Why do we need flaps in Aircraft?

What is Flaps?

Flaps are an attached piece of metal mounted on the trailing edge of the wing which helps the aircraft as well pilots to take-off and land more precisely and safely. The maximum angle present in most aircraft is 45 Degree. Flaps increase the surface area of wings to lift and drag. It is very helpful to reduce the stalling speed of an aircraft wing while taking off or during landing.

Types of Flaps

Generally, Plain Flap, Split Flap, Slotted Flap, Fowler Flaps are the 4 common Flap position found in a Commercial Aircraft.

Plain Flap

The most simplistic flap is the plain flap. Plain flaps connect to the back of the wing, and they twist down when you extend them. However, they’re fairly inadequate in the amount of elevation they can create. That’s because as air moves over the wing, it loses energy and starts to separate from the wing. By extending flaps, the airflow separation is even more pronounced, creating a large wake behind the wing. The drag produced by the wake lets you fly a more precipitous descent to landing without increasing your airspeed.

Split Flap

Split flaps divert from the lower surface of the wing. Split flaps produce slightly more elevation than plain flaps, but like their plain counterparts, they also produce a lot of drag. 

Slotted Flap

Slotted flaps are the most commonly used flaps today, and they can be used on both small and large aircraft. It helps to increase the wing camber as well as when extended, They uncover a slot between the wing and the flap. By opening a slot between the wing and the flap, high-pressure air from the bottom of the wing flows through the slot into the upper surface. This supplements energy to the wing’s area delays airflow separation and produces less drag.

Fowler Flap

Fowler flaps increase the area of the wing by extending out on rails or tracks. Fowler flaps often have a set of slots to add energy to the airflow as well – they’re called slotted Fowler flaps. When they are extended, there’s a large increase in elevation, but little increase in drag, making the setting ideal for takeoff in a large jet. As they continue to extend, the flaps move downward more and more, creating a little more lift, but a lot more drag.

What would happen if there are no Flaps?

If there are no flaps in the aircraft, the wings will have a lower elevation of lift than they should have to lift the aircraft before the runway ends. The wing is not going to generate enough lift at a given airspeed and angle with the airflow which causes the aircraft’s nose to lift up and the tail would be scratching down the runway thus causing serious accidents or simply the aircraft will run out of runway causing the aircraft to crash or sometimes if lucky it would stop in the field.

In Conclusion, Flaps are a necessary component of Taking off and landing in an aircraft’s cycle. Although there might be few arguments saying that flaps are not needed and Many aircraft have landed successfully even after the flaps have failed to refract, In the end, it always safe to have an additional safety feature in your vehicle.

Flap Equation

Scientists have developed an equation to help aircraft manufacturers as well as engineers to calculate the amount of drag generated to help the flight land and take-off safely.

L = 1/2 p V^2 S Cl

Where 1/2 p is air density times airspeed resulting in energy., S is wing Area and Cl is coefficient lft.

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Aadin Zeeshan

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