planetf1.com

There seems to be such a fine line with setup in formula one, between qualifying and the race they add the fuel and the cars change completely.

What are the things that the teams can change to affect the way an f1 car handles?

I know that a lower front end and higher rear means oversteer and vice versa, the lower you go the more grounding will occur too.

_________________

Basically, wing levels, suspension setting, tyre pressures and position of ballast are the main areas used to change the handling characteristics of a car.

_________________
Going to Spa? Check out my site. http://visit-spa-francorchamps.page.tl/
My own Google Earth Motor Sport file. http://www.mediafire.com/?jzm1ieatytv
Follow me @asphalt_world
Oh and Bernie, National flags should be raised not flipped. Sort it!

I'd also like to add brake balance, which affects corner entry. Also, gearing can affect balance, because when the car gets higher on the revs in a corner, it tends to oversteer. This is most noticable in flat out turns.

_________________
Supporter of:

Fernando Alonso
Pastor Maldonado
Sergio Perez
Michael Schumacher
Lewis Hamilton

Brake bias coupled with KERS harvesting will change the balance in the braking phase and if the driver carries his braking into a corner, this will have an effect there too.

Does Camber affect this as well?

_________________
Jenson Button Fan.

Camber's more used for stability, but it can also be used to fine tune balance. If the car's in a corner and the back end starts to step out a little, you can counter that by adding more negative camber to the rear.

_________________
Supporter of:

Fernando Alonso
Pastor Maldonado
Sergio Perez
Michael Schumacher
Lewis Hamilton

Oh boy:

Suspension springs stiffness
Suspension damper setup/tuning (bound and rebound, slow speed and high speed,,,etc.)
Anti roll bar stiffness
Front downforce
Rear Downforce
CG position (using ballast)
Engine Map (fuel, RPM, power,,,etc)
differential setting
Suspension Geometry (Toe, Camber, Caster , KPI, roll centers, pitch axis,,,etc.)
Ride height front and Rear
Brake Bias

the list can go on

Each one of the things that i have previously mentioned has many subtopics under it, so each system has many areas to fiddle with. Given that each change in any single parameter can have an effect on nearly everything else the possibilities are endless and can be made to suite even a baby driving (maybe not that much but you get the point).

Since this is becoming the civilized part of the forum, i'll tell you something i found very interesting.

I am a Mechanical engineer and worked in a form motorsports in the past 2 years (very, very amateur). Recently i was with someone VERY experienced and knowledgeable (worked in F1 for a while and in nearly every single racing and car series there is). and he wad discussing (explaining) the stiffness difference in the car (i.e balance that drivers usually refer to) and he was saying that in a very amateur racing series the drivers could sense a 0.5% change in setup in terms of balance. In a more professional series (Indy or F1 i don't remember) they swaped cars between two drivers in the same team and each one of them came in saying the same thing "how does he drive that car!" the difference in balance between the two cars was 0.2%!

from then on whenever i hear Jenson reporting balance issues i sympathize with him and that explains the sump he has been having in terms of setup

Basically, just about everything on a car can be altered or adjusted. There are some parameters that are tough to touch, such as track, where in almost every circumstance you want the wheels as wide apart as possible, and the regulations specify a maximum width. But wheelbase (different arms), camber, toe-in, ride height, you think of it, change can be done.

Understeer is basically that when cornering, the front end doesn't grip as well as the rear, and you can reach a state that the driver cranks in lots of wheel, the wheels turn, but the car doesn't turn as much as desired. Oversteer is when the opposite happens, more grip at the front than rear, and the back end can come out and around, sometimes too quickly. That's when you see a driver in a corner suddenly loop it.

But we hear a term all the time, and that's "balance", where the car isn't oversteering or understeering. Now it can get tricky, because handling can be broken down into two disciplines, mechanical handling, and aero handling. If you took all the wings and thingys off that pressed the car into the ground, all you have left is how the suspension controls the wheels, and give it maximum grip. You can set the car up to be balanced just mechanically. Now mix in the wings and stuff, and if you have more rear wing that front, the car can be understeering when going fast, but balanced when slow. And if it's oversteering when slow, you can have a nasty condition where it's oversteering when slow, and understeering when fast, or the reverse.

