Maintenance Manual STEMME S10-VT
Date of Issue: Jan. 01, 1998
Page 3-8
Amendment Nr. 0
Date: --
A4011121_B23.doc
Doc. No. A40-11-121
3.3 Flight Control System
Longitudinal Control
(figure 3.3.a)
Both control sticks are coupled by a connection tube. The control movements are transmitted via push-pull
rods to the end of the tail boom and then straight up to the elevator fitting. In the tail boom, the push-pull rod
is supported by linear motion ball bearings. Adjustable stops for the longitudinal control are installed in the
middle of the connection tube beneath the right control system cover in the cockpit. A control tube connection
in the central steel frame is linked to two symmetric springs, pushing the stick forward with an almost
constant force (down-spring to improve stability elevator free).
Longitudinal Trim
(figure 3.3.a)
Longitudinal trim is achieved by means of a slidable spring system, acting upon the connection tube of the
longitudinal control in the cockpit.
Wing Flap Control System
(figures 3.3.b and 3.3.c)
Both flap control levers are coupled by a connection tube beneath the control system cover in the cockpit.
Control inputs are transmitted from this connection tube via push-pull rods to a "mixing shaft" in the central
fuselage. From this "mixing shaft", the control inputs are transmitted via bell-crank levers, push-pull rods and
quick release couplings to the control rods in the wing. The control rods in the wing are supported by means
of linear motion ball bearings. The control movement is transmitted to the flap drive fittings via bell-crank
levers.
At the mixing unit, the wing flap control is supported by a gas spring against the central fuselage framework.
This is to minimise loads on the flap lever at appropriate airspeeds related to the respective flap setting. A
viscosity damping acting in both directions isolates shock loads from the flap lever and the flap lock-in. The
flap positions are locked at the output lever on the connection tube in a gate beneath the control system
cover.
Lateral Control
(figures 3.3.d and 3.3.e)
Lateral inputs with the control sticks are transferred via an adjustable push rod to a central bell-crank lever
beneath the connection tube of the longitudinal (elevator) control. From this bell-crank lever, control inputs
are transmitted via push rods to the "mixing shaft" in central fuselage. Via this "mixing shaft", bell-crank
levers, push-pull rods and quick release couplings, the control rods in the wing are moved. Both sides of the
central wing contain a straight-through control rod, supported by several linear motion ball bearings and
equipped with a quick release coupling (L´Hotellier) at the division of inner and outer wing. From the push-pull
rods in the outboard wing, the control movements are transmitted via two bell-crank levers to the drive fittings
of the ailerons.
By means of the "mixing shaft", the ailerons are moved together with flap position changes and the flaps are
moved together with aileron deflections. The percentage of co-movement depends on the position of the
control surfaces. Stops for aileron control inputs (adjustment screws) are located LH and RH side of the
elevator connection tube beneath the covers of the control system well in the cockpit.
Control of Air Brakes
(figures 3.3.f and 3.3.g)
The air brake-levers are coupled by means of a connection tube. Travel of the levers is transmitted via push
rods and bell-crank levers to a driving lever (elbow lever) in the centre fuselage, from which it is transmitted
via push rods and quick release couplings to push-pull rods in the wing, which then move the air brakes. The
push rods in the wing are supported by linear motion ball bearings.
The airbrakes are locked in retracted position by over-centre-locking of the elbow lever. The locked position
can be adjusted by a stop screw at the elbow lever. The fully extended position is determined by a fix rubber
stop, which one end of the driving lever butts upon when this position is reached.
Directional Control
(figure 3.3.h)
From the LH and RH rudder pedal supports, control cables are led through the central fuselage to the tail
boom entrance, where the control cables of the left pedals and the right pedals meet to be directed further to
the rudder driving lever. The rudder driving lever is connected to the tailwheel by a spring assy. The stops for
the directional control are mounted on the lower rudder support, the pertinent adjustment screws are located
at the rudder on the drive fitting.
