>>      >
    >>      > 3) The VAM muffler *almost* fit.  The exhaust pipe hits
   one of
    >>     the mount
    >>      >
    >>      > tubes, preventing the exhaust manifold flange from seating
    >>     against the
    >>      >
    >>      > engine correctly.  There seem to be 3 possible solutions:
    >>      >
    >>      >    A) Make an insert for the manifold flange which adds appx
    >>     1/4".  Not
    >>      >
    >>      > convinced the bolts are long enough for this.
    >>      >
    >>      >    B) Cut the exhaust manifold pipes & lengthen them so the
    >> VAM
    >>     moves
    >>      >
    >>      > 1/4" - 3/8" farther away.
    >>      >
    >>      >    C) Cut the VAM exhaust tube & increase the angle toward
    >> aft so it
    >>      >
    >>      > clears tube.
    >>      >
    >>      >
    >>     Mark,   When I built the muffler, I did it with the engine
    >> mount in
    >>     place.  I had it off and on many times.  It had to be angled
    >> just so to
    >>     slip it over the flange studs, but it did fit. I have no
    >> ideal  why it
    >>     would not fit now.  Of your proposed solutions, the last one
    >> would be
    >>     easy to do. Cut through three sides of the exhaust so the
    >> last  side can
    >>     act as a hinge. (It can be cut on a band saw or with a
    >> plasma)  Heat
    >>     with a torch and pull it the position  you want.  I can
    >> send    you some
    >>     321 strips for the patch and also some 347 tig rod (required
    >> to  weld
    >>     321).   Or, you can patch it with 304, readily available
    >> everywhere.  To
    >>     weld 304 to 321, use 309 rod.
    >>
    >>       I am very disappointed that you are having difficulties,
    >>
    >>       Jerry
    >>
    >>
    >> We were able to get the muffler over the studs no problem.  The
    >> trouble
    >> was getting it to fit completely against the engine - in this
    >> case,  the
    >> bottom could not touch because the exhaust pipe was contacting the
    >> engine mount.  How thick is the gasket material which fits between
    >> the
    >> engine & the muffler flange, Jerry?  We were doing a dry-fit,
   but it
    >> didn't seem that close to fitting -- perhaps you had gasketing in
    >> there
    >> & it was enough?
    >>
    >> Agree that increasing the angle of the exhaust square-tube is the
    >> easiest way to adjust it.  Do you suppose there is any reason to
   make
    >> this adjustment way up by the VAM, or could it be done a couple of
    >> inches down (where it will be easier to do)?  The only
   difference is
    >> that doing it a couple of inches down would put a 'bend' in the
    >> pipe --
    >> can't see that a bend would make any difference.
    >>
    >> Mark & Mark
    >>
    >> It was kind of loud on the dyno so a bend might help.
    >> Also you might want to weld in a few of these while you are
    >> at it. They are reputed to reduce the noise.
    >>
    >> BTW Mark if you use the stock M2 cowl what are you going to
    >> do with the cheeks?
    >>
    >> Paul Lamar
    >>
    >
    > Mark,  I agree that the bend will be of no consequence.  As far as
    > the "silencers" I would wait until  you run it and make a real sound
    > check.   It would also be possible to "drop in" turbulators   into
    > the exhaust pipe portion.  If it is too loud put in one or two and
    > then test.  Keep adding them  until you get the sound you
   want.  This
    > is exactly what I intend to do, once the system is bolted to my test
    > engine.  The turbulators would be made from pieces of SS angle.  You
    > can put them in a grid to disrupt the exhaust gas flow as is done in
    > the Spin Tech.     Jerry
    >
    > Its pretty load Jerry as is. It does have a somewhat mellower sound
    > however.
    >
    > Paul Lamar

   Mark,  this is an opportunity if you are willing to do the work.
   Without changing anything, test the sound level of the engine.  Also,
   check peak static rpm.  If it is too loud, you can add the louvers
   and test both sound and performance again.  And so on.  We are so
   starved for real data on the exhaust.  Everything we think is
   speculation and quite possibly not worth a damn. If  you can,  get
   measurements of the exhaust  temp at the flange, inside the muffler
   and also air temps entering and exiting  the cool tube.   This data
   would be a major contribution.   I think Bob White is planning to do
   the same.    Jerry

   Don't forget guys this is not your average puppy rotary engine.
   It is a 250 HP P-port. I am the only one on here that has actually
   heard it run :)


As it happens, I have a decibel meter which can meter both fast and slow
response (A type and C type, as I recall) sound levels.  I will take
measurements all along the way to first flight.  Better still -- there
is a large open field near the hangar that I can taxi into.  I will take
measurements out there so there is no echo mucking up the readings.  I
will also take measurements every 90-degrees around the airplane at
various useful distances, at various meaningful RPM levels.

This of course presumes we actually get the thing installed, running,
and are in a state to move out of the hangar w/o being a hazard to
ourselves or others!

Mark & Mark

Speaking of being a hazard guys take it easy when you feed the power
into this beast. Tracy nearly killed him self with only 200 HP on his
first flight.

I would wait for 100 MPH before I opened throttle all the way. Unless
of course you are already up at 8000 feet out there in CO.

Paul Lamar

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