TWIST—Rotation of the suspension line
casing induced generally during final assembly of
the canopy, suspension lines and connector links.
TWIST OF THREAD OR CORD—The
direction (right or left) in which the strands of
thread or cord are wound around one another.
If the thread unwinds when turning it to the left,
it is right twist; if it tightens, it is left twist. Right
twist is also known as Z-twist. Left twist is also
known as S-twist.
TYP—Abbreviation for typical.
UNDERFOLD—Insufficient cloth folded
inside a seam. The raw edges of cloth will show
when underfold is excessive.
UNEVEN STITCHING—Stitching wavy, or
number or stitches varying.
UNTACK—To remove a tacking. See also
TACKING.
V-RING—A metal fitting shaped in the form
of a closed letter V. For example, V-rings, used
with quick-ejector snap fittings, secure a harness
assembly on a wearer.
V-TAB—Webbing reinforcement at the point
where the suspension line enters the canopy.
VENT—The circular opening at the peak or
top of the canopy. As the parachute opens and
descends, some of the air in the canopy escapes
through this vent, thus reducing the strain on the
canopy and steadying descent. It is about 18
inches in diameter for personnel parachutes.
WARNING—Indicates danger to personnel.
The warning precedes the step or item to which
it refers.
WARNING FLAG—A tag attached to
an assembly, indicating that the assembly is
not operational. Often the flag is attached to
safety-pins on pyrotechnic devices to indicate
necessity of removal before operation. Also, it is
used to flag defective or incomplete equipment
to preclude use.
WARP—The threads that run parallel to the
selvage edge of cloth; those that are crossed by
the filling threads.
WEAVE—To manufacture a web or cloth on
a loom by interlacing the warp and filling yams.
Also the particular pattern employed in weaving
cloth. The cloth for parachute use is one up and
one down (plain weave), two up and one down
(twill weave) or ripcord.
WEAVE SEPARATION—Looseness of
weave caused by strain or poor weaving.
WEB (WEBBING)—A strong, narrow,
closely-woven tape of synthetic, cotton, or linen
fiber designed for bearing weight. For example,
it is used in the manufacture of the parachute
harness.
WEBBING, ELASTIC—A webbing having
elastic threads to give it greater elasticity than
regular webbing. It is used in the fabrication or
elastic ripcord pockets.
WEBBING, REINFORCEMENT—Short
lengths of webbing sewn to the skirt hem at the
junction points of the suspension lines and the
canopy.
WEBBING, TUBULAR—Strong synthetic or
natural fiber webbing woven in the form of a tube.
WET LOCKER—A tower or compartment
maintained for hanging parachutes that are damp
or have been immersed in water.
WHIPSTITCH—A stitch used to join two
piece of webbing and to reinforce weak seams.
WHISKER—A thread filament protruding
from cloth.
YOKE AND PLATE ASSEMBLY—The
removable end of connector link.
AI-17
