IRL car weight without driver.

[PA Rick]

I heard on the Mid Ohio broadcast that Tracy's 200 lb weight added about 3/10th seconds to a lap time. I know champcar and F1 set the minimum weight to include the driver.
I thought the IRL had changed the rule last year but according to the IRL home page specs the weight is "1,565 pounds minimum for ovals and 1,630 pounds minimum for road courses, including lubricants and coolants. Does not include fuel or driver."
This means larger drivers like Ryan Hunter-Reay and Justin Wilson (and PT) are at a disadvantage. And if a team had a good 100 lb driver they should be able to walk away with the title.

[Hoop-98]

I heard on the Mid Ohio broadcast that Tracy's 200 lb weight added about 3/10th seconds to a lap time. I know champcar and F1 set the minimum weight to include the driver.
I thought the IRL had changed the rule last year but according to the IRL home page specs the weight is "1,565 pounds minimum for ovals and 1,630 pounds minimum for road courses, including lubricants and coolants. Does not include fuel or driver."
This means larger drivers like Ryan Hunter-Reay and Justin Wilson (and PT) are at a disadvantage. And if a team had a good 100 lb driver they should be able to walk away with the title.

There are weight classes that compensate for the difference in drivers weight. Above 180 you may lose out a bit.

Something that no one allows for is the higher center of gravity of the drivers with larger upper body mass (in other words Milka with the same weight would have a disadvantage to Danica or Dan Wheldon).

The fact that Justin runs well sort of shows that the driver is still the most important factor in some situations.

rh

[PA Rick]

Something that no one allows for is the higher center of gravity of the drivers with larger upper body mass (in other words Milka with the same weight would have a disadvantage to Danica or Dan Wheldon).

...
rh

I thought movable aerodynamic devices were banned but there appears to be some exceptions.

[Hoop-98]

I thought movable aerodynamic devices were banned but there appears to be some exceptions.

not so much aero, but certain centers of mass and polar moments of intertia are not created equal...

[anthonyvop]

In the paddock it is called the "Danica Rule"

Every other major professional auto racing series sets a minimum weight with the driver included. As weight is one of the main factors in performance including the driver is to maintain a level playing field.

[TURN3]

There are weight classes that compensate for the difference in drivers weight. Above 180 you may lose out a bit.

Something that no one allows for is the higher center of gravity of the drivers with larger upper body mass (in other words Milka with the same weight would have a disadvantage to Danica or Dan Wheldon).

The fact that Justin runs well sort of shows that the driver is still the most important factor in some situations.

rh

Something I don't understand with respect to mass (weight) in a race car is they always talk about what the disadvantages are. While I agree more mass can detract from certain properties of physics, the coefficient of static friction for example is increased with mass. In other words, tires should have more grip which would in turn allow less wing (drag). Any input Hoop?

[Easy Drifter]

Hoop can probably explain things better but the more mass there is the more energy it takes to get it moving. The same applies to stopping. More mass harder it is to stop.
Think of a train pulling one freight car as opposed to one with 50 loaded cars.
Same thing applies although on a far lesser scale.
Basically the slight gain in friction is outweighed by the amount of energy reqired to start (accelerate) or stop.

[TURN3]

Hoop can probably explain things better but the more mass there is the more energy it takes to get it moving. The same applies to stopping. More mass harder it is to stop.
Think of a train pulling one freight car as opposed to one with 50 loaded cars.
Same thing applies although on a far lesser scale.
Basically the slight gain in friction is outweighed by the amount of energy reqired to start (accelerate) or stop.

I understand the principles of physics pretty well and I agree with what you've said. The big question I've never really put much thought into is exactly what you ended with...about gain in friction vs amount of energy required. When they are cranking wing into and out of the car, effectively they are adding/subtracting downforce (at speed of course) which has the exact same effect as adding/subtracting weight but without the drag. In the case of the wing adjustments, they are also effecting drag. Lots of dynamics involved, way too much to get involved with unless I'm getting paid!!!

