Effectivity: 912 Series
Edition 1 / Rev. 1
d04635
page 47
May 01/2009
BRP-Powertrain
INSTALLATION MANUAL
12) Cooling system
12.1) Description of the system
See Fig. 21.
The cooling system of the ROTAX 912 is designed for liquid cooling of the
cylinder heads and ram-air cooling of the cylinders.
The cooling system of the cylinder heads is a
closed
circuit with an expansion
tank and overflow bottle.
The coolant flow is forced by a water pump, driven from the camshaft, from the
radiator to the cylinder heads. From the top of the cylinder heads the coolant
passes on to the expansion tank (1). Since the standard location of the radiator
(2) is below engine level, the expansion tank located on top of the engine allows
for coolant expansion.
The expansion tank is closed by a pressure cap (3) (with pressure relief valve
and return valve). At temperature rise and expansion of the coolant the pressure
relief valve opens and the coolant will flow via a hose at atmospheric pressure
to the transparent overflow bottle (4). When cooling down, the coolant will be
sucked back into the cooling circuit.
09152
Fig. 21
2
4
1
3
The shape, size and location of one or more radiators depend mainly on the
space available.
On good installation in the airplane the radiator by BRP-Powertrain (optional)
has enough cooling capacity to keep within the normal specified operating limits.
Also the flow of coolant liquid through the radiator is not restricted and the tube
size is sufficient.
