A few of my club members had this plane and all were disappointed as it builds heavy. One had an O.S. 1.20AX (2-stroke) and was not happy with the power. I'd agree with nitrowing in that a YS 1.40 to 1.60 is in the right ballpark, O.S. 1.60FX is also a good choice and one of my favorite engines, Saito 1.80. You would probably need a 40cc gasser, which will be heavy.