Please check out the recent blog post from kit planes on our pusher engine cooling solution. Our biggest issue taking the Innovator from build to flight was keeping the engine in the pusher configuration cool on the ground. This is a common issue with pushers. We think that this being our biggest problem is a good indicator of our design and development process. We solved the problem using naca ducts and armpit scoops. Air flow was also increased when we changed the configuration of the exhaust pipes for aerodynamic improvement purposes. Finally, we installed the cooling plenum which was graciously covered by Kit Planes. Please check it out! (Airbrushed Cooling Plenum Because Why Not)