Turbinas Eólicas de Eje Vertical, lo último en generación eólica. - YouTube
lenz airfoil - Google Search
Wind turbine maximum efficiency
Vertical wind turbine alternative from Italy. [The Future of Energy: http://futuristicnews.com/category/future-energy/]
How to Build a Retractable Awning • Ron Hazelton Online - This is a bit rough and ready but the idea is sound. I think I would add baton or bamboo to create a more orderly shape. I'm sure it would work....