- Отрасли: 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 piece of formed sheet metal or extrusion riveted to a larger piece of thin sheet metal to give it rigidity and stiffness. Some types of aircraft sheet metal structure have large areas of thin sheet metal that vibrate and cause noise and weaken the metal. To prevent this metal from vibrating, a stiffener in the shape of a hat section, a channel, or an angle is riveted across the sheet. This stiffens it enough to stop the vibration.
Industry:Aviation
A piece of heavy metal on which such electrical components as power transistors are mounted. Heat from the component is transferred into the heat sink by conduction, and from there it is dissipated into the surrounding air. A silicone grease may be spread between the component and the heat sink to help transfer the heat.
Many heat sinks on which high-power components are mounted have fins to increase their cooling area.
Industry:Aviation
A piece of magnetizable material, such as hard steel, that has been exposed to a strong magnetizing force. This force aligns the spin axes of the electrons surrounding the atoms of the material, and thus the magnetic domains within it. When the material is removed from the magnetic field, it is magnetized and the domains remain in alignment until a strong demagnetizing force is applied.
Industry:Aviation
A piece of material or a device that has the ability to attract pieces of iron or steel and to generate an electrical voltage in a wire passing near it. A piece of ferrous metal (metal containing iron) contains billions of tiny magnetic fields, called magnetic domains. When the metal is not magnetized, these domains lie in a random fashion, and their fields cancel each other, so the metal has no overall magnetic field.
But when the metal is magnetized, the domains are aligned so all the north poles point in one direction, and all the south poles point in the opposite direction. The metal now has a magnetic field. Invisible lines of magnetic flux leave the north pole of the magnet and travel by the easiest path to the south pole. These lines leave and enter the magnet at right angles to the surface. A magnet attracts pieces of iron or steel (ferrous metals), and if a wire is moved through the lines of magnetic flux between the poles, electrons are forced to flow in it.
There are two basic types of magnets: permanent magnets and electromagnets. Permanent magnets are pieces of metal with the magnetic domains in alignment. The metal used as a permanent magnet has a high retentivity; therefore it keeps, or retains, its magnetism.
Electromagnets are made of a coil of wire wound around a core of soft iron. When direct current flows through the coil, the domains in the soft iron line up, and the core becomes a strong magnet. Iron has very low retentivity, however, and as soon as the current stops flowing in the coil, the domains in the iron core lose their alignment, and the iron is no longer a magnet.
Industry:Aviation
A piece of plywood glued to an aircraft structural member. The saddle gusset has a cutout to hold a backing block or strip tightly against the skin to allow a nailing strip to be used to apply pressure to a glued joint in the skin.
Industry:Aviation
A piece of precision electrical test equipment containing two or more sets of precision resistors mounted on ten-position rotary selector switches.
A typical decade resistance box may have one switch with resistors having values of between 0.1 and 0.9 ohm and another switch with resistors having values of between 1.0 and 9.0 ohms. A third switch may have resistors with values of between 10.0 and 90.0 ohms.
By the proper positioning of the three switches, any value of resistance between 0.1 ohm and 99.9 ohms may be selected.
Industry:Aviation
A piece of precision electrical test equipment used to measure capacitance. The bridge measures the capacitance of an unknown capacitor by comparing its capacitive reactance with that produced by a known value of capacitance.
Industry:Aviation
A piece of quartz or Rochelle salt which has piezoelectric characteristics. A piezoelectric crystal produces a voltage between two of its opposite surfaces, or faces, when it is bent or compressed. A crystal also distorts when a voltage is placed across two of its opposite faces.
All physical objects have a natural resonant frequency at which they vibrate most easily. A piezoelectric crystal will, when it is placed in an electrical circuit and excited with a pulse of electrical energy, vibrate at its resonant frequency. As the crystal vibrates, it produces an AC voltage whose frequency is the same as the resonant frequency of the crystal.
Industry:Aviation
A piece of radio communications equipment in which all of the circuits for the receiver and the transmitter are contained in the same housing.
Industry:Aviation
A piece of sheet metal used to strengthen and stiffen an aircraft skin at the location some component is to be attached. A doubler is normally riveted to the inside of the aircraft skin where a radio antenna is mounted.
Industry:Aviation
