Hi - welcome to the fieldlines! I don't usually get into VAWT discussions because I honestly have no experience with it. There have been a few interesting developments here though over the course of time, but I'm not sure there have been any really successful machines other than perhaps Ed's design (windstuffnow) which seems to still be in the experimental stage - but very interesting! Micheal posted a fun story about an H Rotor he's working on a few days back, that's worth a read for sure!
Some comments:
"This means that I don't realy have to buy or run up a tower which gives some nice advantages."
All wind turbines like good clean non-turbulant wind. I think it's a misconception that VAWTS can live near the ground. I think folks like to believe that (because it's so hard to get them up into the air sometimes). You can put a HAWT near the ground too - it just wont work nearly as well (neither will a VAWT). To roughly quote Mick Sagrillo 'you may as well just leave it in the box if your not planning a tower', think this applies to either type of machine.
"I should be able to couple a Power Take Off to any store bought generator I want."
If your talking sails then I expect your talking a pretty slow machine, you'd really have to gear things way up. Probably feasable if you build it pretty big - probably not cost effective... hopefully lots of fun though!
Initial questions are.
"Which one and how large?"
Ed's design is pretty neat - look up postings and diaries by 'windstuffnow'. I also think the H Rotor probably holds some promise although I'd still not personally go the VAWT route (Id rather wait and let somebody else figure out all the problems for me first ;-) )
"Also I have not seen any vawt on the net or anywhere else similar to the one I have in mind."
There may be a reason for that!
Are there any windmill ideas which are presently patented?
"What I am imagining is a vawt which has sails instead of blades."
I think it would be very slow, and the changing wind direction every rotation would be very hard on sails.
"Has the laughter stopped yet?"
Hopefully not! Laughter is a healthy thing!
Try building a miniature version first. Years ago up here we were playing with a similar idea. It had sails. The bottoms of the sails were hooked to stationary 'arms' (4 of them) that were hooked to the bearing, and the tops of the sails were hooked to moving arms, which moved up and down according to a cam shaft which could rotate in the wind via a tail - so the blades always opened for the wind, and closed when they were coming into the wind. We called it the 'flapper' - and it was lots of fun. The first one we made was only 12" in diameter and it was quite amazing when you'd blow into it, itd spin up quickly and it was fun to watch the sails opening and closing just like they should. The next one was 4' in diameter and didn't work very well at all, it was very slow and didn't have much power (barely enough to turn itself around because there's quite a bit of work in opening and closing sails plus we had a lousy bearing).... but it was lots of fun.