Originally Posted by
The Sultan
CTR
One thing you missed on actuators is they don’t rotate continuously at 600 to 24000 rpm under load like gearbox components and associated bearings and therefore not relevant to the discussion of gearboxes not operating for extended periods in high vibratory environments.
Actually, as one example the V-22 conversion actuator gearbox input speed is approximately 6,000 RPM, an output of approximately 600 RPM, and continuous bearing contact stresses higher than in high speed gearboxes (which I have also designed parts for). Actuator gears and bearings on the V-22 actuators also experience full load reversal and impact loads from emergency stop braking. With the exception of high temperature run dry requirements, the V-22 conversion actuators are subjected to a more severe environment than a typical tail rotor gearbox.
This is not to say the X-2 gearboxes are properly designed to deal with the environment. Only that the technology to design gearboxes to withstand the environment is not new or unique.