Prev: Here is an example how STOOOPID SKEPTOS are!
Next: The participants in these newsgroups are arithmetic morons
From: Cwatters on 30 Jul 2010 13:23 "Richard Henry" <pomerado(a)hotmail.com> wrote in message news:7c17888f-d4d3-4f5d-822e-c77eaa741f98(a)n19g2000prf.googlegroups.com... On Jul 30, 2:40 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. >The first notch on the bullshit meter is conservation of energy. It doesn't break conservation of energy.
From: John Doe on 30 Jul 2010 14:08 jbriggs444 <jbriggs444 gmail.com> wrote: > "Cwatters" <colin.wattersNOS... TurnersOakNOSPAM.plus.com> > wrote: >> "John Doe" <j... usenetlove.invalid> wrote in message >> > 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 soluti > on >> 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. Where is the United States patent? >> > 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. > > [Apologies -- my first time seeing the conundrum] > > Let me see if I can reason through it from first principles... > > So if you were going upwind To be clear, you mean "pointing upwind". > you'd be drawing power from the propellor in the air The wind against the propeller pushes backwards on your vehicle at the same time it produces power. > and generating thrust from the propellor in the water (or from > the tires on the road). > > And if your efficiency was bad, you could just gear things down > until the propellor in the air is spinning madly while the > propellor in the water (or the tires on the road) barely turns. > > Sure, that's not just plausible. That direction is freaking > obvious. Obviously backwards. A propeller cannot generate enough power to overcome the negative thrust of the wind against the propeller. -- > > > If you are going down-wind you [eventually] need to > reverse things. Now you are using the propellor in the > air for thrust and you are drawing power from a lesser > backward drag at a higher relative speed. > > [Below wind speed you can use the propellor for > power and the tires for thrust because the drag > on the propellor points in a favorable direction, but > that way of doing things is a trap] > > Sounds, good, but the intuition wants a sanity check. > > So *build's a mental picture*. You're cruising down > the road on a bicycle. It's downwind and you're > just barely keeping up with the wind. You have > this huge propellor in the air, but it's not turning > yet. It's just pulling you downwind at wind speed. > > You have a little generator that you can snap down > so that it spins against the sidewalls of your tires. > It generates enough current to run your headlight > when you're riding at night. > > So you snap the generator down and you wire > the output into the propellor in the air. > > Your relative speed with respect to the air is zero. > You can generate a large thrust from a small > power input. > > Your relative speed with respect to the ground is > large. You can generate a large power output > from a small amount of drag. > > OK. I'm convinced. The intuition tried valiantly > to use the "there's no power available when you're > moving at wind speed" argument. But that's > because the intuition was still trying to run the > thing the wrong way. > > Path: news.astraweb.com!border5.newsrouter.astraweb.com!news.glorb.com!news2.glorb.com!postnews.google.com!p11g2000prf.googlegroups.com!not-for-mail > From: jbriggs444 <jbriggs444 gmail.com> > Newsgroups: sci.physics > Subject: Re: Sail downwind faster than the wind! > Date: Fri, 30 Jul 2010 09:46:20 -0700 (PDT) > Organization: http://groups.google.com > Lines: 97 > Message-ID: <d8e63cee-3d00-4ce8-8c86-5f6e8c82587a p11g2000prf.googlegroups.com> > References: <4c529e1b$0$21228$c3e8da3 news.astraweb.com> <QbSdnX9E88HPOM_RnZ2dnUVZ8tGdnZ2d brightview.co.uk> > NNTP-Posting-Host: 149.32.224.33 > Mime-Version: 1.0 > Content-Type: text/plain; charset=ISO-8859-1 > Content-Transfer-Encoding: quoted-printable > X-Trace: posting.google.com 1280508380 2777 127.0.0.1 (30 Jul 2010 16:46:20 GMT) > X-Complaints-To: groups-abuse google.com > NNTP-Posting-Date: Fri, 30 Jul 2010 16:46:20 +0000 (UTC) > Complaints-To: groups-abuse google.com > Injection-Info: p11g2000prf.googlegroups.com; posting-host=149.32.224.33; posting-account=nHkyWQoAAAAZj13mfknn7vPxoYn-Mvx3 > User-Agent: G2/1.0 > X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.04506.648; MS-RTC LM 8; InfoPath.2),gzip(gfe) >
From: John Doe on 30 Jul 2010 14:15 "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. The (simplified) idea that you can just transfer that energy to wheels in order to make you move forward against the wind is silly. That might be true to someone who does not realize the negative pressure of the wind against the propeller. In another group, someone suggested using a cog, but you would still want not overcome the negative pressure from the wind blowing against the wing.
