OS .61FX in mine with only 2 ounces of lead in the nose and built stock. Flies very scale and draws plenty of attention doing just that. It seems that most people wind up with a very tail heavy plane, wasn't the case with mine but my CG is a bit aft of the recommended setting. First few flights had an additional 2 ounces (4 total) in the nose which IMO made it tougher to slow down on final. By design this plane just wants to keep on flying and too much nose weight can make that worse. Definitely one of the nicest ARF's of it's type and the price is good too.