Propeller Gearbox - Rotax 912 series Operator's Manual

9.5)

Propeller gearbox

See fig. 8.
For the engine type 912 two reduction ratios are available.
reduction ratio
crankshaft : propeller shaft
Depending on engine type, certification and configuration the propeller
gearbox is supplied with or without an overload clutch.
NOTE:
fig. 8
NOTE:
The design incorporates a torsional shock absorber. The shock absorbing
is based on progressive torsional cushioning due to axial spring load acting
on a dog hub.
On the gearbox version with overload clutch the design incorporates a
friction damped free play at the dogs to warrant proper engine idling.
Due to this backlash at the dogs a distinct torsional impact arises at start,
stop and at sudden load changes, but due to the built-in overload clutch it
will remain harmless.
NOTE:
Alternatively either a vacuum pump or a hydraulic governor for constant
speed propeller can be used. The drive is in each case via the propeller
reduction gear.
Effectivity: 912 Serie
OM initial issue
912 UL / A / F
2,27 : 1
2,43 : 1
(optional)
The overload clutch is installed on serial production on all
certified aircraft engines and on the non-certified aircraft
engines of configuration 3.
02531
Fig. 8 shows a propeller gearbox of configuration 2 with
the integrated overload clutch.
This overload clutch will also prevent any undue load to
the crankshaft in case of ground contact of the propeller.
AIRCRAFT ENGINES
912 ULS / S
2,43 : 1
02719
page 9 - 5
July 01/98