so narrow, so it'd seem like they're not very efficient for catching the wind, whereas with an axial-flow electric fan (your traditional basic fan), the blades are rather wide, which seems to be because that'd make them more efficient because of more surface area for pushing the air–so that they could go faster with the same amount of wind, maybe? And then if they go faster, wouldn't they generate more voltage, which in turn generates more current, which could then be spread over more batteries at once, maybe?
Or in other words, if there's more surface area on the blades of a basic fan, because that would tend to push more air than just little narrow, slivery blades, then why aren't the blades that RECEIVE air shaped the same way–so that they could probably catch more air and therefore probably go faster, and therefore generate more electricity at once (more voltage, therefore more current)?
Hey, will you come back and see my responses to your answers, please?
Thanks,
Mike
Hey, both of you so far (Boogerhead and Jamus), thanks for your answers. They both sound pretty good. But I still have a hard time understanding how a relatively thin bar on these wind turbines–compared to the blades on a basic fan (rather than a squirrel cage type–different discussion for a different day), and with proportion taken into consideration, too, of course–can catch more air than if you had the more cupped shape of the blades of…oh, say…a scaled-up Patton high-velocity fan. What's the purpose of the cupped shape of the blades on a fan? That would push more air than if the fan had little needlishly-shaped (though somewhat wing-like, as you've said), wouldn't it?
Oh, and consider the much greater amount of space between the blades on one of these wind turbines vs. the lesser amount of space on the fan. When you have so much space between blades, then how does so much wind not get passed on by? For example, if I were to design 2 desk fans, and one had traditionally-shaped blades and the other had these little narrow blades, and if I blow on the traditionally-shaped one, won't it spin much better than if I blow on the one with little narrow blades? Isn't that because 1. there's less space between the blades and 2. the blades are cupped a little? Then how can these wind turbines–even with their wingish shape–be so "efficient"?
If you first two answerers have something to add to answer my follow-up question, will you edit your answer and then just add your follow-up below the original, please?
And to others reading this, of course I welcome your new answers, too.
Thanks, guys,
Mike
Oh, one more thing. Okay, so some fans don't have the cupped shape in their blades, but most still have a lot less space between their blades than these wind turbines do.
Different design constraints:
In either case, the blade is an airfoil (a wing). One may characterize an airfoil in terms of the ratio of its lift to its drag. A wing with a high ratio of lift to drag makes more of what you want and less of what you don't want (so you might want to say it's more efficient).
A long, narrow wing will tend to have higher lift/drag, so it would be preferred for a glider or windmill, where high efficiency is desired.
A short, fat wing will be less efficient, but it will fit in a smaller space, so you'd want to use it for a portable fan.
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