Nodoubt this plane was designed for a 1.80 or 2.10 glow engine and its no secret the lighter your wing loading the better it will fly especally for 3D. You can fly a plane this size with a gas engine and it will fly well especally if you don't care about 3D which I don't.

I have had a few people tell me the GSP Katana would not fly well with a gas engine. I have a GSP Katana 72" W/S (992 sq in) with an RCS 180 gasser weighs 13.5 pounds dry. I flew the plane with a Saito 180 and today with the RCS 180 and let me tell you the RCS 180 is 100% better. The plane flys awsome and lands a lot better than with the Saito.