"Bravo Delta" wrote in message
...
Can somebody please explain to me the technique to measure your plane's
true
airspeed by flying in 3 or 4 different directions for a while and
recording
GPS ground speed ? Do you just fly the same amount of time each leg and
average the groundspeed readings ?

Go out and fly three headings that are 90 different from each other. It
doesn't matter what they are but it is easier to just use cardinal headings
like N, S, E or W. Let the ground speed stabilize and write down the
ground speed. Then plug it into one of these websites. The website will
also tell you the wind direction and speed. To verify the results use four
cardinal headings and use any three of them. You will see the TAS and wind
come out the same.


www.reacomp.com/true_airspeed/index.html

www.csgnetwork.com/tasgpscalc.html