Page:Dictionary of aviation.djvu/290

 266 DICTIONARY OF AVIATION

wings or sustaining^planes of a flying^machine ; a supple- mentary winglet, such as an aileron : as, movable *wm%t tips : see Up.

plural wingftips, several or many tips on each wing; mul- tiple tips at the lateral extremity of a supporting?plane. compare tipafeather.

swinging wingttip, a wing^tip, in a flying^machine, which is capable of a swinging movement; as en a hinge.

wing-tract 'wir^tjcekt n. the fether^act or pteryla, of the wing, upon tuhich grow all the wing^fethers except the scap- ulars (which grow on the humeral tact) ; the pteryla alaris.

wing-warping 'wirj,we:z-pirj n. the process of warping, bending, or contorting the wings or aerofoils, as of an aeroplane flying^machine.

wing-warping 'wirj,we:z-pirj adj. designed or used for wing^warping : as, *wing#warping devices.

wing-weight 'win/weet n. the weight of the wing or wings of a bird or f lymg^machine ; aerofeilsweight.

wing- wheel 'wir^uuril n. a small tuheel mounted under the wing or lower main^plane of a flying^machine, cemmonly at the tip, in order to keep the wing free of the ground or facilitate its motion along the ground, as in starting or landing.

wingy 'wirji adj. having wings; also, soaring as en wings; lefty; rapid, sunft.

wire -tightener 'waiz,tai-tn-9z n. any device, as a turn- buckle, for tightening a wire stay or other part made of wire; a strainer.

wrist-link 'zist^ink n. the wristejeint, as of a bird's wing.

��zenith 'zri-niO n. the point directly above the observer's bed; the vertical point of the hevens at any place ; the vertex : as, the blue *zenith ; to dwindle in the *zenith : the epposit of nadir.

astronomical zenith, the point at tuhich a plum^line, sus- pended at the point of observation would, if produced up- ward, touch or pierce the celestial sfere; the plum^line ze- nith. The astronomical zenith is farther from the equator than the geocentric zenith, see angle of the vertical, under vertical.

geocentric zenith, the point at tuhich a line drawn from the center of the earth and passing thru the observer would, if produced upward, touch or pierce the celestial sfere. contrast astronomical zenith.

plumbfline zenith, same meaning as astronomical zenith.

�� �