An unusual VAWT

[jimpep]

VAWTMAN:

I like the VAWT experiments. I am lucky to have access to free magnets and metal so I have only a few hundred dollars into my experiment, a  12' x 4'... 2 square meters area savonius... but the reality is that to harness some more practical energy,  we need something the size that windstuff proposes earlier. This can done more economically with a HAWT and the available area appears to be a lot easier to obtain. If the tower could stand it I will place a HAWT on top of the VAWT tower I already have and show both devices at once to the public.

Jim

[vawtman]

Hello Jimpep

  I agree that these need to be large maybe 4 times the swept area of the hawt.I did a calculation on Wind4regs calculator posted awhile back and found that doubling 8x8 I could get 4 times more power at the same windspeed.

 That was for an true hrotor.I Think has posted earlier when I go to 16ft this summer it would benefit to have more blades

  You idea would be cool to watch.Sorta like my counter rotating vawt idea.

[oztules]

just an observation vawtman, notice how the calculator you refer to has no input for No. of blades?... Does this indicate that blade no's have no bearing on the power output for a given size?

..............oztules

[vawtman]

Oztules

  My thinking is that multiple blades would help with low wind performance.And from Anthonys comments on thin blades spinning faster(i dont think we want that with Hrotors in high winds)Maybe a wider profile could control the speed in high winds.

  My goal is to add more blades and see how it compares to the calculator.

 The figures seem pretty lean to me.

  P.S you where right about the 5Hp being too much for the 8x8.I havent connected it yet but i think shes gonna struggle to spin it.

[vawtman]

Sorry Oz

  Im sure the reason it doesnt show blade numbers is because Hrotors are usually 2 bladed machines.Maybe when Im done testing we could add more figures to see differences if any.

[oztules]

Oh joy yet another project for vawtman....

must have a very patient wife.

my first guess is that it will affect speed and torque, but not the power, until you start to get shadow and solidity effects from too many blades at a set RPM....similar to the hawts.

If true, then the less blades the better to keep rpm up, and gearing down.

.........oztules