<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2722.900" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2>Having run my fair share of YS 4 strokes all I can
say is place one on a test bench, run it for awhile and touch the case in the
rear bearing area while it is running. The only one that was ever hot to the
touch that I've run was a SC. An ill fitting/installed rear bearing will
generate excessive heat. I've tried this with a ST2300 and found the
case barely above ambient temperature. I think what is happening
with the YS is being it is a supercharged engine, at full
throttle it requires a substantial supply of intake air. The scoop(s) in the
engine bay area supply additional air that the engine needs to produce full
power. Look at the nose of our planes and where the intake is on a YS. I
believe cooling is a good thing up to a point, just feel the
power increases seen are largely due to the increased supply of air for the
engine to ingest then cooling. Ever run one of the "air filters" on the YS and
notice a power decrease ??</FONT></DIV>
<DIV><FONT face=Arial size=2>Ed M.</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=weedon@wwnet.net href="mailto:weedon@wwnet.net">Thomas C. Weedon</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> Wednesday, February 05, 2003 5:06
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: Thoughts about air
scoops.</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=150510022-05022003><FONT face=Arial color=#0000ff size=2>I
had a mid-air this last summer that slightly damaged the nose of my plane.
Eric H. suggested that when I repair the nose, I should add an air scoop just
above the rear bearing of my YS-120FZ. He said that it would help cool the
rear bearings and would improve my top RPM. Guess what? He's right! My engine
had a little more power. The rev's increased about 100 to 150 RPM on the
ground and I noticed an improvement in the verticals. So, now I'm finishing a
new fuse and I'm adding another air scoop over the rear of my YS-140FZ. I
think it will help.</FONT></SPAN></DIV>
<DIV><SPAN class=150510022-05022003><FONT face=Arial color=#0000ff size=2>Tom
Weedon</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<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>Adam Quennoz<BR><B>Sent:</B> Tuesday, February 04, 2003 8:34
PM<BR><B>To:</B> Pattern List<BR><B>Subject:</B> Thoughts about air
scoops.<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>It seems the trend these days are air
scoops. Before a scoop is effective, the area of the air exit
must equal or exceed that of the air intake thus allowing a positve air flow
to occur. With all the scoops people are putting on the nose of the
aircraft, there must be a pretty good sized hole somewhere for the air to
escape. There are cheek scoops, chin scoops and now with the concern
of cooling the crank cases, there are scoops above the engine
compartment. I call them "nose scoops". </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Has anyone thought of making EXITS on
the top of the nose above the engine, and/or exits on the cheeks?
Basically put the scoops on backwards. The air flowing over the
backward facing scoop would actually create lower pressure inside the engine
compartment allowing a larger volume of air to enter the chin
scoop. The air entering the chin scoop can flow all around the engine
as it makes way to the exits of the engine compartment, and what's
left can flow down the pipe tunnel. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I'd like to hear what others have to say
about this idea. I'm thinking of trying it on my pattern
plane.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,<BR>Adam Quennoz<BR>AMA 383866<BR>IMAC
2439<BR>NSRCA 3546<BR></FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>