I really don't think you need a 75. I have the 40 size one. It flies fantastic ona Super TigerGS-45. That is at the maximum suggested size. The 75 probably won't hurt it. But it more than likely be overkill. As stated before this is not a 3-D plane. And putting a big engine on it will really not gain you much. Good luck with yours. I love mine. BTW be sure to reinforce the gear block mounts in the wing. They can be a little weak.

Mark Shuman