Randy,

Thanks for the comments. I finally got some advice back from a member of the Australian F3D team, who has had no trouble tracking F3D models up to 350km/hour on the course from over 100m away using a Stalker Sports unit. He reckons you do not need the Stalker Pro to measure the speed of anything we fly.

I recently got an Eagletree Flight Data Recorder to see what my models were doing. While the data is great, it is a pain to download at the field and try and view on a computer screen in bright sunlight (lots of that downunder this time of the year). I concluded that if you want to do a lot of experimenting to determine what works best, you need a radar gun. The only question was what sort of gun.

By the way, I am told that speeds measured with the Stalker Sports Unit have calibrated very well with Eagletree results.