What is the baffle in the muffler for? and what happens if I remove it?

Basically it is there for noise reduction and back pressure.

You can definitely remove it. I've done it on several engines. I've enlarged the hole in the muffler outlet too. It did give me more RPM on the engines I did it on. They had to be re-tuned after doing it of course. It may not benefit every engine out there though but you can always put it back in if you aren't happy.

In my opinion, the gain in RPM is not worth the effort for the noise incerase.

This has been debated several times before with those that insist that it is worth it, and those that say it's not.

My take on it is that noise does not necessarily equate to power, just more aggravation for those around you at the field and for the neighbors nearby your flying field. If you live in an area with no houses around for about a mile or two, well, it may not matter. But many clubs have noise limits. Our's does.

CGr.

Yea, we have a noise limit also. Our pitts style just under the limit. BTW, snowing hard here today. Guess I will have to work on some planes. Maybe my spot-on-fifty or my Calmato. Was looking at the dates for the SPA, gee, nothing close by to my area. I think I will build a Birdi Killer Kaos. Or is it Chaos

We instituted a noise measureement process in where members that show up when those of us with noise meters are present, do the measurements on the planes that they brough with them that say and send that to the club secretary. The reason is because we had a problem neighbor that, out of the clear blue, started to complain about the noise. Problem is, he is about a mile away from the flight line to the left and rear of where we fly.

I've been near his house and heard absolutely nothing when we were flying so a lot of this is simply harassment. But, he is a neighbor and has a right to complain. We are using this field by the good graces of the Forestry Service and don't want to lose the privileges because someone complains to a politician. So, we measure and document our noise levels, should it come to that. And, we try our best to limit the noise as well as the traffic by his house (see the Google Earth screen capture of the field and the neighborhood involved).

CGr.

I think for general sport flying yo are absolutely right. For pylon racing or something where it is full throttle all the time it can be beneficial. Noise is definitely another concern.

Ah, Ok.. well, for pylon racing, all bets are off, including engine life..

CGr.