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Well, took out the new muffler design out for its
first flight today. Guess, the old adage about it takes "noise" to make
power must be true. The system produces too little noise and therefore too
little power {:>).
So put it back on the ground and after some thought
concluded that I had too many discs (7) Which while effective in
suppression of the noise - did equally well in the suppression of power
{:<(. Could not get the engine above 5600 rpm whereas with the old
exhaust system I could hit close to 6600 rpm.
Took the tubes off and will disassembly them and
remove several of the discs and see what effect that has. Based on some
belated calculations I made, it may turn out that I need to go to at least a
2.5" dia tube in order to insure adequate exhaust gas flow.
This results was not totally unexpected and I
believe that I can back off on the nose reduction (can't hear exhaust at WOT due
to prop noise now - so some room to make adjustments before it gets too
loud).
Stay tuned, should have the new version on the
aircraft by mid week.
Ed
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