That TTC project looks really nice guys ! I know that you have the
knowhow and the right set of hands to get this accomplished. In
Europe, we're still only a rare few to fly rotary, there's an RV10
in Denmark, a Sportsman in
Germany, and me with my Glasair in France. I'm hoping to get the
g-300 Maule flying for mistral in the near future.
Noise is my greatest concern. We still fly with the non-compatible
absorption muffler, and i'm really worried about the bad reputation
the rotary is getting here because of noise. I keep flying limited
to 3 flights per month because of that, a hard feat after spending
12.000 hrs building.
I'm now sticking my antenna's out and aim to get a good solution.
Mistral is helping but they have other priorities for the near
future.
I gather you have less pressure to get low noise emission in the
US, but if
you find a good ( even temporary solution) i'd like to hear from
you.
Paul sent me a good set of data on a muffler which was used on an
RV, but i tried that and it was still too loud.
The tangential muffler by rochhausen in munich is promising, but i'd
say there's still a lot to be squeezed out in Db.
Good luck and have fun with the project
Paul Janssens
IMHO That anti private airplane noise is just a political ploy to
punish non egalitarians :-)
There are too few private pilots in Europe so the counter political
power is inadequate.
We have the AOPA and the EAA fighting the boring alcoholic
egalitarians :-)
There is a Brezzy in Germany as well. Karl Frederich Schmidt is
building a Brezzy'
You may need two mufflers. A tangentially in the cowl with a 3 meter
long coaxial under the air plane.
The large diameter of the coaxial out let lowers the frequency of
the noise making it more acceptable
to people.
Start with 25... 5 mm holes in the inner pipe. If that affects the
power drill more.
Larger holes are shown but the area of 25 ....5 mm holes should be
sufficient.
The 150 mm size of the outer pipe will lower the noise frequency.
The stationary noise will be higher so don't compare. The only valid
comparison is a fly over.
The air flow between the outer pipe and inner pipe is key to the
coaxial. It also cools well..
Here are the 3D's
Paul Lamar