Basically, the lower you get a wing or part of the car to the ground, the more downforce it generates. That's why everyone wants that front wing almost dragging on the ground, remember the flexi-wing last year? Remember Turkey last year, where Massa's car was bouncing and bucking braking from the long straight? What was happening, apart from Massa getting his teeth fillings loosened, was that the front wing and the rest of the car was creating lots of downforce when the wing was close to the ground, then loosing a lot of it when bucking up, and so forth, quicker than the eye can see.

If it starts to sound complicated,it is. The suspension, tires, so much of the car control how the car handles, and changing just one thing can alter the car radically. For instance, when the cars drive around Monza with the trees making shade at some spots, that altered the traction and handling. Go into the shade, the car handles one way. Go into the sunlight, it handles another way.

I agree with Blinky on most things but i just have some modifications.

I think in an F1 car the track can be slightly adjusted, the wheelbase i am not so sure, if they have different pickup points (which i guess they do) then yeah.
You don't necessarily want the wheels as wide as possible, wide wheels create more inertia around CG which produce a "lazy" car, on the other hand a wide track is better for weight transfer, but that can be handled by the springs and anti-roll bar. Also changing track dimensions can adjust the over/under steer seen on the car due to the effect of load transfer sometimes a narrower track front or rear is required.



All F1 cars have higher downforce at the rear than the front, do you know how that is countered for a stable car?

Also i agree that the front wing is better off mounted low, but its main function is partially downforce and MAJORLY lower the drag caused by the wheels. Also the rear wing when mounted lower will produce lower downforce because of the engine and cockpit blocking air flow but that also results in less drag so it is usually a compromise between circuits.

To change the wheelbase you do not change the chassis, but instead build new A-arms with different geometry. It's a major change in the car, but can be done.

The wheels themselves are fixed by the regulations in diameter and width, but I was referring moving them closer or further apart relative to the centerline of the car.

Just like changing the wheelbase, build new arms with new geometry.

For the downforce, approximately these are the numbers.
Front Wing 450kg - 630kg
25 - 35%

Rear Wing 630kg - 810kg
35-45%

Diffuser 360kg - 450kg
20-25%

Bodywork 90kg - 180kg
5-10%

The weight distribution is fixed by the regulations with little play. It is 45.5 to 46.7% front, 53.3 to 54.5% rear. Taken as a whole the car is closely balanced. Minor tweaks can be made by altering the angle of a winglet on the front wing. It can be done during pit stops by turning small screws. This is an old picture, but there are two mechanics standing on each side of the front jack man, at the front of the car and leaning over the wing and holding what are basically electric drills, pre-set to turn a certain direction and number of turns. They insert them in the top of the vertical outer element, pull the trigger, and the change is performed.



In this website (cannot link, copyright) there is an excellent picture of Massa getting his front wing adjusted, and you can see one mechanic holding the powered adjuster, which looks like a blue cordless drill. Click the link and click on the picture of the Ferrari pit stop to see it in better resolution.

http://www.formula1.com/inside_f1/rules_and_regulations/sporting_regulations/8714/

For the front wing, the outer elements channel air sideways around the tire. The parts further inboard in front of the tire channel air over the tire, and the rest generate downforce. Most of the front wing generates a lot of downforce.

@blinky

Not Usually the team takes the time to build new A-arms and design new geometry, some teams make a chassis with adjustable/different suspension pickup points and run the geometry simulation before to know what to predict from each combination. with changing the pickup points they can change the roll centers, track and wheelbase as well as the whole geometry. These changes can be minor, but i have it on good authority that f1 drivers can feel a change of less than 1mm on rear toe change for example, the drivers really are that good and the cars are that sensitive.

Yes i know what you were referring to, the track and wheelbase was what i was talking about. I was not talking about tire dimensions.

according to your numbers the F1 cars have 630 kg of rear downforce MORE (due to the use of rear wing + diffuser) than the front, these are normally reacted upon by the wider rear tires to improve stability with respect to the slip angles needed.

I have to say that with the time i spent in aerodynamics i didnot think that the front wing generated that much, but i guess i forgot the speeds the car is running through.


Really incredible it is what the F1 mechanics and engineers can do for a car at a pitstop isn't it, it can be a whole new car from a driver's perspective. while they can take the whole car apart and put it back in 2 hours and the driver won't feel a thing.

