What a dragster!

  • #1
3,077
3

Main Question or Discussion Point

Why are a dragster's tires allowed to slip, rather than obey positraction? Is it that friction of rubber is idealy a nonlinear function in this particular range of temperature, or that the Clorox applied needs to be evenly distributed and incorporated for coherence? (Maybe to avoid starting out with a wheelie?)
 

Answers and Replies

  • #2
krab
Science Advisor
896
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In order to get really sticky, the tires need to reach a certain temperature.
 
  • #3
374
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In a race, the idea is for them NOT to slip. If you start wheelspinning, you've lost!
As Krab says, the burn out at the start is to get the tyres to their (very hot) operating temperature.

Incidentally, the 6000bhp 'top fuel' cars do the 1/4 mile in around 4.5 seconds with a terminal speed of over 320 mph! Awesome!
 
  • #4
Stingray
Science Advisor
671
1
The big wheelspin before staging is to warm up the tires. There is still a little bit of slip during the race though. Smoky burnouts don't give any traction, but all tires must slip a little to generate forces. The simple type of friction taught in most physics classes doesn't apply to rubber at all.
 
  • #5
Originally posted by Loren Booda
Why are a dragster's tires allowed to slip, rather than obey positraction? Is it that friction of rubber is idealy a nonlinear function in this particular range of temperature, or that the Clorox applied needs to be evenly distributed and incorporated for coherence? (Maybe to avoid starting out with a wheelie?)
As a scientific person I am rather certain you will understand that 'Bleaching' is actually a process, not a substance, (in this use of the term) as the stuff they put on the tire, for the warming up the tires, by 'burnout', is water.

As for the 'slip' of the tires, the positraction simply ensures the energy transfer to the tire with the most traction, but can do nothing to stop either of the tires from slipping, as it has no 'control effect' upon the amount of torque being exerted.
 
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