The Angle it Attacks
Angle of Attack, or AOA as we’ll call it going forward, is technically defined as such:
THE ANGLE AT WHICH THE RELATIVE WIND MEETS THE CHORD LINE OF THE WING.
Now, that sounds awful fancy, so let’s break it down a bit.
The Chord Line is the line that goes from the leading edge of the wing to the trailing edge.
To define AOA, we are looking for the difference between the angle that the “relative wind” is meeting the wing at, and the chord line. The difference between these two lines gives us our AOA.
At high angles of attack (around 16 degrees or so for most GA airplanes), the airflow begins to become turbulent over the top of the wing instead of smooth, and thus a loss of lift occurs since most of our lift comes from the low pressure airflow over the top of the wing.
Have a close look at the video in the next TOPIC to see this in action.