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Sprint car chassis logic

  1. Nov 14, 2015 #1
    I haven't posted here in forever, BUT I gained lots of valuable knowledge a couple years ago from some ofthe guys here gaining us our 5th and 6th track championships, now after stepping out of racing for a while I am coming back, and looking at sprint cars and the setup of these cars, I have been looking at the Jacobs ladder, and getting conflicting theories, is it a tool for adjustment and chassis tuning or just another item needed for locating the rear end.? I know this may open a can of worms, but I feel the bet answers can be found here, lol you guys are smart and have helped me greatly in the past. thanks in advance
    the dr.
     
  2. jcsd
  3. Nov 15, 2015 #2

    Averagesupernova

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    Basically a Jacobs ladder accomplishes what a panhard rod does. It prevents the rear axle from moving side to side in the chassis. It also raises the roll-center and these cars need that. The first time I got up close to one I said to myself: What the heck can that thing do? http://www.scrafan.com/column/rich/rich01.html
    -
    You sure you still want to do this?
     
  4. Nov 17, 2015 #3

    Ranger Mike

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    The Jacobs ladder does both. It is used on the sprint car to locate as well as tune the rear end. A panhard bar with the same minimal angle change during cornering would be too long to mount in the narrow chassis. When a panhard bar is used, the rear roll center is lowered during cornering as the chassis rolls to the right, while the rear roll center rises as the chassis rolls to the right on a car with a Jacob's ladder. This lowering of the roll center helps tighten the rear of the car on cornering, which can be an advantage on a dry slick track. The rising roll center with a Jacob's Ladder works better on a heavy/tacky track, where it produces less “ weight transfer” during cornering. With either style rear end, spring and shock choice is going to be the major player on how much “weight transfer” takes place and when it occurs.
    my pet peeve- there is no weight transfer. This is a visual to help the layman understand cornering forces better.
     
  5. Nov 17, 2015 #4

    JBA

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    With regard to your post subscript "Real Race Cars don't have Fenders." I would agree with you if it were not for the fact that in the 1950's when Mercedes dominated the Grand Prix racing world they used open wheeled cars for maneuverability and weight saving on short courses such as Monaco and full body fender cars for aerodynamics on the longer high speed courses like the Nurberging and Spa.-Francorchamps. Of course, they also had Juan Fangio and Stirling Moss to help with the effort as well.

    And, yes, my age is showing here.
     
  6. Nov 18, 2015 #5

    Ranger Mike

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    OK,JBA... I see you input but dispute the assumed fact as relevant by using logic :

    You are arguing from the Specific to the General. One Exception can nuke your argument. example- I own a car and its color is red , therefore all cars are red. I , however, argue from the general to the specific and the logic is impeccable. example – all cars have 4 wheels, I own a car therefore it has 4 wheels.
     
  7. Nov 18, 2015 #6

    JBA

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    That is as convoluted a response to a basically simple statement as I have ever seen. Simply stated, I said "that, in my opinion, there are cars with fenders that are real race cars" and gave an example of specific race cars to which I felt that statement applied. My response was not a serious one, it was presented strictly in jest.
     
  8. Nov 18, 2015 #7

    Ranger Mike

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    thank you..a little humor makes things go better:wink:
     
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