Sail downwind faster than the wind!
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From: jimp on 30 Jul 2010 14:53 John Doe <jdoe(a)usenetlove.invalid> wrote: > For me, UseNet is the authority. Not everyone is right all the > time, but here discussion is unmoderated and I can read between > the lines. Then you are an idiot. Ever since anyone with a credit card and a modem could connect to the Internet, USENET has become inundated with the ignorant babblings of the mentally ill. -- Jim Pennino Remove .spam.sux to reply.
From: John Doe on 30 Jul 2010 15:20 "Androcles" <Headmaster Hogwarts.physics_z> wrote: (Corrected the non-UseNet format) > "Richard Henry" <pomerado hotmail.com> wrote >> John Doe <j... 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. >> >> The first notch on the bullshit meter is conservation of >> energy. > The needle didn't get to the first notch. Neither did your perpetual motion craft. > Moving with the same speed as the wind, Newton's first law > applies, only wheel bearings and gear friction can provide a > retarding force. A given, the same force that retards perpetual motion. This is Earth. > So the only energy needed is that required to overcome that > negligible friction. Not true. You also have wind forces against the propeller and the craft. > To go even faster than the wind requires extracting SOME wind > energy. You may justifiable claim there is none available to > turn the propellor since the propellor is stationary wrt to the > wind, But the propeller never even reaches that point. > but you've ASSUMED the wind speed is uniform at all heights. > However, the wind will encounter friction with the ground and > will be passing the vehicle at the top of the mast whilst the > vehicle passes the wind at wheel level. So the vehicle goes > faster than the wind, If tailwind speed is slower at vehicle height, the vehicle encounters more resistance. You pretend the vehicle generates energy while you overlook the negative wind pressure on the vehicle. -- > than the wind, the propellor blade at the top of its arc > goes slower than the wind. > > > > > > > > > > > Path: news.astraweb.com!border2.newsrouter.astraweb.com!border2.nntp.dca.giganews.com!nntp.giganews.com!npeer02.iad.highwinds-media.com!feed-me.highwinds-media.com!cyclone02.ams2.highwinds-media.com!news.highwinds-media.com!npeersf01.ams.highwinds-media.com!newsfe18.ams2.POSTED!7564ea0f!not-for-mail > From: "Androcles" <Headmaster Hogwarts.physics_z> > Newsgroups: sci.physics > References: <4c529e1b$0$21228$c3e8da3 news.astraweb.com> <7c17888f-d4d3-4f5d-822e-c77eaa741f98 n19g2000prf.googlegroups.com> > Subject: Re: Sail downwind faster than the wind! > Lines: 44 > MIME-Version: 1.0 > Content-Type: text/plain; charset="iso-8859-1" > Content-Transfer-Encoding: 7bit > X-Priority: 3 > X-MSMail-Priority: Normal > X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 > X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5931 > Organization: virginmedia.com > Message-ID: <3iF4o.1370$2d1.297 hurricane> > NNTP-Posting-Date: Fri, 30 Jul 2010 18:59:11 UTC > Date: Fri, 30 Jul 2010 19:58:47 +0100 > Bytes: 2711 > >
From: John Doe on 30 Jul 2010 15:26 jimp specsol.spam.sux.com wrote: > John Doe <jdoe usenetlove.invalid> wrote: > >> For me, UseNet is the authority. Not everyone is right all the >> time, but here discussion is unmoderated and I can read between >> the lines. > > Then you are an idiot. Simply calling someone an idiot is the lamest insult known to mankind. > Ever since anyone with a credit card and a modem could connect > to the Internet, USENET has become inundated with the ignorant > babblings of the mentally ill. Like your mother. You just have to be brighter than they are in order to filter it out. So naturally you have a difficult time here. And yet you persist... -- > > > -- > Jim Pennino > > Remove .spam.sux to reply. > > > Path: news.astraweb.com!border5.newsrouter.astraweb.com!news-out.octanews.net!indigo.octanews.net!news.glorb.com!feeder.erje.net!news.mixmin.net!aioe.org!not-for-mail > From: jimp specsol.spam.sux.com > Newsgroups: sci.physics > Subject: Re: Sail downwind faster than the wind! > Date: Fri, 30 Jul 2010 18:53:52 -0000 > Organization: Aioe.org NNTP Server > Lines: 17 > Message-ID: <0njbi7-3td.ln1 mail.specsol.com> > References: <4c529e1b$0$21228$c3e8da3 news.astraweb.com> <QbSdnX9E88HPOM_RnZ2dnUVZ8tGdnZ2d brightview.co.uk> <A6OdnS6_C4ZFM8_RnZ2dnUVZ8gCdnZ2d brightview.co.uk> <4c52b7da$0$8901$c3e8da3 news.astraweb.com> <dNWdnUaLmrg8Yc_RnZ2dnUVZ8oidnZ2d brightview.co.uk> <aM2dneK2TdailM7RnZ2dnUVZ8jidnZ2d brightview.co.uk> <4c53191a$0$17915$c3e8da3 news.astraweb.com> > NNTP-Posting-Host: 5FQzpG9PgxCHgWX2ynv4yg.user.speranza.aioe.org > X-Complaints-To: abuse aioe.org > User-Agent: tin/1.8.3-20070201 ("Scotasay") (UNIX) (SunOS/5.10 (i86pc)) > X-Notice: Filtered by postfilter v. 0.8.2 >
From: bert on 30 Jul 2010 16:34 On Jul 30, 7:50 am, "Androcles" <Headmas...(a)Hogwarts.physics_z> wrote: > "John Doe" <j...(a)usenetlove.invalid> wrote in message > > news:4c52ae63$0$9845$c3e8da3(a)news.astraweb.com... > | "Cwatters" <colin.wattersNOSPAM TurnersOakNOSPAM.plus.com> wrote: > | > | > "John Doe" <jdoe 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. > | > > | > 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. > | > | When you are tacking, the wind does not stop blowing against your > | sails. I believe it is all part of some joke warfare... > | -- > A sail is an aircraft wing tipped vertically. The wing is there to fight > gravity. > The sail produces the same lift but has no gravity to fight against. > Tacking makes use of the "lift" to drive the boat "up" except that "up" > is now forward. The aerodynamic principle is the same, the terminology > is different. Another name for a glider is a sailplane. A yacht is a > sailplane > tipped on its side. The second "wing" is the keel. To Ya All Iceboat went 122 mph in 40 mph wind. Reality is the curve of sail creates a partial vacuum. It is litterly being pulled. Curve of airplane wing gives it great lift. TreBert PS Water on ice makes for little friction Water causes drag.
From: John Doe on 30 Jul 2010 16:38
"Androcles" <Headmaster Hogwarts.physics_z> wrote: > ASSUMED the wind speed is uniform at all heights. However, > the wind will encounter friction with the ground and will be > passing the vehicle at the top of the mast whilst the vehicle > passes the wind at wheel level. So the vehicle goes faster > than the wind, the propellor blade at the top of its arc > goes slower than the wind. So it is a joke. You are saying that the propeller/sail/whatever is not part of the vehicle. That wind speed at the sail is used for power but wind speed at the base vehicle is used for measuring vehicle speed versus wind speed. |