The latest Hammacher-Schlemmer catalog offers a hot air balloon for $49,000. The description of what you get includes an airspeed indicator. Since the airspeed of a balloon is zero, except for gusts, what is this thing? One thought that occurred to me was that it's really a ground-speed indicator, using a GPS, which would tell you how fast the air mass you're in is moving, which I suppose might be useful. But that would be an odd use of words, unless maybe balloon people have their own jargon. Anybody know?

I'm with you. Unless I am missing something the airspeed is zero. GPS based speed is a logical conclusion....

Scott

Vertical speed? But even there I'd expect the GPS based idea to provide both ground and vertical speeds.

I vaguely remember mention from a hot air balloon instructor that they have an anenometer type instrument strapped to the side of the gondola that they use to sense windspeed and direction changes as they move through boudary layers as the climb/decend so they can bettee inform the chase crew where they may end up.

granted with Gps receivers/trackers now, that is probly an outdates tech that is less likely used.

You may still have some relative wind, but GPS-based groundspeed is all it can be.