For pusher- and/or fuselage-installation behind cockpit it must be ensured that the inlets are not
blocked due to unsymmetric flight attitude
A typical engine installation is shown in Fig. 3-1. To obtain the maximum cooling performance,
the upper plenum must be as large as possible.
The shape and size of the inlet and exhaust openings must be designed not to exceed the tempera
-
ture limits (refer to the operating manual) under worst case conditions (full power climb at the
lowest permitted speed).
For the maximum reliability and safety, it is not recommended to exceed a cylinder-head temper-
ature of 160° C at high-power cruise.
The engine has an oil cooler (O) which must be positioned correctly and is the responsibility of
the aircraft designer. It is possible to drain the oil from the oil cooler at regular intervals. The oil
cooler must have a separate duct for the cooling air. This air is directed through the chamber of
the upper plenum (cold section) of the engine cowling to the oil cooler. There is also a venting
outlet. To assure a sufficient oil temperature during winter operation, it could be useful to reduce
the effective inlet surface of the oil cooler by using an aluminum shielding. Other changes to the
fins and/or the oil cooler are not permitted.
For cabin and carburetor heating a heat muff (M) around the exhaust may be used. It also helps
to cool the exhaust, which may reacht temperatures of more than 800 °C. Use ducting hose (H) to
attach the heat muff to an opening in the cowling. The heated air may then be supplied to the car
-
buretor or to the cabin. Make sure that you have a proper exit (X) to the outside in case the cabin
heating is switched off and that the duct (X) does not block the cooling air exit (E)
Caution: Use a carbon monoxide warning device to protect the crew from a defictive heating system!
Note: The cooling system will absorb power, which is no longer available for flight propulsion. A well
designed cooling system will minimize these losses and increase the flight performance and/or
lower the fuel consumption.
It is very important that all of the components in the cooling system are installed carefully.
For more information see Technical Bulletin 44 in it´s current edition.
3.1.2 L 2400 EF Engine
The cooling system of the L 2400 EF engine consists of 4 different sub-systems. The general sys-
tem layout is shown in Fig. 3-2:
•liquid cooled cylinder-heads
•direct air-cooled cylinders
•oil cooling
•direct air-cooled generator
The major portion (70%) of the engine heat is dissipated by the cylinder-head cooling syst em.
The cylinders are cooled with air, the oil mainly removes the heat caused by friction from the en
-
gine (5%). The cooling system is not designed for continuos operation at full power when the
aircraft is on the ground. During flight the flow of air increases considerably and the cooling
property also increases considerably.
The cylinder head is designed so that the liquid coolant, a water/ethylene-glycol mixture, flows
through the passages in the cylinder head under pressure. A pump circulates the liquid coolant
through the pipes (CO) to a radiator (R). The coolant is the returned to the coolant pump through
a pipe (CR). Cooling air (AR)flows through the matrix of the radiator which cools the liquid cool-
ant. A sealed duct to the cowling is ncessary to ensure full flow through the radiator. The syst em
