Checking Of The Friction Torque - Rotax 912 Series Maintenance Manual

7.1)

Checking of the friction torque

See fig. 18.
- Fit the crankshaft locking pin. See Chapter 05-50-00, para 2.7.
- With the crankshaft locked, the propeller can be turned by hand 15 or 30
degrees depending on the profile of the dog gears installed.
This is the amount of movement allowed by the dog gears in the torsion load
absorption unit.
WARNING: Ignition "OFF" and system grounded. Disconnect negative ter-
- Turn the propeller by hand back and forth between ramps, taking into
consideration the friction torque. No odd noises or irregular resistance must
be noticeable during this moment.
- Attach a calibrated spring scale to the propeller in distance (L) from the
center of the propeller. Measure the force required to pull the propeller
through the 15 or 30 degree range of rotation. (See Fig. 3)
- Calculate friction torque (Nm) by multiplying the force (N) obtained on the
spring scale by the distance the scale is attached from the center of the
propeller (L). The friction torque must be 15 Nm to 45 Nm (130 to 400 in. lb).
See calculation example.
- Remove crankshaft locking pin. See Chapter 12-00-00, para 2.7.
- Reconnect negative terminal of aircraft battery.
WARNING: If the above mentioned friction torque is not achieved, ispect,
- Detailed inspection of all gearbox components.
00883
For example minimum torque:
F x N = 20 N x 0,76 m = 15 Nm
For example maximum torque:
F x N = 60 N x 0,76 m = 45 Nm
Effectivity: 912 Series
AIRCRAFT ENGINES
MAINTENANCE MANUAL
minal of aircraft battery.
repairor overhaul the gearbox in accordance with the ROTAX
instructions for continued airworthiness.
Länge L (m) /
length L in m
Kraft F in N /
fig. 18
12-00-00
Rev. 1, Jan. 01/2002
®
force F in N
page 41