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The Collaborative International Dictionary

aeroplane \aer"*o*plane`\ aeroplane \a"["e]r*o*plane`\, n. [a["e]ro- + plane.] (A["e]ronautics)

  1. A light rigid plane used in a["e]rial navigation to oppose sudden upward or downward movement in the air, as in gliding machines; specif., such a plane slightly inclined and driven forward as a lifting device in some flying machines. Also called airfoil.

  2. hence, a heavier-than-air flying machine using such a device to provide lift. In a modern aeroplane, the airfoils are called the wings, and most of the lift is derived from these surfaces. In contrast to helicopters, the wings are fixed to the passenger compartment (airframe) and do not move relative to the frame; thus such a machine is called a fixed-wing aircraft. These machines are called monoplanes, biplanes, triplanes, or quadruplanes, according to the number of main supporting planes (wings) used in their construction. After 1940 few planes with more than one airfoil were constructed, and these are used by hobbyists or for special purposes. Being heavier than air they depend for their levitation on motion imparted by the thrust from either propellers driven by an engine, or, in a jet plane, by the reaction from a high-velocity stream of gases expelled rearward from a jet engine. They start from the ground by a run on small wheels or runners, and are guided by a steering apparatus consisting of horizontal and vertical movable planes, which usually form part of the wings or tail. There are many varieties of form and construction, which in some cases are known by the names of their inventors. In U.S., an aeroplane is usually called an airplane or plane.


airfoil \air"foil`\ n. 1. 1 a surface such as the wing of an airplane designed to provide reactive force when in motion relative to the surrounding air.

Syn: aerofoil

Douglas Harper's Etymology Dictionary

1922, U.S. form of aerofoil.


alt. 1 (context American spelling English) A structure shaped to produce lift when moving in air. 2 (context American spelling English) A wing of an aircraft. n. 1 (context American spelling English) A structure shaped to produce lift when moving in air. 2 (context American spelling English) A wing of an aircraft.


n. a device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight [syn: aerofoil, control surface, surface]


An airfoil (in American English) or aerofoil (in British English) is the shape of a wing, blade (of a propeller, rotor, or turbine), or sail (as seen in cross-section).

An airfoil-shaped body moved through a fluid produces an aerodynamic force. The component of this force perpendicular to the direction of motion is called lift. The component parallel to the direction of motion is called drag. Subsonic flight airfoils have a characteristic shape with a rounded leading edge, followed by a sharp trailing edge, often with a symmetric curvature of upper and lower surfaces. Foils of similar function designed with water as the working fluid are called hydrofoils.

The lift on an airfoil is primarily the result of its angle of attack and shape. When oriented at a suitable angle, the airfoil deflects the oncoming air (for fixed-wing aircraft, a downward force), resulting in a force on the airfoil in the direction opposite to the deflection. This force is known as aerodynamic force and can be resolved into two components: lift and drag. Most foil shapes require a positive angle of attack to generate lift, but cambered airfoils can generate lift at zero angle of attack. This "turning" of the air in the vicinity of the airfoil creates curved streamlines, resulting in lower pressure on one side and higher pressure on the other. This pressure difference is accompanied by a velocity difference, via Bernoulli's principle, so the resulting flowfield about the airfoil has a higher average velocity on the upper surface than on the lower surface. The lift force can be related directly to the average top/bottom velocity difference without computing the pressure by using the concept of circulation and the Kutta-Joukowski theorem.

Usage examples of "airfoil".

He leveled off, keeping his weight back but centered, adjusting the airfoil to slow the precipitous drop.

He fought with his airfoil controls and tail rotor in order to jerk the aircraft around.

Nor did the lower one show any sign of floats, stabilizers, or airfoil surfaces.

The butler tried hurling his tray at her, from clear across the pool, but the metal disk sailed in an airfoil curve and only smashed a window.

I dreamed forebodingly of driving the several miles to the airfoil shed and doing such-and-such to one of the cutting-edge craft by torchlight, by dreamlight.

Now the only control the crew on the flight deck could exert over their fate was through the limited influence of airfoil surfaces on thin air.

With a rumble of displaced air, the Libra-class freighter broke through the high wisps of cloud, airfoil body providing lift to assist the engines as the freighter decelerated and turned to the strip heading from orbit.

The craft was an enormous wedge-shaped airfoil about eight hundred feet across and one thousand feet long.

The landing craft now nestled into the underside of a hundred-meter-long biopackage built by the alien Bgarth, supported four thousand meters above the surface by vast airfoils filled with buoyant hydrogen, driven by biomechanical turbojets.

The airfoils hissed just like eroding orbital dust, as if death, an amateur poet, required an exact rhyme.

This was where the big payload ships rode their boosters up through the atmosphere or glided back to Earth with their airfoils extended.

Icefire dissipated, and the twisting coronal glow around the edge-effect airfoils faded away, and Melinda started breathing again as she looked it over.

Those little airfoils you saw on the field when you came in have no range at all.

Several swamp buggies and airfoils were rusting on a parking stand just beyond the forest fringe.

They sat quietly, not talking, listening intently for some new note, but knowing all the while that any sound the Pirate might make would be concealed by the whirring roar of the air sweeping past the giant airfoils of the plane.