wing head has fewer grease fittings, because oil
ethyl ketone. Protect bearings and Thomas
reservoirs (tanks) are used on the hub plate at the
couplings from solvent and dirt. Blend out the
vertical hinges. These reservoirs lubricate upper
damaged area using crocus cloth. The blend radius
and lower hinge bearings and the stack bearings
must not exceed specified limits, Wipe the area
in sleeve spindles.
with a clean cloth moistened with methyl ethyl
Principal parts of the head are the hub and
ketone. Prime the area with zinc chromate primer,
swashplate. The hub consists of a hub plate, lower
and touchup with matching paint.
plate, and hinges between each arm of the plates.
NOTE: Limit your repair of the drive shaft
The hub contains sleeve spindles that are attached
to the outside diameter of the tubular
to the hinges and damper-positioners. The
shaft. Repair must be done in the scratched
swashplate consists of a rotating swashplate and
area only.
a stationary swashplate. The rotary wing head
has antiflapping restrainers, droop restrainers,
ROTOR SYSTEMS
adjustable pitch control rods, and the rotating and
The rotor system consist of the main rotor
stationary scissors. The swashplate and adjustable
head, main rotor blades, tail rotor head, and tail
pitch control rods permit movement of the flight
rotor blades. This section on rotor systems
controls to be transmitted to the rotary wing
discusses the general components and identifies
blades. The hinges allow each blade to lead, lag,
some of the different features or materials being
and flap. The damper-positioners restrict lead and
used.
lag motion and position the blades in preparation
for folding. Sleeve spindles allow each blade
MAIN ROTOR HEAD
rotation on its spanwise axis to change blade pitch.
The antiflapping restrainers and droop restrainers
The fully articulated rotary wing head is
restrict flapping motion when the rotary wing
splined to the rotary wing shaft of the main gear-
head is slowing or stopped. The control lock
box. The head is supported by the rotary wing
cylinder unlocks to permit the sleeve to turn about
shaft. The head supports the rotary wing blades,
the sleeve spindle axis. The stationary scissors are
connected to the stationary swashplate and main
The head transmits movement of the flight
gearbox upper housing. The rotating scissors are
controls to the blades. Its design permits
connected to the rotating swashplate and lower
automatic folding of the blades from a control
hub plate.
panel in the cockpit.
There are two types of rotary wing heads in
MAIN ROTOR BLADES
use. They are the grease-lubricated and self-
The rotary wing blades provide the lift
lubricating heads. See figure 7-17. The grease-
necessary for flight. See figure 7-18. The blades
lubricated rotary wing head contains grease
are of the nitrogen-pressurized spar type. The
fittings for lubrication. The self-lubricated rotary
Figure 7-18 .-Rotary wing blade.
7-21
