Active noise cancelling muffler for light planes

This one should be right up your alley audioguru

I`m not sure how successful it would be.

For Light planes and power requirements max of about 5amps/12v after that you need a bigger alternator.
Regards Tony

Benefits of an Active Noise-Canceling Muffler
1.By using an active muffler the exhaust noise can be easily tuned, amplified, or nearly eliminated.

2.The backpressure of a conventional muffler can be essentially eliminated, thus increasing engine performance and efficiency.

3.By increasing engine efficiency and performance, less fuel will be used and the emissions will be reduced.

Regarding 2 and 3...

How does an audio circuit producing destructive interference increase engine efficiency? Unless there is something I am misunderstood about engines a regular muffler only does that by using the exhaust shockwave to increase the compression in the engine. An electronic circuit with a speaker can't do that.

Personally, points 2 and 3 sounds like marketing BS to me. Where did you find them?

EDIT: It seems I mistook a tuned pipe for a muffeler.

Sorry dknguyen I should cite
Engineering Acoustics/Specific application-automobile muffler - Wikibooks, collection of open-content textbooks

The reason is no restriction /less weight/no back pressure
1 inch exhaust versus 4'' versus no exhaust