How does wings work

If you tilt it up ever so slightly, your hand goes up. It turns out that y our hand can be a pretty good approximation of an airplane wing. Out the window of a moving car, your hand is at once a wing, an aileron, a spoiler and a flap.

And if you stretch out your fingers, maybe even a slat. Airplane wings are a majestic and highly complex piece of engineering. Two experts helped me demystify how the components work together. Chip Kiehn, Director of Sales and Marketing for Aviation Partners Boeing, which makes and installs a part of the wing called a winglet, has spent close to 20 years at this Boeing joint-venture project. Winglets are those curved ends jutting up from the end of the wing on many planes, including current models of the Boeing and Airbus A Ailerons — a commercial aircraft has two — control the movement of the aircraft on its longitudinal axis, causing it to roll left to right.

The ailerons are located on the outside trailing edge of the wing. Indeed, when your aircraft is banking in a turn, you may notice that the aileron returns to its flush-with-the-wing position, yet the aircraft continues to bank. It does this because of centripetal force holding it in a turn. When the control column is shifted to the right by a pilot or by the autopilot more often than not , the aileron on the right wing is then raised while the aileron on the opposite wing drops down.

They move opposite each other. The act of raising the aileron on the right wing reduces the lift on the right wing — and when wings have a reduction in lift, they drop. Here, the right wing dips down in a controlled turn to the right. As the name suggest, spoilers spoil something. Here, they ruin the lift produced by the wing, much the same way an aileron does. Spoilers allow the plane to lose lift and descend in a controllable way.

It also allows the aircraft to descend at a quicker but comfortable rate if you have a lot of altitude to lose. There are often two sets of spoilers on airplane wings. The set close to the fuselage is called ground spoilers or airbrakes. Plumb explained that the pilots pre-arm the system during descent to automatically activate when the wheels touch down.

That first machine-like whirring noise you hear as your aircraft descends for landing is the sound of the flaps deploying. Flaps are both lift and drag devices.

Deploying flaps allows the pilot to descend and maintain lift at a much slower speed on approach. At the same time, deploying flaps provides drag, which slows the aircraft.

On most jetliners today, there are inboard flaps and outboard flaps, with the inboard flaps being closest to the fuselage. They are deployed in degrees, as the aircraft descends for landing. The flaps are raised and lowered via aircraft hydraulics inside the torpedo-shaped bodies under the wing, called track fairings. To show that this common explanation is wrong, Babinsky filmed pulses of smoke flowing around an aerofoil the shape of a wing in cross-section.

Babinsky is quick to stress that he is far from the only aerodynamicist who is frustrated by the perpetuation of the myth: colleagues have in the past expressed their concerns in print and online.

Where he hopes his video will help debunk the myth once and for all is by providing a quick and visual demonstration to show that the most commonly used explanation cannot possibly be correct.

The original video, created by Babinsky a few years ago using a wind tunnel, has now been re-edited in high quality with a voice-over in which he explains the phenomenon as it happens.

One of his visions is to design a wing that will enable aircraft to fly faster and more efficiently. This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page. Our selection of the week's biggest Cambridge research news and features sent directly to your inbox. Enter your email address, confirm you're happy to receive our emails and then select 'Subscribe'. I wish to receive a weekly Cambridge research news summary by email.

The University of Cambridge will use your email address to send you our weekly research news email. We are committed to protecting your personal information and being transparent about what information we hold. Please read our email privacy notice for details. Read on Issuu. In a qualitative look at Euler's Equations, the movement of the fluid flow around the curved upper surface of the wing may be likened to that of a car going around a bend.

Similarly, as the fluid particle follows the cambered upper surface of the wing, there must be a force acting on that little particle to allow the particle to make that turn. This force comes from a pressure gradient above the wing surface. Starting at the surface of the wing and moving up and away from the surface, the pressure increases with increasing distance until the pressure reaches the ambient pressure. Thus, a pressure gradient is created, where the higher pressures further along from the radius of curvature push inwards towards the center of curvature where the pressure is lower, thus providing the accelerating force on the fluid particle.

Thus due to the curved, cambered surface of the wing, there exists a pressure gradient above the wing, where the pressure is lower right above the surface. Assuming a flat bottom, the pressure below the wing will be close to the ambient pressure, and will thus push upwards, creating the lift needed by the airplane.

At angles of attack below around ten to fifteen degrees, the lift increases with an increasing angle. However, if the angle of attack is too large, stalling takes place. Stalling occurs when the lift decreases, sometimes very suddenly. The phenomena responsible for stalling is flow separation see Figure 9. Flow separation is the situation where the fluid flow no longer follows the contour of the wing surface. Fluid particles flowing along the top of the wing surface experience a change in pressure, moving from the ambient pressure in front of the wing, to a lower pressure over the surface of the wing, then back up to the ambient pressure behind the wing.

The region where fluid must flow from low to high pressure adverse pressure gradient is responsible for flow separation. If the pressure gradient is too high, the pressure forces overcome the fluid's inertial forces, and the flow departs from the wing contour. Since the pressure gradient increases with an increasing angle of attack, the angle of attack should not exceed the maximum value to keep the flow following the contour.

If this angle is exceeded, however, the force keeping the plane in the air will decrease, and may even disappear altogether. Viscosity can be described as the "thickness," or, for a moving fluid, the internal friction of the fluid. Viscosity measures the ability of the fluid to dissipate energy. A parameter of viscosity is the coefficient of viscosity, which is equal to the shear stress on a fluid layer over the speed gradient within the layer.

Viscosity is essential in generating lift; it is responsible for the formation of the starting vortex, which in turn is responsible for producing the proper conditions for lift. Viscosity is responsible for the formation of the region of flow called the boundary layer. There are two types of boundary layers: Laminar Turbulent In a laminar boundary layer, the fluid molecules closest to the surface will slow down a great deal, and appear to have zero velocity because of the fluid viscosity.

In turn, these surface molecules create a drag on the particles flowing above them and slow these particles down. The effect of the surface on the movement of the fluid molecules eventually dissipates with distance from the surface.