Date: Tue, 14 Mar 2000 09:13:50 +0200
To: "olsen@eai.com" <olsen@eai.com>,
    "Lancair List" <lancair.list@olsusa.com>
From: "colmar" <jones@colmar.demon.nl>
Importance: medium
Priority: normal
Message-Id: <953021630-0-jones@colmar.demon.nl>
Subject: Re:Oil cooling for a 320?
Mime-Version: 1.0

          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> 
>>
Colorado of course may be much tougher for cooling than here in
Holland.......but;

I have very standard o320D1F without any extra penetrations of the cowling.
(NACA duct at input or grill for outlet). The duct for oil cooler is at left
rear cylinder (not right, as I seem to remember the manual shows), though I
don't think the resulting shorter ducting length makes any difference.
I can get red line oil temps if I do repeated circuits at air T>20C, but I have
never seen red line CHT's (and I have the single probe on the cylinder nearest
the ducting outlet to the oil cooler). On the other hand, when air T<0C, I
really need to install a partial blockage in the ducting if I want to get the
oil temp INTO the green during cruise.
 
My conclusion is that the differences of oil and CH temps between different
planes is mostly linked to the DETAILS of sealing (with silicone) ALL, repeat
ALL, of the possible escape routes for what comes in those holes at the front! I
am supported in this by the different problems of oil cooling which several
360's here have had. The only one which has not needed to post-install NACA
ducts and grills uses as the plenum a completely self-contained metal box within
the cowling - hence no sealing onto the upper cowling. Of course the box
rigidity allows very low leak areas to be achieved - and this is the key, I
think.

In fact, I am more concerned about temps of the firewall mounted units than
about the oil and CH temps. Despite having several 3/8" or 1/2" tubes to take
cool air from the right rear side of the plenum directly to some units, I find
these units too warm to the touch when I reach the FBO. But no quantitative
data, and who knows whether this temp was just built up during the landing and
taxi? I don't know. I suppose it would be inproved by enlarging the "escape"
aperture on the lower side of the cowling  - but that cost so much work to make
it look good, I hate to start cutting it up without "undeniable cause".

Which brings me to the only advise I would give, which is you should just take
very great care about all the possible leak paths - and then fly it (preferably
unpainted, if you can allow logic to overcome emotion!) before you start messing
up that lovely shape with ducts and grills!

Regards, Colin Jones (PH-COL)   
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
LML website:   http://www.olsusa.com/Users/Mkaye/maillist.html
Builders' Bookstore:   http://www.buildersbooks.com/lancair

Please send your photos and drawings to marvkaye@olsusa.com.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>