Hi Paul,
I would like to subscribe to your news letter.
I have read of your ideas and believe some can be incorporated into my own project, a one-off, scratch-built helicopter.
I am a machine designer and lifelong machinist. I have completed both gearboxes and some of the airframe. I am building up an o4 Mazda Renesis rotary engine which will drive through a modified centrifugal motorcycle dragster clutch . I have done a lot of work with exhaust augmented cooling and had considered building a helical muffler many years ago. I would like to know how your design worked out as far as noise. Any insights you have regarding the Renesis engine would be appreciated.
Keep up the good work.
Jeff Jeter

I have only listened to a RX8 engine mounted in an RV6 in Western
Australia. No measurements so far but it is very quiet with
most of the noise coming from the prop.

http://www.youtube.com/watch?v=XgLw3a8DZgM


Paul Lamar