Page:Dictionary of aviation.djvu/226

 202 DICTIONARY OF AVIATION

actually in contact with, the propeller, and which has a certain forward motion; the difference between the tjans- latory speed which a propeller would have if it were re- volving in a solid nut and the t^anslatory speed which it actually has when revolving in the air or other fluid while propelling a vehicle : distinguish^ from true slip, coefficient of slip, see under coefficient, negative slip, apparent slip whose numerical value is less than zero; apparent slip in which the speed of tjanslatory motion which a propeller actually has with reference to the main body of the surrounding air or other fluid is greater than the speed of tjanslatory motion which the pro- peller would have if it were revolving in a solid nut; ap- parent slip in which the speed of the ship is greater than the speed which the screw propeller would have if it were traveling in a solid nut.

true slip, the slip in reference to that portion of the surrounding fluid which is immediately in front ef, or actually in contact with, the propeller, regardless of the forward motion which this portion of the fluid has rel- ativly to the main body of the fluid : distinguisht from ap- parent slip.

slip stip intr. move in continuous contact with a surface, without rolling; slide, glide.

slip-angle 'stip^ngal n. the angle of slip ; the angle be- tween the curv which would be described by a point en a propeller?blade if the propeller were revolving in a selid nut and the curv which is actually described by the same point when the propeller is revolving in the air or other fluid while propelling a vehicle.

slope stoop n.

revolving slope, a revolving sloping structure devised by Merrill to afford a starting^place for gliders or flying^ma- chines.

smoke-balloon 'sMOok-b9,luun n. a balloon whose inflating* gas is warm air mixt with smoke and other products of combustion of a fire placed underneath; a fire^balloon.

smoke-cloud 'sMOok,ki.aod n. a mass or cloud of smoke.

smoke-principle 'sMOok,p:sinsi-p9J n. the principle or nat- ural law by which smoke rises or remains suspended in the air or atmosfere.

smoke-reek 'sMOok,ziik n. reek or exhalation consisting of smoke; smoke^fild air.

smuggle 'sMAgal v. import or export secretly or in a manner forbidden by law.

smuggler SMAgtez n.

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