An engine mount assembly for coupling an engine to an airframe. The engine mount assembly includes a torsion bar coupled to the engine and a lateral movement control assembly coupled between the torsion bar and the airframe. The lateral movement control assembly includes a spring having a lateral stiffness. The torsion bar rotates in response to lateral movement of the engine such that the lateral movement of the engine is controllable based on the lateral stiffness of the spring.

An engine mount assembly for coupling an engine to an airframe. The engine mount assembly includes a torsion bar coupled between the engine and the airframe. The torsion bar includes an external spline. The engine mount assembly also includes a bell crank having a clamp forming an internal spline with the internal spline of the bell crank adapted to mate with the external spline of the torsion bar to secure the bell crank to the torsion bar such that the bell crank rotates with the torsion bar responsive to movements of the engine.

A rotorcraft, such as a tiltrotor aircraft having helicopter and airplane modes, includes an airframe, an engine and an engine mount assembly for coupling the engine to the airframe. The engine includes an engine lug forming an aperture. The engine mount assembly includes a mount having an aperture substantially aligned with the engine lug aperture. A sleeved bolt assembly extends through the apertures to secure the engine lug to the mount. The sleeved bolt assembly includes a bolt undersized relative to the apertures forming a circumferential gap within the apertures, a sleeve disposed around at least a portion of the bolt substantially filling the circumferential gap and a nut adapted to thread onto a threaded portion of the bolt. The use of the undersized bolt within the sleeve permits increased clearance between the sleeved bolt assembly and the engine while maintaining strength requirements in high load environments.

An engine mount assembly for coupling an engine to an airframe. The engine mount assembly includes a torsion bar coupled between the engine and the airframe. The torsion bar includes an external spline. The engine mount assembly also includes a bell crank having a clamp forming an internal spline with the internal spline of the bell crank adapted to mate with the external spline of the torsion bar to secure the bell crank to the torsion bar such that the bell crank rotates with the torsion bar responsive to movements of the engine.

An engine mount assembly for coupling an engine to an airframe. The engine mount assembly includes a torsion bar coupled to the engine and a lateral movement control assembly coupled between the torsion bar and the airframe. The lateral movement control assembly includes a spring having a lateral stiffness. The torsion bar rotates in response to lateral movement of the engine such that the lateral movement of the engine is controllable based on the lateral stiffness of the spring.

A rotorcraft, such as a tiltrotor aircraft having helicopter and airplane modes, includes an airframe, an engine and an engine mount assembly for coupling the engine to the airframe. The engine includes an engine lug forming an aperture. The engine mount assembly includes a mount having an aperture substantially aligned with the engine lug aperture. A sleeved bolt assembly extends through the apertures to secure the engine lug to the mount. The sleeved bolt assembly includes a bolt undersized relative to the apertures forming a circumferential gap within the apertures, a sleeve disposed around at least a portion of the bolt substantially filling the circumferential gap and a nut adapted to thread onto a threaded portion of the bolt. The use of the undersized bolt within the sleeve permits increased clearance between the sleeved bolt assembly and the engine while maintaining strength requirements in high load environments.