I have a Brodak 40 in Gieseke Nobler that is speeding up during flight. Set up is;
stock venturi, TT 11x4.5 prop, PM 10/22 fuel, uniflow with pressure.
The issue is it is going from 5.4 second laps to 5.0 or faster by the end of the pattern.
Now, I tried a tongue muffler and it made it worse..like 5.4 to 4.8...put the stock muff back on and it goes from 5.4 to 5.0, not as bad but still speeding up more than i like, and I much prefer the run (minus speed up) with the tongue)
I did find a leak in the uniflow solder joint at the front of the tank,fixed that thinking it would solve the issue but...nope. This plane flies really well and I do like a LITTLE speed up at the end but the clover can be exciting at 4.8 to 5.0. I will try bypassing the copper tubes that run through the fuse next outing, maybe an air leak there. Am I expecting too much for a run to go from 5.4 to 5.2? I know it's only 2/10 of a second but at 5.0 it's hard to keep shaped right starting at the vert 8s.....at least that's what I'm blaming on this week