VAWT blades with twist

[funkyspider]

Hi, I'm a fairly new hobby level user designing for 3D printing.

Spotted this VAWT design in a recent Starfield demo video and thought they'd make a nice desktop sculpture.
Tried all the ways I can think of and find tutorials for to create the twisted blades.  Closest I got was a Loft with a rail.
Taking the right hand blade in the image it starts on the top-right, bows out with a twist finishing bottom-left. 

 

[etfrench]

Try a surface workspace sweep.  You may need to combine multiple sweeps with different pitches.

[Bunga777 · Accepted solution]

It looked interesting, so I made it.

First, I made an extension of the blade. This is to connect the surface with G1.

Create profiles at the start, middle, and end points and Roft with Tangent(G1),Align Edge.

I added thickness to the surface and rotated copy.

It looks a little quaint, but I think I can get away with adjusting the orientation of the profile the rest of the way.

I have attached the data.

[funkyspider]

Thanks.
First prototype designed and printed 🙂

[Bunga777]

Excellent!!!

Does this thing really spin when you blow on it?

[funkyspider]

When I'm happy with the design I'll switch the blades to a wing profile, scale it up to print large enough to hold bearings and a 8mm rod down the middle and it should spin outside. 

The desktop version I'm working on will be driven by a small motor. I'll publish on printables.com when complete. 

[wersy]

On your Darrieus turbine you have succumbed to an optical illusion.
The profiles must not be twisted!

But you will be very disappointed, Darrieu's turbines have a very low starting torque. That means it needs a lot of wind to get it moving.

As a starting aid, I have combined it with two kinds of Savonius blades 😉

https://autode.sk/3te1ImM

[Bunga777]

@wersy 

Are you sure?　It's not screwy?

I had modeled it as something completely twisted.

I need to look into it a bit too.

[Bunga777]

I see what you mean.

The principle behind the rotation of these wind turbines is the same as the mechanism by which airplane wings gain lift, so they don't have to be twisted.

Rather, the cross-sectional shape of the blade has to be similar to that of an airplane wing.

[wersy]

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@Bunga777  schrieb:

I had modeled it as something completely twisted.

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Then you have created something like Savonius 😉
However, unlike Darrieus, Savonius does not move faster than wind speed.