"Andy Dingley" wrote in message
...
On 12 Feb, 21:51, "Arthur2" wrote:

All wind turbines seem to be blades mounted vertically on a horizontal
axle/axis.
These can only be 100% efficient if the wind blows directly onto the face
of
the blades.

That's why they can be trimmed into the wind

Or indeed out of it, as one way to survive over-strong winds.

Vertical axis machines have much lower efficiencies in comparision.
They're getting better, and in gusty, crowded urban settings they
might even have the advantage.


Also I think the bladed turbines are more difficult to design mechanically
and maintain.
If the Anemometer had several sets of 'cups' of differing sizes with I
dunno...a sophisticated gearing
system that demesh cup sets if the wind is too strong and optimise for
starting up after a wind drop.

Arthur