Fred,
This is an interesting treatise on
cooling.
Can you post some photographs of your
current baffling.
My coolest cylinder is #3.
The hottest,
#4.
#2 is second hottest, and both these lie
behind the prop control on the O-320 D1F.
I discuss this with LAME’s all the
time, and like Fred, had the “ramp” ahead of #2, and indeed #1, cut down.
I also had the air filter in front on the
former ramp in front of #2 inverted to become flush, so as not to impede
airflow.
All these measures had an effect of
lowering CHTs’s, but not as dramatically as expected.
Recently, I had a sudden jump in oil and CH
temps.
I downloaded the EDM data and sent if off to
an expert. He reported that other pilots had also experienced the same thing at
the same time, and an inquiry to oil companies indicated that the octane rating
of the fuel had been lowered closer to the minimum allowed (100) following the recent
burst in oil price.
Dom Crain
-----Original Message-----
From: Lancair Mailing List
[mailto:lml@lancaironline.net] On Behalf Of belle
and Fred Baron
Sent: Sunday, 7 November 2004
12:28 PM
To: Lancair Mailing List
Subject: [LML] LNC2 Cooling
I really do appreciate all
the posts in the last month or so on cooling and insight gained from Ada.
However, I did find it all a bit disjointed but was able to pull bits a pieces
of info from all the posts. This subject is very hard to verbalize, but I will
try.
Cyl.# 1- Always has been
very cool (170 C) ,so it is a non issue.
Cyl# 2-The hottest (200 to
210 C) in cruise. I actually had to replace it at 850 hours due to it being
"out of round".From the List I learned that you have to drive the air
down thru the FRONT on # 2, at the flat spot, where there are very small
to no cooling fins. This was very easy to do by cutting 3/4" off of the 45
degrees ramp that is actually touching the cylinder. This opened up a gap about
1/4" directly in the front center of # 2. No air was going over the front
lower quarter of # 2. Now air is going over and under # 2. The result is a 10
to 15 degree C drop in temp. The piece that I cut off has no structural value
to the baffling and looks like it was designed to force the air
up into the plenum area.
Cyl # 4- Always ran cool
like # 1 ( I need 4 ahead of 3 as a reference)
Cyl # 4 has a curved
baffling piece about 1/2" from the flat spot in the very rear of
the engine that allows air to be forced downward at
the very place it needs the most air.Again, a flat spot with very small if any
cooling fins.
Cyl#3- Always hot like #
2. Looking at the rear of # 3, you can see how the air cannot go through
the top rear of 3 # (guess what, the flat spot).It should be a fairly simple
matter to make the rear of # 3 look like the rear of # 4 ( a curved piece that
stands off from the top rear of # 3)
I'm sorry that this is so
wordy, but that is the nature of conversation. Also, I really love my airplane,
but feel that Lancair let us down in the design of the baffling. I will
report on the progress of # 3 next week.
Sincerely, Fred N. Baron,
Lancair 9BF (Don't fly like my brother)