Sail downwind faster than the wind!
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From: Cwatters on 31 Jul 2010 13:01 "John Doe" <jdoe(a)usenetlove.invalid> wrote in message news:4c5316c3$0$21145$c3e8da3(a)news.astraweb.com... > "Cwatters" <colin.wattersNOSPAM TurnersOakNOSPAM.plus.com> wrote: > >> Oh I agree. Next time you hear they plan to run the vehicle buy >> yourself a plane ticket and go measure it's performance >> yourself. It's probably the only way you will believe that it's >> possible to go down wind faster than the wind. > > Or I could buy a ticket to a magic show. > > A simple explanation would do. The idea that a propeller spins in > the wind and that power can be transferred to wheels is easy. That's correct when going upwind but wrong for the DDWFTTW case. Going downwind it's actually the other way around. The wheels power the prop. In effect the cart is "squeezed" between the ground and the wind. That will sound like nonsense but I promise you that's the correct explanation. Don't take my word for it, go read the explanation provided by the people that designed it.
From: Cwatters on 31 Jul 2010 13:02 "John Doe" <jdoe(a)usenetlove.invalid> wrote in message news:4c531526$0$4980$c3e8da3(a)news.astraweb.com... > Where is the United States patent? Since it's been public domain since 1950 or 60 I doubt it can be patented. I believe there is a British patent for a boat version but can't be bothered to look it up.
From: Cwatters on 31 Jul 2010 13:39 "Benj" <bjacoby(a)iwaynet.net> wrote in message news:28ee6fb7-1a04-4383-b075-576009418afa(a)x21g2000yqa.googlegroups.com... On Jul 30, 7:40 pm, Sam Wormley <sworml...(a)gmail.com> wrote: >> In 2009, the world speed sailing record on water was set by a >> hydrofoil catamaran sailing at 1.71 times the speed of the wind. >> See:http://en.wikipedia.org/wiki/Sailing_faster_than_the_wind >Oh sure, Sam! If it's in Wikipedia it MUST be true! Sure, that's one >reliable source you've got there! how about some peer reviewed >scientific papers? Aren't any are there? That' s because EVERYBODY >knows you can't sail faster than the wind! It's just nonsense. Only you think it's nonsense. The rest of the world just gets on and does it. Before you embarrass yourself again go read some of the many books on the subject. There are plenty out there.
From: spock on 31 Jul 2010 21:02 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.
From: Y.Porat on 1 Aug 2010 07:59
On Jul 30, 12:11 pm, "Cwatters" <colin.wattersNOS...(a)TurnersOakNOSPAM.plus.com> wrote: > "John Doe" <j...(a)usenetlove.invalid> wrote in message > > news:4c529e1b$0$21228$c3e8da3(a)news.astraweb.com... > > > 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. > > That's exactly how it works. The maths proof of how it works and a solution > for the conditions under which it works is also out there on the web. A land > based version was recently built and tested. It achieved more than twice the > wind speed. See Youtube. I believe the first working machine to do it was > built in the 1960's. > > > The follow-on argument appears to be that you can sail directly > > into the wind. > > Also possible and has been demonstrated many times, including on full size > boats. > > > 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. > > This has been discussed a million times on different forums. . > > Aside: America Cup yachts manage to sail between two points (one directly > downwind of the other) faster than the wind by "tacking" downwind. If they > can do it the rest is just engineering. ----------------- about "sailing agisnst the wind' it is an illusion!!! as usual mathematicians are discussing 'paper discussions '' on issues tha they never experienced in reality!! th ereality is that **the wind is never steady in just one exact direction it is always do some swirling movement now the sail is not as 'innocent as you immagine it is built as on one of its edges you have the stiff mast while onthe otherr edge of the sail you have a flexible cable bottom line youget a sort of a push selector that accumulates manulty the push force on th e mast and nearly neglects the force in the cable !! now together with the steering system you can direct the boat to the desired direction!! 2 in addition to that the boat is moving in a zig zag line against the wind one thing is sure sailing at those times was much more knowledgeable and exciting than in our boring days (:-) not 0nly the technique but discovering new unknown lands and continents as well !!! our days it van be done in science as well (:-)!! Y.Porat ------------------- |