ORIGINAL: rgoldy
If you can find them, BME takes a Super Tigre 90 and converts it-absolutely screams. With the re-organization at BME, they may start making them again, we can only hope.
Have you purchased and run one? I have. They do not make the claimed power.
The smallest realistic gas engine is a 140 sold by RC Showcase. It makes good power for it's weight and size.
There are engines claimed to be released over the next few months in the 180 size range weighing two pounds w/ muffler and ignition with a selling price of $400.00. We'll see.