Page:Dictionary of aviation.djvu/77

 DICTIONARY OF AVIATION 53

equilibrium, when an airzcurrent is blowing against it; the center of pressure.

center of action, the area of high or low barometric pres- sure, which appears to be the most activ or conspicuous en a wether^map.

center of aspiration, the region in a cyclonic sterm-area where air is rising, etc.

center of bearing, the center of the surface with which an aerofeil bears en the air, or presents itself to the resist- ing force of the air; the center of surface.

center of effort, the center or peint at which the whole amount of the propulsiv effort or thrust of one or more propellers may be applied with the same effect as when distributed; the center of thrust.

center of gravity, the center or point about which all the parts of a rigid bedy or rigidly connected system of bodies exactly balance each other, and which being supported, the bedy or system will remain at rest in any position; the center of attraction; the center of mass; the center of inertia; the center of weight.

center of gyration, the center or, peint at which, if the whole mass of a revolving bedy were collected, the rotatory motion would remain the same.

center of mass, the center or peint in relation to a bedy or system of bodies, so situated that any plane which passes thru it divides the bedy or system into two parts of which the masses or weights are equal; the mass^center; the cen- ter of gravity.

center of lift, the center or peint at which the whole amount of lift or vertical component of the upward air* pressure upon an aerofoil may be applied with the same effect as when distributed.

center of motion, the center or peint in relation to a bedy, which remains at rest while all the other parts of the bedy move round it.

center of power, the region in a sterm^area or cyclone characterized by the greatest cendensation of water vapor.

center of pressure, the center or point at which the whole amount of pressure may be applied with the same effect as when distributed; the peint at which an aerofoil must be supported in order to remain in equilibrium when an air* current is blowing against it; the center of air-pressure.

center of pull, the center or point at which the whole amount of poll may be applied with the same effect as when distributed.

center ef resistance, the center or peint at which the

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