the leg causes contraction and extension of the shock absorber. The leg is transversely pivoted at 24 to a member 25 pivoted to an aircraft wing on a fore-and-aft retraction spindle 27. Retraction is effected by a jack (not shown) acting to rotate member 25. A telescopic side-stay is connected between the wing and the leg. A drag strut 30 is connected between the wing and the leg as described in Specification 809,950. A telescopic bogie damper 21 is connected between the leg and the nose of the bogie, so that the bogie is in a nose-up attitude on touch down. Brake compensating links are provided, a pair 37 (one shown) connected between non rotary parts of the front wheel brakes and one arm of a bell crank lever 34, and a single link 38 connected between non rotary parts of the rear wheel brakes and the other arm of the bell crank lever. A link 39 extends between the other arm of the bell crank lever and a pivot on the leg 11, so as to be parallel to the trailing link. Each link 37, 38 is disposed so that it axis and the line joining the pivot of the leg and bogie frame to the corresponding wheel axis, intersect at ground level as shown. Fig. 1 shows the shock absorber 19 pivoted on the pivot 16 between the leg and the trailing link, but to compensate for the moment about pivot 16 caused by the rolling resistance of the wheels, the shock absorber may be connected to the bogie frame rearwardly of pivot 16.