the Aviation Dictionary

build-up and vent valve - A manually operated valve
on a liquid oxygen converter. In the build-up position,
is allowed to reach a preset value and excess
pressure is vented into the atmosphere. In the vent
position, gas is vented into the atmosphere without
pressure buildup.
bulb angle - An extruded angle of metal with a rounded
edge resembling a bulb on one of the legs.
build-up and vent valve . burring
burble point - The angle of attack at which burbling
first occurs on an airfoil.
burn down coat - A coat of dope with some of its
thinner replaced with retarder. The coat is sprayed on a
blushed area to soften and reflow the surface in order
to remove the blush.
burned areas - Localized areas of a turbine engine
combustion chamber liner that have been heated to an
bulb root - A means by which turbine engine rotor extent to cause visible damage. -
blades are attached to the rotor hub. The base of the
burned surface - A condition resulting from high
blade is cylindrical and larger than the rest of the blade.
surface temperatures with relatively low pressures and
This fits into a mated hole in the rotor hub.
accom~anied bv heat discoloration. This condition mav
bulb temperature - A unit of a carburetor induction or may not mark the surface. The cause is usually
system that monitors the air inlet temperature to be sure improper clearance or insufficient lubrication. Areas
the inlet temperature does not exceed the maximum affected are bearings or journals.
value specified by the engine manufacturer.
burner - The section of a turbine engine into which fuel
bulbed Cherrylock@ rivet - A special form of blind is injected and burned. The within the engine
rivet manufactured by the Cherry division of Textron where combustion occurs.
Inc., in which the stem is locked into the hollow shank
burner cans - Any number of individual combustion
by a special locking collar that swages into a groove in
the stem.
chambers in the combustion section of a gas turbine
engine.
bulb-fit - A design of compressor blade attachment to
the disk shaped in a bulb fashion.
bulkhead - A structural partition in a fuselage or wing.
Bulkheads usually divide the fuselage or wing into
bays and provide additional strength to the structure.
bumping - The shaping or forming of sheet metal by
hammering or pounding. During this process, the metal
is supported by a dolly, sandbag, or die.
bundled cable - Any number of individually insulated
electrical wires tied together with lacing cord or with
special plastic wire-wrapping straps.
bungee - A shock-absorber cord made from natural
rubber strands encased in a braided cover of woven
cotton cords and then treated to resist oxidation and
wear.
bungee cord - An elastic cord encased in a braided
cloth cover that holds and protects the rubber, yet
allows the rubber to stretch. Bungee cords are used in
some of the simpler aircraft landing gears to assist in
retracting the landing gear and to absorb shock.
buntover - The tendency of a gyroplane to pitch
forward when rotor force is removed.
buoyancy - The property of an object that allows it to
float on the surface of a liquid, or ascend through and
remain freely suspended in a compressible fluid such
as the atmosphere.
burble - A breakdown of the laminar airflow over an
airfoil caused by too high an angle of attack. The result
is an increase in drag and a loss of lift.
-
burner compartment - A section of the cowling behind
which the burner section of a turbine engine is located.
burner pressure (Pb)- Static pressure signal used as a
measure of mass airflow through the engine and sent to
the fuel control unit for fuel scheduling purposes.
burning - 1. Surface damage due to excessive heat. It is
usually caused by improper fit, defective lubrication, or
over temperature operation. 2. The combustion process
that occurs when fuel is mixed with air and ignited.
burning in - An electronic components manufacturing
process in which the equipment is operated for a
specified period of time in order to stabilize the
operating characteristics of the components.
burning point - The lowest temperature at which a
petroleum product in an open container will ignite and
continue to bum when an open flame is held near its
surface.
burnish - To polish a metal surface by rubbing it with a
smooth, extremely hard tool, called a burnishing tool.
A lubricant is usually required. Small scratches can be
smoothed by burnishing.
burnishing - The process of polishing a surface by
sliding contact with a smooth, harder surface.
Displacement or removal of metal does usually not
occur during burnishing.
burr - A sharp or roughened projection of metal usually
resulting fiom machine processing.
burring - The forming of a sharp or roughened
projection usually as a result of a machining operation.
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