I mounted the Engine on the Engine Mount and installed the Muffler on the Engine. I then held the assembly, with the engine in the horizontal position, against the firewall, centred on the thrust lines. The Muffler fouled the fuselage sides (it's a 2 stroke) so I rotated it clockwise until the Muffler cleared the fuselage by about 1/8". Making sure the mount was still centred on the thrust lines, I marked the mounting holes and also the positions of the fuel lines. I then installed the blind nuts in the firewall and mounted the engine (minus muffler).

I tacked four small 1/16" balsa spacers to the back of the Spinner Back Plate (1 at each compass point) and then tacked the Plywood Spinner Ring to them, ensuring the Ring and Plate remained perfectly aligned. I then installed the Spinner/Ring assembly onto the engine (a broken prop hub works well). Then I installed the 3/8" balsa sheet cowl top and bottom blocks. They need to be fitted so that they protrude slightly above the fuselage and the Spinner Ring, to allow for later trimming. The 1/4" balsa sheet sides were then added, again protruding above the fuselage and spinner ring. The right side was cut to fit around the engine; a close fit but not too close (the Engine has to be able to be removed and installed).



With The Engine removed, I installed 1/2" balsa triangle strips alongside all four inside corners between the Spinner Ring and the Firewall.



I also installed 1/2" triangle strips to the back of the firewall and between F2 and F1, again to allow for trimming.