On 25, Jul , at 8:27 AM, Jerry Hey wrote:

. But it is hard (IMPOSSIBLE?) to build a single rotor p port with less than 100 hp. Jerry

Jerry
are you not intending to fit a throttle? That is the horsepower limiter!
What is wrong with having some extra power with no extra weight? When you operate from those high altitude lakes,
you can have the same hp you have at sea level. In the old days they had gated throttles for different altitudes and other reasons,
like hot days etc.
Fit the prop you want, spin it at the rpm you want ------that is all there is to it
I think you see a problem that does not exist,  TJ is right on the money, build it --- just don't plan to use it :)
BR, Dave McC