Actually the "dimples" might help. As long as you can keep the air flowing over the surface your fine, but you will be breaking the air from the drum each time the wing passes. This creates turbulance and will break the coanda effect. If its running fairly fast it won't have time to reorganize effectivly.
There was another one that used the venturi effect but to a lesser degree, a 2 blade unit with a Football shape in the center. Suposedly, they run fairly efficiently. It was patented back in the early 80's... its called a Ropatec
I started the Lenz turbine project shortly after a guy sent me an email about another one that used the venturi effect, also patented back in the early 80's. After building one from the specs he sent I wasn't impressed with it at all but was intrigued by the idea. Below is a patent drawing of the venturi turbine emailed to me...
Below is the one I originally built as a test machine...
Then of course the infamous 700 rpm coffee can ...
I made up a mini dyno to check the locked rotor torque at any angle of rotation while in the wind and found all the failings of the machine. Decided to start from scratch with some new ideas out of the results and that's how the Lenz turbine was born. 1 machine and several tweeks later it ran ( runs ) quite well but still has several bugs that need to be worked out before I'm satisfied with it...
Fun little machines!
Winstuff Ed
Have Fun!
Windstuff Ed
[ Parent ]