From: John Doe on 30 Jul 2010 14:25 "Cwatters" <colin.wattersNOSPAM TurnersOakNOSPAM.plus.com> wrote: > "Cwatters" <colin.wattersNOSPAM TurnersOakNOSPAM.plus.com> wrote >> "John Doe" <jdoe usenetlove.invalid> wrote >>> "Cwatters" <colin.wattersNOSPAM TurnersOakNOSPAM.plus.com> wrote: >>>> http://www.wired.com/autopia/2010/07/its-settled-downwind-faster-than-the-wind-officially-possible/ >>> >>> Lots of things are possible on moderated websites/forums, just >>> depends on the editor. I am sure there is hype about perpetual >>> motion machines too. ....that is a dynamic that makes reading (to an extent) more enjoyable. Wondering when the sensible opposition is going to be axed by the moderator, like slapstick comedy. >> Probably but does that somehow stop you researching this >> project yourself? 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. >> If I remember correctly it was sponsored by Google and a few >> other corporations. > Here you go.. > > http://www.fasterthanthewind.org/ > > It was designed by "Thin Air Designs" in collaboration with the > San Jose State University Aero department and sponsored by > Google and others. Sounds like a New World Order thing, a California university and Google. > They have some data suggesting that >3x the wind speed is > possible. A simple explanation would do. > If you want to see the maths that was published here... > > http://www.boatdesign.net/forums/propulsion/ddwfttw-directly-downwind-faster-than-wind-25527.html > > See this post by Guest625101138... > > "Mark Drela Yeah, he is an MIT professor, and that is disappointing. Then again, the origin of the tinfoil hat insult came from the doings of an otherwise brilliant scientist. Some professors are full of it. -- > has provided the theory of operation of a DDWFTTW boat using an > air propeller and a water turbine. In the attached papers he provides the > necessary conditions on efficiency and drag to achieve the objective"... > > http://www.boatdesign.net/forums/attachments/propulsion/28167d1231128492-ddwfttw-directly-downwind-faster-than-wind-ddw2.pdf > > http://www.boatdesign.net/forums/attachments/propulsion/28168d1231128492-ddwfttw-directly-downwind-faster-than-wind-ddwe.pdf > > > > > Path: news.astraweb.com!border5.newsrouter.astraweb.com!feed.news.qwest.net!mpls-nntp-03.inet.qwest.net!usenet-01.nntp.cybernetik.net!nntp.cybernetik.net!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!nntp.brightview.co.uk!news.brightview.co.uk.POSTED!not-for-mail > NNTP-Posting-Date: Fri, 30 Jul 2010 12:17:51 -0500 > From: "Cwatters" <colin.wattersNOSPAM TurnersOakNOSPAM.plus.com> > Newsgroups: sci.physics > 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> > Subject: Re: Sail downwind faster than the wind! > Date: Fri, 30 Jul 2010 18:17:52 +0100 > 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 > X-RFC2646: Format=Flowed; Response > Message-ID: <aM2dneK2TdailM7RnZ2dnUVZ8jidnZ2d brightview.co.uk> > Lines: 42 > X-Usenet-Provider: http://www.giganews.com > X-Trace: sv3-pGb+a6QMcnV30HJoY2l1/BrzNr9EbZ+BuSF7ZZRISah/qzXRT1FoOSjeKLqfgBdGtNEnQWkfEnWU+lY!aWsInDBpAmmWRIWuFcx9joPLZbvxC5pNZcgyhMciRqAzaNY/13TZHVOewbapo147Svq+Spi7poA+!5YB42wue36O/WCHFEp5DOAgoRtE= > X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers > X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly > X-Postfilter: 1.3.40 > >
From: Androcles on 30 Jul 2010 14:58
"Richard Henry" <pomerado(a)hotmail.com> wrote in message news:7c17888f-d4d3-4f5d-822e-c77eaa741f98(a)n19g2000prf.googlegroups.com... On Jul 30, 2:40 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. The first notch on the bullshit meter is conservation of energy. ========================================= The needle didn't get to the first notch. Moving with the same speed as the wind, Newton's first law applies, only wheel bearings and gear friction can provide a retarding force. So the only energy needed is that required to overcome that negligible friction. 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 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, the propellor blade at the top of its arc goes slower than the wind. |