Cooling System; Fan Cooling (Rotax 447 Ul Scdi, Rotax 503 Ul Dcdi); Free Air Cooling (Rotax 447 Ul Scdi, Rotax 503 Ul Dcdi); Liquid Cooling (Rotax 582 Ul Dcdi And 582 Ul Dcdi Mod. 99) - Rotax 447 UL SCDI Installation Manual

11.)Cooling system

11.1) Fan cooling (ROTAX 447 UL SCDI, ROTAX 503 UL DCDI)

The engine driven cooling fan provides sufficient cooIing air, provided that the cooling
air has free access and the hot air is not recirculated to the fan.
On aircraft equipped with engine cowlings the exit must be of sufficient size and in a
low pressure area allowing the air to cool engine cabin and crankcase.

11.2) Free air cooling (ROTAX 447 UL SCDI, ROTAX 503 UL DCDI)

Means ram air cooling, for engines without fan.
In case of a tractor propeller configuration, with the propeller blowing air onto the
cylinder(s), this air stream serves for engine cooling.
On 2-cylinder-engines the air stream must be directed from the exhaust side towards
the carburetor side with suitable ducting (available from ROTAX).
Pusher propeller configurations should not be used with free air cooled engines
without consulting the engine manufacturer (in writing).

11.3) Liquid cooling (ROTAX 582 UL DCDI and 582 UL DCDI mod. 99)

These engines have an integrated water pump. The cooling circuit must be arranged
as shown on the illustrations 12 to 17. Pay attention to the following:
◆ NOTE:
11.3.1)
11.3.2)
Effectivity: 447 UL SCDI, 503 UL DCDI, 582 UL DCDI /mod. 99
AIRCRAFT ENGINES
INSTALLATION MANUAL
The 582 UL DCDI mod. 99 has a two circuit cooling system. (see latest
revision of the current operators manual 447 UL SCDI-503 UL DCDI-
582 UL DCDI.

Coolant flow

Should be in the range of 60 - 70 litres/min. at engine r.p.m. 6500. See ill.
18.

Cooling liquid temperature

The radiator must be of adequate size, and the airstream of sufficient
intensity to maintain the coolant temperature below the maximum permit-
ted value of 80°C (175 °F) under the most severe conditions, i.e. at full load
operation (= at take-off).
The average coolant temperature must be 60 - 80°C (140 -175 °F).
In case of a pusher propeller installation, take particular care that coolant
radiator has sufficient air flow.
The max. temperature difference of the coolant between radiator entry and
exit must not exceed 6 °C (11 °F), the average difference must be around
3 and 5 °C (5 and 9 °F).
If temperature limits are exceeded or coolant flow rate is below specified
values (excessive flow resistance), vapour is produced in the cylinder
head, causing cooling break-down and engine damage.
page 11 - 1
Initial issue, May 01/99