ORIGINAL: xcellheli
I built my headers from scratch. They where easy to build but require access to a TIG welder. For the flange I placed a piece of paper over the motor exaust port and colored over the top with a pencil to get a tracing. I then cut two flanges from 1/4 aluminum plate. For the header I started with 1 inch .045 wall aluminum tub and cut twenty degree wedges out of the pipe (but not all the full way through). This allowed me to easly bend it. Once I had all the cuts I strung bailing wire through the header and twisted it to hold all the wedges tight and then TIG welded each cut point to make the header solid again. Finally I placed a 1/32 plywood shim between the motor and the flange, in the airframe to line up the flanges and tacked the flanges to the header. The wood acts as an insulator so you don't overheat the motor cylinder. After tacking I removed the header and finished welding the flange. The headers look very nice but have a series of welds where each of the wedges were cut. I would of bent them, but it is almost impossible to find a tubing bending with reasonable cost to bend 1 inch tubing with the tight radiuses that are required.

Non of the DA flanges will fit without modification. DA has their bolts on the same centerline, BME has stagered the bolts to the corners. The BME exhaust flange is much larger than the DA and fits a 1inch tube easily without having to smash the end into a rectangle to fit the port. I have seen that K&S does now offer flanges, bends and straight pieces in stainless steel that can be brazed together. Last time I talked with Don at Don's hobbies, he was working on getting these in stock for BME owners.