Mark;
Before buying a new one of the same design, you may want
to be sure it is designed to handle he pressure. If the tank has flat
surfaces, even just a few inches across, it needs to be about 1/8” thick
if it is aluminum.
I speced my custom design aluminum cooler
(built by Griffin) for 125 psi. I pressure tested it to 140. The oil
pressure on my 20B will get t0 90+ when cold, and runs 70-80 when hot; and you
want some margin, especially since aluminum is subject to fatigue when cycled –
and it is cycled every time you start your engine and shut it down.
You might also like to check if they
have any pressure drop data. Off-the-shelf coolers are generally designed for
flow rates typical of piston engines, typically about half of our
engines. I recall looking at some data on a Fluidyne cooler I was
considering, and the pressure drop was very high for flow up to about 16 gpm. If
yours was designed for single pass, and modified for double pass, it could be
twice as bad.
Just some things to check.
Al G
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mark Steitle
Sent: Monday, December 14, 2009
5:35 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil
cooler
There's a third possibility that I hadn't considered
until I looked at the cooler again tonight after work. It is evident that
the cooler was pressurized to the point that the tank warped causing the
divider to pull away from the core (not welded where it meets the core).
This allowed the oil to go in and right back out again. The tubes
look fine, but the center of both tanks where there is no support, is
ballooned outward.
I'm debating on whether to send it back to
Fluidyne for inspection & repair, or to bite the bullet
and order a new one (assuming that this size is still
available). This one is definitely repairable, but not sure I'd feel
comfortable flying behind it afterwards.
I also need to ask Gary what the working pressure is
for the Fluidyne coolers. I'm wondering if I may have damaged this cooler
with 90 psi oil pressure without realizing it?
On Mon, Dec 14, 2009 at 6:58 PM, Lynn Hanover <lehanover@gmail.com> wrote:
I called Fluidyne today and spoke with Gary, the
owner. While the cooler is not under warranty, they are willing to look
at it and determine if it can be repaired. I'll send it off and see what
they say.
There should be evidence of a TIG bead half way around
the end tank near the center. Either its there or it isn't. If not and both
fittings are in the same end, it is the problem.......