Unit 3. WING

T. Look at the picture, please. What is this?

S. It is a wing.

T. Is it a principal structural unit of the аіrplane?

S. Yes, It is. The wing is the principal structural unit of the airplane.

T. What is the function of the wing?

S. The function of the wing is to provide lift and support the аіrplane in the air.

T. Right you are. Look at the wing.

You see the leading edge (1), the trailing edge (2), the tip (3) and the root (4). Remember the terms: the leading edge – передня кромка, the trailing edge – задня кромка, the tip – кінцівка, the root – коренева частина крила.

The shape of the wing may be: rectangular, triangular, elliptical and swept back «To sweep» means - «відхиляти», «back» – «назад», so «the sweeepback angle» is «кут стріловидності». Do you know what the amount of the sweepback angle depends upon?

S. The amount of the sweepback angle depends upon the type of the аіrplanе and its design, doesn't it?

T. Yes, absolutely. So the sweepback angle is the angle between the wing and a perpendicular to the longitudinal axis of the аіrplanе. And what kind of aircraft has a greater sweepback angle?

S. High-speed jet aircraft has a greater sweepback angle, I guess.

T. That's right. Now let's speak about the dihedral angle. It is the angle between the wing and a horizontal plane («the dihedral angle» – кут поперечного V крила). The dihedral angle may be positive and negate. The angle of attack is the angle between the chord of the wing and the direction of the relative wind. The chord is the distance between the leading edge and the trailing edge of the wing. As you know the function of the wing is to provide lift. Sometimes lift should be increased. What can increase lift?

S. The angle of attack does.

T. Quite right. There is another wing angle. It is the angle of incidence – кут установки крила. It is the angle between the longitudinal axis of the аіrplane and the chord of the wing. The angle of incidence is fixed. It cannot be changed by the pilot. The airplane may have parasol, high-wing, mid-wing and low-wing constructions.

The number of the wings may vary. Now, tell me what the airplane with one wing is called.

S. It is called a monoplane.

T. What is the airplane with two wings called?

S. In Ukrainian it is «біплан».

T. In English it is a «biplane». A multiplane has many wings. Pay attention to the word beginning with «multi-». It means «many». Can you translate the word «multinational»?

S. Багатонаціональний.

T. You are right. The wing may be made of wood, fabric or metal which depends on the design of the aircraft.