GB602256A - Mountings for engines for aircraft - Google Patents

Abstract

602,256. Aircraft engine mountings. LORD MANUFACTURING CO. June 4, 1945, No. 13983. Convention date, May 19, 1944. [Class 4] [Also in Group XXXII] An aircraft engine mounting element includes a supporting member comprising a housing and a supported member comprising a core within the housing, the members being movable relatively to each other against the action of resilient means in one direction in response to engine vibrations and in a transverse direction in response to propeller thrust, and is fitted with a friction damper having parts associated with the members sliding against each other in response to engine vibrations and moving apart in response to propeller thrust to relieve the damping. As shown, the power plant is supported from the mounting ring 13, Fig. 2, by a series of elements arranged in pairs ab, cd and ef, the axes of the elements converging to a point on the longitudinal axis of the engine adjacent the centre of gravity. Each element comprises an outer housing 15, Fig. 4, secured to the ring, and an inner core having a stem 19 secured to a bracket 20 on the engine by a nut 19a, the housing being closed, after insertion of the core, by a screwed cover-plate 17. The core, Fig. 5, consists of resilient soft rubber members 21, 22 shaped as shown when unloaded and vulcanized to opposite sides of a head 119 formed on the stem and to plates 21a, 22a fitting respectively into a recess in the bottom of the housing 15 and against the inner surface of the cover 17. The members 21, 22 are formed with recesses 21d, 22d and their elasticity is such as to allow relatively free radial movement of the core head. The latter is eccentrically positioned in relation to the plate 22a so that under load it will assume a central position in the housing 15. The plate 21a and housing are formed with corresponding apertures for the reception of a locating pin to ensure correct assembly of the elements. The cover 17 is screwed up sufficiently to place the elements 21, 22 under initial compression so that their circumferential walls are slightly bulged. Under excessive loads, the bulged walls engage the frusto-conical and cylindrical parts 115 and 116, Fig. 4, of the wall of the housing 15 and exert a scrubbing action to limit movement of the power plant. To damp out vibrations, of large amplitude at idling speeds, the elements e, f are fitted with friction dampers, Fig. 9, each of which comprises an annular brake lining 30, riveted to a plate 31 carried by a collar 32, and a dish-shaped spring 33 secured in position by a circumferential channel strip 34. The damper is assembled with the collar 32 fitting into a recess in the bracket 20 and the lining engaging the outer face of the cover 17, the spring 33 resting against the rim of the bracket 20 and being put under compression by screwing up the nut 19a. At higher speeds, the compression of the rubber members 21, 22 to accommodate the engine thrust is sufficient to relieve the compression of the spring and render the damper inoperative.