Fin angle? Increase the performance!

[letmepost]

Hi,

I'm going to redesign my turbine's fin, and change it to an aerodynamic shape.

This is my previous design.

www.ImageShack.us" src="http://img49.imageshack.us/img49/6526/p1010005va2.th.jpg">

www.ImageShack.us" src="http://img239.imageshack.us/img239/5967/photo0022cz0.th.jpg">

and I redesign the fin from a semi circle to an aerodynamic shape.

this the idea,

however I'm not sure which angle of the fin can have a better performance

and these are the angle that I figure out,

1.

2.

3.

4.

A guide vane will be added for tested too, but I wonder if there is a guide vane to direct the wind, will the angle of the fin be not so important anymore?

and other idea to enhance are most welcomed =)

thanks

[electrondady1]

you are well down a road very few have travelled .

are the vane shapes you are suggesting for a  redirecting mechanism for your existing squirrel cage?.

or for a new squirrel cage design ?

[electrondady1]

from your drawing i am wondering if overall solidity might become a factor .

check out this place.

http://www.vawts.net/index.spark

[letmepost]

hi, is for both to test out and compare.

by the way, i just tried idea 1 today. it failed

1.

turbine was turning anti-clockwise instead of what i expected(clockwise).

the result was not satisfied, so I change the angle into second idea.

2.

the result was improved, and turbine was able to turn @ 2m/s. (without guid vane)

I'm in doubt and don't understand the failure of idea 1. Why it turned at an opposite direction?? and why second idea is better than first idea? is there any formula or software to determine the resultant force of this aerodynamic fin??

thanks =)

[electrondady1]

hello

if you can consider one side of the axis to be up wind (the drag side). and the other side to be down wind(the power side),

i would imagine in position one the upwind side somehow is  presenting an overall better surface for the wind to  give energy.

is it possible to construct your prototype with vanes that are adjustable?

it looks as though small variations in fin angle could produce large differences in

output.

i like your design,

here is a new forum just for vertical axis mills

http://www.vawts.net/index.spark