Nose steering systems are hydraulically actuated
and can be either electrically or mechanically
controlled. The steering actuator serves the dual
function of providing steering and dampening (when
steering is not engaged).
ELECTRICALLY CONTROLLED
NOSE STEERING SYSTEM
This type of nose steering system is an electrically
controlled, hydraulically actuated system which
provides power steering. When not engaged the system
provides automatic nose gear shimmy dampening.
The nose gear is steered by an electrically
controlled, hydraulic powered steering cylinder which
is mounted on the nose gear recoil strut. The cylinder is
connected through mechanical linkage to an
eccentrically mounted drive stud on the recoil strut inner
cylinder.
MECHANICALLY CONTROLLED
NOSE STEERING SYSTEM
This nose steering system is mechanically con-
trolled and hydraulically actuated in much the same
manner as an electrically controlled nose steering
system. The steering actuator is of a different design but
serves the same dual function of providing steering and
dampening, when steering is not engaged.
NOSEWHEEL STEERING
SYSTEM COMPONENTS
The nosewheel steering system provides directional
control of the aircraft during ground operation in two
modes of operation. These modes are nosewheel
steering and shimmy dampening.
Operation
Steering on the typical aircraft is accomplished by
swiveling the lower portion of the nosewheel shock
strut. A rotary-vane type of hydraulic steering unit is
mounted on the fixed portion of the shock strut, and is
linked to the swiveling portion to which the nosewheel,
or wheels, arc attached. The nosewheel steering power
unit, shown in figure 12-13, uses gears. The steering
range varies with each aircraft. For specific degrees of
steering range for a particular model of aircraft, you
must consult the applicable MIM. For turns requiring a
greater steering angle, the pilot can usually use
differential braking, in which case the steering unit is
Figure 12-13.-Nosewheel steering power unit.
automatically disengaged and the nosewheel, or wheels,
swivel freely.
A typical hydraulic steering unit (fig. 12-14) has
built-in valves and a follow-up system, and auto-
matically reverts to the shimmy damper mode when not
being used as a steering actuator. The valve varies with
the type of aircraft. One method is by means of
mechanical linkage tied directly to the rudder pedals.
Gearing, through a caroming arrangement, gives the
necessary sensitivity range, permitting satisfactory
maneuvering of the aircraft through all speed ranges and
turn rates.
Methods of arming or activating the steering
systems of the various aircraft used in naval aviation are
numerous, and for convenience, a typical aircraft that
has capabilities for both land- and carrier-based
operations is discussed.
During land-based operation, steering is armed or
activated by the pilot. During shipboard operations, the
12-12
