"Thomas Borchert" wrote

Again, I mentioned two examples, one common, one maybe not so:

1. Take-off. Leave throttle at full and reduce RPM to 2500 is better for
the hardware in most cases than reducing to 25/2500.

I'm not so sure about that - but I also don't really know. As you said,
these engines are fuel/air cooled, but as you ask for more power you also
produce more heat, and I suspect that the engine is actually less efficient
thermodynamically at full power than it is at reduced power. In other
words, as you approach full power you get increasingly more heat and less
actual BHP for that heat.

I wonder if the oversquare-phobia is a carry-over from adjustable-pitch
props where it was much easier to "lug" the engine (like driving in 4th gear
at low speed and heavy on the gas).

BDS