I put a YS120 (4 stroke) with a 14x8 prop on my Razzle. The plane weighed out at 7.25 lbs (approx. 19 oz per square foot). She will hover at less than 1/4 stick. The plane flies very nice and very predictable. After a few more flights I will be adding additional weight to the tail so that more aggressive 3d action can be experienced (It is flying pretty aggressive now...). The only problems I am experiencing is when I try to Harrier. The wings tic-toc back and forth a little. The only modifications I made to the plane was that I located the fuel tank over the CG line and I had to raise my landing gear and install 3.5" foam wheels so that the prop would clear. I did not install the engine cowling so if anyone need a replacement, I have a brand new one for sale. One last thing, be careful when handling the model....it is easy to crack the wood on the top side of the fuselage and on the wing pan if you squeeze too hard.