The OS unit is a dedicated aircraft engine, so I don't think it's suitable for cars. There are mixed feelings from aircraft RCers about it; it seems to drink a lot of fuel though, but looking at how much development has gone into piston engines to get them where they are versus how much has been done with a rotary, that seems like barely an issue.
Davidka, that's actually a possibility, and not just with a Wankel: perhaps a cooling fan could be fitted to the crankshaft to help cool the engine... So many interesting concepts to persue...
