Header,teflon, Muffler?

[Gene Maurice]

Buddy,

What I used on my YS's is a MAC's 3.5cc Quiet Pipe. The only mod I did to
them was open up the two holes in the muffling baffle to 1/4". I used this
set up on both 120 AC's and a 140 L. As compared to a Hatori, it may be 100
RPM less due to the reduced size but it only weighs 2.4 oz. and is less that
$40 at most hobby shops (at least the last time I bought one). It's an
effective, simple, and cheap alternative.

Gene Maurice
gene.maurice at comcast.net
Plano, TX
AMA 3408
NSRCA 877

  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On
Behalf Of BUDDYonRC at aol.com
  Sent: Saturday, September 27, 2003 8:49 AM
  To: discussion at nsrca.org
  Subject: Header,teflon, Muffler?


  I have been having occasional problems with RPM and what seems like
overheating on my YS-140-L. I have come to believe the problem is
restriction in the muffler, but the muffler seems to be open and OK
  The problem seems to have something to do with the prop size also.
  Running a 15-1/2 x 13N rpm at about 8200 everything is fine, switched to a
16 x11 and running @ 8400 rpm and later in the flight the power back's off,
I think it is heating up.
  Yesterday I switched to a 16 x10 prop turning 8800 rpm and half way
through the flight I heard a loud pop, After that the engine would not turn
up. I landed and found that the Teflon coupler had split long ways about
three inches long and had curled inward restricting the flow. This has
happened on two different mufflers a Hatori and a Johnson that is shaped
like the Hatori Has anyone run into this problem before? and what is the
solution?  Is there another Aluminum muffler that will work? I have another
setup using a CF muffler and have not had problems with it even at 9000rpm
with a 16 x11 prop but choke when I think of spending $175.00 for another
muffler.
  Buddy
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