218 DICTIONARY OF AVIATION
strepsiptera ,st$ep'sipt3-z9 n. pi. an order of parasitic in- sects (including the genus Styleps) the wings of the male members of which are mere twisted filaments or pseudely- ta, the females having no wings.
stretch stet$ n. reach or extent; wing-spred. see f rases under wing.
string stirj n. the line or cerd attacht to a kite and extend- ing to the hand of the person flying it; a kite^stjing ; a kitesdine.
stroke stook n. a sweeping movement, as of a wing; one of the two motions of a flapping wing or other reciprocating part, see dowmstroke and upfstroke.
strut stAt n. a brace, as in the frame of an aircraft, de- signed to receive a direct thrust; a support, as of wood or metal, which resists a pressure acting in the direction of its length.
strut-socket 'str.At,sekit n. a socket into tuhich a str,ut fits; a hollow piece of metal or other material into which the end of a brace or support rests or is fastend.
subalary ,SAb'ee-te-zi adj. situated below the wings.
subtorrid ,SAb'tezid adj. same meaning as subtropical.-
subtropic ,sAb't0pik adj. same meaning as subtropical.
subtropic ^Ab'tjepik n. a subtropical region.
subtropical ^SAb'tjepi-kal adj. having a climate or charac- ter between tjepical and temperate; quasitend; subtjepic.
suction-anemometer 'sAk$9n-3eni,memi-t9z n. an anemom- eter for mesuring the velocity of the wind by means of the suction or decrease of barometric pressure produced in a tube by the passage of the wind across the open end of the tube.
sulphur-rain 'sAlfo^zeen n. [also spelt sulfurzrain] same meaning as yellow rain, see under rain.
summer-cloud 'sAni9z,kz,aod n. cumulus cloud; day^cloud.
summer-lightning 'sAma^lait-nirj n. sheet lightning with- out thunder, the result of a sterm at a great distance; heat#lightning.
sun-dog 'sAn,de:g n. a meck^sun; a parhelion.
sunset 'sAn,set n. the descent of (the upper hm ef) the sun below the horizon at evening; also, the cloudzeffect or other atmosferic fenemena accompanying the setting of the sun; and, the time when the sun sets; sundown; evening.
double sunset, a sunset in which the sun is seen to set twice by the same observer who, just after witnessing the first sunset, rises in an aircraft beyend the limits of the earth's shadow, or above the twilightecurv, whence he sees
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