Flap (aeronautics)

Planes have parts on their wings.

These parts are called flaps. They change the shape of the wing. This helps the plane fly at slow speeds.

Using flaps helps a plane take off quickly. They also help a plane land in a short space. Flaps can make the plane go slower by catching the air. This is called drag. Pilots use them to see the runway better. It is a smart way to fly safely.

Flaps are special parts on an airplane wing. They help a plane fly safely at slow speeds.

Most flaps are on the back edge of the wing. When a pilot uses them, the wing shape changes. This change is called camber. A bigger camber helps the wing make more lift. Lift is the power that keeps the plane in the air.

Because of this extra lift, a plane can fly slower without falling. This is called a lower stall speed. This helps planes take off and land in short spaces.

Flaps also create drag. Drag is a force that slows the plane down. This can help a pilot fly a steeper path when landing.

There are many kinds of flaps. A plain flap is a simple part that hinges down. A slotted flap has a small gap. This gap lets air flow through to help the wing work better. A Fowler flap is even more complex. It slides backward and then down. This makes the wing area much larger.

Using these parts helps pilots control the plane during every flight.

Flaps are very important tools on an airplane wing. They are high-lift devices that help a plane fly safely.

These parts help reduce the stall speed of an aircraft. A stall speed is the lowest speed a plane can fly while staying in the air. When flaps are used, the wing can create more lift at lower speeds. This makes it much easier to take off and land.

Using flaps helps a plane use less runway during these times.

Flaps work by changing the shape of the wing. When they extend, they increase the camber, which is the curvature of the wing. This change allows the wing to generate more lift. Some flaps even increase the total area of the wing surface.

As the wing shape changes, it also creates more drag. Drag is a force that pulls back on the plane and slows it down. This extra drag can be helpful during landing. It allows a pilot to fly a steeper path toward the runway.

People have been studying how to improve wings for a long time. The Royal Aircraft Factory and National Physical Laboratory tested flaps in 1913 and 1914. These tests were in the United Kingdom, but the flaps were not used on real planes yet. In 1916, the Fairey Aviation Company made big improvements. They built the Fairey Hamble Baby, which was the first aircraft to fly with flaps. Later, in 1917, Breguet added automatic flaps to a reconnaissance bomber. These early steps helped all modern planes fly better today.

There are many different designs for these wing parts. Plain flaps are simple and hinge downward on a single pivot. Split flaps were invented by Orville Wright and James M. H. Jacobs in 1920. These flaps only move on the bottom part of the wing. Slotted flaps are different because they leave a small gap for air to pass through. This air helps the wing work even better. Fowler flaps are even more advanced because they slide backward before they hinge down.

This movement makes the wing surface much larger.

You can see these ideas working in many types of flying machines. Many jet airliners use special parts called Krueger flaps on the front of the wing. Some gliders use flaps to help them stay in rising air called thermals. Even fighter jets like the Nakajima Ki-43 used them to make tighter turns during combat.

When a plane lands, the pilot might even raise the flaps quickly. This helps the weight of the plane stay on the tires for better braking. Whether it is a small glider or a huge airliner, flaps make flight possible.

In aeronautics, a flap is a high-lift device used to manage an aircraft's flight performance. These components are usually mounted on the trailing edges of a fixed-wing aircraft. Their primary purpose is to reduce the stalling speed of the wing. The stalling speed is the minimum velocity required for a wing to generate enough lift to maintain flight. By using flaps, pilots can decrease both take-off and landing distances.

Flaps function by altering the physical properties of the wing. When extended, they increase the wing's camber, which is the curvature of the airfoil. This change increases the maximum lift coefficient, or the upper limit of lift a wing can produce. Some flap designs also increase the total surface area of the wing. According to the airplane lift equation, increasing the wing area (S) or the lift coefficient allows the aircraft to generate the same amount of lift at a lower airspeed (V). This mechanism is essential for Short Take-Off and Landing (STOL) operations.

Most aircraft use partial-span flaps, which extend from near the wing root to the inboard end of the ailerons. Extending these flaps changes the spanwise lift distribution across the wing. This causes the inboard half of the wing to provide a larger proportion of the lift. Meanwhile, the outboard half of the wing provides less lift. This reduction in outboard lift also reduces the angle of attack on that part of the wing. This is beneficial because it increases the margin above the stall for the outer wing. This helps maintain aileron effectiveness and reduces the risk of an asymmetric stall or spinning.

While flaps increase lift, they also increase drag. This happens because the altered lift distribution increases lift-induced drag. Some flaps also increase parasitic drag by increasing the wing's surface area. During an approach to landing, this extra drag can be useful. It allows the aircraft to descend at a steeper angle. However, flaps are retracted when they are no longer needed to avoid unnecessary resistance.

There are several distinct types of flap designs. Plain flaps are the simplest, where the rear portion of the airfoil rotates downward on a hinge. Split flaps, invented by Orville Wright and James M. H. Jacobs in 1920, only move the lower surface of the wing. These can act like spoilers by adding significant drag. Slotted flaps are more advanced because they create a gap between the wing and the flap. This gap allows high-pressure air from below to flow over the flap, keeping the airflow attached. Fowler flaps are a type of split flap that slides backward before hinging downward. This movement increases both the camber and the wing area.

The history of flap development shows a steady progression in aviation technology. In 1913 and 1914, the Royal Aircraft Factory and the National Physical Laboratory tested flaps in the United Kingdom. Although these tests were successful, the flaps were not yet installed on actual aircraft. In 1916, the Fairey Aviation Company improved upon these ideas. They created the Fairey Hamble Baby, the first aircraft to fly with flaps. These were full-span plain flaps that also acted as ailerons, a design known as flaperons. By 1917, Breguet had incorporated automatic flaps into the lower wing of their reconnaissance bombers.

Flaps are used in many different flight scenarios. During takeoff, pilots may use partial flap settings to reduce the ground roll. For example, the Cessna 172S Pilot Operating Handbook recommends 10 degrees of flaps for short runways or soft ground. During landing, flaps are often fully extended to allow for a slower approach speed. In gliders, flaps are used to optimize the wing for different speeds. Pilots may use them to fly more slowly while thermalling in rising air. Even fighter aircraft, such as the Nakajima Ki-43, have used special flaps to improve maneuverability during combat.