I just saw this build thread. I built this plane for my son many years ago. It was a lot work but fun too. I did build a number of scale exhausts. This was a learning experience as there aren’t many places that can or will make bends in small tubing as required in this. I made my own out of stainless steel and TIG welded the whole system. It was very functional and fit within the cowl. The hard part is insulating the heat and separating it from the motor heat.

we had a 5.8 hotrod motor based on the Sachs crankshaft. The prop drive was the weak point and busted a couple of expensive spinners. The exhaust allowed over 8000 rpm so balance was important.

Overall the build went well. Be careful of excess weight. When you glass this plane it can build up very fast. I carefully finished the frameup so there was almost no filler required. We used a powered aluminum finish so the There was almost no weight in the final color.

Ill try and dig dig up some pictures. He still has the plane.