224 DICTIONARY OF AVIATION
swirl swsizl tr. [past participle and preterit swirled, swirld] whirl thru the air; send whirling.
switchback 'swit$,baek adj. characterized by back^and^forth or alternate motion thru the air; zigzag: as, *stuitchback hovenngs; the *switchback theory; a *switchback flight* path.
switchback 'siuitS/baek n. a switchback flight; an aerial zig- zag.
swoop swuup 'v. [past participe and preterit swooped, swoopt]
1. intr. rush or sweep downward; as a hawk or other bird of prey does upon its quarry or victim; descend swiftly and at a sharp incline thru the air; stoop.
2. tr. descend upon suddenly and swiftly and seize while en the wing; take or capture with a downward sweep.
swoop swoup n. a sudden pouncing or downward sweeping movement in flight : as, the *swoop as a feature in aerial warfare.
sympiesometer ,simpi-i'semi-t3z n. an instrument for mesuring the pressure of a current; also, a form of barom- eter.
��tack taek n. a temporary change of a few points in the di- rection of sailing, as in erder to take advantage of a side*: wind; one of a series of movements of a water^ship to star- board and port alternately out of the general line of her course.
tack taek intr. change the course of a ship, as by turning her hed toward the wind, etc.; shift one's course, veer.
tacking 'taekirj n. the action of the verb tack; veering.
tail tee! n.
1. the posterior extremity of an animal, especially when consisting of an appendage prolengd beyend the rest of the body; the caudal appendage; the cauda; also, in birds, the tail^f ethers, collectivly; any appendage resembling the tail of an animal or bird, or placed in a similar relativ posi- tion; a rear extremity.
tail of the wing, see under wing 1 (sense i).
2. the cerd or stjip with pieces of paper or other mate- rial knotted to it at intervals, attacht to the lower part of a kite; a balancmg?tail.
3. an aerofoil or other part attacht to and extending out behind a flymg^machine and used as an aid in balancing or steering, or as a support for some balancing* or steer- ing?device; sometimes, specifically, a rear henental plane
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