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webmaster, pls move this to applicable forum. I have much respect for members on this website and hope I may show the absolute requirement of good working knowledge of Physics..to compete successfully in Auto Racing...
Many of you have expressed interest in a subject I have tried to master for decades..and still find it tuff. Race car handling.
We could go into a lot of practical Physics like Internal Combustion engine function, volumetric efficiency, thermal dynamics, et al..and I gladly welcome these conversations..but the basic challenge is to make your car win races and it all comes down to Tires, Tires, Tires. Specifically, the tire contact patch.
Just calculating the Gs in a turn is a good start, What you ultimately want to do is have the biggest tire contact patch in contact with the track surface at all times. Suspension settings like camber, toe out, Akerman, bump steer are adjustments that improve tire contact patch area. Springs and shocks , "Sway Bars (anti roll bars) regulate the amount of spring weight transferred to the front / side of the car during cornering, acceleration, deceleration ( braking).
Tire traction- realize the more load placed on a tire, the more traction ..but...the tires coefficient of friction decrease. However, up to the design limit of the tire, its traction capacity ( ability to actually transmit force to the road) as opposed to dimensionless coefficient of friction, increases with vertical load.
simplified - vertical load on a given tire increases, the area of the rolling contact patch remains virtually constant, and so the unit pressure of the footprint increases. As the unit loading rises, the rubber has less resistance to frictional shearing and so the coefficient decreases. However, the curve is so gentle , if you graphed this, that the increase in vertical load overpowers the decrease in coefficient of friction.
longitudinal load transfer which occurs in the longitudinal plane under linear acceleration or deceleration = acceleration (g) x Weight x ch height ( center of gravity) / wheelbase
assume 1760 lb formula car with 100 inch wheelbase, 13 inch center of gravity
704 lb front weight , 1056 rear wheel weight
braking at 1.2 g
crank thur the formula and 275 lbs. is tansfered ..i.e. ft wheel weight is now 979 lbs, rear wheel weight is now 781 lbs.
but...there is also left to right side weight that occurs as well!
this is lateral load transfer (lb) = Lateral accelaeration (g) x weight x cg height / track width
the track width is distance from the center the right rear tire to the center of the left rear tire...just about all race cars have wider rear track width so you use the widest track width on the car
Many of you have expressed interest in a subject I have tried to master for decades..and still find it tuff. Race car handling.
We could go into a lot of practical Physics like Internal Combustion engine function, volumetric efficiency, thermal dynamics, et al..and I gladly welcome these conversations..but the basic challenge is to make your car win races and it all comes down to Tires, Tires, Tires. Specifically, the tire contact patch.
Just calculating the Gs in a turn is a good start, What you ultimately want to do is have the biggest tire contact patch in contact with the track surface at all times. Suspension settings like camber, toe out, Akerman, bump steer are adjustments that improve tire contact patch area. Springs and shocks , "Sway Bars (anti roll bars) regulate the amount of spring weight transferred to the front / side of the car during cornering, acceleration, deceleration ( braking).
Tire traction- realize the more load placed on a tire, the more traction ..but...the tires coefficient of friction decrease. However, up to the design limit of the tire, its traction capacity ( ability to actually transmit force to the road) as opposed to dimensionless coefficient of friction, increases with vertical load.
simplified - vertical load on a given tire increases, the area of the rolling contact patch remains virtually constant, and so the unit pressure of the footprint increases. As the unit loading rises, the rubber has less resistance to frictional shearing and so the coefficient decreases. However, the curve is so gentle , if you graphed this, that the increase in vertical load overpowers the decrease in coefficient of friction.
longitudinal load transfer which occurs in the longitudinal plane under linear acceleration or deceleration = acceleration (g) x Weight x ch height ( center of gravity) / wheelbase
assume 1760 lb formula car with 100 inch wheelbase, 13 inch center of gravity
704 lb front weight , 1056 rear wheel weight
braking at 1.2 g
crank thur the formula and 275 lbs. is tansfered ..i.e. ft wheel weight is now 979 lbs, rear wheel weight is now 781 lbs.
but...there is also left to right side weight that occurs as well!
this is lateral load transfer (lb) = Lateral accelaeration (g) x weight x cg height / track width
the track width is distance from the center the right rear tire to the center of the left rear tire...just about all race cars have wider rear track width so you use the widest track width on the car
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