----- Original Message -----
Sent: Friday, May 12, 2006 10:41
AM
Subject: [FlyRotary] Re: oil cooling
issues
I have seen 260 F. many times, and I
consider that normal during climb
and taxi. I also use Mobil One
Synthetic oil, to tolerate the heat.
During cruise it will stabilize at
220F.
You need to get the oil above 220 F, to evaporate the
moisture anyway.
The
"standard" (closest we have to one) for measuring oil temp is to measure it
as it returns to the engine, after the cooler. According to Racing
Beat, this temp should never exceed 210 F. Lot's of folks have
exceeded this for short periods, up to 240 F or so, and have had no
problems, but it's not something you really want to keep
doing.
As I
understand it, the issue is not the breakdown of the oil, but the
melting of the rotor bearings.
Hum-m. I
was under the impression that the limiting factor side seal
O-rings.
I’ve had the oil
temp (after cooler) up to 220 -225 a few times for very short periods on the
ground. With no effective air flow through the cooler, the
before-cooler temp was only 3-4 degrees higher. It’s a different issue
when running at high power where before-cooler temps may be 30-50 degrees
higher.
Al
That is my
impression as well. Auto racing is another matter. They are
stressing the rotor bearings a lot more than we are (mainly due to RPM) so
that is probably the weak link in their use.
Your
numbers for pre/post oil cooler temps are what I am seeing when in-flight,
I.e. 180 after the cooler = 220 - 230 in the pan. This is a
valuable number with which to judge oil cooler effectiveness. If
you don't get this much delta or more, your cooler is too small or airflow
too little.
Tracy
(still can't figure out why I can't change text color after Al's
stuff)