OS1.40 Pipe > Couplers

[Joe Dunnaway]

I picked up a Webra 1.45.  The pipe is 3/4" and the header is 7/8".  I
haven't run it yet. I'm still building on the plane it's going in.

Joe



----- Original Message ----- 
From: "Brian Young" <b4598070 at yahoo.com>
To: <discussion at nsrca.org>
Sent: Monday, March 01, 2004 2:36 PM
Subject: Re: OS1.40 Pipe > Couplers


> Joe, I picked up a Webra pipe. Previous was a muffler.
> Karl Mueller might have a 3/4" 2-C header available if
> you have the same mismatch I had.
>
> Are you running a 2 cycle now?
>
>
> Brian
>
>
> --- Joe Dunnaway <dunnaway at geopath.com> wrote:
> > Hey Brian,
> >     Which pipe did you get?  I've got the same
> > problem.
> >
> > Joe Dunnaway
> >
> >
> > ----- Original Message ----- 
> > From: "Brian Young" <b4598070 at yahoo.com>
> > To: <discussion at nsrca.org>
> > Sent: Monday, March 01, 2004 10:47 AM
> > Subject: Re: OS1.40 Pipe > Couplers
> >
> >
> > > I remedied the difference in size this weekend w/
> > a
> > > new pipe that matches the header diameter.
> > >
> > > The previous muffler was for a 1.20-1.40 size
> > engine
> > > but used a 3/4" inlet, headers available happened
> > to
> > > be 7/8".
> > >
> > > Anyway, new pipe is lighter and more power just
> > hope
> > > its not too loud. Couplers will probably survive
> > > better with same size pipe and header.
> > >
> > > --- "Karl G. Mueller" <kgamueller at rogers.com>
> > wrote:
> > > > Brian,
> > > >
> > > > If you are using a larger dia. header than your
> > pipe
> > > > inlet you're
> > > > restricting the flow of the spent gases into the
> > > > pipe. What is
> > > > happening is that you're pushing fresh gases
> > mixed
> > > > with a certain
> > > > amount of exhaust gases back into the combustion
> > > > chamber. This creates
> > > > additional heat and less performance. A better
> > > > combination would be
> > > > same size header or smaller diameter than the
> > pipe
> > > > inlet. What you
> > > > want to achieve is a high velocity (more
> > important
> > > > than volume) in the
> > > > header.
> > > > Judging by the size of the pipe inlet you must
> > be
> > > > using a 10cc pipe
> > > > which might be a little on the small side in
> > volume.
> > > >
> > > > Karl G. Mueller
> > > > kgamueller at rogers.com
> > > >
> > > >
> > > >
> > > >
> > > > ----- Original Message ----- 
> > > > From: "Brian Young" <b4598070 at yahoo.com>
> > > > To: <discussion at nsrca.org>
> > > > Sent: Monday, March 01, 2004 10:24 AM
> > > > Subject: RE: OS1.40 Pipe > Couplers
> > > >
> > > >
> > > > > Interesting to see all the solutions to this.
> > Are
> > > > > these on planes that have exposed or enclosed
> > > > tunnels?
> > > > > Same size pipe inlet and header, or different?
> > > > >
> > > > > Im particularly interested in the teflon that
> > > > lasts
> > > > > for 1000 flights. I think im getting about
> > 50-100
> > > > > flights per silicone coupler on a 7/8 diameter
> > > > header
> > > > > and 3/4 diameter pipe inlet.
> > > > >
> > > > > Thanks,
> > > > >
> > > > >
> > > > > --- "Henderson,Eric"
> > <Eric.Henderson at gartner.com>
> > > > > wrote:
> > > > > > One of the pilots that I support with OS
> > 1.40's
> > > > has
> > > > > > run the cut header set up for three seasons
> > with
> > > > no
> > > > > > failures. Also he was breaking headers until
> > he
> > > > > > changed over to the two-coupler set up.
> > > > > >
> > > > > > It is interesting how we get opposing views
> > on
> > > > what
> > > > > > appears to be the same situation. I suspect
> > that
> > > > the
> > > > > > choice of coupler material and cooling has a
> > lot
> > > > to
> > > > > > do with the result. BTW I have had great
> > success
> > > > > > with 1/16" walled 500F+ Teflon tubing where
> > non
> > > > > > flexible, but directional, needs occurred.
> > > > > >
> > > > > > Regards,
> > > > > >
> > > > > > Eric.
> > > > > >
> > > > > >
> > > > > > -----Original Message-----
> > > > > > From: discussion-request at nsrca.org
> > > > > > [mailto:discussion-request at nsrca.org]On
> > Behalf
> > > > Of
> > > > > > David Lockhart
> > > > > > Sent: Monday, March 01, 2004 9:56 AM
> > > > > > To: discussion at nsrca.org
> > > > > > Subject: Re: OS1.40 Pipe
> > > > > >
> > > > > >
> > > > > > Same experience here.  I've got 2 2.25" rise
> > MAC
> > > > > > headers that were bent slightly and then cut
> > > > about
> > > > > > 1.5" after 2.25" rise.  Both have over 1,000
> > > > flights
> > > > > > and no problems with breakage or burning up
> > > > > > couplers.  Currently using Teflon couplers
> > w/
> > > > the
> > > > > > constant tension spring clamps (Central has
> > > > them).
> > > > > >
> > > > > > Dave
> > > > > >
> > > > > > ----- Original Message ----- 
> > > > > > From: mike mueller
> > <mailto:mups1953 at yahoo.com>
> > > > > > To: discussion at nsrca.org
> > > > > > Sent: Monday, March 01, 2004 8:48 AM
> > > > > > Subject: Re: OS1.40 Pipe
> > > > > >
> > > > > >  Lance, I have the same problem with the
> > > > couplers
> > > > > > burning out when they are too close to the
> > > > engine
> > > > > > and I don't have a problem with bending my
> > > > headers
> > > > > > the same way Lance does it. Mike
> > > > > >
> > > > > > Lance Van Nostrand <
> > patterndude at comcast.net>
> > > > wrote:
> > > > > >
> > > > > >
> > > > > > I'm not so sure Eric. I've seen people try
> > to
> > > > cut
> > > > > > the header in the rise
> > > > > > and the couplers used kept burning out. the
> > > > exhaust
> > > > > > temps are very hot
> > > > > > there, but cool quickly. You really don't
> > want a
> > > > > > coupler within 8" of the
> > > > > > exhaust outlet.
> > > > > > My suggestion, the solution I've used for
> > years
> > > > with
> > > > > > Macs headers, is to
> > > > > > use an appropriately sized forstner bit
> > (e.g.
> > > > 7/8")
> > > > > > and drill a hole in the
> > > > > > end of a 2x4. Slide in the header and use
> > the
> > > > 2x4 as
> > > > > > a bending arm. The
> > > > > > hole supports the header and the 2x4 gives
> > you
> > > > > > leverage. Oh, don't leave
> > > > > > the header bolted to the engine!! Bolt it to
> > > > > > something else.
> > > > > > --Lance
> > > > > >
> > > > > > ----- Original Message ----- 
> > > > > > From: "Henderson,Eric"
> > > > > > To:
> > > > > > Sent: Sunday, February 29, 2004 7:21 PM
> >
> === message truncated ===
>
>
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