Wind Triangles and Vector Addition
- Author:
- bilderatsphinx
An airplane's movement across the ground is determined by its movement through the air and the air's movement across the ground. Each of these consists of a speed and a direction:
- The airplane's movement across the ground consists of groundspeed and course.
- The airplane's movement through the air consists of airspeed and heading.
- The air's movement across the ground consists of wind speed and wind direction.
G = A + W
(G: groundspeed and course, A: airspeed and heading, W: wind speed and wind direction) Notice two things:- In the diagram above, if you follow A and then W, one after the other, you end up at the tip of G. This is what it means to say G = A + W.
- If you switch the order of A and W, by clicking the button, they still lead to the tip of G. (Where we draw the vectors doesn't matter, as long as their length and direction stays the same.)
- All directions are listed as "degrees from north", so N=0°, E=90°, S=180°, and W=270°.
- In aviation, wind direction is reported based on the direction the wind is blowing from. That's why you see the wind vector pointing in the opposite direction from what the app says.