The cowl measures 8 3/4 inches in diameter. The G26 works well but then so does a Magnum 120. This plane flies totally scale and no engine is going to make it fly any differently. I used the Magnum with an on-board glo-driver and housed both batteries in the weight box above the engine. The plane balanced great. Like the idea of the 4 inch dubros as this thing is a real bouncer on anything but grass and I even managed it there once. As to the four servos on the elevators, I used different holes in the servo arms to get the differential in the throws. I y'd each set and ran the top extension out at the top of the left cabane. I just wrap it around the cabane and plug it into a Ernst connector I put in the fuse at the cabane base. Works great. Getting both wings on at the field is a little time consuming (5 min) but the plane is a dream and well worth it. At one point I even mounted a color video camera (tiny one from Raidentech) between the cabanes. Video is on Members video. Check out the full review I did on this last year in Users Reviews. I'm taking mine out for the first time this year today. Nice clear skies!!