Maintenance Manual STEMME S10-VT
Date of Issue: Jan. 01, 1998
Page 3-27
Amendment Nr. 8
Date: Nov. 11, 1999
A4011121_B23.doc
Doc. No. A40-11-121
The electrical energy to the expansion elements is interrupted (blade pitch automatically to T/O) as soon as
the propeller switch is set to T/O or when the propeller dome handle is not locked in OPEN position (engine
master switch is OFF).
If the propeller dome is closed, electrical energy to engine and propeller is separated to save energy when
soaring.
In order to check the pitch range mechanism, a push-button that can be operated from outside is provided on
the right hand side (in flight direction) of the front gearbox frame. Master switch “ON” and “Push” the button
the expansion elements are heated and the propeller is brought into the cruise setting. When the cruise
setting is achieved, the stop switch disconnects the electrical current to the heating elements. For this check,
the push-button must be activated for about 3 to 4 minutes to heat the expansion elements. On releasing the
push-button, the elements cool down and the propeller returns in the start position.
Identification of Propeller System and Assembly
Complete Propeller:
11 AP-V / XXXXX / YYYY
Propeller Blade:
11 AP-VB / XXXXX - ZZ
X: Number of ordering for production share (corresponds to the a/c Ser. No. for complete propeller);
5 digits, starting with 30001, in addition 20038;
Y: Month and Year of production, 4 digits;
Z: Consecutive number of production share, 2 digits.
3.4.11 Power Transmission
The components of the power transmission system are:
Centrifugal clutch (in between engine and drive shaft): a force transmitting clutch actuated by direction-of-
turn and rotating speed. Since the centrifugal clutch transmits torque by friction, it is also an overload
protection.
Drive shaft, which is manufactured in carbon fibre reinforced composite material.
Flexible coupling forward and aft, allowing for angular and torsional elasticity.
The rear terminal of the drive shaft is maintenance-free due to a hard film coating (30 m), which also is anti-
corrosive. The sliding friction coefficient decreases with increasing torque by design. Optimum behaviour of
the coating is only attained if not greased. The condition of the coating should be checked regularly (ref. to
section 5.3.16).
Basically it is possible to install an older model of the drive shaft, e.g. on the occasion of a repair. It must be
observed, only to install a drive shaft with the marking „Fiberspeed“ and that these drive shafts must be
greased regularly with commercial quality greases containing lithium.
3.4.12 Front gear
The Front gear is a helical gear in an aluminium-cast housing with a gear ratio of 1.109. It is almost free of
maintenance. The front gear oil level can be checked by means of an inspection glass with MIN/MAX
markings. The extension shaft is connected to the lower gear drive shaft with a flexible coupling. The
propeller is mounted on the upper propeller shaft of the front gear.
The front gear is attached to a milled aluminium suspension, which is supported by 4 shock mounts in the
fuselage front frame to reduce vibrations. The cut-outs in the front frame for the shock mounts are sealed by
rubber adapter shapes.
