GSC prop as wind turbine???

[clare at snyder.on.ca]

A bit off topic - but what kind of power and speed might I expect to
get out of a GSC 68" 3 blade prop used as a wind terbine?
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[COLIN LAMB]

"what kind of power and speed might I expect to get out of a GSC 68" 3 blade
prop used as a wind terbine?


Are you trying to create wind or electricity?

Colin

[Chris Wells]

Propellers can't be used as wind turbines (at least not efficiently) because they're turned the wrong way.

[Vaughn Simon]

<clare at snyder.on.ca> wrote in message
...
>A bit off topic - but what kind of power and speed might I expect to
> get out of a GSC 68" 3 blade prop used as a wind terbine?

Assuming that you are trying to generate power from wind, the short answer
is "not much". Your prop has the wrong airfoil for that job. A good place to
ask questions about wind turbines is alt.energy.homepower and
alt.energy.renewable.


Vaughn

[[email protected]]

A GSC prop is a wooden ground-adjustable prop, isn't it? By
making the necessary pitch adjustment so that the wind is against the
bottom of the foil and the leading edge moves forward, it should work.
Ordinary fixed-pitch props won't work; they're great for driving, lousy
when driven.

Dan

[[email protected]]

>To do this, he'd have to be able to take the prop to
>significant negative pitch. I'd be surprised if a prop
>intended for an airplane would have sufficient negative
>adjustment range for this application.

Some of those props had blades with round roots clamped into a
hub, and the blade could be turned all the way around. The Warp Drive
prop is similar.
It occurred to me that the blade's twist would be all wrong for
the wind turbine application, anyway. The blade would have to turn a
lot to get the root to the right angle, and by that time the tip would
be close to feathered, just the opposite of what we need.

Dan

[clare at snyder.on.ca]

On Fri, 17 Mar 2006 06:41:21 GMT, "COLIN LAMB" >
wrote:

>"what kind of power and speed might I expect to get out of a GSC 68" 3 blade
>prop used as a wind terbine?
>
>
>Are you trying to create wind or electricity?
>
>Colin
>
Put it this way - not wind.
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[clare at snyder.on.ca]

On Fri, 17 Mar 2006 12:24:26 +0000, Chris Wells
> wrote:

>
>Propellers can't be used as wind turbines (at least not efficiently)
>because they're turned the wrong way.
So you turn them around. Flat side to the wind, fat side to the wind.
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[Chris Wells]

> So you turn them around. Flat side to the wind, fat side to the wind.


Nope, twist is the wrong way.

[COLIN LAMB]

The optimum wind generator blade in terms of efficiency is a thin two bladed
prop. It will have about 70% efficiency. The power output depends upon
wind speed and will increase based upon the square of the wind speed.
However, a governor is required to prevent overspeed.

An efficient 68" two bladed prop would have about 5 watts output with a 5
mph wind, 100 watts with about a 14 mph wind and 500 watts with a 24 mph
wind.

I have both commercial and home built wind generators and what has been said
about using an aircraft propellor is true, they are not good wind generator
blades. It is fairly easy to carve a blade and I have made them with a
table saw and hand plane.

But, you cannot simply put the system up without a bit of thought. My first
wind generator I installed was a "temporary" one. Just a hand carved blade
attached to an electric motor. We normally do not have much wind, but that
night we had a 30 mph wind. The next morning I noted the blade was missing
on the wind generator. I looked for a month before I found the blade lodged
in a tree about 100 feet away.

Two bladed props are most efficient, but they create havoc. They shudder
when the wind changes direction and create stresses on the entire mechanism.
3 bladed props solve that problem, but are harder to make at home. Another
problem area is the gear boxes. Alternators like higher rpm than created by
the blades and the varying wind can put terrific loads on the gear boxes.
Many of the early commercial units suffered gearbox problems. A low rpm dc
motor can be used as an efficient generator. One of my home built designs
uses a 36 volt 900 rpm permanent magnet motor and works quite well.

Wind generators need a governor. Otherwise, high or medium winds will tear
it apart. In that situation, they can become lethal.

They are certainly fun to watch. Much more fun than a soap opera.

Colin

[clare at snyder.on.ca]

On Fri, 17 Mar 2006 15:47:08 -0500, T o d d P a t t i s t
> wrote:

>clare at snyder.on.ca wrote:
>
>>>Propellers can't be used as wind turbines (at least not efficiently)
>>>because they're turned the wrong way.
>>So you turn them around. Flat side to the wind, fat side to the wind.
>
>As someone else pointed out, you can't just "turn them
>around." First, you have to reverse the pitch, which you
>can only do on a limited number of props. Second, even if
>you reverse the pitch, the twist is wrong. You'd need to
>reverse the twist too, and that is something you can't do.
>It might still work, but probably not very well..

With the exception of the twist, it was all possible. I knew I had to
be missing something, and I'll dig the prop out tomorrow and confirm.
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[00:00:00Hg]

On Fri, 17 Mar 2006 11:31:11 -0800, Dan_Thomas_nospam wrote:

> It occurred to me that the blade's twist would be all wrong for
> the wind turbine application, anyway. The blade would have to turn a
> lot to get the root to the right angle, and by that time the tip would
> be close to feathered, just the opposite of what we need.

I have sort of reinvented the windmill.

If you are interested.