Exhaust Manifold

The exhaust manifold on the OX-5 was made for 20 gauge (0.035") mild steel sheet.  It was stamped in 2 shells which were spot welded together and then the edge of the top shell was folded over the edge of the bottom shell to make a nice finished edge.

For planes like the WACO NINE a short extension with a 90 degree bend was welded to the end of the manifold.  This extension was also made from 2 shells.

The engine shown here is at the Air Power Museum in Blakesburg, Iowa (Antique Airfield).

The manifold is bolted to the engine with flanges stamped from 3/16" thick steel.  The shell extends inside the flange and the flange welded to the manifold shell.  These flanges are welded at an angle so the manifold tips down relative to the cylinders.  As a result one manifold will not work for both sides pf the engine.

There is also a steel fin welded to the top of the flange.  It appears to be a heat shield to protect he valve mechanism.  It may be a heat sink but so far I have not found a factory explanation of it's purpose.

The manifolds on my engines are shot so new ones are needed.  I probably would not have made new ones at this point except I have a chance to make some for a Jenny.

The factory parts manual shows the hot air box on the bottom of the Right Hand manifold.  You can also see the longer extension which would allow the exhaust to be directed away from the crew.

My project is to fabricate new manifolds for the Jenny and my WACO NINE.