Prop RPM vice Engine RPM

[Ex Bonanza Bucko]

Will have a new S-LSA next month. Learning about it.

What will the prop be turning at a give engine RPM? IE: at 5500 on the engine what will the prop be turning? Is that relationship the same for all RPMs?

Thanks,
EBB

 

[sandpiper]

Divide the engine RPM by the gearbox ratio to get prop RPM. For the ULS I think the ratio is 2.43.

 

[Ex Bonanza Bucko]

Sanpiper:
Thanks a bunch. That means the prop is just about at optimum (as I understand it) and the engine is producing its torque with RPM which is also good. 2.43 works for me!
EBB

 

[BigJohn]

"............ Is that relationship the same for all RPMs?........

Yes. It is just a gearbox, not like the transmission in your car, that varies the ratio.

 

[roger lee]

2.43 for the 912 gearbox ratio is correct for most newer 912's.