What are flaps and how do they work?

Photo: Pinterest

Flaps are essential control surfaces located on the trailing edge of an airplane's wings. They play a crucial role in enhancing flight performance during takeoff and landing. By altering the wing's shape and manipulating aerodynamic forces, flaps enable aircraft to achieve higher lift and lower speeds, making them indispensable for safe and efficient operations. In this article, we will explore the mechanics of flaps, their functions, and their influence on an airplane's flight characteristics.

What Are Flaps? 

Flaps are trailing-edge high-lift devices attached to the wings of an airplane. These movable surfaces can be extended or retracted, allowing pilots to adjust the wing's configuration according to specific flight phases. Flaps are designed to modify the camber and chord line of the wing, thereby affecting lift and drag forces.

Functions of Flaps

The primary purpose of flaps is to enhance lift production during takeoff and landing. By increasing the wing's surface area and camber, flaps enable the aircraft to generate more lift at lower speeds. This feature is particularly useful during takeoff, where flaps help aircraft with low-profile wings achieve the necessary lift for a shorter takeoff roll. During landing, flaps allow for a steeper approach angle while maintaining a slower airspeed, ensuring a safer descent and reducing the required runway length.

Types of Flaps: There are several types of flaps commonly used in aircraft design. The four main types are:

Plain Flaps

Plain flaps are simple hinged surfaces that extend from the wing's trailing edge. They increase the wing's camber and chord length, providing additional lift and drag. Plain flaps are commonly found on light aircraft and some small jets.

Photo: Havkar

Split Flaps

Split flaps are divided into two sections, which extend downward and backward from the wing's trailing edge. These flaps significantly increase drag but provide less lift compared to other flap types. Split flaps are commonly used on older aircraft designs.

Photo: Kitplanes

Slotted Flaps

Slotted flaps feature a gap between the wing and the flap itself, known as the slot. This design allows high-pressure air from below the wing to flow over the top, delaying the onset of airflow separation. Slotted flaps provide increased lift with less drag and are commonly found on modern commercial airliners.

Photo: Aerocorner

Fowler Flaps

Fowler flaps are complex multi-segment flaps that extend backward and downward while simultaneously increasing the wing's chord length. This design significantly enhances lift production and is often used on large transport aircraft.

Photo: Aerocorner

How Do Flaps Work? 

The aerodynamics of flaps involve manipulating the angle of attack (AOA) and airflow over the wing. When flaps are extended, they change the chord line and camber of the wing, increasing the wing's AOA without changing the aircraft's pitch. This change in AOA results in higher lift production. Additionally, the increased camber and wing area contribute to improved lift characteristics, enabling the aircraft to maintain controlled flight at lower speeds.

Flap Settings for Takeoff and Landing

The selection of flap settings depends on the aircraft type and the specific phase of flight. During takeoff, aircraft with low-profile wings may use a small amount of flaps to reduce the required takeoff speed and runway distance. In contrast, during landing, pilots often select higher flap settings to increase lift and drag, allowing for a steeper approach and a lower stall speed.

Photo: Pinterest

Flaps are crucial components of an airplane's wings, providing the necessary lift and control during takeoff and landing. By altering the wing's shape and manipulating airflow, flaps enable aircraft to operate at lower speeds, ensuring safe and efficient flight operations. Understanding the mechanics and functions of flaps is vital for pilots and aviation enthusiasts to grasp the intricacies of aerodynamics and flight control systems.