[Easy Drifter]

Yep. Today they have all sorts of computer simulations that in theory tell them exactly what to do. Note --- in theory.
Then the driver goes out and comes back in and tells them where to place the computer! And the sun don't shine there.
In this old f--ts day we watched the car, listened to the driver, assuming they had a clue what was going on, and made a change based on experience.
Then sent said driver back out and studied the results on a stop watch.
Sometimes we got it right, sometimes not but if you weren't right most of the time it was find a new job time pretty soon. :D

[Hoop-98]

I'm busy so a short reply.

Acceleration = F/M the more mass the lower the acceleration. 25 pounds on a 1800 pound car would make a difference of 1.3 %.

The 25 pounds will pick up about 40 pounds of grip but in a 3 G turn it will add 75 pounds of force.

If a tire has 1000 pounds of load and 1500 pounds of grip that is a tire mu or coefficient of friction of 1.5.

As tire loads increase the coefficient of friction decreases so the best traction would be if all 4 tires were at their initial static loading. When you have weight transfer the tire gaining weight loses grip faster than the tire losing weight gains.

Downforce does add drag, usually around 3 pounds of downforce = 1 pound of drag. Downforce does not add Mass, so when you are cornering at 3gs you have 3 times the cars weight forcing the car to the outside but adding downforce only increases tire loading not, centripetal force to be overcome by the tires.

A heavier driver is also at a disadvantage because the weight is higher in the chassis than the ballast, so it increases weight transfer.

rh

[TURN3]

Good explanation, thank you.

So basically, the weight of a heavier driver is pretty negligible from a friction/grip/reduced capacity of aero/etc. That being more or less a wash doesn't account for making up in what you lose with weight transer on the roll and the higher cg.

Hope I interpretted you correctly.

[Hoop-98]

Good explanation, thank you.

So basically, the weight of a heavier driver is pretty negligible from a friction/grip/reduced capacity of aero/etc. That being more or less a wash doesn't account for making up in what you lose with weight transer on the roll and the higher cg.

Hope I interpretted you correctly.

It's like losing 9 HP and about .6 MPH in a 150 MPH corner.

A disadvantage for sure, but setup and skill differences tend to overshadow this. That said it is a disadvantage, in this case about .3

rh

[PA Rick]

There are weight classes that compensate for the difference in drivers weight. Above 180 you may lose out a bit.

.....
rh

On the IRL web site it says
"1,565 pounds minimum for ovals and 1,630 pounds minimum for road courses, including lubricants and coolants. Does not include fuel or driver."
I read stories from 2007 saying there was to be three weight classes, and a 2008 story saying the driver is to be considered part of the minimum weight. What is it. Do the cars get weighed in tech with or without the driver? Is the driver's listed weight added to the car weight? Are the rules on the IRL site wrong?

[Hoop-98]

On the IRL web site it says
"1,565 pounds minimum for ovals and 1,630 pounds minimum for road courses, including lubricants and coolants. Does not include fuel or driver."
I read stories from 2007 saying there was to be three weight classes, and a 2008 story saying the driver is to be considered part of the minimum weight. What is it. Do the cars get weighed in tech with or without the driver? Is the driver's listed weight added to the car weight? Are the rules on the IRL site wrong?

The drivers are weighed and depending on their weight class the minimum weight is adjusted. Kinda goofy IMO, but I guess they don't wanna be like horse racing. Danica's minimum weight is more than Wilson's.

rh

[PA Rick]

The drivers are weighed and depending on their weight class the minimum weight is adjusted. Kinda goofy IMO, but I guess they don't wanna be like horse racing. Danica's minimum weight is more than Wilson's.

rh

I wonder if this rule is written down or is sorta like a guideline. My guess is the rules at the IRL site are out of date.
In any case a 100 lb driver has an advantage over a 200 lb driver in IRL but not F1.

[Hoop-98]

I wonder if this rule is written down or is sorta like a guideline. My guess is the rules at the IRL site are out of date.
In any case a 100 lb driver has an advantage over a 200 lb driver in IRL but not F1.

