Faster than the wind?

[GLS]

Nice videos about a non-intuitive physics problem:

 

[Urwumpe]

Well, if sailing yachts and iceboats can do that easily....

But I am not sure if wind turbines are THAT effective compared to a sail.

EDIT: OK, they did not know about the trick with the pendulum hub, that makes it possible to let wind turbines operate with minimal vibrations, despite lift of the blade dropping when it is passing the tower structure...

 

[N_Molson]

Well, if sailing yachts and iceboats can do that easily....

Yes, a good and well-skipped sailboat is able to build her own wind - relative wind. That's a bit counter-intuitive, and from my own experience requires a lot of practice more than theory - but that's how it works.

 

[steph]

I think the whole confusion comes from the fact that this works more by pushing against the wind rather than being pure wind-driven as one might expect. Going at windspeed you'd have zero thrust from the wind, but this isn't built or geared like that., so you basically have the wheels driving the prop to allow it to go faster before other forces intervene. It's still wind-driven, but it's more efficient.

 

[N_Molson]

I think the whole confusion comes from the fact that this works more by pushing against the wind rather than being pure wind-driven as one might expect. Going at windspeed you'd have zero thrust from the wind, but this isn't built or geared like that., so you basically have the wheels driving the prop to allow it to go faster before other forces intervene. It's still wind-driven, but it's more efficient.

Actually, with a sailboat (I mean a modern Marconi Jib/Mainsail configuration) as you build speed, the apparent angle of the wind shifts. The faster you go, the closer from the wind you can go, and sailboat races are all about mastering that phenomenon (as well as efficient teamwork). Of course there are limits, I'm speaking about a few degrees of heading, but it makes the difference (with narrower angles you can travel shorter distances by making turns against the wind).

 

[jedidia]

Actually, with a sailboat (I mean a modern Marconi Jib/Mainsail configuration) as you build speed, the apparent angle of the wind shifts.

As I understand it, modern sailing boats are propelled forward by the same effect that generates lift from an airplane's wings...

 

[N_Molson]

As I understand it, modern sailing boats are propelled forward by the same effect that generates lift from an airplane's wings...

And that's it. The faster an airplane goes, the more lift the wings generate (up to a limit of course).

 

[Arvil]

Even the square-rigged sailing ships, as the wind passed between sails, it produced ‘lift’ forward, they didn’t understand the physics of it, but, they were expert on how to use it.