ORIGINAL: ccostant
This reply is for bubbagates. Looks like you have some very low readings. Did you do anything special to get there? I did some preliminary measurements on my Zenoah G62 last summer and this what I got. Unfortunately noise measurements are becoming required by most clubs in the New England area. The measurement method previously mentioned is typically how it is being done.
Zenoah G62
Slimline smoke/Pitts style
6800 RPM
Mejlik 22x10
Grass
100 dB
Allot of my readings have to do with the prop being used. My G26 with a Mezjlik was tons louder (did not measure it) that with the Belia. The Belia prop is allot wider hence it turns allot slower. My Mezjlik turned 8300 and the Belia at 7700.
Supersonic mufflers are very quiet but they do rob a bit of power. Bambula props are very quiet and not too bad performers.
The Brison is fairly quiet and that surprised me to a degree. It seemed louder until we measured it and we did that from the front and both sides of the plane.
We use a cheapy Radio Shack meter and maybe it's not as accurate as most but I can tell you this, the Roto was definitely quieter than most of the glow engines and the Brison was flown with a few glow engines up there with it and was consistent.
I do have the Aerotrend blue exhaust tubes on ithe Brison and G26 to redirect the exhaust. That may be where the difference is.
Maybe it's a different kind of grass
