Re: What about this?
Interesting.
1674 publicly visible posts • joined 5 Jul 2010
The average airspeed is indeed zero. Regarding testing, the problem with a tethered truss is that can't move freely with the breeze, and is therefore artificially subject to wind pressure.
See our fantastical flying truss video, which demonstrates how, if you've got a tether, the truss is pulled down towards the ground by any wind, while it floats gracefully once released.
We often get asked about the PARIS balloon, Vulture 1 and payload passing through the jet stream, as if they subject to extreme winds as you would be if you were a house in a hurricane.
Our PARIS experience showed that the biggest potential problem is long payloads spinning closer to the ground, although a swivel fitting ensures the lines can't get tangled.
Clarification: the rod does indeed pass through the Vulture 2 fuselage. The sleeve's internal diameter is bigger then the rod, so the aircraft can "rock" slightly during the ascent, to prevent icing.
We're going to test the whole assembly in dry ice, to see what happens at really low temperatures. Watch this space...