From: "R\351mi Guerner" <ai...
Craig Ellison wrote
=E2=80=9D I was unable to get the oil temp up in the green before the CHT went
into the yellow and had to shut
down. Aprox time .25hr/OAT 45F. Also when done there was oil from the
exhaust down the port side of the aircraft. Mostly small black spray spots.
Is this normal?=E2=80=9D
Craig,
Cooling is a recurrent problem with the Rotax / Europa cowl combination. On the
ground the coolant warms up a lot faster than the oil, and the coolant can boil
over if you cannot take off quickly . In flight there is too much cooling
especially
in winter. The possible fixes are: cowl flaps, thermostatic valves,
Evans coolant. The Evans coolant definitely solves the boil over issue. I have
tested different cowl flap solutions and am still working to improve them.
Regarding the black spray spots on the port side of the aircraft, coming out of
the exhaust stack: I got just that when I was using the 914 and I was concerned
about it. Now I am using a new 912S and I am still getting some black
deposits.
I believe this comes from a too rich mixture on some cylinders. However,
as it seems that some cylinders are running a lot leaner than the others, I
believe it would be very risky to adjust the carbs to a leaner average mixture.
This is a weakness of the Rotaxes and I think we have to live with it.
Remi Guerner
F-PGKL, XS S/N395 monowheel, 288 hours on a 914 + 89 hours since upgrade to
the
912S.
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