Which characteristic is typical of a thrust bearing used in most radial engines?

A thrust bearing used in most radial engines is characterized by its design to accommodate axial loads while providing smooth rotation. In the context of radial engines, a deep-groove ball bearing is particularly effective because it is able to handle both radial and axial loads efficiently. This type of bearing features a raceway that allows for the balls to move smoothly, minimizing friction and wear during operation.

The design of deep-groove ball bearings allows them to provide high speed capabilities and help in maintaining the alignment of engine components under varying load conditions, which is essential in radial engine applications. Their ability to manage higher speeds and loads compared to other bearing types makes them suitable for the demanding environment of an aircraft engine.

Other bearing types mentioned, such as spherical or roller bearings, do not provide the same combination of axial load support and high-speed capability required in typical radial engines. Plain bearings lack the rolling element design, leading to increased friction and wear, which is less desirable in high-performance applications. Thus, the use of a deep-groove ball bearing aligns perfectly with the performance needs of radial engines, making it the correct choice.