Aeronautics glossary

Stability

Movements

Control

Manoeuvres

Aerodynamics

Functioning

Aerodynamic forces

Wing structure

created by Kate Marshall

Take-off

Before take-off, the pilot files a flight plan and calculates take-off speeds. After completing checks and receiving permission, the aircraft accelerates down the runway. At a certain speed, known as flying speed, the airflow around the wings lifts the airplane, allowing it to take off.

Lift < Weight

If the lift decreases below the airplane's weight, the plane will begin to descend.

Lift = Weight

For an airplane to fly straight and level, thrust must equal drag, and lift must equal weight.

Yawing

Gusts of wind can also cause dangerous yawing, where the nose is forced to the left or right. The fin or vertical stabilizer helps to minimize yawing.

Airplanes achieve thrust through the use of propellers or jet engines, and the strength of the engines directly influences the amount of thrust produced.

the Thrust

Thrust is an aerodynamic force generated by an airplane to counteract drag, with both forces acting in opposite directions.

ailerons

Ailerons, attached to the outer ends of each wing, are used to change direction. Lowering the aileron on one wing and raising it on the other turns the plane. To bank right, the pilot lowers the left aileron and raises the right aileron.

Composite Materials

Airplanes are constructed from aluminum alloy or composite materials, which are very light, helping to reduce the overall weight.

Landing Gear

After take-off, passenger jets retract their landing gear to reduce drag. The drag produced by the landing gear is so significant that, at cruising speeds, it could cause the gear to be torn off the plane.

spoilers

Spoilers can slow down an aircraft or make it descend when deployed on both wings. They can also generate a rolling motion if deployed on only one wing. Airliners use spoilers because they react more quickly than ailerons and require less force to activate, though they always decrease the aircraft's total lift.

Dihedral Angle

The dihedral angle of the wings helps to reduce rolling during flight. Dihedral can be positive (wings angled upward), neutral (flat), or negative (wings angled downward, also known as "anhedral"). Positive dihedral enhances stability, making the plane resist rolling and maintain level flight on its own.

Horizontal Stabilizer

The tail-plane or horizontal stabilizer helps to reduce pitching.

Centrifugal Force

When a plane turns at speed, centrifugal force and weight push it outwards and downwards. The lift force from the wings balances these forces

Stability

Certain parts of an airplane enhance stability by minimizing unwanted movements. Positive dihedral increases stability, allowing the plane to resist rolling and maintain level flight independently. However, greater dihedral makes the plane more stable but less agile.

Camber

The wing's surfaces are curved, or cambered, to generate lift. Increased camber and a higher angle of attack result in greater lift. Typically, the top surface of a wing is more curved than the bottom surface.

flaps

Flaps and similar parts enable the pilot to control the flight. To increase lift, the pilot raises the angle of attack and lowers the flaps.

angle as the airplane moves forward, along with the wing area and the aircraft's velocity. The pressure difference around the wing creates an upward force, effectively lifting the wing.

the LIFT

Lift is the force that counteracts the weight of an airplane, keeping it airborne. This lift is primarily generated by the wing's shape and

Centre of Gravity

The centre of gravity is often thought of as a single point where the airplane's weight is balanced. During flight, the airplane rotates around this point, but the weight force always points towards the center of the Earth.

Gusts

Gusts of wind can cause dangerous pitching, yawing, or rolling at any time, posing a risk to the aircraft's stability.

the DRAG

Drag is an aerodynamic force that opposes the motion of an object through a fluid, such as air or water. By reducing their size, objects can minimize drag and increase their speed, particularly when moving downhill. The drag generated by a jet's landing gear is so significant that, at cruising speeds, it could cause the gear to be torn off the plane.

the weight

Weight is the force exerted by Earth's gravity on an airplane. This force's magnitude is determined by the mass of the airplane's components, the fuel, and any payload, including passengers, baggage, and cargo. As the aircraft consumes fuel during flight, its weight continuously decreases.

rudder

The rudder, attached to the fin, moves left or right to align the fuselage with the direction of flight.