Yea, and if that isn't complicated enough, the amount of grip also changes based on the speed the driver is cornering at. Since downforce is generated by aerodynamics, going slower in a corner can alter dramatically the amount of grip available. Add to that ever-changing grip levels as the tyre degrades, and it's really amazing how these drivers can the most from their cars lap after lap!

Because we are on the margins of acceptable grip due to the reduced down force and Pirelli's, there is very little that does not influence the change of under steer or over steer. McLaren have traditionally gone for a very stiff front end, such you can hardly see the front wing flexing over some bumps. I cannot fail to see that with such a set up that you don't trigger the break away point earlier when presented with a bumpier track. The more and better contact the tyres have with the road, the more control you will have in this area. Track conditions are very important with bumps and camber adding to the equation.

Great info here lads! Just wondering, is there any books out that on this subject that you'd recommend? Doesn't have to be just for F1, just on the subject of race car set up in terms of both mechanical and aero setup, more so mechanical if possible!

Fundamentals of Vehicle dynamics (by Gillespie)
Tune to win (or the to-win series by Carroll Smith overall)
The Science of Formula 1 Design (David Tremayne)

Start in reverse order, i have more but these should have you covered for the next 2 years

The Carroll smith series of very cheap on the Carroll smith website as the family is selling them in his memory and are very well written.

P.S you can find these books online, but that is illegal and unethical to say the least

Cheers for that! Been looking around for ages to find a few books like that.

What about Differential settings? This will be specific to left or right corners, but will make a difference

_________________
I find television very educating. Every time somebody turns on the set, I go into the other room and read a book.

Marx (Groucho)

That's a dynamic process, where the driver selects the differential setting at will. In theory, he can program different differential settings for each corner. When a Formula One car accelerates out of a corner, the outside wheel is turning at a different rate than the inside, and also the torque spit is divided. If it was equal, most likely the inside wheel would slip because of load transfer. And the requirements of the differential can alter as the car accelerates out of the corner, where you have to set it for the apex, mid way out, and further out of the corner.



This is a picture of Heidfeld's 2009 wheel, and numbers 18, 19, and 20 all are to make different differential settings. That's how important the differential settings are, because you want as perfect drive as possible out of the corners. So the next question is how does it work, and for that we need to take a look inside a differential. Here's a drawing of one. The power is delivered from the transmission by the small shaft and then takes a 90 degree turn. You can barely see that shaft in the bottom left. Torque then passes through the small wheel on the bottom left, which engages the larger geared wheel, where a planetary gear and the rest of the differential reside inside it. On each side of the planetary gear are little clutch packs, controlled by hydraulic pressure. They spit and control the torque to each side.



When the driver gets the balance right, the differential will control the yaw rate coming out of the corner, and deliver the power where it's needed and avoid wheelspin.

Great post Blinky, I'd like to add that diff settings are of great importance to corner entry balance as well.

When decelerating the diff is being influenced by engine braking or 'backtorque', so the more it resists allowing the wheels to rotate at different speeds, the more the car will resist changing direction. An extreme example of this is a V8 Supercar or Porsche 956 which both use what is called a 'spool' axle, so there no differential action at all and the rear wheels rotate at the same speed at all times.

Both of these cars require a peculiar driving style of braking in a straight line, then turning in hard and getting on the power early to induce some slip at the rear to make the car rotate past the apex. In my opinion that's why we didn't see many F1 drivers cross over to Group C, and is probably why Jacques Villeneuve is currently propping up the back of the V8SC grid.

_________________
I watch the people in their cars in slow motion they're beautiful like breaking glass, not yet broken...

Downforce is a big factor, but it's mainly Mechanical grip. Springs can cause more Understeer the stiffer they are, if you unstiffen them then you'll have more Oversteer. Brake Bias is another big factor aswell, front bias means more understeers (but better for braking in a straight line). Rear bias bring more oversteer, but means that you can brake easier around more corner braking zones as the fuel load is generated to the back of the car.

_________________
Lewis Hamilton - 2008 World Drivers Champion! Mercedes - 11 Grand Prix Victories.

Although this guide is for sim racing, it's modeled after real world physics, and can help dismiss some common misconceptions. I suggest it as a good read for anyone wishing to learn more about suspensions.

http://membersmedia.iracing.com/pdfs/iRacing_Car_Setup_Guide_20100910.pdf

Chris Harris recently drove a Porsche 962 and interviewed Norbert Singer.

