I have a Moki 2.10 mounted inverted with an on board glow driver, inverted Bisson Pitts muffler, four gallons through it (Wildcat 5% Jet A) on a 15.5 pound Dave Patrick Edge 540, Zinger 22X6 prop over 9000 RPM totally unlimited vertical. Very good braking on down lines and landing. I am amazed how little fuel this engine uses compared to the Saito 180 I had on another plane. I have a 24oz tank and after a ten minute flight I still have about 1/3 left even spinning as many RPMs as it does, very happy with this engine.