What type of load is primarily absorbed by roller bearings in a free power turbine engine?

In the context of a free power turbine engine, roller bearings are designed predominantly to manage radial loads. Radial loads occur when forces act perpendicular to the axis of the bearing, which is typical in turbine applications due to the weight of the rotating components and the centrifugal forces generated during operation.

When the turbine spins, the rolling elements within the roller bearings accommodate this radial force, allowing for smooth rotation and reducing friction. This is crucial for maintaining efficiency and performance within the engine.

In the case of other types of loading, such as axial loading, the forces act along the axis of the bearing, which is not primarily what roller bearings are designed to handle. Similarly, shear loading and circumferential loading are also not main considerations for roller bearings in this specific application. Instead, those types of loads are managed by other types of bearings or structural elements that are designed to deal with forces acting in those directions. Thus, the selection of roller bearings in free power turbine engines aligns with their primary function of handling radial loads effectively.