jacques0, you wrote:
"I'm a little baffled by all this talk of a sail. The strat, according to what I've seen so far, is going to have rear vertical and horizontal stabilizers. These are, essentially, sails.
Think of a weathervane. The stabilizers would, I assume, keep the strat oriented nose-into-the-wind so that the props would only be needed to maintain position over a point on the ground.
Close your eyes and picture a big rooster on top of a barn."
While I think we all agree that an additional sail is not necessary to make the current design work, I believe the problem of maintaining station is a little more complex than motoring into the wind. The Strat is being designed as an aerodynamic lifting body, and will not be attached to an anchored pivot point as a ground-based weather vane would be. The planned six GPS positioning systems are surely intended to maintain position in three dimensions, so the engines will also probably need to pivot and work in conjunction with the lift and drag of the airship while minimizing the power requirements. And all this needs to be done in the low-density, occasionally volatile environment of the stratosphere.
While your rooster analogy is valid to an extent, I think it is a gross simplification of the actual navigation problem they are tackling, which should not be underestimated. Kudos to the team for hopefully coming up with a working solution to this multi-variable equation.
AI
