188 DICTIONARY OF AVIATION
are used in fireworks, warfare, and life-saving, and have been proposed as a means of propelling balloons.
rocket 'zekit intr. fly stuiftly straight up into the air, as a fesant when flusht; tower.
rocketing 'zeki-tirj n. the action of the verb rocket; a fly- ing rapidly upward as a fesant does when flusht; towering.
rocket-rising 'zekit,zai-zir) adj. rising swiftly in flight like a sky-recket, as a flying-machine.
roll zool intr. go down or sink en one side and then en the other, as an airship; turn, swing, or oscillate from side to side about a longitudinal axis, compare pitch.
roll-cloud 'zoo^ksLaod n. a roll-shaped, cylindrical, or spindle-shaped cloud as in cirro-cumulus, stratus, or cu- mulo-str.atus ; a cloud resembling a roller or breaker of the sea.
roller 'zoo-laz n. one of a series of vertex-filaments in a system of flow which act as rollers between the live fluid and the ded-water; a vertex roller.
root zuut n. the part of a bird's wing toward the anatomi- cal shoulder.
rotation zo'tee-$3n n. the act or process of rotating or turn- ing, as do the parts or particles of a fluid; the action or state of whirling around.
rotation-anemometer zo'tee-$9n-seni,memi-t3z . an ane- memeter for mesuring the velocity of the wind by means of the rotation of blades or cups moved by the wind.
rough-winged 'zAf,wind adj. [also spelt rough*wingd\ having rough wings; having the outer web of the first pri- mary retersely serrulate : as, the common *rough-wmgd swallow.
rower 'zoo-9z n.
1. one of the remiges or flight-f ethers of a bird's wing; a quill-fether of the wing.
2. a bird that rows with its wings, or practises rowing flight.
rubbersilk 'zAb3z,silk n. a balloon-fabric of rubberized silk introduced by T. S. Baldwin about 1908, or earlier, used also in aeroplane-wings.
rudder 'zAdaz n.
1. a device, usually at the rear or front of an airship, by means of which the craft is guided or steerd; a steering- plane; a rudder-plane.
\)ox rudder, a rudder in the form of a bex with two epposit sides or ends wanting; a rudder typically consist- ing of four planes joining at right angles in lines lying
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