Hi Paul

Renesis engine people might like to see these figures from a Jabaru
fitted with a Renesis engine and a straight out exhaust. 3 off 90 degree
2" bends into a 2" pipe
then down along under the cowl and vertical out pipe. Quote:
"Engine (with straight exhaust) sound levels at a 10 metre circle were

1000rpm- 75 db
3000 rpm- 90 db
4000 rpm - 98 db
5000 rpm - 102 db
6500 rpm - 110 db

(This is lower than our freind's RR/Continental 100HP measured the same
day under the same propeller rpm conditions. (It doesn't sound noisier
than other aircraft)"

Ian . Building new exhaust. RV7

Thanks again Ian. This is in the ball park with what we have
measured in the past. Namely over 100 db at full chat. It does sound
different and people need to learn to accept it :) It is also
lower than an AT6 and a Cessna 210. A whole lot of it is
prop noise and you are not going to be able to do a whole lot
about it. Not unless you are willing to give up some take
off performance. Just take off at 90% max  throttle if it
is safe to do so. That will drastically lower the tip speeds.

Paul Lamar ...No rotor no motor.

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