AIRCRAFT WING

PRESENTED BY:

THIRUMAL,

B.TECH[AERO].

What is Wing?

• A wing is a type of fin with a surface that produces aerodynamic force for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid. As such, wings have an airfoil shape, a streamlined cross-sectional shape producing lift.

Types of Wings?

Based on

Structure

Position

Based on Position

1.High wing,

2.Mid wing,

3.Low wing,

4.Parasol wing,

5.Anhedral wing,

6.Dihedral wing,

7.Gull &

Inverted gull.

Based on Structure

1.Straight,2.Eliptical,3.Tapered,4.Sweptback5.Delta

ORIGIN AND WORKING

The Ancient Chinese discovered that kites with curved surfaces flew better than kites with flat surfaces. Lilienthal and Cayley, in the 1800s, demonstrated that a curved surface produces more lift than a flat surface. This led to the conclusion that a wing needs to have camber. That is, the top needs to be slightly curved, like a hump. The bottom is left flat or straight. An object with this shape is called an airfoil. Often, the words "wing" and "airfoil" are used interchangeably, but they shouldn't be. Airfoil shapes are designed to generate as much lift as possible while incurring as little drag as possible.

HIGH LIFT• When an airplane lands it is desirable to fly as slowly as possible.

Ideally for landing, an airplane would have a large wing with a very cambered airfoil. However, airfoils designed to perform well at slow speeds are not good for flying at faster speeds, and vice versa. Airplane designers have developed a set of features that allow the pilot to increase the wing area and change the airfoil shape to compensate for this.

• The trailing edge of the wing is equipped with flaps which move backward and downward. These are not to be confused with ailerons, which are also located on the trailing edge of the wing, but have an entirely different purpose. The flaps increase the area of the wing, and the camber of the airfoil. With this increase in area, the airflow has farther to travel which spreads the pressure difference between the top and bottom of the wing over a larger area.

Wing parts

Flaps: Flaps adjust the camber of the wings, increasing lift. Flaps are normally fitted at the trailing edge of the wings. Extending the flaps increase the camber of the wings airfoil, thus increasing lift at lower speeds, an important feature for landing.

Slats:Slats adjust the angle of attack of the wings, increasing lift. Slats are fitted at the leading edges of the wings, and deploying them increases the angle of attack of the wings, allowing the pilot to increase the lift generated by the wing.

3.Aileron:Ailerons increase or decrease lift asymmetrically, in order to change roll and, thus, move the aircraft left or right while flying. Ailerons are hinged sections fitted at the rear of each wing. Ailerons work asymmetrically as a pair: as the right aileron goes up, the left one comes down and vice versa, thus making the aircraft roll right or left, respectively.

Aerofoil• Leading Edge = Forward edge of the aerofoil

• Trailing Edge = Aft edge of the aerofoil

• Chord = Line connecting the leading and trailing edge. Denotes the length of the aerofoil

• Mean Camber Line = Line drawn half way between the upper and lower surface of the aerofoil. Denotes the amount of curvature of the wing

• Point of Maximum Thickness

= Thickest part of the wing

expressed as a percentage of the chord

Working of AerofoilThe basic principle behind an aerofoil is described by bernoullis theorem. Basically this states that total pressure is equal to static pressure (due to the weight of air above) plus dynamic pressure (due to the motion of air).Air that travels over the top surface of the aerofoil has to travel faster and thus gains dynamic pressure. The subsequent loss of static pressure creates a pressure difference between the upper and lower surfaces that is called lift and opposes the weight of an aircraft (or thrust that opposes drag).As the angle of attack (the angle between the chord line and relative air flow) is increased, more lift is created. Once the critical angle of attack is reached (generally around 14 degrees) the aerofoil will stall.

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