Velocity

The lift needed to keep an airplane in the air is mainly generated by the wing's shape and angle as the airplane moves forward, along with the wing area and aircraft velocity. This significant change in the wing's operating conditions requires aircraft designers to increase the wing area and modify the airfoil shape.

elevators

Elevators, located on the tailplane, can be moved up and down. Lowering the elevator raises the tail above the nose, causing the airplane to dive (move forward and downward). Raising the elevators drops the tail below the nose, preparing the airplane to climb.

Winglets

Wingtip fairings are installed at the ends of wings, while Boeing and Airbus utilize "winglets" to reduce drag. These winglets help improve aerodynamic efficiency and fuel economy by minimizing the vortex drag created at the wingtips.

Bernoulli’s Equation

Bernoulli's equation, a key principle in fluid dynamics, explains that as the speed of a fluid increases, its pressure decreases. This phenomenon causes faster-moving air to create lower pressure on the top surface, while slower-moving air maintains higher pressure on the bottom surface.

Rolling

Wind gusts can produce dangerous rolling, where one wing is forced up and the other is forced down. The dihedral angle of the wings helps to reduce rolling during flight.

They are typically deployed during take-off and landing to improve aerodynamic performance.

Slats

Slats, like flaps, temporarily modify the wing's shape to enhance lift, but they are located at the front (leading edge) of the wing rather than the rear.

Landing

Landing is one of the most challenging maneuvers. The pilot lowers the undercarriage, reduces speed by turning into the wind, and decreases engine power. To increase lift, the pilot raises the angle of attack and lowers the flaps. When the speed drops below flying speed, the airplane lands on the runway.

Aerofoil

The wing, also referred to as an aerofoil (or airfoil in the US), is the most crucial part of an airplane. The aerofoil on the left is characteristic of a stunt plane, while the one on the right is typical for supersonic fighters.

Anhedral

Negative dihedral (anhedral) wings make a plane quite unstable and prone to rolling easily. Anhedral wing designs are typically seen on military aircraft, where agility is prioritized over stability. An anhedral wing can cause uncommanded rolling, which is undesirable for passenger planes.

Controlled Turn

To bank right, the pilot lowers the left aileron and raises the right aileron, causing the airplane to turn at an angle. In this position, the lift force from the wings balances the centrifugal force and weight, enabling a controlled turn.

Pitching

Gusts of wind can cause dangerous pitching, where the nose of the plane is forced up or down. The tail-plane or horizontal stabilizer helps to reduce this pitching motion.

Stall

If the angle of attack is excessively steep, the airflow can become turbulent or rough, leading to a sudden reduction in upward force, this can cause the airplane to drop or stall. The stalling angle changes depending on the airplane's speed.

Vertical Stabilizer

The fin or vertical stabilizer helps to reduce yawing.

If the thrust exceeds the drag, the airplane will accelerate.

Thrust > drag

Thrust = drag

For an airplane to maintain straight and level flight, thrust must equal drag, and lift must equal weight.

If this angle is too steep, the airflow can become turbulent or rough, affecting the wing's performance.

angle of attack

The angle of attack is the angle at which the wing meets the oncoming air, controlling the thickness of the air slice the wing cuts through.

Wings

The wing, also called an aerofoil (or airfoil in the US), is crucial for lifting an airplane into the air. Wings come in various shapes, each tailored to the specific tasks they are designed to perform.

Cruising

Generally, airplane wings are designed to generate sufficient lift and minimize drag during cruising. However, the drag produced by a jet's landing gear is so substantial that, at cruising speeds, it could cause the gear to be torn off the plane.

Streamlining

Streamlining reduces drag by ensuring that air flows smoothly around the airplane. When air encounters a short, blunt object, it becomes turbulent. However, the streamlined shape of an airplane allows air to pass easily and safely around its thin, curved surfaces, minimizing resistance.

Banking

Banking occurs when an airplane turns, not due to the rudder's force (yawing), but because of the banking motion. This creates an unbalanced side force on the large wing, generating a lift force that curves the aircraft's flight path.

speed falls < flying speed

Flying speed

Flying speed is the speed at which the airflow around the wings generates enough lift for take-off. Conversely, when the speed falls below flying speed, the airplane lands.