Message text written by McFadyean
>The success of the cooling systems on Europas seems to be somewhat
variable. Alot either overheat or can't sustain a prolonged climb without
temperatures red-lining. Others are okay. There must be pattern to this,
but I don't know what it is;<
If we are to analyse this it would be helpful for owners to indicate which
Rotax variant and what ratio of antifreeze they are using. We are all meant
to use 80:20 which will allow the coolant temp to go to higher values
safely although as we know the conductivity of a 50:50 ratio allows better
cooling. Looking at the 912/912S Owners Manual the max coolant temp of 130
degC (80:20 ratio) can be raised to 150 degC provided the system is
pressurised. This is the same as the max CHT. If we use a 20deg safety
margin the max temp could sensibly be interpreted to be 130degC. To be
totally comfortable coolant temp as well as CHT should be displayed if you
intend operating near to this limit.
If the engine is in its first 20 hrs or so it will be getting hotter whilst
it is bedding in. In my case the oil temp was a problem initially but it is
now well under control and I think some of this was because the engine was
a bit tight to start with. I get the impression that the XS is more
limiting on coolant temp due to the smaller radiator area whereas the
Classic in 912S fit needs the oil cooler relocating to control oil
temperature.
Both oil and coolant are potentially easier to control in the Classic by
the use of cowl flaps. With the XS the separate radiator cowl makes
adjustments more difficult.
Nigel Charles
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