Heh.. you guys haven't even gotten into the "percent by weight vs. percent by volume" argument yet. SIG measures by volume, a lot of the RC fuel suppliers measure by weight. When you consider that the specific gravity of nitromethane is 1.14 and the s.g. of methanol is 0.8, it really DOES make a lot of difference. 15% nitro Byron or Cool Power fuel would be the equivalent of, say, 11% SIG fuel. When they say 18% oil it'd only be 14% by volume.

Last time I bought castor oil - 17 liter can (looks like the ones at the Chinese takeout restaurant), about $60.

I used to like to carve up cheap chinese engines, too - I flew Brat .28s and the like in Fast Combat. Finally did a Magnum .36 - it lasted three rounds at the Nats, and ended up breaking a crank - after I scored the kill, thank goodness. For RC sport flying, one would use maybe a 10x6 on that engine - I'd run a Scimitar 8x6. On the .28s I ran Taipan 7x6s. Amazing how much more power you get by just grinding on the crank - I was opening them up to 35 degrees ABDC to 57 or 65 degrees ATDC. Of course, you couldn't compete with the Nelsons - the Nelson had a 17mm crankshaft, the Magnum 12.5mm.

Iskandar