I have been using a Garmin 101 handheld GPS for a few years now to measure the speeds in my r/c cars and boats. I suppose it could be stuffed into an airplane as well, it is fairly small but probably not as small as newer units today, I don't know. Anyway, it measures max speed, average speed, and all that other junk too.
I don't understand the KMZ and Google thing and what the point of it is. I have seen some photos of the 'tracking' a model airplane did during its flight and it just looks like a jumble of squiggly lines to me.
