flyboycpa Heliman Location: Nashville, TN
| GPS is good but don't forget...Hey all,
Just another point to give on using GPS for determining straight-and-level speed:
I use a Garmin GPS III-Pilot in my full-scale airplane (along with a panel mount) and have used it to accurately determine my airplane's speed in level flight, at different altitudes and power settings. Since I'm in the plane, I can read out the current groundspeed. I fly on each of the cardinal headings (N,S,E, &W) for 3 minutes each, and record the groundspeed, then average it. This negates the effect of any winds-aloft (for the most part).
Remember, the GPS uses determines "GROUNDSPEED", not "true airspeed."
The GPS is only accurate when the wind is dead calm, otherwise you're groundspeed readout includes the effect of the wind.
So, your GPS is gonna tell you the max speed for the flight, which of course, is your downwind leg.
Take care,
Sam Swift |