This is the 2nd 50cc plane I built , they kinda skimp on the glueing. On the one I recieved the front engine mount was loose, and the fuel tank compartment. Also I'm replacing all the hinges on the ailerons, rudder and elevator with true robart hinges. The included ones look weak and I have found flaws in the plastic. I use gorilla glue on them it expands in the hole for a great bond, I learned this from Wild hare. It's a great place to get servos and battery packs. I'm adding 2 more to the rudder and 2 more on each side of the elevator. I own a 28% sukohi purchased from wild hare and it has the same size of elevators but has 4 hinges per side. Other than that It's a great plane for the price. Another issue I found with mine is the blind nuts on the main landing gear were the wrong thread size for the supplied bolts. Did you figure out what the 4 square blocks are for? Good luck with your build.

Bruce