Recent content by endlessplane

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    Car Goes Downwind 2.5 Times Faster Than the Wind

    ... or you simply don't understand Newtonian physics. Thats the most likely option, given that even a simple cotton reel disprooves your naive ideas about mechanics.
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    According to your misconceptions, even a simple cotton reel "violates Newtonian physics". E7vcQcIaWSQ
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    I don't have to believe anything, since I can understand the math that was provided by the MIT-professor, the researchers from the Danish Technical University and the American Association of Physics Teachers. You on the other hand, have failed to provide any math to support your claims.
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    This is correct. If you look at the diagram above, it is obvious that the propeller blade will accelerate the air backwards.
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    MIT aerodynamics professor Mark Drela did the calcs. http://aeroastro.mit.edu/faculty-research/faculty-list/mark-drela Here his analysis: http://www.boatdesign.net/forums/attachments/propulsion/28167d1231128492-ddwfttw-directly-downwind-faster-than-wind-ddw2.pdf Here some more comments...
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    On the contrary. The vectors are basically the same as in tacking, and easily explain DDW speeds beyond 1.0WS (here for 1.5WS):
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    Tell me, Gonzo, do you understand that the center of mass of the car can move DIRECTLY DOWNWIND while the propeller blades are TACKING? It's basic vector math, and can also be easily visualized: UGRFb8yNtBo
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    I would say yes, you are correct. - The prop always slows down the air relative to the ground (extracting energy) - The prop always experiences an aerodynamic force forward - The prop always rotates opposite to the aerodynamic torque on it - The wheels always turn the prop via the transmission...
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    No, the aerodynamic torque at the propeller never turns the propeller, but rather always opposes its rotation. The aerodynamic force at propeller pushes the entire vehicle forward, thus indirectly turning the wheels.
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    That is correct. The aerodynamic torque is counter clockwise (looking from behind). It doesn't defy aerodynamics. There is more aerodynamics happening here than just aerodynamic torque. There is also an aerodynamic force that pushes the whole thing forward and creates a torque at the wheels...
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    Yes, Bob Dill and Bob Schumacher build the Iron Duck for relatively low cost compared to the Greenbird, and yet their record (116.7mph) stood for ten years. More info is here: http://www.nalsa.org/speed_record.htm http://home.comcast.net/~dolord/irondk.html...
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    You mean the Greenbird? TRFRQXPtXTs The Greenbird record has been ratified by the same organisation as the Blackbird records: http://www.nalsa.org/ In fact, the below video of the Blackbird, was shot by Richard Jenkins, the Greenbird pilot from the video above: 5CcgmpBGSCI The American...
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    Awesome. I suggest you submit it to the AAPT's American Journal of Physics: http://scitation.aip.org/content/aapt/journal/ajp You should specifically reference the AAPT's own analysis, and point out why it is wrong: http://www.aapt.org/physicsteam/2013/upload/E3-1-7-solutions.pdf
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    It's a paper about physics, not about investments. Read it again, if you still have reading comprehension problems.
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    Car Goes Downwind 2.5 Times Faster Than the Wind

    Did you read it gonzo? Apparently not. The paper deals with both: - directly upwind (section 2.2) - directly downwind faster than the wind (section 2.3) This is from the conclusions:
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