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Why are wind turbine blades long and skinny instead of short and fat? - Page 10

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Posted by Bob F on April 11, 2010, 5:11 pm
 


Energy Guy wrote:

Except for turbulance and structural considerations. Also, Imagine the twist
these wide blades would have to have from the blade center to tip to match the
differing velocity (in the same wind speed) from the slow moving center to the
fast moving tip.

Ever notice that the most efficient airplanes have very narror wings. Take a
look at gliders for instance. Or the new electric planes. Wide wings have much
more turbulance. They are more sensitive to stalling. Tip vortices are way more
loss inducing.

A airfoil wing shape has lift when moved through the air. Part of the vector of
that lift is directed in the direction of rotation, increasing the power. The
airfoil also has low turbulance, reducing losses.


How do airplanes maintain speed during a glide?

They get forces forward from the forward vector of the lift when angled slightly
downward.


The blades can be designed that way, or they can be strong enough to not need
it, allowing optimization of the blade for higher power.


Most of the airplane propellers I've seen certainly do have an airfoil shape.



Posted by vaughn on April 11, 2010, 6:08 pm
 




Bye!  You just made my troll list.



Posted by Guy that is Energy on April 11, 2010, 6:18 pm
 

vaughn wrote:


And you just voluntarily surrendered this thread and argument to me.

Posted by wmbjkREMOVE on April 11, 2010, 7:33 pm
 

On Sun, 11 Apr 2010 14:08:51 -0400, "vaughn"


The funniest part is that if energy-nut's theory was correct, it would
have to mean that a whole lot of successful folks are very stupid.
What does he think, that none of them ever noticed how much air that
skinny blades were letting "escape"? The mind boggles. Note to any
gullible readers: energy guy's theory is popularly touted on Ebay in
order to help fleece buyers of poorly constructed wind turbines. Wise
up, blades are cheap. If adding extra ones would create a performance
advantage, then reputable makers would be all over it.

Wayne

Posted by Josepi on April 13, 2010, 2:37 am
 

Two blade turbines, apparently, produce just as much power as multi-bladed
ones.

However, I understand two bladed turbines can stall and not self start again
so three blades have become popular.

On Sun, 11 Apr 2010 14:08:51 -0400, "vaughn"


The funniest part is that if energy-nut's theory was correct, it would
have to mean that a whole lot of successful folks are very stupid.
What does he think, that none of them ever noticed how much air that
skinny blades were letting "escape"? The mind boggles. Note to any
gullible readers: energy guy's theory is popularly touted on Ebay in
order to help fleece buyers of poorly constructed wind turbines. Wise
up, blades are cheap. If adding extra ones would create a performance
advantage, then reputable makers would be all over it.

Wayne



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