the Aviation Dictionary

bastard file . bead welds
weave is less stable than the plain weave but produces
a flatter and stronger - fabric. It is also a more pliable
fabric than the plain weave and maintains a certain
degree of porosity.
bastard file - A double-cut, metal-working file that has
coarse cutting teeth. There are five grades of cuts fiom
the coarsest to the finest: coarse cut, bastard cut,
second cut, smooth cut, and dead-smooth cut.
batch - In composites, material that was made with the
same process at the same time having identical
characteristics throughout. Also referred to as a lot.
bathtub capacitor - A bathtub-shaped capacitor that is
sealed in a metal container.
battery - A device made up of a number of individual
cells used to store electricity by converting it into
chemical energy. Electrons are caused to flow from one
pole, the anode, to another pole, the cathode, by a
chemically produced potential difference.
battery analyzer - A transformer rectifier unit used to
charge nickel-cadmium batteries. The analyzer has a
built-in load bank as well as timers, indicators, and
controls for deep-cycling and recharging these
batteries.
battery bus - The electrical tie point in an airplane
where power from the battery is distributed to the
various loads.
battery charger - A power supply that converts
alternating current into direct current for charging
batteries.
battery chargerlanalyzer - A power supply that
converts alternating current into direct current for
charging batteries. The chargerlanalyzer is a special
device with a timer, load bank, and monitoring
equipment for complete servicing of aircraft batteries.
battery ignition system - An ignition system that uses a
battery as its source of energy, rather than a magneto.
This system is similar to that used in an automobile. A
cam driven by the engine opens a set of points to
interrupt current in a primary circuit. The resulting
collapsed magnetic field induces a high voltage in the
secondary circuit, which is directed by a distributor to
the proper cylinder.
baud - In computers, a measure of data transmission
rate. One baud is equal to one bit per second.
bauxite - A clay-like substance that is the source of
aluminum. To extract the aluminum, the bauxite is
changed into alumina (aluminum oxide). Then the
alumina is reduced to metallic aluminum by an
electrolytic process.
bay - Any specific compartment in the body of an
aircraft. It may also refer to a portion of a truss, or
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fuselage, the area between adjacent bulkheads, struts,
or frame positions.
bayonet - Something that is detachable and can be
easily put on or removed.
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bayonet exhaust pipe - The elongated and flattened end
of the exhaust pipe of a reciprocating engine. It is
designed to minimize exhaust noise prevent exhaust
valve warpage by maintaining a relatively constant
temperature at the exhaust ports of the cylinders.
bayonet exhaust stack - See bayonet exhaust pipe.
bayonet gauge - A dipstick-type gauge used to measure
the quantity of a liquid such as oil or hydraulic fluid.
bayonet thermocouple - A thermocouple used to
indicate engine temperature. The bayonet probe fits
into an adapter that is screwed into the cylinder.
bayonet thermocouple probe - A pickup for cylinder
head temperature that presses into an adapter screwed
into the side of a cylinder head. Used for measuring
cylinder head temperature on an air-cooled aircraft
engine.
B-battery or B-power supply - In electronic vacuum
tubes, positive plate voltage is called B+ voltage. The
source of voltage for these plates is referred to as B-
battery or B-power supply.
beacon - See radar, nondirectional beacon, marker
beacon, airport rotating beacon, aeronautical beacon,
and/or airway beacon.
bead - 1. A trough-like impression formed in a sheet
metal member for the purpose of stiffening the
member. 2. A raised rounded ridge formed near the end
of a piece of rigid tubing. A hose is slipped over the
end of the tube, then the hose clamp is installed
between the end of the hose and the bead. The bead
keeps the tube from being pulled from the hose.
bead heel - On tires, the outer bead edge that fits against
the wheel flange.
bead seat area - The highly stressed portion of a wheel
where the bead of the tire seats against the wheel.
bead thermistor - A component in a fire detection
system that signals the presence of a fire or an overheat
condition. The heads in the detector are wetted with a
eutectic salt, which possesses the characteristic of
suddenly lowering its electrical resistance as the
sensing element reaches its alarm temperature. The
lowered resistance starts the fire-warning procedure by
turning on the fire-warning light and sounding the firewarning
bell.
bead toe - On tires, the inner bead edge closest to the
aircraft tire center line.
bead welds - The part of a weld that joins edges of
metal parts that have been heated and melted together