Page:Dictionary of aviation.djvu/51

 DICTIONARY OF AVIATION 27

same vertical plane and tangent to the advancing edge of the aerofoil ; the entrant angle ; the leading^angle : the eppo- sit of angle of trail.

angle of impact, same meaning as angle of incidence.

angle of incidence, the angle at tuhich an aerofoil, as a whole, strikes or impinges upon the air; the angle umich the sustaining^planes of an aircraft, in entering the air, make with the apparent direction of the air^current; the angle formd by the line of motion of an aerofoil with the line (or chord of the curv) of intersection of the aerofoil with the vertical plane passing thru the aerofoil's line of motion; the angle of impact; the angle of attack.

angle of the vertical, see under vertical (noun).

angle of the wing, see under wing (noun, sense i).

angle of trail, the angle at tuhich the rear edge of an advancing aeroplane or aerocurv trails or is drawn along thru the air as it leaves it behind; the angle at tuhich the following edge of an aerofoil leaves or comes out of the air; the angle fermd by the line of motion of an aerofoil with a line in the same vertical plane and tangent to the following edge of the aerofoil ; the tjailmg^angle : the oppo- sit of leadingtangle and angle of entry.

carpal angle, the bend or flexure of a bird's wing; the angle of the wing; the bend.

entrant angle, same meaning as angle of entry.

law of the angle, the law relating to the angle of inci- dence at tuhich a wing or aerofoil is presented to the air.

negative angle of incidence, the angle of incidence of an aerofoil whose line of motion slants downward or below the horizontal; the negativ angle of inclination of the line of flight of an aeroplane or aerocurv.

negative angle of inclination, the angle of the inclina- tion of an aerofoil, or of its line of flight, when it slants or slopes downward, or below the horizontal.

optima angle, the best or most advantageous angle of incidence at tuhich a wing, aeroplane, or aerofoil may be presented to the air.

positive angle of inclination, the angle of the inclination of an aerofoil, or of its line of flight, u)hen it slants or slopes upward, or above the horizontal. antenna ,aen'ten3 n. [plural antennae! a receivingsdevice

used in wireless telegrafy. antennae ,sen'te,ni n. pi. see antenna.

anthelion ,aen'0ii-li-9n n. [ploral anthelia] a luminous and usually colord ring or nimbus seen (single or in concentric series) surrounding the shadow of the observer's hed pro-

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