Page:Dictionary of aviation.djvu/260

 236 DICTIONARY OF AVIATION

tion after sunset (or before sunrise) produced by the r

flection of sunlight from the upper air. compare gloamin

glooming, dusk. twilight-arc 'tumi-lait,a:zk n. same meaning as twiligh

curve. twilight- curve 'tioai-lait,k8:ev n. [also spelt twilighticun

the curv or arc, sometimes very sharply defined, censtitu

ing the visible part of the circular outline or boundary (

the projection of the earth's shadow upon the sky, luhic

rises in the east just after the sun has set and, as :

passes to the zenith and thence to the western horizoi

gradually cuts off the tunlighteglow ; the tu>ilight#arc. twilight-glow 'ttuai-lait,gloo n. the glow or luster of th

twilight. twisting-action 'tu)istirj,3ek$Dn n. an action of tunsting c

spirally turning. twisting-effect 'tunstirj-i,fekt n. an effect having the ns

ture of a tunst or spiral turn. two-bladed ,tuu'blee-did, (assumptivly) 'tuu,blee-did ad t

having two blades, as a screw propeller. two-winged ,tuu'wind, (assumptivly) 'tuu,wirjd adj. [als

spelt two*wingd\ having two wings or winglike sustaining

surfaces. tying-point 'tai-ir^pomt n. the point al which the guylin

or stjing of a kite is altacht, as to the hanger or bridle; th

tying^en peint. typhoon ,tai'foun n. [also spelt tyfoon] a violent hurncan

occurring in the China seas and thereabouts, mostly fron

July to October.

��unclouded ,An'ktao-did adj. net clouded : as, an *unclouded

but misty, sky. underbody 'Andazjbedi n. the bedy or framework fermins

the under part of an airship; the rigid underst^ucture at

tacht or suspended beneath the float^vessel ; the fuselage. underplane 'And9z,pi.een n. a stationary plane situated jus

under a moving or soaring plane; a plane surface, such a

a level piece of land or a water^surface, lying close be

neath an aeroplane or flyer, in flight. underrun ,And9'zAn tr. run or pass under or underneath

as, the thunder^squall *underruns humid air^currents. understructnre 'And3z,stjAkt$3z n. a structure unde

another; the lower part or parts of an airship, underneatl

the gasbag; the underbody; the underwork.

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