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<DIV>I ran the following engines on their stock mufflers and tuned pipes.
The same prop, day,</DIV>
<DIV>plug, fuel, etc. was used, just changed the exhausts from the stock
mufflers to the </DIV>
<DIV>tuned pipes:</DIV>
<DIV> </DIV>
<DIV>OS 25 FSR gained 1200 RPMs with a Mac's pipe</DIV>
<DIV> </DIV>
<DIV>OS BGX 2.1 cubes gained 900 RPM with an OS pipe</DIV>
<DIV> </DIV>
<DIV>Tartan twin 2.6ish cubes gained 600 RPMs on Chapman pipes</DIV>
<DIV> </DIV>
<DIV>Zenoah G-62 gained 700 RPMs on a German muffled pipe. This was the same
pipe</DIV>
<DIV>the German fliers used at the TOC...I think it was '92ish time.</DIV>
<DIV> </DIV>
<DIV>The airplanes became different animals once the pipes were added.
Horse power (or camel</DIV>
<DIV>power where I'm from) is equal to the RPM increase cubed. Let's take the
G-62 for example,</DIV>
<DIV>it tached 7000, then tached 7700 on a pipe...</DIV>
<DIV>That's a 10% increase in RPMs....cube 10% and it's a 33% in horses. 10% can
be written</DIV>
<DIV>as 1.1
1.1x1.1x1.1=1.33 or 33% increase.</DIV>
<DIV> </DIV>
<DIV>The BGX went from 7500 to 8400....That's 12% more RPMs, so it's
1.12x1.12x1.12=1.40</DIV>
<DIV>or 40% gain in horses...</DIV>
<DIV> </DIV>
<DIV>I then adjusted the prop size to achieve the desired performance
I was looking for. With the exception</DIV>
<DIV>of the Tartan, the rest of the engines were stock. The G-62 was converted
to glow. Tinkering with</DIV>
<DIV>exhaust port timing would have increased the horses even more, but I was
content ;-)</DIV>
<DIV> </DIV>
<DIV>Later,</DIV>
<DIV>Amir</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV><BR></DIV>
<DIV><SPAN class=772544020-01042004>Karl's right.</SPAN></DIV>
<DIV><SPAN class=772544020-01042004> Dean</SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT
face=Tahoma>-----Original Message-----<BR><B>From:</B> Karl G. Mueller
[mailto:kgamueller@rogers.com]<BR><B>Sent:</B> Thursday, April 01, 2004 3:37
PM<BR><B>To:</B> <A
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR><B>Subject:</B>
Re: Mintor Review<BR><BR></FONT></DIV>
<DIV>Steve,</DIV>
<DIV> </DIV>
<DIV>With proper exhaust port timing and setup with a good pipe you
will</DIV>
<DIV>loose that bet. My bet is that you will gain closer to 20%
improvement</DIV>
<DIV>in power, of course with more power comes a higher fuel
consumption</DIV>
<DIV>as well. Most engines are very conservatively ported in the
exhaust</DIV>
<DIV>timing to run on a muffler as well as on a pipe. Just an
other compromise</DIV>
<DIV>by the manufacturers.</DIV>
<DIV> </DIV>
<DIV>Karl G. Mueller<BR><A
href="mailto:kgamueller@rogers.com">kgamueller@rogers.com</A><BR>
</DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Patternrules@aol.com
href="mailto:Patternrules@aol.com">Patternrules@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, April 01, 2004 9:49
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Mintor Review</DIV>
<DIV><BR></DIV>
<DIV>
<DIV>In a message dated 4/1/2004 9:28:50 AM US Eastern Standard Time, <A
href="mailto:d.pappas@kodeos.com">d.pappas@kodeos.com</A> writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
face=Arial>Mintor 140 article, how does it run on a muffler
as<BR>opposed to a pipe. I would expect some loss in power<BR>but also a
loss in cost.</FONT></BLOCKQUOTE></DIV>
<DIV><STRONG> I don't use pipes on any on mine engines Jeff Hughes
and I have been using the Bolly 590r which is a muffler, no tuning head
aches, no midrange problems, if you change props, fuel or anything else
NON PROBLEMS, I have been running the Mintor 140 with it and it runs
super, don't know how much less power you get from just running a muffler
but I'd bet it's not over 5%, I use Coolpower 15% fuel.</STRONG></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV><FONT lang=0 face="Arial Baltic" PTSIZE="10"
FAMILY="SANSSERIF"><B><I>Steve
Maxwell</B></I></FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>