Sail downwind faster than the wind!
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From: Tom Roberts on 1 Aug 2010 08:16 Y.Porat wrote: > about "sailing agisnst the wind' > it is an illusion!!! You know as little about sailing as you do about physics or math -- i.e. NOTHING AT ALL. There is no "illusion" about sailing upwind, and sailors do it all the time. Not directly upwind, mind you, but a good boat and crew can approach 45 degrees from directly upwind. Using alternate tacks the boat can have a long-term path going directly upwind. BTW a modern sailboat on a reach can sail considerably faster than the wind. But no boat can do so when running before the wind. If you don't know what these terms mean, look them up. They are standard sailing terms. Tom Roberts
From: bert on 1 Aug 2010 08:53 On Jul 31, 9:02 pm, spock <sp...(a)strato.net> wrote: > On Jul 30, 5:40 am, John Doe <j...(a)usenetlove.invalid> wrote: > > > It is discussed on the website (http://www.physicsforums.com) > > recently as this year. > > > I see some problems with the idea as argued. They keep talking > > about wind speed with respect to ground speed as if that is a > > power generator. They also seem to be pretending that gearing, or > > the difference between wheel and propeller rotation speeds, is > > somehow a power source. > > > The follow-on argument appears to be that you can sail directly > > into the wind. > > > I see no prior discussion here on UseNet. On the Internet, I see > > it is discussed as early as 2007. Apparently the idea was > > originated by Jack Goodman in 2006. > > A sailboat and wind turbines are not exclusively powered by the wind > no more than an airplane wing is exclusively powered by it motion > through the air. Sailboats cannot sail faster than their power source. > A sail on a sailboat and wing on an airplane use aerodynamic force to > generate motion and oppose other forces, and the power source for > aerodynamic force is relative airflow. Relative airflow does not > require the motion of an object through air or the motion of air > around an object or the motion of an object while in the air > (rotation) but either one, or combination of these ways of generating > relative airflow will cause aerodynamic force. > > The sailboat is powered by not only the wind but by its motion > through it (relative airflow or apparent wind to sailors). A sailboat > cannot sail faster than the relative airflow that is influencing it > and is ultimately what is powering the boat. The propeller on an > airplane not only moves it through the air it holds it in moving air > to produce a relative airflow. Think vacuum Think why golf balls have those tiny craters Think wind going across tall chiminey Curve wing of birds TreBert
From: bert on 1 Aug 2010 08:57 On Aug 1, 8:16 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Y.Porat wrote: > > about "sailing agisnst the wind' > > it is an illusion!!! > > You know as little about sailing as you do about physics or math -- i.e. NOTHING > AT ALL. > > There is no "illusion" about sailing upwind, and sailors do it all the time. Not > directly upwind, mind you, but a good boat and crew can approach 45 degrees from > directly upwind. Using alternate tacks the boat can have a long-term path going > directly upwind. > > BTW a modern sailboat on a reach can sail considerably faster than the wind. But > no boat can do so when running before the wind. > > If you don't know what these terms mean, look them up. They are > standard sailing terms. > > Tom Roberts No matter which way the wind blows he sets his own sail. He can set it to go faster than the wind blows.He is the master TreBert
From: Hayek on 1 Aug 2010 09:51 Tom Roberts wrote: > Y.Porat wrote: >> about "sailing agisnst the wind' >> it is an illusion!!! > > You know as little about sailing as you do about physics or math -- i.e. > NOTHING AT ALL. > > There is no "illusion" about sailing upwind, and sailors do it all the > time. Not directly upwind, mind you, but a good boat and crew can > approach 45 degrees from directly upwind. Using alternate tacks the boat > can have a long-term path going directly upwind. > > BTW a modern sailboat on a reach can sail considerably faster than the > wind. But no boat can do so when running before the wind. Are you sure ? Sometimes you can go faster by slightly downward tacking. Especially if you follow wind shifts, also a supreme tactic when going upwind. I remember they laughed at my compass. When I beat them for the first time, they all ran at the shop and installed one too. (Laser class) Uwe Hayek. > > If you don't know what these terms mean, look them up. They are > standard sailing terms. > > > Tom Roberts -- We are fast approaching the stage of the ultimate inversion : the stage where the government is free to do anything it pleases, while the citizens may act only by permission; which is the stage of the darkest periods of human history. -- Ayn Rand I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them. -- Thomas Jefferson. Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery. -- Winston Churchill.
From: Y.Porat on 1 Aug 2010 10:57
On Aug 1, 2:16 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Y.Porat wrote: > > about "sailing agisnst the wind' > > it is an illusion!!! > > You know as little about sailing as you do about physics or math -- i.e. NOTHING > AT ALL. > > There is no "illusion" about sailing upwind, and sailors do it all the time. Not > directly upwind, mind you, but a good boat and crew can approach 45 degrees from > directly upwind. Using alternate tacks the boat can have a long-term path going > directly upwind. > > BTW a modern sailboat on a reach can sail considerably faster than the wind. But > no boat can do so when running before the wind. > > If you don't know what these terms mean, look them up. They are > standard sailing terms. > > Tom Roberts ------------------ and i said similar thing and even more than a chemist can know !! and dig out as a parrot crook from the net... about the structure of mast etc your impertinence is much bigger than your personality Y.P -------------------------- |