REFLECTOR:INTAKE COMBUSTION AIR
Ronnie Brown
reflector@tvbf.org
Sun, 14 Sep 2003 09:10:38 -0400
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We asked Duane about the open baffling on the cooling shrouds on the =
factory XL Continental (shrouds don't wrap under the bottoms of the =
cylinders). He said the angle valve Lycoming and Continentals with =
their larger cooling fins don't need the tight shrouds. =20
However, I did wrap the cylinders all the way to the bottom of my IO 360 =
C1C - 200HP and only have about a 1.5 to 2" opening at the bottom of my =
cylinders. My engine runs cool with the NACA down draft cooling - 350 - =
360 degrees while leaned out to 100 degrees rich of peak. I have never =
seen 400 degrees on my heads, even on 90 degree days and during a long =
climb out. Even taxiing at Oshkosh only produced 300-320 degrees. =20
And, I am only running one oil cooler. My A&P/IA friend says one cooler =
and those long oil lines should be plenty of oil cooling IF the engine =
is cooled adequately. After 85 hours of mostly summer flying, I agree.
I worried a lot about a hot running rear mounted engine while I was =
building and watched the reflector and VV's for any information for =
improving cooling. Now I am happy to say, this has been a non issue for =
my Velocity. I LOVE IT!!!
Ronnie
----- Original Message -----=20
From: SlvEgl99@aol.com=20
To: reflector@tvbf.org=20
Sent: Sunday, September 14, 2003 8:18 AM
Subject: Re: REFLECTOR:INTAKE COMBUSTION AIR
I have an XL FG with Lycoming IO540, two oil coolers.
I have always had a bit of a cooling issue. Not so much that temps are =
high, but that they are uneven between cylinders. The center two (3&4) =
are significantly cooler than the end four. Thisa is sometimes 70 =
degrees or more.
After a lot of time trying to get diverters in the ducting to move a =
greater amount of air to the ends of the plenum, I took a hard look at =
how Lycoming has the air flow controlled between the cylinders and noted =
that they have baffles between the cylinders that force the cooling air =
to stay within the cylinder fins nearly to the bottom of the cylinder. =
On the other hand, the XL plenum stops half way down the front and rear =
cylinders, allowing the air to "escape" from the cylinder fins at this =
point.
I also took a look at a a long EZ and how that engine is baffled. I =
saw that the baffling has the air confined to the cylinders with just a =
small (2.5") opening for the air to exit the fins.
By coincidence just this week I decided to extend the ends of the =
plenum to near the bottom of the cylinders, cutting them off at the =
approximate length of the Lycoming baffles.
How does it work? I don't know yet as I have just completed the job =
and have not had a chance to fly it yet.
The other heat issue I have is that the front oil cooler puts too much =
heat into the nose., and then into the cockpit. I have a piece of foam =
above the canard inside the hatch cover to block the heat from the nose =
and insulated it as well as I can by adding insulation around the body =
of the cooler and insulating the oil lines. I point out that I have a =
FG, thus no nose gear door to allow air into the nose. I have toyed with =
the idea of adding a small vent to bring in cool air to this area.
Any thoughts or ideas or concerns?
Bob Wood
N658SE
XL FG Bob II=20
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<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT size=3D2>We asked Duane about the open baffling on the =
cooling shrouds=20
on the factory XL Continental (shrouds don't wrap under the bottoms =
of the=20
cylinders). He said the angle valve Lycoming and Continentals with =
their=20
larger cooling fins don't need the tight shrouds. </FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>However, I did wrap the cylinders all the way to the =
bottom of=20
my IO 360 C1C - 200HP and only have about a 1.5 to 2" opening at the =
bottom of=20
my cylinders. My engine runs cool with the NACA down draft cooling =
- 350 -=20
360 degrees while leaned out to 100 degrees rich of peak. I =
have=20
never seen 400 degrees on my heads, even on 90 degree days and during a =
long=20
climb out. Even taxiing at Oshkosh only produced 300-320=20
degrees. </FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>And, I am only running one oil cooler. My =
A&P/IA=20
friend says one cooler and those long oil lines should be plenty of =
oil=20
cooling IF the engine is cooled adequately. After 85 hours of =
mostly=20
summer flying, I agree.</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>I worried a lot about a hot running rear mounted =
engine while=20
I was building and watched the reflector and VV's for any information =
for=20
improving cooling. Now I am happy to say, this has been a non =
issue for my=20
Velocity. I LOVE IT!!!</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Ronnie</FONT></DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3DSlvEgl99@aol.com =
href=3D"mailto:SlvEgl99@aol.com">SlvEgl99@aol.com</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Sunday, September 14, =
2003 8:18=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: REFLECTOR:INTAKE =
COMBUSTION=20
AIR</DIV>
<DIV><BR></DIV><FONT face=3Darial,helvetica><FONT lang=3D0 =
face=3DArial size=3D2=20
FAMILY=3D"SANSSERIF">I have an XL FG with Lycoming IO540, two oil=20
coolers.<BR><BR>I have always had a bit of a cooling issue. Not so =
much that=20
temps are high, but that they are uneven between cylinders. The center =
two=20
(3&4) are significantly cooler than the end four. Thisa is =
sometimes 70=20
degrees or more.<BR><BR>After a lot of time trying to get diverters in =
the=20
ducting to move a greater amount of air to the ends of the plenum, I =
took a=20
hard look at how Lycoming has the air flow controlled between the =
cylinders=20
and noted that they have baffles between the cylinders that force the =
cooling=20
air to stay within the cylinder fins nearly to the bottom of the =
cylinder. On=20
the other hand, the XL plenum stops half way down the front and rear=20
cylinders, allowing the air to "escape" from the cylinder fins at this =
point.<BR><BR>I also took a look at a a long EZ and how that engine is =
baffled. I saw that the baffling has the air confined to the cylinders =
with=20
just a small (2.5") opening for the air to exit the fins.<BR><BR>By=20
coincidence just this week I decided to extend the ends of the plenum =
to near=20
the bottom of the cylinders, cutting them off at the approximate =
length of the=20
Lycoming baffles.<BR><BR>How does it work? I don't know yet as I =
have=20
just completed the job and have not had a chance to fly it =
yet.<BR><BR>The=20
other heat issue I have is that the front oil cooler puts too much =
heat into=20
the nose., and then into the cockpit. I have a piece of foam above the =
canard=20
inside the hatch cover to block the heat from the nose and insulated =
it as=20
well as I can by adding insulation around the body of the cooler and=20
insulating the oil lines. I point out that I have a FG, thus no nose =
gear door=20
to allow air into the nose. I have toyed with the idea of adding a =
small vent=20
to bring in cool air to this area.<BR><BR>Any thoughts or ideas or=20
concerns?<BR><BR>Bob Wood<BR>N658SE<BR>XL FG Bob II</FONT>=20
</FONT></BLOCKQUOTE></BODY></HTML>
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