One thing I wish I had done but never got around to it was to section some rusty stock mufflers on their way to the recycler. I don't recall anyone having done this in order to replicate Mazda's shapes and routing. A cursory look at the rx7 auto sites don't provide much.
Todd
Hi Thomas,
Thanks for the photo.
The exhaust pulse from the rotary is just incredible powerful. Any flat surface perpendicular to the pulse (such as the end of you muffler), appears to be doomed to fatigue failure from the pounding of the pulse.
I once squished the tips of 2" dia SS steel tubes together and drilled holes to make a "fishtail" sound suppressor. After a 30 min flight, I came back to find chunks of the SS tube missing where the pulse had hammer and fatigued the tips during that short flight.
Rather than a flat surface, a cone or angle surface which deflects some of the pulse energy appears to be required for longer term survival.
Better luck on your next choice
Ed
I just did an inspection of my muffler and found that it was basically coming apart inside. This is a Burns Stainless, 17" 2-Stage muffler after 50 hours of flying behind a 2-rotor engine. Now, it could be that 50 hours is a reasonable life for something like this, I don't know. But, it certainly confirms the stories of muffler disintegration. I've inspected this muffler several times over the last 50 hours, but this is the first time that I've seen damage. But, when it comes apart, it really comes apart. It is unfortunate, as the muffler was really effective in reducing the noise and was light-weight.
Best Regards,
Steve Thomas
|