Now tell me more about the muffler, since I probably have something very similar on my 3-rotor.  You got this from Atkins?  Inconel headers (2”) tangentially into 5” inconel tube?  Was this welded by Atkins buddy, Mark Sadikas? 

 

OK – it is similar to Dave Atkins – Racing Beat flange, 2”D x 4”-5” stubs out into the top of a 5” tube (I bought from Dave). Out the end of the 5” tube is a 13” long exit tube. All out of Inconel and all welded by a master welder with Inconel welding rod. The attached picture shows the finished muffler – except after the crack that occurred last February I changed that figure-8 output so that there is a complete 2” tube on one side so that the 8 is joined in the middle (the “finishedEngine7” picture shows the revised exit tube).

 

The heat shielding was really only intended to be that – radiant heat shielding and a “pan” under the injectors to take any spilled fuel away from the exhaust.  It was made out of 2024-T3 – and of course disappeared where the 1400 deg exhaust pulses hit it! It was open on the bottom and got a good shot of air from underneath the engine as it headed for the opening in the cowl behind the exhaust.

 

I think the design has too many welds/joints subject to thermal and mechanical stress which Inconel, being brittle,  cannot handle.  I also suspect, as Lynn has pointed out SO many times, the flow through this “homogenizing” type of exhaust system is WAY less than ideal. So, I’m headed in a different direction – one that is a lot more robust and perhaps has better performance. I think I can come up with something that is better for not much more weight.

 

Hope that answers your questions!