the Aviation Dictionary

hurricane eye hydroplaning
hurricane eye - The circular, nearly cloud free region
approximately 10 to 20 nautical miles in diameter,
located in the center of the storm.
hurricane warning - The warning issued within 24
hours of the arrival of hurricane conditions.
hurricane watch - Issued when hurricane conditions
are expected in a particular area within a day or more.
hybrid - In composites, the combination of two or more
types of reinforcing materials into the composite
structure.
hydraulic booster unit - A unit for moving the flight
controls in a large, high-speed aircraft. It is actuated by
the normal cockpit controls but greatly amplifies the
force the pilot exerts.
hydraulic brake - An aircraft brake operated by means
of hydraulic fluid under pressure.
hydraulic filter - A unit that removes foreign particles
from the hydraulic system.
hydraulic fluid - A liquid used to transmit and
distribute forces to various units being actuated.
hydraulic fuse - A unit designed to stop the flow of
hydraulic fluid if a leak occurs downstream of the fuse.
hydraulic lock - A condition that occurs in a
reciprocating engine having cylinders below the
crankcase. Oil leaks past the piston rings and fills the
cylinder with an incompressible fluid. The engine
cannot then be rotated without damage.
hydraulic motor --
hydraulic fluid.
-
A motor driven by a flow of
hydraulic pump - An engine-driven, electric
motor-driven, or hand-operated pump used to move
hydraulic fluid through a system.
hydraulic reservoir - A container for the hydraulic
fluid supply in an aircraft.
hydraulic system - An aircraft's entire fluid power
system, including the reservoir, pump, control valves,
actuators, and all of the associated plumbing.
hydraulic valve lifter - The hydraulic units in the valve
train of a reciprocating aircraft engine used to
automatically adjust for any changes in dimensions of
the engine caused by expansion and also to keep the
operating clearance in the valve mechanism at zero.
hydraulics - The branch of science that deals with the
transmission of power by incompressible fluids under
pressure.
hydrocarbon - An organic compound that consists
mostly of carbon and hydrogen. The vast majority of
our fossil fuels, including gasoline and turbine fuel, are
hydrocarbons.
hydrodynamics - The study of forces produced by
incompressible fluids in motion.
hydrofoil - An airfoil-shaped plate attached to the
- bottom of an airplane or boat that lifts the vehicle out
of the water by hydrodynamic action when the vehicle
is moved through the water at high speed.
hydrogen - A basic element with a symbol of H and an
atomic number of 1. In chemical formulas, free
hydrogen appears as H2 because there must be two
atoms of hydrogen to form one molecule of free
hydrogen gas.
. - -
hydrogen bomb -A nuclear weapon that produces heat
and light from the fusion of hydrogen atoms.
hydrogen brazing - Braze welding in which hydrogen
is used as the fuel gas.
hydrogen embrittlement - A brittle condition caused
by the metal absorbing hydrogen while it is being
electroplated.
hydrogen fuel - A proposed jet fuel of the future that
could be stored as a gas or cryogenic liquid. The
present high cost and storage problems prevent its
current use.
hydrogen peroxide - H20L, An compourld used
as an oxidizing agent, antiseptic, and a fuei for rocket
engines.
hydmlogieal cycle - The movement of moisturt from
the earth to the atmosphere and back to the earth again.
hydromechanical fuel control - A fuel control that
utilizes hydraulic and mechanical forces to operate its
fuel scheduling mechanisms.
hydrometeor - Atmospheric water vapor. Liquid or
solid water formation that is suspended in, or falling
from, the air, including clouds, fog, ice fog, mist, rain,
and hail also any water particles blown by the wind
from the Earth's surface.
hydrometer - A device used to
measure specific gravity of a
liquid. It consists of a weighted
float with a long stem in the
enlarged glass tube of a
syringe. Liquid is pulled up
into the tube and the float rides
vertically on the surface. The
amount the float is submerged
is a function of the density of
the liquid. The number on the float's stem opposite the
liquid level is the specific gravity.
hydroplaning -A condition that exists when landing on
a surface with standing water deeper than the tread
depth of the tires. When the brakes are applied, there is
a possibility that the brake will lock up and the tire will
ride on the surface of the water, much like a water ski.
Aircraft Technical Book Company
P.O. Box 270
Tabernash, CO 80478
http:llw.ACTechbooks.com