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Wind-Powered "Greenbird" Seeks Land-Speed Record
Mike writes with this tantalizing excerpt: "Dale Vince of Ecotricity and engineer Richard Jenkins are setting up on the salt flats at Lake LeFroy in Western Australia, hoping to catch the right breeze and break the wind-powered landspeed record of 116.7 mph in their sleek wind-powered vehicle, the Greenbird."
You may not know, since your hobby seems to be bitching about the accomplishments of others, but when you try new things, you tend to learn new things.
Things that can be put into practice in other ways.
I hate to do this but...
http://justfuckinggoogleit.com/search.pl?query=sailing%20faster%20than%20wind%20speed
>;-)
You are not entitled to your opinion. You are entitled to your informed opinion. -- Harlan Ellison
Yes, I know how this is possible, and if you took elementary physics, you should be able to figure it out.
I'll give you a line of thought to follow, to get you started.
What happens when the wind hits the sail? Force is exerted on the sail, which is transferred into forward momentum of the vehicle. What happens when the wind hits the sail from directly behind the vehicle (in relation to its path)? What is the force exerted by the wind on the sail when the speed of the vehicle is equal to the speed of the wind?
OK, now what happens when the wind is coming from an angle (say, 45 degrees)? And what happens when the speed of the vehicle is equal to the speed of the wind? What force is exerted on the sail then?
"Trolls they were, but filled with the evil will of their master: a fell race..." -- J.R.R. Tolkien on Olog-hai
Really stupid ;-)
Just kidding, of course. The thing does have a sail, but it might not be obvious to the uninitiated. It's that thing that looks like a vertical airplane wing. As you may be aware, the sail on a modern sailboat functions much like the wing of an airplane. The rigid sail on this landsailer is actually much more efficient than a cloth sail.
This ain't rocket surgery.
For more information, people can go to the Greenbird web page or to the relevant wikipedia page.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
Being a sailor, I get that queston quite often. The explanation is simple and appears to be a bit contradictory; the sails generate lift from the wind created by the boat's own movement. If you are familiar with vector addition, it is trivial to see that the resulting "apparent wind" is the "true" wind (the wind speed and direction as seen by a stationary observer) added to the the speed of the boat, both which are vectors with different angles.
This is also the reason why iceboats (and probably also the "boat" mentioned in the article) almost exclusively sail with the wind from the side, not higher. They are faster than the true wind speed, and the direction of the apparent wind turns against the boat.
The phenomena of the apparent wind has a lots of uses in the world of sailing, and I'm just scraping the surface here.
Quantum hacker.
I wonder why that design hasn't become more popular. I suspect it was made illegal for racing.
Rigid sails are extremely inflexible compared to their soft counterparts. Every wind needs its own sail shape; different wind speeds, directions, wave heights, etc. all require different shapes. There is no rule against rigid sails, it's just too hard to bring dozens of huge metal foils on a boat.
Quantum hacker.