The cowl/canopy fit is real tight. I just finished my second ShoeString kit last night. It was easier the second time around! Check all your glue joints. Reinforce/reglue the engine mount or anything else that looks like it has a poor glue joints. I always lightly sand the inside of the cowl, there is usually some snaggy stuff from manufacturing. Follow the assembly guide, mount motor, check placement of Cowl with Eflite recommended spinner for correct distance. It take several trial fits to get it right, sand around where it goes over the wing. Once it is positioned right, I tap for the small screws. Screw it down and THEN fit the canopy in. The instructions say to fit with the canopy in place, I tried that the first go around and it made it very, very difficult. Make sure you have it positioned right with refrence to the spinner back plate. Gently Sqeeze the cowl, attack it from an angle so that the graphite hold down pins of the canopy get into position, push forward then drop the back of the canopy down eyeing up the hooks in the back at the fuslage then push down and lock back. If you need to, to ease removal and replacement you can very slightly sand the length of the hooks helping to pass it down thru the fuslage. You may want to consider replacing the aluminum wing tube with a graphite one as well. Darrol Cady's pylon racing website and Brian Batch's B&B Hobbies in Spokane, WA. both have graphite replacement tubes for the ShoeString. Hope this helps.

Ed 23G