The 52 should go in but you may have to use a different motor mount and redue the mounting holes --NO BIG deal. I've put a 60 in one with out much trouble. Just be carefull about your CG. When you get it all back tgeather RIGHT I believe you will really like it. I still fly one and have a kit ready to be built if I need to, it's one of my favorites !!! ENJOY !!! RED