- Industry: Aviation
- Number of terms: 16387
- Number of blossaries: 0
- Company Profile:
Aviation Supplies & Academics, Inc. (ASA) develops and markets aviation supplies, software, and books for pilots, flight instructors, flight engineers, airline professionals, air traffic controllers, flight attendants, aviation technicians and enthusiasts. Established in 1947, ASA also provides ...
A type of valve lifter in a reciprocating engine that uses a hydraulic device to keep all clearance out of the valve train. Each time an intake or exhaust valve is opened, a specific amount of oil leaks from the hydraulic valve lifter, and while the valve is closed, engine oil pressure refills the lifter so it keeps all of the operating clearance out of the valve mechanism.
Industry:Aviation
A type of variable resistor used in some electrical equipment.
A carbon pile is made of a stack of thin, pure carbon disks whose resistance is changed by varying the pressure on the stack.
Carbon piles are used as the control element in some types of voltage regulators. They are also used for dissipating (using up) large amounts of electrical power in certain types of electrical load banks and test equipment.
Industry:Aviation
A type of vertical speed indicator that compensates for the lag inherent in these instruments. When the aircraft pitches at the beginning of a climb or descent, two accelerometer-actuated air pumps inside the instrument case send a change of air pressure into the indicating bellows to start the pointer moving in the correct direction. As soon as the aircraft actually begins changing altitude, the change in static air pressure actuates the instrument mechanism.
Industry:Aviation
A type of vibration isolator used between a moving vehicle and a component sensitive to vibration. Shock mounts allow the component a certain degree of free movement, but absorb the high-frequency vibrations that are so destructive to delicate mechanisms.
Industry:Aviation
A type of visual display used in digital watches, computers, calculators, and some of the newer aircraft instruments. An extremely thin layer of a normally transparent liquid crystal material is sealed between two sheets of glass. The outsides of the two pieces of glass are coated with an electrically conductive oxide. The oxide coating on one side of the glass is etched to form the segments of letters and numbers, and each segment is connected by a printed circuit lead to a connector at the edge of the display.
The back of the display is covered with a reflecting material, and a piece of transparent polarizing material is placed over the display to polarize the light passing through it. When light is polarized, all its waves vibrate in the same plane.
When a voltage is placed between the oxide coatings on the two sides of the display, the molecules in the liquid crystal material arrange themselves in such a way that the polarized light cannot pass through them. The liquid crystal material under the segment having voltage on it shows up as though it were black against the reflected background.
Industry:Aviation
A type of visual fuel-quantity indicator used on large aircraft to measure the amount of fuel in a tank. The drip stick, which is normally locked in the tank in its up position, is unlocked and slowly pulled down from the bottom of the tank. The bottom of the drip stick is watched until the first drips of fuel come from it. At this point, the top of the drip stick is level with the top of the fuel in the tank.
Marks on the outside of the drip stick at the point it leaves the tank show the amount of fuel in the tank.
Industry:Aviation
A type of voltage regulator used in an aircraft electrical system to control the output voltage of an alternator. A zener diode senses the alternator output voltage, and power transistors control the amount of current flowing through the alternator field coil.
A transistor voltage regulator is not the same as a transistorized voltage regulator. In a transistorized voltage regulator, the alternator or generator output voltage is sensed by an electromagnetic relay. Only a small amount of current flows through the relay contacts, just the base current of an output transistor that controls the larger alternator field current.
Industry:Aviation
A type of warning system that warns the flight crew that an engine nacelle or wheel well is too hot for normal operation, but there is no localized high temperature that indicates the presence of a fire.
Industry:Aviation
A type of welded joint in which the pieces of metal to be joined are placed so their edges touch, but do not overlap. The edges of both pieces of metal are melted, and filler rod is added to form a bead between the two pieces.
Industry:Aviation
A type of wheel brake that uses the momentum of the aircraft to increase the friction applied by the brake. The brake drum is a hollow cylinder, turned by the wheel that rides over the brake shoes.
Brake linings, made of a material with a high coefficient of friction, are bonded to the surface of steel brake shoes and are pressed against the inside of the drum by the piston in a hydraulic brake cylinder. When the brakes are not being applied, a spring holds the shoes away from the drum. When the pilot depresses the brake pedal, hydraulic fluid forces the piston out and moves the shoe against the drum. The shoe is mounted in such a way that when it contacts the rotating drum, friction wedges it tightly against the drum. Movement of the aircraft increases the friction produced by the brake.
Industry:Aviation
