Message-ID: <001701c10390$2045bde0$3f6b1b3f@F.Schaefer>
Reply-To: "dfs" <dfs@gateway.net>
Reply-To: lancair.list@olsusa.com
From: "dfs" <dfs@gateway.net>
To: "Lancair list" <lancair.list@olsusa.com>
Subject: Oil and lower cowl cooling
Date: Tue, 3 Jul 2001 00:16:47 -0700
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From direct exerience, it seems that the primary controlling factor in
getting good oil cooler performance is how much air is supplied to the
cooler.

I added a 4 - 5 inch wide NACA scoop to my cowl side and originally fed the
cooler via a 2 inch dia SCAT tube (no special ducting of the outlet, just
dumped the exit air into the engine bay behind the baffles). With this
set-up I always experienced oil temps that just nudged the red line on the
gauge. Changing the SCAT tube to 3 inch dia (which required some judicious
surgery on the NACA scoop plenum) without changing the cooler outlet,
resulted in significantly lowered oil temps. So much so, that the nominal
running temps are a bit lower than I like to see. So I installed a flapper
plate to restrict the air outlet coming out of the cooler - works fine.

I was surprised at the extra amount of cooling that resulted from merely
increasing the inlet tube diameter, but the numbers don't lie.

Bottom line: If you're seeing oil temps running too high, try the simple
stuff first, like increasing the inlet flow to the cooler. Might just be the
answer without a lot of effort.

Dan Schaefer

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