The Titan T-51 with the GM LS3 430hp motor uses a 2.2 ratio Autoflight PSRU that is designed for up to 300hp at 6000 rpm.
The prop can spin up to 2550 rpm (so call it 2500,) so the engine can spin to 5500 rpm within that prop speed limit. (Redline on the engine is 6600 or so, so irrelevant.)
I am told the cure for this "engine makes too much power for the gearbox" situation is to limit the revs to less than the engine makes 300 hp, which is about 4000.
But the engine makes 400 ft-lbs of torque all across that rev range, so by spinning the engine slower you are exposing the gearbox to stronger impulses per rev, which is a bad thing, no?
Seems to me it is better to run the engine and gearbox faster and limit the horsepower being generated by limiting the throttle / MAP rather than using full throttle at a lower rpm.
What am I not understanding?
Jim
The prop can spin up to 2550 rpm (so call it 2500,) so the engine can spin to 5500 rpm within that prop speed limit. (Redline on the engine is 6600 or so, so irrelevant.)
I am told the cure for this "engine makes too much power for the gearbox" situation is to limit the revs to less than the engine makes 300 hp, which is about 4000.
But the engine makes 400 ft-lbs of torque all across that rev range, so by spinning the engine slower you are exposing the gearbox to stronger impulses per rev, which is a bad thing, no?
Seems to me it is better to run the engine and gearbox faster and limit the horsepower being generated by limiting the throttle / MAP rather than using full throttle at a lower rpm.
What am I not understanding?
Jim