My twin table leg turbine!

I have shrunk it Matt, I've moved the blades down towards the centre with the addition of just one more hole. ;)
The blade angle is 25degrees,not a radius though just a single bend put in with a wooden jig and the weight of my car :mrgreen:
Totally still here now but supposed to be 20mph winds arriving tomorrow. 8-)

I misunderstood what he was suggesting. I thought he was talking about a VAWT, not a conventional HAWT. My mistake. But adding more blades past 3 is not going to help. If anything you'd want to decrease blade count, but that adds vibrations...

You already know how to gain more rpm's with this setup, and that is to decrease that curve. Wish you had yourself a 4' brake.

You could also try adding a few more blades. This would allow you to shorten the blades even more and you would increase your rpm's even more. And by adding the extra blades, you should be able to maintain, or possibly even increase, your start-up torque.

Of course, at a certain point adding more and more blades will work against you and the turbine will actually spin slower. But, if adding more blades allows you to dramatically decrease the blade length, while maintaining the required torque, then you will definitely increase your rpm's.

Then again, a properly designed blade set will have the TSR and swept area to match the alternator and design voltage at the target wind speed.

"There can be only one." -Conner MacLeod

My shrunk diameter is working!
25mph winds yesterday and last night and its flashing 5 LEDS of the 8 available on the grid tie. :mrgreen:
Think I might be better going the other way though as it needs at least 18mph winds to do anything right now. If I aimed for a 14v cut-in as with some inverters I think I could make power in much calmer conditions going back to the original 2m diameter.
It will be in a state of stall but I only need 200w from it! :?

hi Shawn

i like your downwind approach to mills .....

coning the blades might be interesting to help with general stability /running ....its something
i hope to experiment with ...
downwind ...(i think) ...seems to be a little bit like being seduced by the dark side ......sometimes frowned upon ........but always interesting

if a windmill wore a mini skirt .......i,d like to think it was an inch higher downwind

good luck with your testing Shawn

niall

I've tried coning and dishing :mrgreen:
Tried it last year. It just lets the air escape more easily and you get less power or that's how it seemed to me :mrgreen:
Look at "Proven" they use coning to furl.
Got no testing equipment just an eye for it I hope! :mrgreen:
Downwinds are really stable compared to upwinds I've had both with the same blade sets on. You don't need to furl if you can soak up all the extra power in my opinion. :?
With a grid tie capable of pulling a constant 200w an occasional 1kw could easily be run off especially with a battery being used to soak up the extra and keep down the volts. ;)