A Wankel engine is a rotary internal combustion engine. Theoretically more efficient that the piston engine in most cars. Only one company has had much success with it and that’s Mazda with it’s amazing RX-7 and RX-8 models. This guy has built a 12 rotor (like 12 cylinder) engine for motor boat racing. Not much larger than a V-8 but with 1500hp.

via Road and Track