Dennis,
Just aft of the firewall, I initially used a stainless flexible joint with the woven exterior. It also had a woven layer inside of the bellows. The interior layer swelled up and quieted the exhaust for a short time. Then after about 20 hours, suddenly those
wires blew out into the muffler. The pieces of wire in the muffler were mostly about an inch long or less and didn't cause a blockage.
After about 150 hours, the bellows burned through and was replaced by a ball joint.
Steve Boese
After about 700 hours and 8 years flying I have decided to design and build a new exhaust system for my RV-7A powered by a 4 port RX 8 Renesis engine. Bobby Hughes has offered advice and greatly assisted me in this endeavor.
The new exhaust was designed with three header pipes routed into a 3 to 1 collector that is 3 inches in diameter. The headers and collector direct the exhaust toward the firewall. A combination of 3 inch and 2.5 inch pipe
take the exhaust down and out the bottom of the cowl and the exhaust exits about 12 inches back from the firewall.
I have flown with the new exhaust and discovered it causes a lot more vibration to the airframe than the old exhaust. (I have a ball joint in the down pipe at the firewall). I want to add a flexible joint down stream of the
3 to 1 collector and have about 3 inches space for it. MY Question - Has anyone used a flex coupling or a flex bellows as seen on Summits web site? The flex coupling is a woven stainless joint with a liner inside and weldable ends. The flex bellows looks
like a metal bellows on the outside and has a slip joint built inside.
Anyone have any experience with these on the rotary?
Thanks,
Dennis Haverlah