Singer had some fascinating stuff to say about ground effects. Harris had asked about the Gurney Flap on the back of the 962 (at 11:40 in the video), and Singer replied that the flap "helps the front axle". He elaborated, "...when the ground effects is really working, when you do something on the rear end it's very often you have a response from the front. A bigger response from the front. And then you know your ground effects is working.... And the other way around; you do something on the front it has influence on the back. So, this is an amazing thing."

Great thread!

I'm amazed by all of this technology. How do they respond to the disruption to air caused being in traffic vs open track? Doesn't all this planning and work become undermined by the "dirty air" or do they run different settings in traffic?

I think before the driver adjusted the front wing angle a bit in traffic to gain a bit of aerodynamic downforce to compensate for the turbulence caused from the car ahead. This however was banned this season and thus the drivers are limited to adjusting diff setting to compensate for lower grip levels

Yeah the FIA introduced the movable front wing a few years back so the driver could increase downforce when they were in turbulent air, but instead the teams used it to balance their cars aerodynamically (lowering the wing on the straight and raising it for a corner). It was banned following 2010 and is likely the predecessor for DRS.

_________________
Supporter of:

Fernando Alonso
Pastor Maldonado
Sergio Perez
Michael Schumacher
Lewis Hamilton

I'm going to really enjoy geeking-out over this document. The setup reference chart at the bottom seems quite a useful guide if your lost in setup.

Thanks for posting.

You are very welcome. Recent advances in available sim technology has now reached the point where they accurately replicate real world results. In other words, such sims as iRacing act just like the real world, in fact even setups can be identical.

Here's a series of videos that are driving tutorials (they did it in collaboration with Skip Barber) and even if you don't race, they offer information that will make any fan better informed and educated. Enjoy.

iRacing.com Driving School Chapter 1: Introduction to the school http://youtu.be/I5eueqw24co
iRacing.com Driving School Chapter 2A: Vehicle Dynamics http://youtu.be/blUk8W3ogRo
iRacing.com Driving School Chapter 2B: Vehicle Dynamics http://youtu.be/T4Vvh3tsjEI
iRacing.com Driving School Chapter 3A: Fundamentals of the Racing Line & Cornering http://youtu.be/LxMSdvnm0Ms
iRacing.com Driving School Chapter 3B: Fundamentals of the Racing Line & Cornering http://youtu.be/ZTSpf6utKto
iRacing.com Driving School Chapter 3C: Fundamentals of the Racing Line & Cornering http://youtu.be/iTOs5xBRSt4
iRacing.com Driving School Chapter 4: Using Your Eyes http://youtu.be/67QdwMZPxkY
iRacing.com Driving School Chapter 5A: Braking Technique http://youtu.be/nwf5CZL4GZM
iRacing.com Driving School Chapter 5B: Braking continued http://youtu.be/IL1kww4BVDY
iRacing.com Driving School Chapter 6: Downshifting http://youtu.be/x_e2Ztnuamg
iRacing.com Driving School Chapter 7A: Race Craft & Passing - Understanding Race http://youtu.be/RuvYtSfEG90
iRacing.com Driving School Chapter 7B: Race Craft & Passing - Technique http://youtu.be/2DScBhHNLKU
iRacing.com Driving School Chapter 8A: Race Starts - Surviving Turn 1 http://youtu.be/ADB1cIuvhzc
iRacing.com Driving School Chapter 8B: Race Starts http://youtu.be/IcmQ9PfncDg
iRacing.com Driving School Chapter 9: Pre-Race http://youtu.be/smYCWdA6cOc


http://youtu.be/0p_sCrM1CcI

Much of what is written on this thread is factually incorrect. Your best bet is the books mentioned above. Especially the Carrol Smith series, plus also How to Make Your Car Handle by Fred Puhn.

I watched a couple of the iRacing videos. They are VERY elementary. A good starting point but they barely scratch the surface of vehicle dynamics.

As a note to the OP, rake (higher front or low end) doesn't directly affect understeer/oversteer in the way you mentioned.

I agree Crunchy Frog, but a valid and fundamentally simple understanding is better then urban myths.

A low front end does not produce oversteer, it is produced when when the car is unbalanced and there is more traction at the front.

Please do elaborate