RE: 50% Extra 300 scratch built
The motorbox was constructed of 1/4" thick pieces of Dow 40 foam with 4 layers of .007 carbon fiber laid bidirectional for strength in 90 and 45 degrees. We cut the foam on a cnc router that my friend Mark McClellen built. Mark is a Big help in this build as you will see. Mark showed me how to draw in autocad and I spent about 1 week drawing the first design of the motorbox. We cut the box out two times in 1/8 lite ply to check the changes and adjust the fit of the parts. With the help of others we changed a few things we didn't like about the design of the motorbox. I went back to drawing and changing things till we came up with the new design. The landing gear plate and the firewall are constructed of foam, 5 ply 1/8 ply, and 4 layers of .011 carbon laid bidirectional.