3 shocks at the front.

[marcush.]

I notice that Brawn did not want anyone to see the other two springs fitted to each shock. It would be possible to estimate the spring rate then of course.

The other two shocks don't have coil springs fitted. It's a torsion bar suspension - the spring is provided by the torsion bar running from the bell crank pivot down in to the gearbox housing.

Agreed, but why have spring platforms on the twin shocks in that case?

I fail to spot the origin of those shocks ...its not Ohlins ,not quite penske ,and also not Dynamic ,any ideas ?
was this maybe some remains from Honda -Showa ??parts ?? it may be just some generic part they put in the presentation... i have not seen dampers with piggybag reservoirs for some time in modern dampers..

http://www.showa1.com/en/motorsport/index.html

[marcush.]

Your right Caito, there's no anti-roll bar on the front suspension, anti-roll bars are no longer used on the front or rear suspension in F1.

Somehow I doubt that. Granted they have a ton of spring rate for the cars, I find it hard to believe they would leave out a huge component for chassis tuning....

it is because with the low cg heights you can control the roll with springs and dampers .
ARBs are necessary if the rool cannot be restricted by other means.and as stated before the option for the arb is in the H-shaped lever acting on the 3rd spring
at the rear.

[RacingManiac]

i have not seen dampers with piggybag reservoirs for some time in modern dampers..

Uh what?

http://www.mulsannescorner.com/AcuraARX-01-4.html

Reservoir location is purely a packaging concern. If you have room for a separating piston with gas volume for a in-line monotube, then you don't need one. If you want an additional valving or you don't have room for inline monotube, you'll need a reservoir, either remote or piggy back. Racing shocks like these, since they are mounted in odd orientation(ie, not up and down, usually), are precharged with a seperate gas volume. So they are not orientation restricted.

Road car shocks can do without that and can be made into twin/tri/quad tube with gas ON liquid(without a separating piston) since they are mounted up and down, you don't have to worry about fluid valving exposed to gas when they are tilted over.

it is because with the low cg heights you can control the roll with springs and dampers .
ARBs are necessary if the rool cannot be restricted by other means.and as stated before the option for the arb is in the H-shaped lever acting on the 3rd spring
at the rear.

Low CG or not, if your roll center is not on the CG you still going to generate a roll moment, and at up to 5G cornering I don't imagine its insignificant. If it is on the CG, all the roll load goes into your suspension links, so they would have to be made stronger(heavier), so I am not sure if that's desirable. To control the roll moment with ride really stiff spring only at their cornering load just seems undesirable(granted, F1 tracks are smooth, so they can get away with a ton of stuff you won't be otherwise). I'd imagine packaging an ARB isn't that bad anyway...



F1 tub obviously is smaller, but they don't have the need for a coil over like that arrangement neither...

[RH1300S]

This reminds me of something I have wondered about before.

In single wheel bump - one wheel comes up and with that connection bar it looks like it will try to force it's opposite wheel down. That implies that the droop travel must be at least the same as the bump travel otherwise it will lock solid.

For years now I was under the (mis?)understanding that F1 cars didn't use droop travel.

Or do they have some kind of clever 'one-way' device to prevent this?

That said, it's not much worse than a conventional ARB where the wheels are effectively joined together across an axle.

The yellow tube looks very much like it would (could) work as an ARB.

[RacingManiac]

The ARB in that Cadillac pic is not seen. The horizontal piece across the bottom is the actuating lever, the actual "bar" is into the tub, and is allowed to pivot up and down to account for pitch/heave of the car. The heave/pitch action pusher the 3rd "spring"(in this case its just that piece of yellow bump rubber, but it can be a spring, a damper or a coil over(maybe an inerter too...not sure).

[marcush.]

i have not seen dampers with piggybag reservoirs for some time in modern dampers..

Uh what?

http://www.mulsannescorner.com/AcuraARX-01-4.html

Reservoir location is purely a packaging concern. If you have room for a separating piston with gas volume for a in-line monotube, then you don't need one. If you want an additional valving or you don't have room for inline monotube, you'll need a reservoir, either remote or piggy back. Racing shocks like these, since they are mounted in odd orientation(ie, not up and down, usually), are precharged with a seperate gas volume. So they are not orientation restricted.

Road car shocks can do without that and can be made into twin/tri/quad tube with gas ON liquid(without a separating piston) since they are mounted up and down, you don't have to worry about fluid valving exposed to gas when they are tilted over.

it is because with the low cg heights you can control the roll with springs and dampers .
ARBs are necessary if the rool cannot be restricted by other means.and as stated before the option for the arb is in the H-shaped lever acting on the 3rd spring
at the rear.

Low CG or not, if your roll center is not on the CG you still going to generate a roll moment, and at up to 5G cornering I don't imagine its insignificant. If it is on the CG, all the roll load goes into your suspension links, so they would have to be made stronger(heavier), so I am not sure if that's desirable. To control the roll moment with ride really stiff spring only at their cornering load just seems undesirable(granted, F1 tracks are smooth, so they can get away with a ton of stuff you won't be otherwise). I'd imagine packaging an ARB isn't that bad anyway...



