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Old 02-26-2021, 05:04 PM   #659 (permalink)
Bicycle Bob
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Originally Posted by freebeard View Post
This is an aerodynamic oddity so I'll drop it here.

I've mentioned a few time that R. B. Fuller advocated for indoor windmills. I've always liked the idea. Here's someone who gets it.

It's not clear about their hubless rotor design but the converging duct is the key. This needs to be embedded at the zenith of a sizable hemisphere. Then the guide vanes can be extended to increase that 40% factor. Putting it on top of the hemisphere increases the nominal wind speed even more.

It appears to be a 1kW device. There is a Kickstarter page, but it doesn't like Raspian's system clock.
Yet, every single analysis shows that unless you are dealing with limited space or other exotic conditions, you always get more bang for the buck by taking material from the ducting and adding it to the turbine.
That said, if I were buying wind turbines, I'd save time and money by using guy wires on the tower below the turbine blades, and add a fairing to the upper tower that turns with the power head. The blades would probably also benefit from short guy wires. Anyone who has put up a dodgy shelf should be able to appreciate the potential savings.
There is no excuse for a land vehicle to weigh more than its average payload.
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