end of the ball screw (screw jack shaft) and
mechanical stops on the actuator body protect the
actuator against possible overtravel during flap
extension and retraction.
Figure 9-36.Flap actuator.
switches shut the electric motor off when the flaps
reach the 40-degree down and full up positions.
FLAP ACTUATOR.The flap actuator shifts
rotary motion of the input shaft to linear flap motion,
using bevel gears and the ball screw jack mechanism.
See figure 9-36. A load-sensing device in each flap
actuator operates a clutch assembly to stall out the
flap system if it is overloaded. An impact plate at the
OFFSET GEARBOXES.The eight offset
gearboxes in the flap system transmit power produced
by the flap drive gearbox around wing structure
obstacles and compensate for wing angularity. They
also reduce the flap drive gearbox speed of 1,080 rpm
to about 550 rpm at the outboard actuators.
FLAP WING-FOLD SHAFT.A wing-fold
shaft consists of two interlocking splined sections and
two universal joints connected to quill shafts. It
provides a telescoping fold joint in the flap drive
system linkage between the inboard and outboard
The slat system, shown
additional lift and stability
speeds in the same manner
in figure 9-37, provides
to the aircraft at lower
as the leading edge flap
Figure 9-37.Slat drive system.