Angle of attack
Angle of attack is the angle between the chord line of an airfoil and the relative direction of the aircraft. This angle is the key factor of an airfoil to generate lift. The lift coefficient of an airfoil increases up to the critical angle of attack. Beyond the critical angle, the lift coefficient drops abruptly due to the flow separation on the upper surface of the wing, eventually causing the airfoil to stall. The angle of attack is denoted by the symbol alpha (α).
Frequently Asked Questions
What is a stall?
In a typical fixed-wing aircraft, there are some situations where the wings will stop producing any lift. This happens mostly when the angle of attack of an aircraft increases beyond the critical angle of attack (stalling angle of attack). In some cases, a stall can happen when there is not enough airspeed for an aircraft to generate lift. Most stalls can be recovered by pitching the nose of the aircraft down, thereby reducing the angle of attack. However, in the case of deep stalls, a dangerous stall where a stalled wing pitches the plane up and masks any airflow to its tail section, the recovery will be hard as the elevators will not be able to help the pilot in pitching down the plane. As there is no lift produced by the wings during a stall, the altitude drops usually and it is always a crucial factor for a recovery maneuver.