F1 tub obviously is smaller, but they don't have the need for a coil over like that arrangement neither...

haha ,got you..

of course this was provocative ...
but Sachs and Ohlins both get away with integrated reservoirs as they have through rod dampers and no need for a reservoir to cater for the rod displacement.

http://www.ohlins.com/PageFiles/26241/P ... anguage=en
http://www.snapdragonmotorsports.com/ohlPN_ttx40.html

this damper is used as is in alot of lmp1 cars currently ,including Peugeot.
Audi as well uses Ohlins on all their cars but those are not off the shelf units.

[marcush.]

the cadillac pic is no diferent to the brawn rear layout,oh well it is : the bump stop here is a droop limiter...whereas on the brawn we see a third spring stiffening in bump..quite a different concept.

if you let the visible symmetric bar swivel freely there is no ARB action.
If you decide to mount the crossbar fixed rigidly to the bar that is diappearing into the tub where it is suspended by a crossshafz bearing sort of thing it is acting as a ARB of course ,as then it is loaded in torsion.

as RH1300S correctly stated things are not really independant so with single bump and no arb activity in the front the other wheel has to move down and will raise the chassis
till droop limitation on the suspension itself will stop it from rising,if there is not enough free movement up and down avalable by the afarementioned droop limiter device /ARB installation.Quite hard to explain ,I´m afraid .

[marcush.]

RH1300S

I´m not clear with the single bump discription here...

so again:if you look at the cadillac picture ,you can see in single bump the sviveling symmetric part is pushed down on one side and should go up on the other ,that was your comment that is correct.

BUT: the svilling point in the centre can move up and down as this is effectively a lever..fixed further back in the tub so it can move an inch or more vertically so
no raising of the car until you reach a mechanical stop for this .

[RacingManiac]

I like that Ohlins PDF....been looking around for something about those dampers for a while....

[marcush.]

I like that Ohlins PDF....been looking around for something about those dampers for a while....

you got a pm

[Just_a_fan]

Yes, the yellow item at 0.40 is the anti-roll bar.

BUT it works only as a torsion spring if the bar on top-the piece the dampers are mounted to) is mounted rigidly to the yellow bar!

It is rigidly mounted at the top. The yellow bar is mounted such that it can pivot fore-aft but not in rotation (at the base). The rockers are linked to the ends of the cross bar of the T such that roll is transmitted to the T bar (and thus resisted by the T bar) but combined vertical movement of the wheels (as in during acceleration) is transmitted to the third spring.

The way that the third spring is mounted means that it can work to prevent heave even when the car is experiencing roll e.g. whilst accelerating out of Parabolica.

[DaveW]

I'm reasonably sure that the front 3rd shown in the BMW video is an inerter. Probably no bar because the corner springs are likely to be be stiff enough in isolation.

I also think the third element in the video labelled "Brawn GP Suspension detail" is probably designed to house an inerter. The quotes are intentional, because the layout shown is atypical. Most, if not all, F1 rear suspensions include a bar, a third damper & a third spring.

[marcush.]

Yes, the yellow item at 0.40 is the anti-roll bar.

BUT it works only as a torsion spring if the bar on top-the piece the dampers are mounted to) is mounted rigidly to the yellow bar!

It is rigidly mounted at the top. The yellow bar is mounted such that it can pivot fore-aft but not in rotation (at the base). The rockers are linked to the ends of the cross bar of the T such that roll is transmitted to the T bar (and thus resisted by the T bar) but combined vertical movement of the wheels (as in during acceleration) is transmitted to the third spring.

The way that the third spring is mounted means that it can work to prevent heave even when the car is experiencing roll e.g. whilst accelerating out of Parabolica.

how can you be aure that it is in fact not rotating freely ?it could be so at top or bottom and if it were not it would of course be a very ,very stiff ARB negating most of the single wheels springs movements..right? so not very useful to propagte soft springing in single wheel bump as you´d always transfer the springforce from the other side as well....

[Just_a_fan]

It is rigidly mounted at the top. The yellow bar is mounted such that it can pivot fore-aft but not in rotation (at the base). The rockers are linked to the ends of the cross bar of the T such that roll is transmitted to the T bar (and thus resisted by the T bar) but combined vertical movement of the wheels (as in during acceleration) is transmitted to the third spring.

The way that the third spring is mounted means that it can work to prevent heave even when the car is experiencing roll e.g. whilst accelerating out of Parabolica.

how can you be aure that it is in fact not rotating freely ?it could be so at top or bottom and if it were not it would of course be a very ,very stiff ARB negating most of the single wheels springs movements..right? so not very useful to propagte soft springing in single wheel bump as you´d always transfer the springforce from the other side as well....

I can be sure because I've seen these systems fitted in F1 cars and had them described to me by a senior F1 engineer.

[proutyc]

Hi I'm new to this site but run a little sports car derived car runing ground effect tunnels (built in my garage)

As I mentioned above this is a home built car so I dont have the privilege of downforce numbers etc but I'm told similiar type cars in the USA have about 1500lbs, and my car weights 1500lbs with me and fuel.

My question is more on setup that anything else.

On the set up of the suspension is it generally accepted that the force of the 3 springs is similiar or do I prodinately want to support the downforce and weight or the car on the 3rd spring? e.g 1000 lbs 3rd spring and 2 500lbs spring for roll?

Many thanks and look forward to your thoughts (this is the first time I've run the car so really looking for guidance of where to start)