TM 55-1520-240-23-4
5-62
ROTARY-WING BLADES
5-62
The rotary-wing blades are composite structures. They
consist mainly of a D-shaped fiberglass spar, a titanium
nose cap, and Nomex honeycomb fairing bonded to the
spar. The blades are tracked and balanced using the
AVA system. Tracking and balancing adjustments are
made by adjusting pitch links, bending the trim tab, or
adding or removing tracking or balancing weights.
SPAR
The spar is made up mainly of center and wraparound
unidirectional straps. The wraparound straps are
continuous elements. They start at the blade tip, wrap
around the vertical pin bore, and return to the tip.
The straps are covered by several layers of cross-ply
fiberglass. These help to prevent twisting. Kevlar
filament windings secure the shock absorber bracket
to the spar. A replacement composite sleeve lines the
vertical pin bore. The nose of the spar is formed around
a permanent balance weight. Tubes are provided at the
tip end of the spar for tracking weights.
LEADING EDGE
The titanium leading edge is bonded to the spar. A nickel
erosion cap is bonded over the outboard 54 inches of
the spar leading edge. The replaceable erosion cap
protects that part of the blade most easily damaged by
the elements.
FAIRING
The fairing is a Nomex honeycomb core covered by
laminated cross-ply fiberglass skin. Core and skin are
bonded to the spar at the leading edge of the core. A
wedge of fiberglass reinforces the core along its entire
trailing edge. Lightning protection is provided by wire
mesh positioned at intervals within the skin. The fairing
is closed by a rubber rib at the inboard end and sealant
at the tip end.
5-270
