alt.energy.homepower

Small engines are usually less efficient than bigger for some reason
or another... otherwise I guess we'd have lots of small engines in
ships instead of one ot two big ones. Anyway, I think you should get a
4 stroke model airplane engine, which should have better specific fuel
consumption than a 2 cycle of the same displacement, and set it up on
a bench with a fuel flow meter and an alternator with a rheostat on
the field coil, and find the 'sweet spot' in the rpm and alternator
load setting that minimizes fuel consumption. Once you know this exact
volts and amps in the alternator, you can get a BLDC kit and put on a
custom winding to match that exact setting. If the load varied more or
less than this tuned setting, the effciency would drop on either
side... careful measurement would show if the power used to excite the
field coils in the alternator (a dozen watts?) could be tolerated in
order to gain the advantage of matching a varying electrical (and thus
mechanical) load. Since I'm a programmer, I think this would be a
great job for a $5 microcontroller, but you might be able to find a
nice young man from Shanghai that would adjust the knob whenever the
generator was running for whatever the prevailing wage is over there.
Couple bucks a day?