Ok, lots more data on the SK .70 muffler. The weather was cool and very damp, actually foggy at the field. This probably has some impact, I guess.

Today I ran my ABC(N) SF .61 with both the SK and the stock mufflers. The SK is a dud. Not at all what I was hoping for. Also, my ringed version is stronger than the ABC. I wasn't expecting that, either.

Here's what I recorded.

Power master 10% with extra castor added.

SK .70 muffler:

APC 11x11 - 9400

APC 11x10 - 10960

APC 12x6 - 11710

APC 12x8 - 10630

Stock muffler:

APC 11x11 - 9730

APC 11x10 - 10720

APC 12x6 - 12130

APC 12x8 - 10750

You can see that the stock muffler actually has a slight edge. Believe it or not, it is noticeably quieter, too (but still pretty loud).

The good news is that the SK is about half the cost of an OS #744B, so, if you need a replacement it's an option.

I still want to run more tests on the ringed engine, but I had to leave the field.

David