When the engine companies give a hp rating it is usually at a much higher speed than the speed you would normally run at. 15,600 must be where you would find peak hp, and now doubt you could get that with a 11-5 or 10-6. But I would stick either a 12-6 or 13-5 on it so that it would turn around 12,000. I flew one for hundreds of flights with no problems on those two prop sizes.

A lot of people have trouble setting the mixture on ST engines. Unlike most engines, you can adjust the midrange mixture as well as the high and low speed needles.

Personally, I liked the older Tigres better, before the clunky heads and cast drive washers. But since most RC pilots fry their engines on every run, I guess the bigger heat sinks became necessary. For the most part, people that flew control line (not talking Cox here) have a better feel for running engines.

The RC crowd also has problems with locating fuel tanks with respect to the carb. Nearly every "trainer" has the tank mounted too low. I guess it's more important to look like a Cessna than to run well.

Maybe one day, the engine guys will figure out that the airplane designers are slow learners. Then they will rotate the carb so it is on the side of the engine.