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Re: [FlyRotary] NPG has been used successfully-Ken Welter'
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 -----
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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