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What exactly is a zero radius turn vehicle?

  1. Dec 1, 2006 #1
    Well for my project in 6th sem, i'm planning to make a zero radius turn vehicle. What i understand by a zero radius turning vehicle is that it should keep the centre of mass at a fixed position and then rotate so that it moves 180 degrees. That is the maximum movement i should be able to show i guess.

    Am i right in my concept??
     
  2. jcsd
  3. Dec 1, 2006 #2

    DaveC426913

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    Certianly sounds like "turn on a dime" to me.
     
  4. Dec 1, 2006 #3
    A helicopter can do it.
     
  5. Dec 1, 2006 #4

    FredGarvin

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    So can some lawn mowers and tanks and fork lifts.
     
  6. Dec 1, 2006 #5

    brewnog

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    And skid-steer loaders, excavators, bulldozers, supermarket trolleys....
     
  7. Dec 1, 2006 #6

    Danger

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    I'm not sure, but I think that the Jeep Hurricane can as well; it has 4-wheel steering.
     
  8. Dec 2, 2006 #7
    so you feel that my idea is correct. i know how to make it work. only thing is that i should not be making something else. and how on earth does a 4 wheel steering work
     
  9. Dec 2, 2006 #8
    by the way, i know a helicopter can do it. but it does not have to rotate wheels to do it. its very different for a helicopter and a 4 wheeled vehicle i guess
     
  10. Dec 2, 2006 #9

    FredGarvin

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    Yes they're different. That wasn't the point.

    For a 4 wheeled vehicle or tracked vehicle to do a zero radius turn, the two opposing sides drive wheels must be able to rotate in opposite directions at the same time.
     
  11. Dec 2, 2006 #10
    that is exactly what i'm planning to do....make the two diagonally opposite wheels rotate in opposite directions
     
  12. Dec 2, 2006 #11

    Danger

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    Last edited: Dec 2, 2006
  13. Dec 4, 2006 #12
    well the both the articles are a great read. but what the howstuffworks article says is using a different concept of turning all the wheels in particular directions resulting in net 360 degree turn. not the way of couple that i thought or suggested.....
     
  14. Dec 4, 2006 #13

    russ_watters

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    Wow, yeah, I was gonna say that 4 wheel steering alone won't get you zero turn radius, but that's crazy how they applied it to that Jeep.
     
  15. Dec 5, 2006 #14
    but just give it a thought..... how do they plan to move the 4 wheels differently.... when in normal conditions they can't do it
     
  16. Dec 5, 2006 #15

    Danger

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    You probably just switch modes with a dash control and the rest is done by computer. This is not the only on-off road vehicle with 4-wheel steering; it's just the most extreme example of it.
    By the way, I didn't realize until I reread the article that it won't be put into production. :frown:
     
  17. Dec 5, 2006 #16

    Mech_Engineer

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    LOL You do realize it had TWO engines in it, right?! While an interesting concept, what a nightmare if you wanted to buy one.

    Exotic, yes. Impractical, absolutely. :tongue2:
     
  18. Dec 5, 2006 #17

    Danger

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    Not just 2 engines--2 Hemis.
    As mentioned elsewhere, my grocery-getter is a 4WD El Camino with 33" tires and a 455 Olds Rocket motor, so practicality has never been near the top of my priority list. :tongue:
     
  19. Dec 6, 2006 #18
    well, this vehicle would be capable of a zero radius turn. but would it be able to do something like a .5 metre radius turn. as probably the dashboard button just fixes the wheels to this angle and then the engine just makes them move.... and by the way which other all wheel steering vehicles exist. never heard of them... all wheel drives i know of but all wheel steering.... and i am yet to understand the concept of making all the tyres separetely maneuvrable.....
     
  20. Dec 6, 2006 #19
    and one more thing.... what is so special about HEMIS.... they are just another breed of engines. what is it in their design that they give the max power. i understand that their combustion chamber is hemispherical in shape.....
     
  21. Dec 6, 2006 #20

    brewnog

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    Obviously, if you actually want an answer to this it should be in a thread of its own.


    A brief overview:

    Getting the best (in terms of performance and emissions) out of a given SI engine requires four main optimisation strategies. A fast combustion process is required which displays minimal cycle-to-cycle variation. This needs to be present over the whole expected duty cycle of the engine in question (speeds, loads ec). A high volumetric efficiency is required at wide-open throttle. Minimum heat loss to the combustion chamber is obviously advantageous, as is the requirement for a low octane fuel.

    Naturally, combustion chamber design and geometry has a huge affect on all four of these factors, and steps taken to enhance one will often have a negative impact on others (increasing flow through the valves, or swirl, for instance). Being a pretty novel (for its day) combustion chamber arrangement, it can only be expected that a hemispherical head would have some pretty drastic effects on all four of these factors.

    If you want to truly understand why a hemispherical head can work quite well, and where its limitations are, you know what to do!
     
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