Angle of Attack
The angle of attack (AOA) is the angle at which the chord of the wing meets the relative wind.
The chord is a straight line from the leading edge to the trailing edge.
At low angles of attack, the airflow over the top of the wing flows smoothly and produces lift with a relatively small amount of drag.
As the AOA increases, lift as well as drag increases; however, above a wing’s critical AOA, the flow of air separates from the upper surface and backfills, burbles and eddies, which reduces lift and increases drag.
This condition is a stall, which can lead to loss of control if the AOA is not reduced.
It is important for the pilot to understand that a stall is the result of exceeding the critical AOA, not of insufficient airspeed.
The term “stalling speed” can be misleading, as this speed is often discussed when assuming 1G flight at a particular weight and configuration.
Increased load factor directly affects stall speed (as well as do other factors such as gross weight, center of gravity, and flap setting).
Therefore, it is possible to stall the wing at any airspeed, at any flight attitude, and at any power setting.
For example, if a pilot maintains airspeed and rolls into a coordinated, level 60° banked turn, the load factor is 2Gs, and the airplane will stall at a speed that is 40 percent higher than the straight-and-level stall speed.
In that 2G level turn, the pilot has to increase AOA to increase the lift required to maintain altitude.
At this condition, the pilot is closer to the critical AOA than during level flight and therefore closer to the higher speed that the airplane will stall at.
Because “stalling speed” is not a constant number, pilots must understand the underlying factors that affect it in order to maintain aircraft control in all circumstances.
'Airplane Flying Handbook_old' 카테고리의 다른 글
| AFH Chapter 4-6 Slow Flight (0) | 2021.07.25 |
|---|---|
| AFH Chapter 4-5 Slow Flight (0) | 2021.07.24 |
| AFH Chapter 4-3 Coordinated Flight (0) | 2021.07.22 |
| AFH Chapter 4 - 2 Defining an Airplane Upset (0) | 2021.07.21 |
| AFH Chapter 4 - 1 Introduction (0) | 2021.07.20 |
댓글