Abstract: A support assembly for coupling a first gearbox to an airframe of an aircraft. The first gearbox has an output gear operable to transfer torque to an input gear of a second gearbox via a common shaft rotatable about a longitudinal axis. The support assembly includes a fixed joint proximate the longitudinal axis. A first directional reacting joint remote from the longitudinal axis provides a first radial growth degree of freedom to the first gearbox relative to the longitudinal axis. A second directional reacting joint remote from the longitudinal axis provides a second radial growth degree of freedom to the first gearbox relative to the longitudinal axis. The first radial growth degree of freedom is not parallel with the second radial growth degree of freedom such that the support assembly maintains the output gear of the first gearbox in substantial collinear alignment with the input gear of the second gearbox.

Abstract: A support assembly for coupling a first gearbox to an airframe of an aircraft. The first gearbox has an output gear operable to transfer torque to an input gear of a second gearbox via a common shaft rotatable about a longitudinal axis. The support assembly includes a fixed joint proximate the longitudinal axis. A first directional reacting joint remote from the longitudinal axis provides a first radial growth degree of freedom to the first gearbox relative to the longitudinal axis. A second directional reacting joint remote from the longitudinal axis provides a second radial growth degree of freedom to the first gearbox relative to the longitudinal axis. The first radial growth degree of freedom is not parallel with the second radial growth degree of freedom such that the support assembly maintains the output gear of the first gearbox in substantial collinear alignment with the input gear of the second gearbox.

Abstract: A drive system for a tiltrotor aircraft includes a first gearbox rotatably mounted to the airframe and rotatable about a longitudinal axis to operate the tiltrotor aircraft between helicopter and airplane modes. A second gearbox extends generally normal to the longitudinal axis of the first gearbox. A common shaft, rotatable about the longitudinal axis, transfers torque from an output gear of the second gearbox to an input gear of the first gearbox. A support assembly couples the second gearbox to the airframe and includes a fixed joint proximate the longitudinal axis, a first directional reacting joint remote from the longitudinal axis providing a first radial growth degree of freedom to the second gearbox and a second directional reacting joint remote from the longitudinal axis providing a second radial growth degree of freedom to the second gearbox that is not parallel with the first radial growth degree of freedom.

Abstract: A drive system for a tiltrotor aircraft includes a first gearbox rotatably mounted to the airframe and rotatable about a longitudinal axis to operate the tiltrotor aircraft between helicopter and airplane modes. A second gearbox extends generally normal to the longitudinal axis of the first gearbox. A common shaft, rotatable about the longitudinal axis, transfers torque from an output gear of the second gearbox to an input gear of the first gearbox. A support assembly couples the second gearbox to the airframe and includes a fixed joint proximate the longitudinal axis, a first directional reacting joint remote from the longitudinal axis providing a first radial growth degree of freedom to the second gearbox and a second directional reacting joint remote from the longitudinal axis providing a second radial growth degree of freedom to the second gearbox that is not parallel with the first radial growth degree of freedom.