the Aviation Dictionary

ethylene dibromide - expansion turbine
ethylene dibromide - A chemical compound of
bromine that is added to aviation gasoline. Used to
convert the lead deposits ffom the tetraethyl lead into
lead bromides that are volatile enough to vaporize and
pass out the exhaust rather than foul the spark plugs.
ethylene glycol - A viscous form of liquid alcohol
(C2HS02) used as a coolant for high-powered, liquidcooled
engines.
eutectic metal - A metal alloy whose melting point, due
to the proportion of its components, is lower than
would be possible before the mixture of the
components.
evacuated bellows - A set of bellows from which most
of the air has been removed and the bellows sealed.
They serve as the sensitive element in an aneroid
barometer for measuring atmospheric pressure.
evaluation - Measures a demonstrated performance
against a criteria or standard, such as a grade of at least
70% to pass a written test. Formal evaluations are
typically in the form of written tests, oral quizzing, or
check flights, and are used to measure performance and
document whether the course objectives have been
met.
evaporation - Change of state from liquid to vapor.
evaporator - The unit in a vapor-cycle air conditioning
system in which liquid refrigerant absorbs heat from
the cabin to change the refrigerant into a vapor. Air
blown over the evaporator loses its heat and is cooled.
execute missed approach - Instructions issued to a pilot
making an instrument approach which means continue
inbound to the missed approach point and execute the
missed approach procedure as described on the
lnstrument Approach Procedure Chart or as previously
assigned - by ATC. The pilot may climb immediately to
the altitude specified in the missed approach procedure
upon making a missed approach. No turns should be
initiated prior to reaching the missed approach point.
When conducting an ASR or PAR approach, execute
the assigned missed approach procedure immediately
upon receiving instructions to "execute missed
approach." (Refer to AIM)
exercise - A principle of learning that those things most
often repeated are best remembered.
exhaust contrails - Forms when the water vapor added
from an aircraft exhaust is sufficient to saturate the
atmosphere.
exhaust gas temperature (EGT) - In gas turbine
engines, temperature taken at the turbine kxit. Often
referred to as T,7.
exhaust manifold - A pipe with several apertures used
to collect exhaust gases from reciprocating engines.
The manifold attaches to the individual exhaust ports
and carries the exhaust gases overboard through a
common discharge.
-
exhaust nozzle - The rear opening of a turbine engine
exhaust duct. The nozzle acts as an orifice, the size of
which determines the density and velocity of the gases
as they emerge from the engine.
exhaust port - The hole in the cylinder of a
reciprocating engine through which the exhaust gases
are expelled.
exhaust stacks - The short, individual pipes attached to
the exhaust ports of the cylinders of reciprocating
engines, through which the exhaust gases are
discharged - overboard.
exhaust stroke - The stroke of the Otto cycle where the
exhaust gases are forced out of the cylinder as the
piston is moving - away from the crankshaft and the
exhaust valve is open.
exhaust valve - The valve in an aircraft engine cylinder
through which the burned gases leave the combustion
chamber.
exit guide vanes - The fixed airfoils at the discharge
end of an axial flow compressor that straighten - out the
swirling air caused by the rotating rotors so that the air
leaves the engine in an axial direction.
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expand - To increase the dimensions of.
expanded plastic - The increase in the volume of
plastic resin generated when the materials that make up
the plastic are mixed. The volume is increased by gas
bubbles.
expander-tube brake - A nonservo brake in which the
composition blocks are forced out against a rotating
drum by hydraulic fluid, expanding a synthetic rubber
tube on which they rest.
expansion boots - Inflatable deicer boots.
expansion coefficient - A number that describes the
change in linear dimensions of a material with a
specified change in its temperature.
expansion reamers -
A precision cutting O\,
tool used to enlarge
and smooth the inside
circumference of a
drilled hole. The
diameter of the reamer
can be changed by an adjustable wedge inside the
blades.
expansion turbine - A turbine wheel in an air-cycle air
conditioning system used to extract some of the energy
from the bleed air. The energy of the bleed air drives
the turbine and the air is further cooled by expansion.
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