Rick Cavallaro wrote:
On Sep 30, 4:28 pm, The Natural Philosopher wrote:

Conceptually its easier to think of it like a air paddle steamer car

The wind blows the car along, which drives the paddles which move
backwards against the wind. Therefore the paddle blades are never in
still air when the car is travelling at windspeed. So they can still
extract energy.

You're exactly right, but I'm sure that's more intuitive for some and
less intuitive for others. On top of that, you have to describe how
the forward moving paddles don't kill the whole deal. They need to
retract or feather in some way.

I'll put them in a housing.