Snowbird wrote:
"Matt Whiting" wrote
Is the prop RPM in cruise really any lower than a Conti? Most reduction
units are simply to get the prop RPM low enough to decent efficiency and
seldom get much lower than a direct drive airplane engine.


The reduction gear ratio on the 912S is 1:2.43. This means a prop RPM of
2386 rpm at max power and around 2000-2100 rpm in cruise. Very sweet and
efficient.



I don't have the efficiency curves handy. That sounds pretty slow for a
small diameter prop.

Matt