If they had a 200 pound driver and a 100 pound driver in F1 the heavier driver would be at a substantial disadvantage.

rh

[Hoop-98]

The following charts show potential corner speeds for 3 different weights, all else the same. In real life it would be slightly worse, but this should be within 98 pct.

http://i31.tinypic.com/vpvxnm.jpg

http://i29.tinypic.com/fmnmvb.jpg

http://i31.tinypic.com/xdee4o.jpg

Just to give people some idea of scale.

An F1 car would have huge problems with a 200 pound driver even though they would weigh the same on the grid. The high vertical weight placement of the driver would greatly increase weight transfer of the much lighter F1 car. I am sure it would hurt a lot more than .3.

To accommodate drivers of that size variation you would have to have a mandated Vertical Center of Gravity ans Polar Moment of inertia.



rh

[mlj]

The following charts show potential corner speeds for 3 different weights, all else the same. In real life it would be slightly worse, but this should be within 98 pct.

http://i31.tinypic.com/vpvxnm.jpg

http://i29.tinypic.com/fmnmvb.jpg

http://i31.tinypic.com/xdee4o.jpg

Just to give people some idea of scale.

An F1 car would have huge problems with a 200 pound driver even though they would weigh the same on the grid. The high vertical weight placement of the driver would greatly increase weight transfer of the much lighter F1 car. I am sure it would hurt a lot more than .3.

To accommodate drivers of that size variation you would have to have a mandated Vertical Center of Gravity ans Polar Moment of inertia.



rh

This is so over my head. So Hoop, you seem to be the man to ask. Tell me where Danica would be in the race if in fact the Drivers were weighed in their car and there was in fact a "level playing field"? Since at 100 lbs she has an advantage, take that away and I wonder how far back in the field she would be.

[Hoop-98]

This is so over my head. So Hoop, you seem to be the man to ask. Tell me where Danica would be in the race if in fact the Drivers were weighed in their car and there was in fact a "level playing field"? Since at 100 lbs she has an advantage, take that away and I wonder how far back in the field she would be.

Her car carries more ballast than a heavier drivers car, so except for drivers over 180 it's about equal weight wise, the CG difference is likely worth a couple tenths.

rh

[Hoop-98]

I wonder if this rule is written down or is sorta like a guideline. My guess is the rules at the IRL site are out of date.
In any case a 100 lb driver has an advantage over a 200 lb driver in IRL but not F1.

Just an FYI, some f1 drivers purposely let their upper body muscles atrophy (They have actual power steering) to lower their upper body mass.

A center of gravity rule could help prevent this.

rh

[call_me_andrew]

Something that no one allows for is the higher center of gravity of the drivers with larger upper body mass (in other words Milka with the same weight would have a disadvantage to Danica or Dan Wheldon).

That's the nerdiest comment to ever warrent a high-five.

[Hoop-98]

I wonder if Milka would consider a breast reduction, prolly worth at least 2 tenths !

If Milka was 6-5, a body builder, with 40d's and weighed 200 pounds she would probably be 4 seconds off! So nothing wrong with her driving, she is just underweight, short, and underdeveloped.

Seriously, we have addressed the weight to various degrees but other aspects (assets?) of a drivers body cause performance advantages.

Certainly height is a dis-advantage, as is a strong or mmmm more massive upper body. Masking or diversion of airflow into the scoop is another issue.

I have often wandered why driver equalizing ballast wasn't put chest high behind the seat.



rh

[grungex]

:rolleyes:

[grungex]

Nice. First you're a sexist pig, now you're a jerk. Good discussion. :rolleyes:

P.S. I've seen your pic, you hardly have room to talk.

[Hoop-98]

Nice. First you're a sexist pig, now you're a jerk. Good discussion. :rolleyes:

P.S. I've seen your pic, you hardly have room to talk.

well gee that breaks my heart, have a nice day, thanks for the stellar commentary on the topic

" what we have here, is, a failure, to communicate..."



rh