[Igor (OP)]

Why are the bodies of racing cars not dimpled like golf balls to reduce drag ?

[elegantlywasted]

Just throwing this out there, but are the dimples because the ball spins, and the drag is reduced on the spining ball. A car doesnt spin hence no dimples... I dont know

[paul.fr]

Just throwing this out there, but are the dimples because the ball spins, and the drag is reduced on the spining ball. A car doesnt spin hence no dimples... I dont know

yes, as i understand it the dimples increase the spin. a standard smooth golf ball would only go around 50metres, so i heard.

racing cars go faster through their aerodynamic design.

[science_guy]

does that design push the car closer to the floor to increase friction of the wheels to make it go faster, or does it push it upwards, like a plane, to reduce friction between the wheels to make it more fuel effecient?

[elegantlywasted]

I would assume, at least for NASCAR that the drag pushes the car down, and in F1 racing that the spolier will lift the car up, to make it lighter

[paul.fr]

does that design push the car closer to the floor to increase friction of the wheels to make it go faster, or does it push it upwards, like a plane, to reduce friction between the wheels to make it more fuel effecient?

oh gosh, from memory i believe the car is closer to the floor. the big wing at the back acts opposite to an airplane wing. ie it helps push the car down not up.

edit: could be wrong though.

[Igor (OP)]

Why are the bodies of racing cars not dimpled like golf balls to reduce drag ?

What about those shark-skin inspired swimming cozzies ...
http://www.memagazine.org/backissues/membersonly/may04/departments/input_output/input_out.html

Couldn't the same principle be applied to racing cars ?.

[Ben6789]

I wouldn't my to spin, that's for sure!

[lyner]

I believe that you push the back of a racing car down so it will corner better.

Don't the dimples on a golf ball just increase the Bernouli effect and keep the ball aloft for longer because of its spin? Speed doesn't particularly matter as long as it will fly further.

[lightarrow]

Why are the bodies of racing cars not dimpled like golf balls to reduce drag ?

I think it's a nice idea!
However there would probably be much more drag because of the not perfect shape of the car, and so making dimples wouldn't make much difference.

[Batroost]

The spoilers on teh back of F1 cars are there to push the back down. This increases the friction between the tyres and the road surface thereby making enabling faster cornering and acceleration without wheel spin or slip.

A few years ago the F1 cars had 'skirts' that reached down to the ground to take advantage of 'ground effect' to improve this even further. Unfortunately not every car maker was successful (particularly the French) and the F1 racing authorities (possibly French?) chose to rewrite the rules to forbid the use of the skirts.

This means that F1 cars are now more prone to spinning off the track at speed; though I suspect that modern traction control systems have gone some way to offsetting the loss of skirts.

NB: Famous BBC TV 'Horizon' episode covered this "Gentlemen, Lift Your Skirts!"; funny the things you remember...

[ukmicky]

Didnt they ban traction control systems in F1 ,could be wrong.

ESP IS COOL THOUGH

[daveshorts]

A lot of the reason with a golf ball is that without dimples it would produce large eddies behind it.
[diagram=214_0]

These will make it wobble from side to side and because they are large cost a lot of energy. The dimples make smaller eddies which stop the big ones forming.

This is known as eddy shedding and is the process that makes the vibration in a flute amongst many others.

An F1 car is designed to to produce major eddies like this, and it is intrinsically asymmetric so they won't wobble one way then the other. Basically it isn't round.

[another_someone]

The spoilers on teh back of F1 cars are there to push the back down. This increases the friction between the tyres and the road surface thereby making enabling faster cornering and acceleration without wheel spin or slip.

A few years ago the F1 cars had 'skirts' that reached down to the ground to take advantage of 'ground effect' to improve this even further. Unfortunately not every car maker was successful (particularly the French) and the F1 racing authorities (possibly French?) chose to rewrite the rules to forbid the use of the skirts.

This means that F1 cars are now more prone to spinning off the track at speed; though I suspect that modern traction control systems have gone some way to offsetting the loss of skirts.

NB: Famous BBC TV 'Horizon' episode covered this "Gentlemen, Lift Your Skirts!"; funny the things you remember...

As you say, the skirts were great at keeping the cars stuck to the ground, but they tended to suck all the grit and gravel off the ground and spit it up at the car following - not so nice if you were following a car that was skirted.

[another_someone]

Didnt they ban traction control systems in F1 ,could be wrong.

ESP IS COOL THOUGH

I have a similar recollection, although I do not know if that rule is still in force.

The arguments were to what extent was motor racing to be governed by the skill of the drivers, and to what extent by the sophistication of the robots.

[lightarrow]

As you say, the skirts were great at keeping the cars stuck to the ground, but they tended to suck all the grit and gravel off the ground and spit it up at the car following - not so nice if you were following a car that was skirted.

Also, there was a very dangerous effect: do you remember how some cars literally flew away in those circuits where the the road goes at the top of a little hill? It was very impressing. I think this was one of the reasons for banning the skirts.