Meet the new Mythbuster, Barack 2010/12/08

Discussion in 'Now Playing - TV Show Talk' started by MikeAndrews, Oct 18, 2010.

  1. MikeAndrews

    MikeAndrews Registered abuser

    Jan 17, 2002


    Ya know, because they've only tested this twice. :confused:

    You'd think Mr. President could more concerned about real controversies like the plane on a treadmill.* :D

    * Where the "real pilot" thinking his plane wouldn't take off should have been required to give up his certificate.
  2. john4200

    john4200 Well-Known Member

    Oct 31, 2009
    Haven't we discussed this before?

    I don't think the pilot was all that ignorant. There is a subtle point in the situation that they did not really address on the show. Theoretically, it is possible for the plane to generate just enough thrust to offset the friction between the plane's wheels and the treadmill, with the result that the plane would have an airspeed of zero and indeed would not take off (although the situation is complicated by any air that the propellers blow over the wings).

    But in practice, the amount of thrust to just offset the friction in the wheels is very low, and I think it is difficult for a pilot to keep the throttle consistently at that low setting. With the result that the thrust of the plane exceeds the friction of the wheels, the plane accelerates relative to the air, and it takes off once its airspeed has exceeded the stall speed of the wing.
  3. Enrique

    Enrique Well-Known Member

    May 15, 2006
    Dec. 8? You think that could have made it before the start of November.
  4. john4200

    john4200 Well-Known Member

    Oct 31, 2009
    You brought it up. If you want to discuss it in another thread, then please provide a link where you wish to discuss it. If you don't want to discuss it, feel free not to reply to me.

    Your first point is irrelevant. Taxiing along a runway is fundamentally different than maintaining zero airspeed (assuming a windless day) on a treadmill. To maintain a constant speed taxiing down the runway requires enough thrust to both overcome the wheels' friction AND the drag of the plane through the air at taxi speed.

    On the treadmill, in steady state the thrust only needs to be high enough to overcome the wheels' friction, since the airspeed is zero and there is no drag. So, to maintain zero airspeed on the treadmill requires lower thrust than to taxi down a runway. (The wheel friction is slightly higher at higher spinning speeds, but it is not enough to offset the drag)

    Furthermore, as you say, to get the plane started on the runway requires a short burst of higher thrust, since the impulse (thrust x time) must equal the momentum (mass x velocity) imparted, and that is on top of the thrust required to overcome the static friction of the wheels to get them rolling. In contrast, the treadmill plane only needs a burst of thrust strong enough to overcome the static friction of the wheels -- it does not need to impart any momentum to the plane.

    So, my point stands. The amount of throttle required to get the wheels rolling, and to maintain the wheels rolling against the treadmill, is significantly less than that required to start a plane taxiiing on the runway, and to keep the plane taxiiing. A typical pilot is likely to exceed the required throttle setting for zero airspeed on the treadmill, thus the plane accelerates to takeoff airspeed and takes off. You can actually see it in the Mythbusters experiment -- the plane clearly moves forward with respect to the fixed ground, and therefore also with respect to the air.
  5. crazywater

    crazywater USS TiVo NCC-1780

    Mar 7, 2001


    Because it will save his party on Election Day if we ask his awesomeness to solve this great mystery all by himself?
  6. StanSimmons

    StanSimmons Senior Moment Member

    Jun 10, 2000
    Too bad they don't tackle the myth that the TSA makes us safer. ;)
  7. YCantAngieRead

    YCantAngieRead Not Entirely Current

    Nov 5, 2003
    I got nervous. And stupid, with the tread title. :eek:

    I thought there was actually going to be a new Mythbuster. I think five's enough. :eek:
  8. DancnDude

    DancnDude Thrice as nice TCF Club

    Feb 7, 2001
    Madison, WI
    I wonder if him "helping" is really just a video of him giving "advice" to the Mythbusters or if he'll actually be doing anything or actually appearing on camera with Adam and Jamie.
  9. kdelande

    kdelande TiVo-Wobble

    Dec 17, 2001
    You forgot Buster -- that's 6! :)

  10. MikeAndrews

    MikeAndrews Registered abuser

    Jan 17, 2002
    I think if safe to assume that he didn't have a day or two of free time to participate in the tests. :D
  11. TheMerk

    TheMerk Always Bid First

    Feb 26, 2001
    Salt Lake...
    If they showed this episode before the Nov election one could argue that Discovery would be obligated to give equal time to a member of the opposing party.
  12. Mars Rocket

    Mars Rocket Loosely wound

    Mar 24, 2000
    Sinnoh region
    If he does anything other than appear uncomfortable while reciting a few well-prepared sentences then I'll be surprised.
  13. Worf

    Worf Well-Known Member

    Sep 15, 2000
    I wonder how they can even do it, I mean, he's the current President and he's got to have a whole pile of Secret Service agents with him constantly... I wonder if there'll be a behind-the-scenes episode showing how they managed to film out all the SS agents.
  14. Jesda


    Feb 12, 2005
    I expect any president on this kind of show to say a few scripted things and leave while the hosts stare in awe.
  15. FuzzyDolly

    FuzzyDolly Active Member

    Dec 29, 2002
    Maybe they'll give him a nametag that reads "Buster" and have him test some myths. ;-)
  16. andyw715

    andyw715 Well-Known Member

    Jul 31, 2007
    Maybe in 2012
  17. MickeS

    MickeS Active Member

    Dec 26, 2002
    I thought for sure the myth would be about a certain birth certificate... no, wait, maybe that's not a myth. ;) :D
  18. Einselen

    Einselen ɹǝsn pǝɹǝʇsıƃǝɹ

    Apr 25, 2006
    You mean something sort of along these lines?
  19. MikeAndrews

    MikeAndrews Registered abuser

    Jan 17, 2002
    The SS can secure the area. They'll send a squad up to a week in advance to scout all the entrances and exits, etc. (I was there when we had a VIP visit my high school and I only missed rubbing elbows with President Clinton due a stupid manager not telling me to be there.)

    Don't be surprised if they meet up at M5 or some other enclosed place. The former Alameda base is too open.
  20. Worf

    Worf Well-Known Member

    Sep 15, 2000
    The problem is, the Archimedes death ray requires an open area... it can be simulated on the small scale in M5, but ramping it up requires an open area to capture the sun...

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