Page:Dictionary of aviation.djvu/231

 DICTIONARY OF AVIATION 207

spinning-screw 'spmir^sksou n. a tey flyer of cardboard or metal, consisting of an aerial screw with two or more blades, attacht to a spindle around tuhich a string is wound, and which is set moving or spinning by briskly polling and unwinding the cerd.

spiracle 'spai-za-ksl n. an aperture or enfis; one of the breathing^holes or external enfises of the tjacheae or windpipes of an insect's bedy.

spiral 'spai-zal adj. ef or resembling a spire, ceil, helix, or whorl; winding or circling and at the same time advancing, rising, or falling; proceeding or fermd like a screw^thred; helical, heliceid: as, a *spiral flight.

sprag spsaeg n. a short wooden prop.

spray-shield 'spsee,$iild n. a shield, as that just back of the elevatmgshydroplane of a Curtiss hydroaeroplane, for pro- tecting the craft from the spray rising from the water be- neath.

spread spsed n. [also spelt spred}

1. expansion; the state, or the capability of being out- spred : as, the peacock's tail has an imposing *spred.

2. the expanse or area of surface; the extent or amount of supportmg^surface presented by a wing, tail, or aerofoil: as, the *spred of a peacock's tail; foil *spred of tail; the altitude^machine will have an immense *spred.

3. the distance or mesurement, from tip^to^tip, of the spred wings or aerofoils of a bird, bat, insect, or flying* machine; expanse or extent of wing; wing^spred (sense j).

spreader 'spsedaz n. [also spelt spreder] a device made of wood and twine used for spreding or booming the pennant? line of a secondary kite away from the mainline or stjing ' of a kite, thus preventing the twirling mainline from weav- ing the pennantsline around itself.

spur spore: n. a herny outgrowth en the pinion^bone of the wing in certain geese, plovers, pigeons, and other birds.

spuriae 'spc.u: -zi,i: n. pi. the packet of fethers growing en the spurious or bastard wing, that is, en the winglet or alula of a bird ; one of the bastard quills of the alula.

spur-winged 'sperzywind adj. [also spelt spurfwingd] hav- ing a herny spur en the pinion of the wing, as certain geese, plovers, and other birds.

squall skiDcrl n. a sudden or violent gust of wind or a suc- cession of such gusts often accompanied by rain, snow, or sleet.

archt squall, a squall markt by peculiar dense archt masses of dark cloud, furious gusts of wind, and terrents of rain, occurring in tjepical regions; a teraado.

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