Page:Dictionary of aviation.djvu/147

 DICTIONARY OF AVIATION 123

heat-stroke 'hiit,str,Dok n. an affection of the nervous sys- tem, often fatal, caused by exposure to excessiv heat; col- laps or fever due to exposure to atmosfenc heat.

heat-wave ''hiit/weev n. a wave of het wether; a het wave.

heaven 'hevan n. [also spelt heven\ cemmonly used in the plural] the sky, the firmament; also, a zone or region.

heavenward 'hevan-wazd adv. [also spelt hevenward] to- ward the hevens; hevenwards; skyward.

heavier-than-air ,hevi-3z-d9'ne:z, (assumptivly} 'hevi-az-da- ,ne:z adj. [also spelt heviertthantair] possessing greater weight in proportion to bulk than the air or atmosfere ; of greater specific gravity than the air, as a gasless aerial ve- hicle : said of gliders, aeroplanes, and other airships which do not depend upon gases lighter than the air, or upon ran- fied air or a vacuum, for sustaining^power : the epposit of lightertthanzair.

heel hiil intr. incline or cant from a vertical position; turn partly over; tilt.

height hait n. [also spelt hight; synonymous cognate highthj

1. the quality of being high; highness, altitude, elevation: as, the *height of the earth's atmosfere; the *height of his flight.

2. the maximum vertical dimension of an aerial vehicle.

3. a high point or position : as, to fall from a given
 * height; to fly from *height to *height.

height-control 'hait-kan^jpol n. the control of the height of

a balloon or airship above the earth; altitude^cont^ol. height-flyer 'hait,fz.ai-9z n. one who flies for a height?

record; an aviator who is trying for altitude. height-prize 'hait,psaiz n. a prize for attaining height, as

in an aeroplane; a prize for high flying. height-record 'hait,zek9zd n. a record for height; the best

recorded achievement in high aeroplane^flying. helical 'heli-kal adj. belonging to or having the form of a

helix; screw^shaped ; spiral.

helicoid 'heli,keid n. (in geometry) a warpt surface gene- rated by a moving straight line which always passes thru

or touches a fixt helix. helicoid 'heh,keid adj. ef or pertaining to a heliceid or a

helix. helicoidal ,heh'koi-dl adj. relating to a heliceid or helix;

screw^shaped ; spiral. heliconef 'helika^ef n. an aeronef or hevier?than?air fly-

ing^machine of the helicopter type invented by H. Chatley. helicoplane 'hehk3,pteen n. a flymg^machine of the heli-

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