hey, sskianpour,
I have a G-38 in my H9 P-47 150, which has an 80" wingspan. and weighs about 19#. The Hellcat is not big enough for this size motor. Will it fit under the cowl? I don't know, never even tried it. One thing for sure, though: She will be waaaay noseheavy. I would shy away from this motor choice. Put a Zenoah 20 in it. It flies great with that engine, believe me.