That is what I used to think, but I can't see how it makes sense... How can you be slower when producing 65% at best economy than when producing 65% at best power?
To first approximation, the following should be true:
- To produce a given RPM on a fixed pitch prop at a given altitude takes a given horse power.
- A given power at a given altitude (and temperature, and so on) should result in a certain cruise speed.
But if I'm not mistaken those two statements together are inconsistent with the cruise speed at a given power setting and RPM depending on the mixture setting. So it appears as if we must look beyond the first approximation...
Might have to dig up some aeronautical engineering textbooks and do the number crunching, unless someone already knows the answers...
