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Message
One other difference. The Mazda cooler has a thermostat
that bypasses the oil until it warms up. the evaporator core has to handle all
the flow even when cold, so the evap core is seeing the high initial startup
pressure.
Bill Schertz
KIS Cruiser # 4045
----- Original Message ----- From: Russell Duffy [mailto:13brv3@bellsouth.net] Sent: 12/18/2004 6:08:31 PM To: flyrotary@lancaironline.net Subject: [FlyRotary] Re: cooler thoughts
The problem might simply be
that the pulses are hitting high pressures and fatiguing the reasonably flimsy
evap cores. There's also the possibility that the pulses hit a
resonant vibration at some point, which causes the failure.
It would be
interesting to see a trace of these pulses, and they may be important; but I am
skeptical about them being the primary cause unless your cooler is near the
engine outlet, and you have rigid (solid metal) lines.
Hi
Al,
If I
thought a standard pressure sensor could catch the pulses, I'd be tempted
to put a scope on it. I just don't think it would be a conclusive test
though. Leon has told me some interesting stories that lead me to
believe in the pressure pulse theory. I also can't think of a better
explanation. I don't quite buy the cycling pressure theory, because
I'm only running about 80 psi at the cooler. I think the evap core
probably sees close to an 80 psi cycle between static, and
operating pressure. Also, I believe the leak started after a
good 20 minutes of flight, not on initial pressure at startup, which wouldn't
indicate that it failed on the pressure
cycle.
Fortunately, I
think the only point we need to prove is that evap cores are a bad idea for
oil coolers.
Cheers,
Rusty
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