A mounting system includes a rotatable machine, a frame circumscribing the rotatable machine, and a plurality of mounting elements. Each mounting element of the plurality of mounting elements includes a pin member and a joint member. The joint member includes a rotatable joint capable of three degrees of freedom of rotation, and the joint member is slidably coupled to the pin member, such that each mounting element is capable of four degrees of freedom of motion. The plurality of mounting elements are further coupled between the frame and the rotatable machine and spaced circumferentially about the rotatable machine, such that the rotatable machine is able to expand and contract radially within the frame. The mounting system provides a uniform stiffness in any radial direction from the engine centerline within the lateral-vertical engine plane.

A method for compensating torsional loads applied to a shaft coupled to a main engine, comprising measuring values indicative of torsional loads applied on the shaft or power demand from the main engine; computing from the values the torsional load over time and a parameter indicative of a cycle; after measuring the group of values, measuring a subsequent value indicative of torsional loads applied on the shaft, and applying a compensating moment or load in a direction determined by whether the subsequent value is greater than or smaller than the value representing the torsional load over time. The direction is a torque direction applied to the shaft by the main engine or the opposite direction.