Hi guys,

Am looking for the most powerful engine for my application, looking to spin a large 30" three bladed prop with a jumping coarse pitch of ... 35" !
Don't ask me why

I am limited in space in a 280mm diam. cowling.
I was planning building a dedicated gearbox. The output required is, at max throttle on the ground :

4000 RPM/12Kw/16HP/26 NM of torque

I run into obvious power limitation here, only thing I see would be a geared electric motor, but I'd like to go the recip way.

" small " 2 strokes engine like bigger OS can produce 3.75HP at 15 000 RPM ( Torque = 1.8 NM ), even greatly reduced, doesn't provide any torque ( yeah, POWER = TORQUE x RPM )
More serious DLE 120cc can provide 12 Hp at 7500 RPM ( Torque = 11.4 NM ), reduced with a 2 : 1 ratio it gives 3750 prop RPM with 23 NM torque ( 12 HP ), that would fit my needs.

But maybe you think about even more powerful and compact engine, being 4 strokes, in-line, radial etc ...

Please lemme know


Cheers,
Hueyman