Just seen this on ebay, weird looking engine check out the air cooling set up.
http://cgi.ebay.co.uk/Certified-cond-Norton-Rotary-aircraft-engine-nil-hours-/150562160707?pt=UK_CPV_Aviation_SM&hash=item230e344043
Bloody expensive as well
The renesis engine is used a lot in aviation, they produce much more power to weight than piston engines, if a piston engine fails then you don\'t have any power, when a rotary fails there is still some power to get the aircraft down. Norton make rotary engines as well, which they used on bikes. That aviation engine also has all the gearing to be able to put a prop on as well which is why is expensive.
http://www.rotaryaviation.com/
Plus its certified, which doesn\'t come cheap either!