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<DIV><FONT face=Arial size=2>Dave,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Do you find that a 2-blade prop will unload
more or less then a 3 blade?</FONT></DIV>
<DIV><FONT face=Arial size=2>Maybe the reason for your longer pipe length is due
to the fact that your running a 3-blade prop. I too have a longer
pipe setup on my 16x11 </FONT></DIV>
<DIV><FONT face=Arial size=2>3-blade then I do on the 17x12 2-blade prop
Pipe length will certainly be determined by the load the prop puts on the engine
and the amount of nitro you use. That's why I like to keep the fuel thing
at a constant and I use 15% Cool Power only so I know that it is the prop
changing the load and not other variables.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Wayne Galligan</FONT></DIV>
<BLOCKQUOTE dir=ltr
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=DaveL322@comcast.net
href="mailto:DaveL322@comcast.net">DaveL322@comcast.net</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> Tuesday, April 19, 2005 12:34
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: RE: OS mixture
question</DIV>
<DIV><BR></DIV>
<DIV>Agree. Good stuff.</DIV>
<DIV> </DIV>
<DIV>I have found a couple of setups (for my flying style at least) that
perform best in the air with the pipe more like 1" longer than what would be
peak RPM on the ground. And I've found several setups that behave very
differently in the air than on the ground.</DIV>
<DIV> </DIV>
<DIV>It is always easier to start long - the engine will be friendly with a
long pipe, but cranky with a short pipe. And cutting is easier than
adding. So I usually fly with what I know is a long pipe setting and
evaluate shortening the pipe based on how it flys.</DIV>
<DIV> </DIV>
<DIV>Dave</DIV>
<DIV> </DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">--------------
Original message -------------- <BR><BR>> This is good info, no doubt!!!
<BR>> Just a thought - many folks want a "starting point" for pipe
length. <BR>> Experimenting with different props/pipes and motors - all
things being about <BR>> equal (I know they're not, really, but it's
okay), I've found the 17 x 12 APC or <BR>> similar load starting point to
be about 23.75 -24" plug to reflector, following <BR>> headers curves,
and the "wave" length. <BR>> <BR>> This measurement will get a person
who's in a hurry in a flyable condition <BR>> pretty fast, with minimal
additional tweaking. <BR>> <BR>> Of course, YMMV, depending on a lot
of things, but the most frequently asked <BR>> question I get by the
newbie two-stroke convert (or a former 2 stroker who has <BR>>
RE-converted)is "what's a good starting point for 1.40 - 1.70's in today's
<BR>> planes?" <BR>> <BR>> Hope this is helpful to someone.
<BR>> <BR>> Bob P. <BR>> > <BR>> > From: "richard.lewis"
<RICHARD.LEWIS@IDMCONTROLS.COM><BR>> > Date: 2005/04/19 Tue AM
11:08:47 EDT <BR>> > To: <DISCUSSION@NSRCA.ORG><BR>> > Subject:
RE: OS mixture question <BR>> > <BR>> > Thanks again Wayne...:)
Very well spoken, clear, and concise 2-stroke <BR>> > tuning
methodology. <BR>> > <BR>> > Richard <BR>> > <BR>> >
_____ <BR>> > <BR>> > From: discussion-request@nsrca.org
[mailto:discussion-request@nsrca.org] On <BR>> > Behalf Of Wayne
Galligan <BR>> > Sent: Tuesday, April 19, 2005 9:12 AM <BR>> >
To: discussion@nsrca.org <BR>> > Subject: Re: OS mixture question
<BR>> > <BR>> > <BR>> > I helped a guy with the a similar
issue this weekend on his Mintor. Way <BR>> > too lean on the bottom
end. His would pop on acceleration or die coming out <BR>> > of the
outside loop. <BR>> > <BR>> > For the OS 1.40 RX Try this:
<BR>> > Use an OS "F" plug. <BR>> > 15% nitro <BR>> > I
have not had to adjust the pump on any of the OS's I have set up to date.
<BR>> > <BR>> > Set the top end till it peaks in rpm(use a tach
if you have one) and back <BR>> > off one click to the rich side.
