the blades are corrected this morning --- RFC

[developer]

http://www.web7days.com/hydro/windmill2/tn/PICT00018.JPG.html

the 16 blades windmill actually spin itself when there is light breeze while
the three blades does not spin at all even though the center piece is a lot
heavier then the blades windmill that I build with aluminium.



RFC
http://www.web7days.com/hydro/windmill/ 16 blades
http://www.web7days.com/hydro/windmill2/ 3 blades

solar power arm board development team


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[Morten]

http://www.web7days.com/hydro/windmill2/tn/PICT00018.JPG.html

the 16 blades windmill actually spin itself when there is light breeze while
the three blades does not spin at all even though the center piece is a lot
heavier then the blades windmill that I build with aluminium.

I have no doubt that the 16 blade will spin in a slight breeze, but you
still _need_ the right blade profile (as mentioned in previous messages) to
do this effiently.

You wan't to extract as much energy from the air as possible and the better
the blades the more energy you can extract.

If I remember correctly the energy in the airstream is such that you will
get about 2kW with a blade span of about 3m, ie a radius of 1.5m at a
40-50Km winds, so to get any usefull energy at lower speeds (and less
efficient blade profiles) will be impossible.

How much energy do you need, are you planning for batteries or is the load
(was it a telly?) going to be driven directly by the alternator?

What's your average windspeed at the location where the windmill is going to
be located?


/Morten

 

[developer]

I have no doubt that the 16 blade will spin in a slight breeze, but you
still _need_ the right blade profile (as mentioned in previous messages) to
do this effiently.

no, in holland and greece, those big windmills does not even have real blade
profile at all.

You wan't to extract as much energy from the air as possible and the better
the blades the more energy you can extract.

If I remember correctly the energy in the airstream is such that you will
get about 2kW with a blade span of about 3m, ie a radius of 1.5m at a
40-50Km winds, so to get any usefull energy at lower speeds (and less
efficient blade profiles) will be impossible.

that is why I corrected three blades and I can extend to 9 inches more.

How much energy do you need, are you planning for batteries or is the load
(was it a telly?) going to be driven directly by the alternator?

the DC motor is being using and not car alternator which require 8000 rpm.

What's your average windspeed at the location where the windmill is going to
be located?

I hoisted to the roof only when I can achieve the next generation of my
design. everything will be aluminium except the three blades.

 

[Steve Spence]

And they aren't running electrical gens, they are grinding grain. You
need a proper profile for electrical generation. It's easily made DIY,
and no excuse for not doing so.

Do you even know what tip speed ratio means?

http://www.scoraigwind.com/selfblade/index.htm

Steve Spence
Dir., Green Trust
http://www.green-trust.org

 

[Steve Spence]

I bet they stop if you put a load on the "gen".

Steve Spence
Dir., Green Trust
http://www.green-trust.org