Airplane Factory SLING LSA
Pilot Operating Handbook
Page | 7-19
Date of Issue: 07 July 2014
Revision : 1.3
7.14
Cooling system (912 ULS / 912 iS)
Cylinders are air cooled.
Cylinder heads are liquid cooled via a closed circuit system with an
expansion tank. A camshaft driven coolant pump circulates coolant from a
radiator through the cylinder heads, then through an expansion bottle and
back to the radiator.
The expansion tank is closed by a pressure cap. At temperature rise of the
coolant an excess pressure valve in the expansion tank opens and coolant
flows (via a hose) at atmospheric pressure to an overflow bottle mounted
on the firewall. When cooling down the coolant in the overflow bottle is
sucked back into the cooling circuit.
Refer to the latest revision / edition of the applicable Rotax engine
operator and maintenance manuals.
Coolant type (912 ULS)
For aircraft fitted with the 912 iS engine refer to the supplement at the
end of this manual.
Either water-free propylene glycol based coolant concentrate or
conventional ethylene glycol based coolant and distilled water mixture
(1:1 mix) can be used. Refer to the latest edition / revision of the ROTAX
912 ULS engine operator manual and the latest revision of Rotax service
instruction SI-912-016.
WARNING
Waterless coolant (propylene glycol based) may not be
mixed with conventional (ethylene glycol/water) coolant
or with additives! Non observance can lead to damage to
the cooling system and engine.