Jed Rothwell wrote:
Jones Beene wrote:
> I do not think those gigantic kites would require ultra-strong tethers. They would not pull on the tether much.
This could not be correct, logically.
IF you were right and the kite "would not pull on the tether much" then you don't need a tehter at all!!
Right, and that just proves that the assertion was incorrect.
Good point. It sounds like a boat sailing into the wind.
Wrong. A boat can't sail into the wind without a keel, and the tether is providing your keel.
A sailboat that can sail directly into the wind, using a turbine and a (wet) propeller, is once again "braced" against the water.
In either case, if you view the boat from the frame of reference of the _air_, you see that the energy to push it is coming from the "relatively moving" water. In a 10 mph breeze with a tide going at 10 mph in the same direct a sailboat of _any_ sort is dead in the water.
You always need to be able to answer the question "where does the energy come from?", and you need to be able to answer it in every frame of reference, including that of the wind.
At least for the initial designs a tether would probably have many advantages
Yes, like, for example, it works. Take away the tether and you've got no energy source. Again, view it from the point of view of an observer comoving with the wind: Where does the energy come from to push the turbine through the air? Answer: The (relatively moving) tether.
On the other hand, a tetherless design would be a lot safer for aircraft in the area.
But it's impossible.
