chamois skin. A piece of soft, pliable leather, from the skin of a chamois, a goat-like antelope. Chamois skin is used to filter gasoline. Gasoline will pass through a chamois skin, but water will not. Gasoline that has been filtered through a chamois skin can be considered to be free from water.
chandelle (airplane maneuver). A maximum performance flight maneuver used in pilot training to develop skill in control and coordination.
The airplane is put into a maximum-rate climb and turned in such a way that its heading changes 180° by the time the airspeed drops off to a given value.
change of state (meteorology). The transformation of water from one form into another. Five changes of state are designated by these terms:
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Condensation is the change of water vapor into liquid water.
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Evaporation is the change of liquid water into water vapor.
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Freezing is the change of liquid water into solid water (ice).
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Melting is the change of ice into liquid water.
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Sublimation is the change of ice into water vapor or water vapor into ice.
Channel-Chrome cylinders. The registered trade name for reciprocating engine cylinders whose walls are plated with hard chromium by a patented process. The surface of this chrome plating forms a spider web of tiny stress cracks. After the plating is completed, deplating current is used to enlarge the cracks and form channels that hold lubricating oil on the cylinder wall.
channel iron. A form of extruded steel whose cross section is in the shape of the letter U. Extruded steel is formed by forcing it through a specially shaped die.
channel section (structural material). A structural material having the cross-sectional shape of a channel, or the letter U. A channel section can be formed (bent) from a flat sheet of metal, or it can be extruded (squeezed through a specially shaped die).
channel wing (aeronautics). A special type of airplane wing made in the form of half of a cylinder. The upper camber of the airfoil section of the channel wing is on the inside of the cylinder, and it forms one half of a venturi. The propeller is installed in such a way that it pulls air through the channel, across the top of the airfoil, and produces lift even when the aircraft has almost no forward speed.
Channel wing aircraft have flown, but technical difficulties have prevented them from becoming popular.
charcoal. A form of black, porous carbon. Charcoal is made by charring, or partially burning, wood in a kiln (a special type of oven) in which there is not enough air for the wood to burn completely.
charge (electrical condition). A condition in which there is an excess or deficiency of electrons on a body. If there is an excess of electrons, the charge is negative. A deficiency of electrons results in a positive charge.
charging a battery. The process of restoring the active material on the plates of a battery to a condition that allows it to convert chemical energy into electrical energy. When a battery is discharged, the active material on the plates changes its chemical composition, and when the battery is charged, this material is restored to its original condition.
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