I have a Garmin Forerunner 201 wristwatch-like device that will record your track, set waypoints, record top speed, and distance traveled.

I converted a Goldberg Eagle II to electric. I put the Garmin inside the hatch. Flew the plane. 117 MPH!!! I wonder if Ishould have put the Garmin somewhere not next to my ESC.

I haven't had a chance to re-run the test, every time Iget to the flying field, I've forgotten to bring foam or something to secure it so it doesn't flop around inside the plane.