STEMME S12, Руководство по обслуживанию

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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-off setting. Check to confirm that the
pitch control mechanism is at the stop in the take-off setting by pressing the half opened
propeller blade to the rear (against the direction of flight), so that the expanding element
(15) is completely compressed. No significant further movement in the direction of fine
pitch should be possible.
• Check the propeller pitch angle for take-off 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 figure 3.4.10.c). Lock protractor and read off result. The setting
angle is -2° 30’ ± 5’. The acceptable difference 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-off 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 (fly-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-off setting). The rated value
is +3° 54’ ± 10’.
• Due to design, after successfully having adjusted the take-off 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.