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  1. #1
    Senior Member joshpants's Avatar
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    Anyone for physics? (article on banking...)


  2. #2
    Elitist carleton's Avatar
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    This means that a cyclist can only go at about 45.5 km/h around a [flat] corner without losing grip
    I always wondered about that.

  3. #3
    Senior Member Speedskater's Avatar
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    That calculation only works when:

    The radius of a turn on a Olympic velodrome is around 20 meters,

    Now Short Track Ice Speedskaters with lots more traction on flat ice can corner way faster!

  4. #4
    Senior Member bitingduck's Avatar
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    Quote Originally Posted by Speedskater View Post
    That calculation only works when:

    The radius of a turn on a Olympic velodrome is around 20 meters,

    Now Short Track Ice Speedskaters with lots more traction on flat ice can corner way faster!
    Speedskates have long sharp edges that dig into the ice in one axis and slide nicely across it on the other.

    The article leaves out a lot of interesting physics about why the turns generally aren't semicircles, as well as some interesting angular momentum effects.
    Track - the other off-road
    http://www.lavelodrome.org

  5. #5
    Senior Member chas58's Avatar
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    Quote Originally Posted by bitingduck View Post
    The article leaves out a lot of interesting physics about why the turns generally aren't semicircles, as well as some interesting angular momentum effects.
    So, what are the other interesting bits of physics, and why are velodrome turns not a constant radius?

  6. #6
    Senior Member Dolamite02's Avatar
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    Quote Originally Posted by carleton View Post
    I always wondered about that.
    Note too, that this is only on a wood surface, not concrete.

  7. #7
    Senior Member bitingduck's Avatar
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    Quote Originally Posted by chas58 View Post
    So, what are the other interesting bits of physics, and why are velodrome turns not a constant radius?
    If you go from the straightaway into a constant radius turn you go instantly from no centripetal acceleration to V^2/R, and it would be instant changes from no "compression" to max compression and then suddenly back. Instead they're a cycloid (or close to it) so the centripetal acceleration comes on slow, hits a max at the middle of the turn, and decreases slowly as you exit.

    Another thing that's fun is conservation of angular momentum-- it helps in the paceline transitions in the corners (in addition to the elevation change effects).
    Track - the other off-road
    http://www.lavelodrome.org

  8. #8
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    Quote Originally Posted by carleton View Post
    I always wondered about that.
    But you are going to strike a pedal way before 45 kph.
    Il faut de l'audace, encore de l'audace, toujours de l'audace

    1980 3Rensho-- 1975 Raleigh Sprite 3spd
    1990s Raleigh M20 MTB--2007 Windsor Hour (track)
    1988 Ducati 750 F1

  9. #9
    cars are fun
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    It is a good start to the basics. The coefficient of friction is a variable on a bicycle. The author's first equation assumes that turning a bicycle is flat. Turning a bicycle on flat ground requires a lean which changes force vectors and friction. He/She doesn't come back to this until the end of the article where a correction is added.

    I think there should have been material on the basics of superelevation.
    the lion from within must guard his palace, because everybody's going to try to take a sip from his chalice

  10. #10
    Captain Ramrod taras0000's Avatar
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    Quote Originally Posted by bitingduck View Post
    If you go from the straightaway into a constant radius turn you go instantly from no centripetal acceleration to V^2/R, and it would be instant changes from no "compression" to max compression and then suddenly back. Instead they're a cycloid (or close to it) so the centripetal acceleration comes on slow, hits a max at the middle of the turn, and decreases slowly as you exit.

    Another thing that's fun is conservation of angular momentum-- it helps in the paceline transitions in the corners (in addition to the elevation change effects).
    Is it a cycloid? I always thought it was some form of Euler curve. I've never thought if a cycloid in being used for a banking. They both make sense to me in some respects, but not being a rocket surgeon, I wouldn't know which is best.
    Taras

  11. #11
    Captain Ramrod taras0000's Avatar
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    Also found this if anyone is interested

    http://en.wikipedia.org/wiki/Track_transition_curve
    Taras

  12. #12
    Sqrl
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    I'm a simplistic kind of guy. The kind who rides bikes in a circle. Fast.



    Somebody want to explain to us ordinary mortals what's going on?
    Quote Originally Posted by carleton View Post
    Doing one-legged squats while holding chickens in each hand will make someone strong...that doesn't mean it's the best way to train for track racing.
    Quote Originally Posted by Nagrom_ View Post
    That would be spectacular. A trail of blood and sealant.

  13. #13
    cars are fun
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    Quote Originally Posted by David Broon View Post
    I'm a simplistic kind of guy. The kind who rides bikes in a circle. Fast.



    Somebody want to explain to us ordinary mortals what's going on?
    To turn fast, you must lean. To go (X) amount of speed, you must lean (C) amount of degrees. (C) amount of degrees is already farther than a bike can lean (A). So to get to the (C) degree angle needed, the track must me leaned as well (B). Therefore (A)+(B) = (C) and we can turn while going (X) amount of speed.
    the lion from within must guard his palace, because everybody's going to try to take a sip from his chalice

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