the Aviation Dictionary

ball peen hammer. barometer
ball peen hammer - A hammer with one side of its
head shaped like a ball.
ballast - 1. Permanently installed weight in an aircraft
used to bring the center of gravity into the allowable
range. 2. An electrical circuit component designed to
stabilize current flow. 3. In gliding, used to describe
any system that adds weight to the glider. Performance
ballast employed in some gliders increases wing
loading using releasable water in the wings (via
integral tanks or water bags). This allows faster
average cross-country speeds. Trim ballast is used to
adjust the flying CG, often necessary for light-weight
pilots. Some gliders also have a small water ballast
tank in the tail for optimizing flying CG.
ballast lamp - A resistance-type lamp connected into a
circuit in a series in order to maintain a constant
current. As current increases, the filament gets hotter
and creates a higher resistance, lowering the current
until a balance (and constant current) is achieved.
ballistic missile - A self-propelled long-range missile,
which is guided by preset mechanisms as it goes
upward, but is free falling as it comes down.
balloon - A lighter-than-air, non-steerable aircraft that is
not engine-driven. Its rising capability comes from
gases or hot air that fill the gas envelope.
balsa wood - The light, strong wood of the balsa, a
tropical tree. It is sliced across its grain and
sandwiched between two face sheets of thin metal or
fiberglass to make rigid, lightweight panels.
balun - A transformer used to match a balanced antenna
to an unbalanced transmission line.
bamboo - A species of tree consisting of light weight,
strong, tubular sections. Used in some early aircraft
construction.
banana plug - A mechanism used to make a temporary
connection to an electrical circuit. The contacts of a
banana plug are springs that have the general shape of
a banana. These springs press out against the walls of
the banana jack in order to make a low-resistance
contact.
band - A range of electro-magnetic frequencies.
band saw - A controllable-speed power saw used to cut
wood, plastics, or metal. The band saw blade is in the
form of a narrow strip of steel with teeth along one
edge. The ends of the blade are welded together to
form a continuous loop, and the loop passes bver two
large wheels, one above the saw table and the other
below the table.
band-pass filter - An electronic filter that passes a band
of frequencies while rejecting all frequencies above or
below the band.
band-reject filter - An electronic filter that rejects a
specific band of frequencies while passing those above
and below the band.
bandwidth - The difference between the maximum and
minimum frequencies in a band.
bank - To incline or tilt an airplane about its
longitudinal axis.
bank indicator - A flight instrument consisting of a
curved glass tube filled with a liquid similar to
kerosene and enclosing a round ball. When the aircraft
is horizontal, the ball is located in the lowest part of the
tube; as the aircraft banks, gravity holds the ball at the
lowest point as the tube rotates from side to side. The
tube can be calibrated to show the angle of banking. It
can also indicate the relationship between the force of
gravity and centrifugal force in a turn. If the bank angle
is correct for the rate of turn, the ball will stay in the
center of the tube. However, if the angle of bank is too
steep for the rate of turn, the hall will roll to the inside
of the turn. If the angle of bank is not steep enough for
the rate of turn, the ball will roll to the outside of the
turn. A bank indicator is built into the face of a turn
and slip indicator.
bar - A metric unit of pressure equal to 1,000,000 dynes
per square centimeter. Pressure is often measured in
meteorological services in millibars, which is 1/1,000 of a
bar. The standard absolute pressure of the atmosphere
at sea level is 1013.2 millibars.
bar folder - A forming machine used for making bends
or folds along edges of metal sheets. It is best suited for
folding small hems, flanges, seams, and edges. Most
bar folders have a capacity for metal up to 22 gauge
thickness.
bar graph - A graph used to show relationships
between different values. Each value in a bar graph is
represented by a bar of an appropriate length.
bare conductor - An electrical conductor that is not
protected with any type of insulating material.
barnstormers - Early aviation pioneers who traveled
from town to town piloting their planes in sight-seeing
flights with passengers or in exhibition stunts. Some
were clowns and characters, but others were more
serious and showed the promises for the future of
aircraft transportation. Barnstorming included
acrobatics and stunts such as picking up handkerchiefs
off the ground with hooks attached to the wing tips etc.
barograph - An instrument used to measure absolute
pressure. Barographs are often sealed and carried in an
aircraft in order to make a permanent record of the
altitude reached by the aircraft.
barometer - An instrument used to measure
atmospheric pressure. Used in forecasting weather or
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