Maintenance Manual STEMME S10-VT
Date of Issue: Jan. 01, 1998
Page 7-21.1
Amendment Nr. 8
Date: Nov. 11, 1999
A4011121_B23.doc
Doc. No. A40-11-121
If both adjustment screws are loose at the beginning of this step, the propeller must be adjusted again (see
section 7.4.10.7 "Checking of Pitch Control and Adjusting the Variable Pitch Propeller").
Connect the power supply to the electric element on both sides.
Screw both sides of the electric covers.
Screw the front cover of the variable pitch mechanism. Observe red marking (red point must correspond
to "red side" of the variable pitch propeller).
Install propeller dome (reverse sequence of removal, do not forget locking).
Check adjustment. If tolerances are not met, re-adjust propeller pitch (see section 7.4.10.7 "Checking of
Pitch Control and Adjusting the Variable Pitch Propeller").
7.4.10.6 Spring Tension of the Propeller Folding Mechanism
Inspection of the spring pre-load for each blade: after the propeller has been installed, keep turning it until
the nose edge of the (folded) lower propeller blade is in a horizontal position. The static holding force (not
the lift-off force) on the rubber catch in this position must be 1.7 N ± 0.1 N (approx. 30 mm / 1.18 in. away
from the tip of the propeller blade measured with a spring balance or weight). Even after swinging out
slightly it must return to the fully folded position of its own accord. Move the propeller to the appropriate
position before repeating the measurement on the other propeller blade.
Removal of the propeller blades (to renew the lubrication of the blade bearings, installation in the reverse
order):
Note:
Completely remove and reinstall the first blade before removing the second blade.
1. Unscrew the union nut of the hollow axle using a flat, size 30 nut wrench (approx. 4.5 mm / 0.18 in. thick)
while holding the hollow axle fast with a flat, size 22 nut wrench (approx. 4.5 mm / 0.18 in). Do NOT
unscrew the castellated nut.
2. Twist the hollow axle (in an anti-clockwise direction) until the spring is no longer pre-loaded (approx. 1½
turns) and then press it out. Make sure the blade does not drop off when doing so and then remove the
blade from the fork (Warning: 2 thrust plate).
3. If necessary, dismantle the hollow axle (now undoing the castellated nut), clean, lubricate and
reassemble it.
4. Push out the inner ring of the blade bearing, remove and clean the needles, inspect them for any
damage, insert the 34 original needles with special grease in the outer ring, then push the inner ring back
in.
CAUTION:
Under
no
circumstances must the needles and the inner rings of the two blade
bearings be mixed up. Should this nevertheless occur, send the entire (dismantled)
propeller to the manufacturer immediately. The needles and inner rings generally have
different tolerances to cater for bearing clearance.
Setting the spring pre-load: the spring pre-load is generated by twisting the spiral torsion spring (23), i.e.
by twisting the pre-mounted hollow axle (3) against the fork (4). Renew the safety plate beforehand:
remove the M4 locking screw for the safety plate (beneath the union nut of the hollow axle), undo the
union nut (see above: Dismantling and …), renew the safety plate, screw the union nut tight again. Twist
the hollow axle to achieve the required spring load. Drill a hole in the new safety plate (diameter 4.3 mm /
0.17 in.) so that the locking screw can be mounted in the required position of the hollow axle (secure the
locking screw by screwing it tight with a self-locking nut and locking compound). Secure the union nut
through the safety plate. Check the function (see above).
