The recently reviewed Hangar 9 Christen Eagle (http://www.rcuniverse.com/magazine/a...rticle_id=1483) has a 54" wing span and appears to fly well with a 125 four stroke (20cc) glow engine. My GUESS is that a 26cc gasoline (petrol) engine in your plane would be fine, but I might go with a 30cc or 35cc depending on how heavy the plane is. If you already have the 26cc laying around, I'd say go for it!

Kerry