RE: Installing Lipo in Old SuperCub...Need Advice
ATVAlliance is correct. I should have mentioned that I also have tried 1800 and 2200 mah packs and had the same result as you. One thing you can do is cut the top out of the front portion of the battery box and slip the battery in vertically. The problem with doing this is you have to shift the reciever aft and the slip the battery past the motor leads. When you do this, the motor leads are not long enough, so you will have to add extensions. Best choice is to go with a 1500 mah or something closer to the size of the battery box, it will give you better performance overall and wont stress the airframe from being too heavy.