I've built some similar to this one. What I found was they tend to work in a "band" of power not the entire blade. When you take a simple savinous for example and you have 2 wings or cups catching the wind you have a "pulse" of torque. If you stack them in line with each other the pulse or torque increases as the area increases. To over come the pulse you can stager the blades which smooths out the pulse but you also reduce the overall torque to the area exposed at a given time. If you have say 4 blade sections that will produce 5 ft lbs of torque each and line them up you'll achieve 20 ft lbs of torque but as a pulse as the blades transition themselves in the wind. If you stager them you get 5 ft lbs of torque over the full 360. So your working in a band of each section that is in place to produce power. So which is better 2- 90 degree pulses of 20 ft lbs or 360 degrees of 5 ft lbs?
It is a nice looking design but I'm not sure the complexity will compete with a standard simple HAWT design. I built one to test the theory using short wing sections that could be adjusted. When they were lined up ( equal amount on each side ) there was a noticable increase in power output as opposed to offsetting them to create the helix.
100's of lifetimes worth of fun and I only have one to play with...
Have Fun
Windstuff Ed
