Checking Of The Overload Clutch - Rotax 914 Series Maintenance Manual

2.2)

Checking of the overload clutch

In the event of lead deposits and/or if slipping is suspected, it will be necessary
to check the overload clutch.
◆ NOTE
- Lock the crankshaft. See 12-00-00 sec. 2.8.
- Remove the propeller as per manufacturer's instructions.
■ CAUTION: Danger of damage to the engine suspension!
- A specially prepared lever (e.g. length 1.5 m (4.92 ft), see Fig. 4) is fitted on
the propeller flange and the breakaway torque measured with a spring scale.
◆ NOTE:
Repeat the measurement several times to get a stable value.
The breakaway torque is calculated on the basis of the spring force (F)
measured in N and the length of the lever arm (L) used at the normal distance
from it in m (N x m = Nm).
- Release the crankshaft, see 12-00-00 sec. 2.8.
The value determined must be between 600 and 800 Nm (369 and 590 ft.lb.).
◆ NOTE:
■ CAUTION:
- If the value is greater or smaller than the limit value, the whole gearbox must
be inspected, repaired or overhauled in accordance with the BRP-Rotax
instructions for continued airworthiness.
Effectivity 914 Series
Edition 1 / Rev. 0
BRP-Rotax
MAINTENANCE MANUAL
Slipping of overload clutch is apparent if at engine speed rise,
the propeller speed does not increase at the same rate.
Depending on the engine installation (e.g. in the case of extremely
lightweight engine suspension), the gearbox must be removed
and the test carried out on a suitable mounting attachment.
Because of difficult measurement of the slipping torque the
breakaway torque is measured.
The engine should have been running shortly before the
inspection (max. 1 day before), as otherwise, the clutch can 'dry
out', resulting in a higher torque.
Do not exceed 800 Nm (590 ft.lb.) otherwise gearbox damage
can occur.
05-50-00
page 5
May. 01/07