Hi Paul and all

       We started our Renesis 4 port last week.
       A few bugs to iron out but otherwise all good.
       There has been a lot of talk about exhausts in the last week.
       Here are some photo's of what we finally decided on.

       The original renesis exhaust headers have been cut back
    maintaining the
       expansion joint in the inner sleave which is about 2" upstream of
       the flange
       which has been tig welded as per the original.
       The rest is 2.5" 064" stainless and slip joint into a "Gonzo"
    mufler and
       then exiting the cowl at ~ 45 deg through what will be a cowl flap.
       The unit is held in place by the header flange and a stainless
    clamp and
       braket.

       The Gonzo mufler consists of spiral flutes between the outer wall
    of the
       mufler and an inner stainless tube of approx 3/4". So looking into
       the end
       of the mufler you can see straight through the inner 3/4" tube
    while the
       rest of the gasses travel down the spiral before exiting via a tail
       pipe.

       Cheers

       Steve Izett
       Perth Western Australia
       Glasair SIIRG Renesis 4 port
       Tracy's RD1-C and EC2


       It is probably OK because it is an RX8 engine with 200 F cooler
    and more
       benign exhaust. You would not get away with it on a 13B however :)

       Interesting motor mount what I can see of it. Can you take
       some pictures of the over all motor mount so we can see how
       you did it?
       --
       Paul Lamar ...No rotor no motor.



    Hi Paul

    I'll get some photo's out over the weekend.

    Steve Izett


Steve,
I tried a Spiral Flow design on my 3-rotor (with turbo housings).  I
welded up an insert from 321SS similar to an auger bit, only it was
segmented and not a continuous spiral. Basically, I tried to copy the
Spiral Flow design. The baffle was inserted into the last 2 feet of the
3" dia. exhaust pipe.  I had lots of trouble keeping the insert bolted
into the exhaust pipe.  It kept melting the bolts, and/or
cracking around the bolt holes.  It did a fair job of damping the sound,
but it was beginning to crack on the upstream end.  So, I decided remove
it and try something else.

A friend loaned me his Hushpower II muffler and it was much quieter than
my design, so I switched to the Hushpower II.  Although it has literally
melted some of the packing material, it seems to be holding up fairly
well, although it has gotten louder than it was on the first flight.  I
only have about 20 hrs total on the HPII, so the jury is still out on
whether or not this will be a permanent solution.

Mark S.



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