> I'm afraid I will have to disagree here on one point.
> It is only necessary to get the carb temperature above
> 0 deg C to melt the ice. I find it hard to believe a
> standard XS with 912S installation (without
> thermostats) will not get the coolant to at least 150
> deg F, even on a very cool day. We have seen coolant
> temps higher than that in the winter time at 12,500
> feet. On the occasion when we had carb ice on the
> ground, it was during the runnup procedure, and the
> carb heat immediately cured the problem when turned on,
> with coolant temps well below 150 deg F.
While you make a good point, there are other factors.
The water in the SkyDrive units is 20 - 30 mm from the
actual butterfly, and more like 60 - 70 mm from the jet
orifice which is where the problem occurs
The pipe to the SkyDrive units is fairly small bore
The water flow to the SkyDrive units is cooled water (it
bypasses the heads where it is heated up !)
If you have the standard two holes behind the spinner you
will get a large amount of cold air getting into the
cowling doing its best to negate the effect of the
SkyDrive units.
I believe the figure for carb ice is 2 degrees C not zero.
One carb (port) is more susceptical to carb ice than the
other as there is a nice hot oil tank on the right hand
side restricting the flow of cold air !
At 12,500 feet the temp was 25 degrees Celsius less than
at ground level. Carb ice will not be a problem at 5, 10
or 15 degrees below freezing as there is little water in
the air to freeze in the carb.
At 12,500 feet you are working the engine very hard and so
plenty of heat is being produced (maybe !)
I had quite a bit of stuttering from my engine last
winter, which I attributed to carb ice. WIth the kit I
just get a small stutter about every 30 - 40 minutes in
the cruise. This year I will have comprehensive "bypass
the radiators" baffling for winter and I will report back
on the success (or otherwise !)
I would still like to put an oil thermostat on, but I have
work to do with the PFA !
Anyways - we all have our opinions and yours is no better
or worse than mine :-) [and I am ready to be shot down in
flames !]
Richard
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