91.3% of it would miss a prop blade regardless of the RPM.
You may be right on this. I bolted a 10x6 prop to my dremel and fired it up. A quick check with my tach said it was turning 6000 RPM,s.
I shot a stream of Brake Clean directly at the prop disc and most of it did indeed seem to go right through undisturbed. A pusher type muffler may be the cleanest way to go. More testing is needed. [sm=71_71.gif]