Does anyone have any comments on his engine choice? I'm also building one of these and am down to picking a power plant. The inside of the fuse at the engine is only 2 1/2" which barley allows for a .40 2 stroke + mount. The text in the instructions states that some prototypes were built with a .25 2 stroke and flew well - the .40 was for reserved for the wild - does anyone have any comments (from experience) about if a .25 would be way under powered and also if the .52 of LJR's above has any chance of fitting in the fuse? I will be getting a .46 recovered from a crash that I'm considering using but thinking it may be a waste of power.