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[FlyRotary] Re: NPG has been used successfully-Ken
Welter'
It could have been the problem
with Dave's but I doubt it as his belt was in fine shape and I did run
NPG down to 30 below zero and that was when I got chicken and switched
back.
My real concern came when my
throttle cable froze wide open and I had to shut the engine down at
13000 ft and glide down to the Columbia river to let it thaw out, my
concern was that if I had to restart the engine that the fluid would
be real thick do to the sub zero temps and high airflow over the
radiator with no heat being generated by the engine.
And let me tell you it got cold in
the cabin in a hurry when I shut that engine down and I was only
wearing a thin sweatshirt as my cabin heaters are so
good.
I really think that Dave's problem
from vapor locking ether do to coolant loss or more likely do to
combustion pressure getting into the water jacket from freeze up
damage no them cold nights.
Ken
Thanks,
Ken
Your information could
indicate that problem Dave Leonard encountered a viscosity related
problem into after filling his cooling system with NPG in cold
mountain weather.
It appears that like
many things - success or not depends on circumstances. It has
been my experience that things that are gang busters for the rotary
racing crowd do not necessarily turn out to be well suited to
our operating environment for the 13B.
I would still have a
great deal of concern about 100% glycol leaking onto a hot
exhaust. The chance of a 50/50 mixture igniting has a very low
probability due to the heat absorbing nature of the water in the
mixture.
Ed A
----- Original Message -----
From: Ken
Welter
To: Rotary motors in
aircraft
Sent: Thursday, February 02, 2006 2:06
AM
Subject: [FlyRotary] Re: NPG has been used
successfully-Ken Welter's Coot
Yes I used NPG for
several hundred hrs and it seemed to work fine but I switched back to
60 percent Sierra 40 water mix do to the availability and my concerns
of the viscosity in the sub zero temps that I fly in, the main concern
was possibly over stressing the belts when it was thick and hot spots
do to slow fluid flow.
I first 300 hrs flying used
the Sierra blend and then switch to the NPG for about 300 hrs and then
switched back and I found that there was no noticeable
temperature/cooling differences between the two.
Yes Rob Golden swears by NPG
and he was the one that turned me onto it in my early days of flying
when I was having cooling problems but he then also had concerns about
the viscosity at high attitudes and cold temps so I them switched
back.
Ken
Welter
Just one more data point. Al Wick
asked if there was anyone else that had used NPG besides Dave
Leonard.
I recall Ken Welter (rotary powered Coot amphib.) used NPG several
years ago. He had no complaints about its cooling ability and he
was running an old Ross redrive at 3.17:1 (no, not 2.17) making LOTS
of horsepower. He said (IIRC) the only reason he went back to EG
& water was that if you ended up doing some field repair work on
your bird you can not just throw in some water in the mix to make it
home. NPG is supposed to be run at 100% with as much water
removed as possible before pouring it in. (Note: I understand
this is not the case with NPG+)
The real problem with NPG in our rotary powered birds is you can't
walk into any auto parts / wal-mart / seven-11 to get an extra gallon
of the stuff to get you home. You can find EG or just water
anywhere.
One more data point while I'm here. Rob Golden of Pineapple
racing in Portland Oregon swears by the stuff. Rob has been
rebuilding and racing rotaries very successfully for over 30 years.
I have not talked to him in over a year but he used to send every
engine out with only NPG and I believe he required it for the
warranty. Now of course he sells the stuff so there is that bias
on the fly in the ointment.
Neither of these above points addresses the super cooling issue that
in theory seems to be able to turn NPG in the radiator to jelly.
Once again we are left to do a thorough test. Those of us like
Dave who like the idea of flying into high cold places like Mammoth
Lakes to go skiing (sorry Dave..boarding) P-)
may need to plan on a winterization kit like they use in the great
white north, i.e. duc-tape over the cowl inlets.
Okay, I've rambled on enough. Talk amongst yourselves....
Mike
Mike McGee, RV-4 N996RV, O320-E2G, Hillsboro, OR
13B in gestation mode, RD-1C, EC-2
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