STEMME S12 User Manual

DOCUMENT NUMBER:
L500-912.820 ISSUE JUL 20, 2016
AMENDMENT: 00
DATE: 
CHAPTERPAGE 735
MAINTENANCE MANUAL STEMME S12
7.4.10.7 CHECKING OF PITCH CONTROL AND ADJUSTING THE VARIABLE
PITCH PROPELLER
• The basic setting of the blade-angle is performed by the manufacturer or by a facility or
Field Base Operator (FBO) authorized by the manufacturer to perform major repairs on
the variable pitch propeller.
• The propeller unit must be positioned in the take-o setting. Check to conrm that the
pitch control mechanism is at the stop in the take-o setting by pressing the half opened
propeller blade to the rear (against the direction of ight), so that the expanding element
(15) is completely compressed. No signicant further movement in the direction of ne
pitch should be possible.
• Check the propeller pitch angle for take-o with a precision protractor with a vernier or
digital scale. Turn the propeller to an approx. Vertical position, place the static arm of the
protractor to the lower left on the reduction gear base-plate, rotate the movable arm to an
approx. vertical position, then rotate the propeller clockwise until both fork cheeks are in
their operating position (see gure 3.4.10.c). Lock protractor and read o result. The setting
angle is -2° 30’ ± 5’. The acceptable dierence in blade angle settings of both blades is 10’.
• Precision adjustment of the propeller pitch (e. g. to achieve correspondence between both
propeller blades) is accomplished by means of two adjustment screws (25). During ad-
justment, the drive lever is only set loosely (M5 screw and M8 nut are not fully tightened).
• Tighten the M5 bolt and the M8 nut. Tighten the adjustment screw and lock nut. Check
tightening torque of the M8 nut (20 Nm / 14.7 lbf) with a torque wrench. Re-check the
setting angle and secure adjustment screw with safety lock wire.
• Check the pitch control mechanism for ease of operation: swivel both blades out by 90
degrees° against the fork and then pull forward on the blades near the tip without using
too much force. The blades must be easily brought into cruise position and, after releasing
them, the spring tension must return the blades to the stop in the take-o position.
• Activate the pitch control mechanism (Master switch “ON”) by pressing the push button
at the front bulkhead for 3 to 4 minutes until the cruise position is reached (y-weights
(19) are forced against the stop).
• Hold the push button (2
nd
person) and check the pitch angle of the propeller blades in the
cruise setting (the method corresponds to measuring the take-o setting). The rated value
is +3° 54’ ± 10’.
• Due to design, after successfully having adjusted the take-o setting, the cruise setting
must be within the permissible limits. If this cannot be achieved, damage or excessive
wear may be presumed. In this case, repair must be performed by the manufacturer or by
a facility or an FBO authorized by the manufacturer.

STEMME S12 Specifications

General

Brand	STEMME
Model	S12
Category	Aircrafts
Language	English