R/C Tech Forums - View Single Post - why 24mm rubber touring car when rules allow wider.
Old 07-19-2004, 12:35 PM
  #31  
DaveW
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rubber molecules + heat + love =



Cobra: What you see as partly wrong, and clarify in your post, is hit on in both posts of mine. In actuality, the friction coefficient can be suprior to 1. Its called downforce. I hit on that also in my above post. I did not however go into how this can be possible. Basically, the effect is multiplied through efficiency. Downforce can multiply the friction coefficient, the gain being stability, longer tire life (considering the circumstances, less lateral slip would create less heat, less tire wear) and more lateral grip. Basically, the friction circle is larger (notice...more than...) for a set of tires that have downforce. Lets say a car has tires and no downforce, this car would have traction relative to a passenger car on a rainy day. Add downforce to the same situation, and the traction would be relative to our passenger car on a dry sunny day, but the asphalt would still be wet. How do you think F1 cars do close to 200mph in the wet? Mathmatically, an F1 car generates enough downforce to let the car drive upsidedown against the force of gravity. Now how can that be, if a "coefficient" cannot be more than 1? Just to let you know, in the best of environments, traction can be up to 5 times greater. How many of you guys ever noticed your R/C car handling differently with or without the body in place... much less the rear wing? Heres a good one, place your wing on your TC upsidedown, drop in a 9x2 and some gear, hit top speed and watch the car lift into the air! Racing is and always will be about the small percents that enable us to push the envelope, to go faster.

- DaveW
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