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<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>Chuck....this is exactly what was happening on the YS 61 Long Stroke with
a </FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>Tettra filter on the intake. I had a hellova difficult time with that
engine</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>so I put it on a test stand and after awhile discovered that the filter
was causing all</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>the wierd problems. It was just like a light switch...put it on...have
problems...take it off</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>without even stopping the engine...no problems. After that revelation I
called Futaba</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>and was told kinda like....'where you been??? Everybody knows that!!
</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002><FONT face="Comic Sans MS" color=#0000ff
size=2>Yeah RIGHT.</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002> <FONT
face="Comic Sans MS" color=#0000ff size=2>Regards</FONT></SPAN></DIV>
<DIV><SPAN class=039095518-18092002>
<FONT face="Comic Sans MS" color=#0000ff size=2>Dave 586</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
discussion-request@nsrca.org [mailto:discussion-request@nsrca.org] <B>On
Behalf Of </B>Chuck Wagoner<BR><B>Sent:</B> Wednesday, September 18, 2002
11:48 AM<BR><B>To:</B> discussion@nsrca.org<BR><B>Subject:</B> RE: OS 140 RX
with Dual Plug Conversion plus Webra Memories
<Long><BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=500465810-18092002>Matt,</SPAN></FONT></DIV>
<DIV><FONT size=+0><FONT face=Arial><FONT size=2><SPAN
class=500465810-18092002>Your point:"</SPAN>The idea is to get uninterrupted
air flow in the throat of the venturi, by moving the spray-bar against the
wall of the venturi. Better breathing results in more power for a given set of
parameters.<SPAN class=500465810-18092002>" is a very good one, and I
think "</SPAN>uninterrupted<SPAN class=500465810-18092002>"
deserves several additional comments, especially for those who have
not seen a slide valve function.</SPAN> </FONT></FONT></FONT></DIV>
<DIV><FONT size=+0><FONT face=Arial><FONT size=2><SPAN
class=500465810-18092002>With the slide valve the air flow is straight
through the variable orifice to the spray bar. However, for the purpose
of comparison consider a</SPAN><SPAN class=500465810-18092002>ir flowing
toward a spray bar through a carb with openings in a rotating barrel
inside a fixed cylinder. The flow path of the air has somewhat of a
'Z' or 'S" shape. This means two relatively gradual changes in direction
of air flow occur at half throttle and increasingly severe changes in
direction happen as the idle position is approached. This rapidly reduces the
velocity and energy of the stream of incoming air and it's ability to
spray the fuel via high quality external atomization from the spray bar.
Quality of atomization decreases at the critical idle position. Local
air-to-ATOMIZED-FUEL-ratio (rich/lean etc.) could bounce around in a
non-linear fashion and reduce combustion stability, heat release
rates, and efficiency. This could cause a richening-mixture effect on
throttle up as atomization improved and efficiency increased. Also it could
promote unwanted combustion quenching (chilling) at or near
idle. </SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT size=+0><FONT face=Arial><FONT size=2><SPAN
class=500465810-18092002></SPAN></FONT></FONT></FONT> </DIV>
<DIV><FONT size=+0><FONT face=Arial><FONT size=2><SPAN
class=500465810-18092002>I feel that a slide valve carb retrofit in
combination with dual plugs could give very serious top and
carefree performance without significantly-increased weight, electronic
complexity, or small diameter fuel injection ports. The Webra slide valve was
not at all sensitive to fuel properties over my one-year period of heavy
use back then with fun fly contests almost every weekend in the
</SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT size=+0><FONT face=Arial><FONT size=2><SPAN
class=500465810-18092002>Ohio, Pennsylvania, and West Virginia circuit. Zero
problems of any kind. My total engine back up on the road consisted of a spare
prop nut and some wooden props. At that time I paid $100 for the new engine.
</SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT size=+0><FONT face=Arial><FONT size=2><SPAN
class=500465810-18092002></SPAN></FONT></FONT></FONT> </DIV>
<DIV><SPAN class=500465810-18092002><FONT face=Arial
size=2>Chuck</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
discussion-request@nsrca.org [mailto:discussion-request@nsrca.org]<B>On
Behalf Of </B>Rcmaster199@aol.com<BR><B>Sent:</B> Tuesday, September 17,
2002 10:11 PM<BR><B>To:</B> discussion@nsrca.org<BR><B>Subject:</B> Re: OS
140 RX with Dual Plug Conversion plus Webra Memories
<BR><BR></FONT></DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial
size=2 FAMILY="SANSSERIF">In a message dated 9/17/2002 12:44:23 PM Eastern
Daylight Time, chuckwagon@charter.net writes:<BR><BR><BR>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px"
TYPE="CITE">Subj:<B>OS 140 RX with Dual Plug Conversion plus Webra
Memories </B><BR>Date:9/17/2002 12:44:23 PM Eastern Daylight
Time<BR>From:<A
href="mailto:chuckwagon@charter.net">chuckwagon@charter.net</A><BR>Reply-to:<A
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR>To:<A
href="mailto:pattern@rcmailinglists.com">pattern@rcmailinglists.com</A>,
<A href="mailto:discussion@nsrca.org">discussion@nsrca.org</A><BR>CC:<A
href="mailto:lee@piedmontmodels.com">lee@piedmontmodels.com</A><BR>File:<B>winmail.dat</B>
(1784 bytes) DL Time (203344 bps): < 1 minute<BR><I>Sent from the
Internet </I><BR><BR><BR><BR>Dual
plugs<BR>anyone?http://www.rcaerosport.com/articles/reviews/evolis/crino/e10.htm
(I<BR>remember my very smooth running dual-plug Merco 60.)<BR><BR>Also
another 2-stroke memory... the great Webra slide valve carb.
Mine<BR>seemed to give INSTANT RPM up from an all-day idle with my stock
single plug<BR>Webra black head engine! It had almost zero spool-up or
spool-down time to<BR>or from any level(s) I chose. Blip...blip...blip
<happy smile>. Once I made<BR>an adaptor and tried the slide valve
with a ST blue head. Same dynamics.<BR>Also gave more HP than the stock ST
carb. Just some thoughts.<BR>Chuck </BLOCKQUOTE><BR><BR>Chuck <BR><BR>the
Dynamix carb, or slide valve carb, that you mention worked extremely well
for me also. Duke Fox first used the concept in model engines back in the
sixties I believe. The concept was not lost on Webra, since their Dynamix
carb was a most effective device.<BR><BR>The idea is to get uninterrupted
air flow in the throat of the venturi, by moving the spray-bar against the
wall of the venturi. Better breathing results in more power for a given set
of parameters.<BR><BR>Matt Kebabjian</FONT>
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