ORIGINAL: Jim Thomerson
I ran a K&B 4011 on Sig Champion 10% nitro, 20% oil, half synthetic, half castor. Tuned like I would for a control line stunt airplane, it turned an APC 11 x 5 at 9,700 RPM. Switched to Eric Clutton Old English diesel fuel. Kept the glow plug lit for maybe 20 seconds until it didn't run undercompressed when I took the battery off. Turned the ST NVA in 1 1/2 turns. Sounds nice, and turns the APC 11 x 5 at 9,700 RPM.
Our two cycle engines are air pumps and how much horsepower they generate depends on how much air (and proper fuel mixture )they pump.
I think it is true that diesels turn big props more happily than a similar glow engine, but have not done that experiment as such.
I'd heard this is mainly because you can vary the compression on a diesel. This allows you to use a wide range of props within reason - if the prop's too big for the compression ratio, it will lead to pre-ignition, but with a diesel you can back off the compression as needed. Only true for a contrapiston-equipped model diesel, of course. You could also run larger props on a glow by adding head shims, I suppose. Power may not be optimal, though.
Iskandar