Bill Freeman wrote:

Paul,

I would put a plus or minus 50% error bar on this sort
of calculation.  Too many completely uncontrolled
variables, like recirculation, wind direction, fraction of
the prop stalled, prop length, prop design,etc, etc.
 Of very limited value.

If you build an engine much like Tracy's or George's or
Ed's, you will have enough thrust to safely fly an RV
or a Cozy, both which need about 150  hp from a
Lyc or Cont.    Beyond this, actual HP developed is
mostly just kinda interesting.

I would say the most accurate **EASY** way to compare
is to have a same-design A/C with a Lyc or Cont to
compare **same wt and same airspeed**  rates of climb.
The biggest uncontrolled
issue here is prop pitch.  But assuming that each has
a "suitable" prop, the actual rate of climb will tell what the
real world available horsepower is, compared to a Lyc
or Cont.   My guess is that even they do not actually make
what the advertised HP is, in many cases due to wear and
installation-based losses such as aircleaners and exhaust
systems.

Bill

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