Fw: Energy harvesting kites?

[George Holz]

Jed wrote: >Still, I do not understand how to calculate the strength of the tether. It seems to me it must be enough to overcome drag only. The Skypower people are talking about building 20 MW units. Obviously a tether could not withstand the force of wind that creates that much energy! The physics are unclear to me, but the wind energy that goes to spin the turbines does not pull on the tether. So what does? Under steady state conditions no energy is transferred to the tether. I think that the tether force can be estimated from conservation of momentum at the blade surfaces. As the air is deflected by the blade the change in momentum causes both the turning force on the blade and the tether force. The reduced forward momentum of the air results in the tether force. Some of the references you have to tower based wind turbines must calculate the wind loading on the tower due to the baldes. These calculations are essentially what you need to calculate the tether force. > http://www.lenr-canr.org/PSJ/CatalogAcrobat.pdf >This is the catalog for an art exhibit now being held at the Japanese Embassy Culture Center in Washington, DC, in case you are wondering. This art exhibit looks fabulous. Is Junko Ono Rothwell your wife?   George Holz Varitronics Systems