GB727255A - Improvements relating to aircraft - Google Patents

Abstract

727,255. Aircraft controls. FAIREY AVIATION CO., Ltd. June 23, 1953 [May 20, 1952], No. 12760/52. Class 4. [Also in Group XXIX] An aircraft having one or more jet-propulsion units and fluid pressure operated thrust direction control means controlled by an operating member in common with control surfaces, is characterized by emergency means responsive to complete or partial failure of the fluid pressure supply for centralizing the thrust direction control means. The embodiment described (Fig. 1) has four jet engines, an upper, a lower, a left and a right engine. The two former are rotatable about vertical axes with the rudder, and the latter about horizontal axes with the elevators. Provision is also made for making the aircraft roll. A lever A pivoted at B has link rods D' slidable in studs A<SP>1</SP> and limited in motion one way by nuts D<SP>3</SP>. These link rods D<SP>2</SP> are pivoted to a lever D operated by control mechanism through rod D<SP>1</SP>. Pivot B is controlled by a jack C, and in the normal position of Fig. 1 lever A is urged to abut nuts D<SP>3</SP> so that lever A moves with lever D without lost motion. Two further links F<SP>1</SP>, connected to lever F, slide in studs A<SP>2</SP> on lever A, and in the normal position lever A abuts nuts f<SP>3</SP> so that lever F rotates with lever A without lost motion. Lever F controls through links or chains a lever G<SP>1</SP> operating a fluid pressure jack G<SP>2</SP> to control the direction of jet thrust. A piston K<SP>1</SP> is subjected on one hand to the pressure in the supply line to the main hydraulic accumulator (not shown) through pipe M, and on the other to the pressure of an emergency accumulator (not shown) through pipe L. The effective areas of the piston are chosen so that the piston is moved when the supply pressure to the main accumulator falls below a certain value. The movement of piston K<SP>1</SP> changes a changeover valve J, admitting fluid pressure to jack C, which draws lever A to the right of the Figure into abutment with two fixed rollers H which square the lever. Lever A also abuts the nuts F<SP>2</SP> without lost motion, to square lever F and centre the jet thrust. At the same time lever A is withdrawn from nuts D<SP>3</SP>, allowing lever D to pivot with the control surfaces unhindered. Pipes J' and J<SP>2</SP> operate the jacks C of the other jet engines. The changeover valve is fed through non-return valves L<SP>1</SP>, N<SP>1</SP> from the main and emergency accumulators, drawing fluid from whichever has the higher pressure. A lever R operated by movement of pivot B may also serve to change certain fluid pressure services, e.g. all except aerodynamic controls, from the main accumulator to the emergency accumulator. A microswitch Q is actuable with the changeover valve J to give a visible warning to the pilot. A manual changeover control may override the automatic control.