Okay, so I wanted a little more ooomph out of my LA-46, so I take the muffler apart (yes, I'm using a stock muffler, or was) and remove the internal baffle (a little cone with a hole in the middle). So, now I got a little more power. "Hmmm", I thinks to myself "if a little is good, a lot should be even better!" So, I further de-constipate it by cutting off the muffler stinger. Now I notice that the stinger pipe itself seems to be a bit constricted at the inner end, so I drill out the hole in the muffler to the outside diameter of the stinger (that I had just removed - follow me so far?)
So, I go fly it today. Ooooh! You immediately know that something is changed as the sound is much sharper and the engine runs faster on the unchanged needle setting from last week. More power, but I notice that it seems harder to needle - much touchier. First flight: too fast; 2nd flight: too slow; 3rd flight: just right. Also, I noticed that the engine seems to be surging (but the guys outside the circle didn't notice that.) Fuel use went up from 4.25 ounces to 5 ounces.
So what do you think? I stuck the baffle back in tonight and hope to fly it again tomorrow to see what that will do.