The front light ply piece is held in place with some zap goo. It works really well and sets up quickly. Note the four holes in the front ply piece. These allow you to take the spinner off at the field and check the tightness of the engine mount. Also note the engine mount ply backplate. You can see how much sanding was done for alignment of the mount. This took the most time so far. I put a couple of small drops of CA when everything was aligned, then carefully took the engine out and then drilled engine mount holes through the firewall. There is a plywood ring that comes with the hardware package. You mount four blind nuts on that and its not glued in but acts a a ring to clamp to the back of the firewall. This allows for fine tuning engine thrust changes later. Now take a break and do something fund. I went at it with a dremel and took open the pipe outlet and engine air openings.