Using groundspeed, course, heading and airpspeed, compute wind speed and direction using the wind side of an E6B. This is required on the instrument pilot knowledge test, and is useful if in an aircraft and you’d like to calculate what the winds are doing outside.
Think of your E6B wind side as having 2 configurations or modes: Wind mode, and Aircraft mode. Work problems simply by setting it up in one mode, and then rotating the wheel into the other mode.
- RED ARROWS: What the airplane is doing in relation to the ground.
- Course is at the top, and represents the track over the ground. You can also think of this as the direction to fly a line written on a sectional chart.
- Groundspeed is under the grommet
- GREEN ARROWS: What the airplane is doing in relation to the air
- Airspeed is represented as an arc that spans the whole card, and is underneath the wind/heading dot.
- Heading is a dot, represented as an amount of degrees from the center line. If your heading is 5 degrees left of your course (i.e. heading is 300 while course is 305) then you are holding 5 degrees left, and the dot would be on the 5 degree left line.
To set up the card in aircraft mode:
- Set the course at the top
- Slide the card so that the ground speed is under the grommet.
- Mark your heading/wind dot on the airspeed arc, at the appropriate amount of degrees difference between heading and course.
- Wind Direction at the top
- Wind speed dot, aligned with the vertical, center line, indicates amount of speed, as measured up from the grommet.