Vacuum Pump - Rotax 912 ULS 3 Operator's Manual

Backlash
Vacuum pump or
hydraulic go-
vernor
Effectivity: 912 Serie
OM Edition 2 / Rev. 0
On the gearbox version with overload clutch the design incorpo-
rates a friction damped free play at the dogs to warrant proper en-
gine 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: This overload clutch will also prevent any undue
load to the crankshaft in case of ground contact
of the propeller. See Service Letter SI-912-015,
latest edition.
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.
BRP-Powertrain page 7-9
April 01/2010