RE: GP U-Can Do
The UCD is a nice flying plane.
The landing gear mounting is weak and should be reenforced - either glass it, or if you can get at it properly, use some bass tri stock.
You DEFINITELY want to add bass tri stock backing to the firewall. All the ones I have seen are just butt glued to the sides with hot glue.
You may also want to reenforce the fuselage in the area of the trailing edge of the main wing. A hard landing has a tendency to crack the fuselage at that point.