Originally Posted by
The Sultan
CTR,
So you don’t know if Brinelling would be an issue as bench test would never yield the aircraft vibratory environment (the whole bolted to Mother Earth thing).
Sultan,
As you probably are aware, rolling element bearing Brinelling is caused by excessive static load and fretting is caused by oscillating motion less than a full bearing rotation from vibration (even under no load).
So if the rotor can freewheel even a couple degrees in flight and the loads are low, both fretting and Brinelling are addressed. Having designed large pitch trim actuators including the C-17, I am intimately familiar with these bearing concerns.