Why use the traditional?

The blades of the turbine, and the hub they are attached to

Why use the traditional?

Postby Maddragoon on Tue Jun 05, 2007 5:11 pm

I've been seeing nothing but the traditional "prop" type blades for use on the wind gennies and i dont really see why. If I ever get the time I am planning on trying a vertical turbine on a small shaft. something i've seen in numerous scifi films and books.

it seems like that would save alot of engineering. it would be omni-directional (no need for a tail fin), the generator would be in a fixed position (no need for brush slide power connection) being an apparently solid object the danger to birds and bats would be reduced (one of the main factors the wind industry is facing here in the USA right now) and the biggest thing (at least to me) the blades wouldnt have to be painstakingly carved and shaped.

nearly any matterial could be used for the blades, as both ends would securely anchored. something as light as nylon cloth or as heavy as steel sheeting. I saw a design by an austrailian fellow that used halves of 50 gallon steel drums to power his vertical wind pump. granted, that heavy of a design would not make a good electric generator directly attached to the rotor but using a gear/pulley system it could be doable.

there alot of things to consider with this design, obviously, but I think it has some serious potential.
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Postby windgat on Fri Jun 08, 2007 1:29 am

Hi there. These vertical axis designs (or VAWT) were invented by Darries in the 1920s. For various reasons, they have faded away, and few if any are manufactured on a commercial basis.

There are two types - drag blades, and lift. Drag blades (like cups, or half drums) are not efficient (about 15%), and lift blades have the catch that the turbine does not always self start - it has to be spun externally at first. Also, drag blades have higher torque (hence are good for pumping) but lower speeds.

Some hybrid ideas are interesting, like the Savonius rotor (remember, Google is your friend...).

Two definite advantages are omnidirectionality, and ground level generator (vertical shaft).

Sometimes there is a good reason why everyone does something the same way... but there again sometimes not! So why not make a model and see what you come up with?
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