Jim,

We need to refresh our thoughts again? In our case: Power is the rate of doing work. Torque is the force that does the work. Agreed?

A weaker torque, applied more times a second, say, could make more power than a stronger torque applied less often. Whether that is true depends on the, in effect, Force times Rate at which it is applied. A smallish diesel may be able to turn a largish prop at the same RPM as a larger glow engine. That only says that both engines are producing the same torque at the same rate (RPM) on that prop. Recent example: ENYA's 25BB diesel cites 9,000 RPM on a 12-5 or 12-6 prop. Many stunt-suitable CL 40's might not be able to do that.

The difference is that on a lighter prop load, the same 40's can run higher RPM, produce more POWER while the ENYA 25BB-D may need destructively high compression settings to try to match them, on those smaller props.

And, relevant to Greg's comments: 1.) yes, of course, volumetric efficiency, as a practical thing, must relfect the trapped volume,

and, 2.) We CAN rev-out glow engines because the methanol-based fuel WILL burn at less than ideal conditions far longer than a kerosene-based fuel can. The torque curves we used to see in the P.G.F. Chinn engine tests (or those by Billinton, or way back, Ron Moulton and Ron Warring) showed torque and horsepower by RPM. Diesel torque curves reached high values around 9,000- 10,000 RPM and fell away gradually. Glow engines torque curves fell more rapidly from peak, but the methanol made the result productive of higher horsepower for a lot more RPM range.

We could probably wind up typical "built-as" diesels if we insisted, but the transfer channel volumes in so many of them are too small to keep it positively productive, however well they serve around torque peak. And the excessive compression settings, to advance the ignition point suitably, would be very punishing on the engine.