TM 1-1500-204-23-5
(4) Bonds and bonding. Bonded blades have
components which are lapped or covered by metallic or
fibrous substances to increase strength and solidity.
Bonded assemblies typically consist of the spar, fairing
assemblies, nose and transition cap, trailing edge, and
trim tabs.
d Blade Classification Data. The data plate on a
main rotor blade usually contains the manufacturers name
and blocks in which the following information is contained.
(1) Part number. This is the number
assigned to the particular type of blade. It is used for
ordering new blades.
(2) Revision. This is normally an alpha
character that is added when the blade is modified.
(3) Serial number. This is the number assigned to each
blade so it can be tracked by flying hours, length of time
installed, repairs made, and similar information.
3-8. Tall Rotor Hubs The function and types of tail rotor
hubs are discussed herein.
a. General. The tail rotor hub and blade assembly
counteracts the torque of the main rotor and also provides
directional control.
Table 3-1. Main Rotor Blade Terms
TERM
DEFINITION
Blade planform
The contour of a blade as viewed from above.
Blade twist
The amount of offset that the chord line at the blade tip has from the chord line
at the blade root.
Blade skin
The outer surface of the blade that provides the airfoil shape.
Tip
That portion of the rotor blade that is furthermost from the rotor hub.
Root
That portion of the rotor blade that attaches the rotor blade to the rotor hub.
Leading edge
The frontmost portion of the rotor blade.
Trailing edge
The rearmost portion of the rotor blade.
Span and span line
The straight line joining the tip and root ends of the rotor blade.
Chord and chord line
The straight line joining the leading and trailing edges of the rotor blade.
Spar
The main longitudinal member or members of the rotor blade that the ribs or
spar tubes are connected to, normally D-shaped.
Doublers
Reinforcing structures which are attached to the spar to give additional strength
to the rotor blade.
Top of blade
The uppermost surface of the rotor blade.
Bottom of blade
The lowermost surface of the rotor blade.
Rotor blade stations
Reference points on the rotor blade which are measured, usually in inches, from
the center of the rotor hub.
3-8
