> > This is a cheap muffler that works well on the
         > rotary because
         > > of the formed steel case. There are no drastic
         > section changes that tend
         > > to fail. It is also stream lined somewhat so it
         > does not add a lot of
         > > drag.
         > >
         > > Paul Lamar ...No rotor no motor.


        Paul,

        We have been thru the rotary muffler issues as well as other users
        in your
        group. We looked at the Hushpower online and were considering
   trying
        it. Do
        you have any input to this muffler as far as temps it will
   withstand and
        constant power, noise level Etc? We would be using this in a
   hovercraft
        application running 5500 to 6000 max RPM with our single engine.

        Any input would be appreciated.

        Eric Barger, President
        Phone 419-694-3000 x 222
        RotaMax Inc.
        15152 Twp Rd 190
        Arlington, OH 45814
        Fax 419-694-1401
        www.rotamax.net <http://www.rotamax.net> <http://www.rotamax.net>

        I don't have any hard data on it as I have never heard the engine
        run with
        one on it without a prop. Typically the prop is half the noise or
        so. I am
        just guessing. At 30 feet off to the side of the airplane with a
        prop it
        is about 103 db plus or minus 3 as a wild ass guess.

        It is cheap enough so give it a try. It seems to work for us.

        What sort of fuel burn are you seeing at 5500 to 6000 RPM in terms
        of gallons
        per hour?

        Paul Lamar ...No rotor no motor.


   Eric,
   I heard a Renesis run at high power with the Hush Power II muffler.  It
   was very, very quiet.  Most of the sound was coming off the prop.
   Reportedly, the neighbors have commented that his airplane is the
   quietest one on the field.  This is a Renesis (side-exhaust port) engine
   which is running a cut down cast iron exhaust manifold, and a small (4"
   dia.) tangential muffler in addition to the Hush Power II.  So, your
   results may vary.

   The downside of the Hush Power II is that it weighs about 10# (my
   estimate).  Even so, I'm considering installing one on my 20B.

   Mark S.

   By way of explanation the Renesis RX8 engine is a side exhaust port
   which is
   much quieter all on its own. Eric's engine is a peripheral exhaust
   port engine.

   So Mark I take it the spiral in the exhaust down pipe was not totally
   satisfactory as far as noise is concerned?  Is it still in there?

   BTW How many hours do you have now? How is your fuel injection working?

   --
   Paul Lamar ...No rotor no motor.


I installed the flowmaster Hushpower with my last upgrades and now have
about 15hrs.  The results were very good.  Tracy reported that the
hushpower was not as quiet as his spintech, but seemed to flow better.
In combination with my turbo, it seems to work very well.  The prop now
supplies the majority of noise.  At 1400 rpm idle, it is possible to
have a normal voice conversation anywhere in or around the plane.  My
wife, who used to hate the noise of the rotary, now says I am quieter
than any of the Cessnas at our field.  My flight instructor was
similarly impressed with the sound improvement  both on the ground and
in flight.  A conversation without headphones is now not difficult
(about the same in-flight noise as a typical C150)

It weighs just under 11# and shows no unusual wear after 15 flight hrs.