Hi Gilles,
I tested the digital thermometer / thermocouple, when I bought it, in
boiling water and, allowing for STP, it is accurate. The CHT is the
standard Rotax sender / VDO gauge and has served me well for 1100 hours, but
I have never tested it for accuracy.
Mine is a Classic so I have the massive rads in the nose, which are about 60
% blanked off in the winter and about 30 % blanked off in the summer to
maintain about 85 to 90 degs C in the cruise. In the early days I ran with
80% glycol and now I run at 50%. I tried the Evans for about 25 hours and
then discarded it because its cooling qualities were so inferior. I have
cowl flaps for increasing the exit area for sustained climbs in hot weather,
which reduce temps by about 10 degs C.
Maybe the heat transfer from coolant to thermocouple by just taping it to
the outside of the tank is not good enough, or perhaps the coolant from the
front pots is reducing the average in the expansion tank by 15 to 20 degs.
Anyway, I have never had problems with high temps, so it is all a bit
academic for my aircraft.
Regards,
William
----- Original Message -----
From: "Gilles Thesee" <Gilles.Thesee@ac-grenoble.fr>
Sent: Sunday, January 14, 2007 11:05 AM
Subject: Re: Europa-List: Rotax Water Temperature.
<Gilles.Thesee@ac-grenoble.fr>
> My exit coolant temp works out at 25 degs C less than the CHT pretty well
> throughout the range.
William,
25C seems a great temperature difference between the CHT and the
coolant flowing out of the heads. That would mean that even at the 135C
CHT red line (Rotax 914), your coolant would not exit the the heads
above110C ? Or flying at 100C CHT, the coolant would not exceed 75C ?
All the measurements I did showed a difference on the order of 5C.
Have you tried checking the two temperature measuring devices in the
same water or oil bath ?
Regards,
Gilles
http://contrails.free.fr
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