<BR>> > Bring it down to an idle and try to set the idle to about
18-1900 rpm. <BR>> > <BR>> > Let the engine idle for at least
20-30 seconds and do not touch the <BR>> > throttle. <BR>> > 1.
if it speeds up or surges at any time during this time the bottom end
<BR>> > is lean. <BR>> > 2. if the engine gradually slows down
and dies...its rich. <BR>> > <BR>> > Advance the throttle with
medium speed and observe: <BR>> > 1. if it burbles and picks up speed
or burbles and dies bottom end is <BR>> > too rich. <BR>> > 2.
if it falls flat or hesitates then accelerates or dies it is lean <BR>>
> <BR>> > This may take several tries to get but once its set then
its just minor top <BR>> > end adjustments depending on weather
conditions. <BR>> > <BR>> > Changing pipe lengths will also
effect the low end transition. A longer <BR>> > pipe setting will
allow you to set the bottom end a little richer and give <BR>> >
better downline braking. <BR>> > I find that running the bottom end as
rich as possible with out it loading <BR>> > up gives the best
downline deceleration. <BR>> > <BR>> > Setting your pipe is a
whole other story. My best method is on a test <BR>> > stand. Set the
pipe long and run engine, tach the top end at peak rpm. <BR>> >
Shorten the coupler or pipe about 1/4" at a time and observe the peak rpm.
<BR>> > It will increase with each shortening of the pipe. <BR>>
> Once it peaks in rpm or no longer increases or drops in rpm this is the
top <BR>> > tuning spot for your engine and pipe for max rpm(not
really the desired <BR>> > tuning). <BR>> > At this point back
the pipe off about 3/8 to 1/2". This will give you a <BR>> > good
starting point. I usually lengthen the pipe if I go to a higher loaded
<BR>> > prop or <BR>> > shorten it with a lighter loaded prop.
<BR>> > <BR>> > The OS 1.40 is a very predictable engine. If it
starts to load up and <BR>> > stall in the midrange for no apparent
reason or drops rpms <BR>> > after the glow plug is removed first
check the plug . If it continues to do <BR>> > the same thing then the
bearing is probably on its way out. <BR>> > Replace the bearing with a
sealed bearing or a stainless steel bearing that <BR>> > goes in the
EFI version. I have about 200 flights on one <BR>> > of my OS's that
has the sealed std steel bearing from Bearings Limited in it <BR>> >
and it is still going strong. Another way to check the bearing is move the
<BR>> > prop by the tips <BR>> > perpendicular to the engine and
if you can feel end play the bearing is <BR>> > getting loose.
<BR>> > <BR>> > Wayne Galligan <BR>> > <BR>> > -----
Original Message ----- <BR>> > From: Kurt
<MAILTO:KURT@BOZARTHHOMES.COM>Bozarth <BR>> > To: discussion@nsrca.org
<BR>> > Sent: Monday, April 18, 2005 7:22 PM <BR>> > Subject: OS
mixture question <BR>> > <BR>> > <BR>> > <BR>> > OS
140 RX (non-EFI) question: <BR>> > <BR>> > <BR>> >
<BR>> > When I advance the throttle, the rpms remain at idle for
approx. one second, <BR>> > "pop" and then advance to full throttle
rpms I am not quite sure if this <BR>> > "pop" and hesitation is a
result of having too lean of an idle mixture or <BR>> > too rich. This
is an older motor released back when Hobby Services offered <BR>> > a
free needle valve assembly replacement to correct for mid-range richness
<BR>> > issues. I do not know if this was done or not - something I
will check for <BR>> > tonight. I have never adjusted the pump
setting. Let me know your <BR>> > thoughts. Thank you. <BR>> >
<BR>> > <BR>> > <BR>> > Kurt Bozarth <BR>> >
<BR>> > <BR>> > <BR>> <BR>> Bob Pastorello, El Reno, OK,
USA <BR>> rcaerobob@cox.net <BR>> www.rcaerobats.net <BR>> <BR>>
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