Advantages of not using rear corner springs

[autogyro]

Nice pic JT but could the lifted wheel just be a result of bouncing over a curb?

[wesley123]

Hamilton certainly has been known to lock inside fronts. Hard to say from us just watching on TV how much is him versus how much is car setup.

Sure, but he didn't lock fronts as often mid season as he did in last race.

From what I understood he is braking slightly into the turn, at that moment the inside wheel has less contact with the surface thus it is more lock up sensitive on that wheel.

[Jersey Tom]

If LH is locking fronts more or less at one point in the season than another... could be for any number of reasons. Could be pushing the car harder at one track versus another... could be varying setups... could be varying tires... you name it.

With regard to lifting wheels, sure they get airborne briefly when you go over a curb. In the case of NASCAR, there's enough front stiffness and load transfer that the car will carry the inside front tire anyway (at certain tracks). I know I've seen some F1 still photos with the inside front very very lightly loaded as well, even without hitting a curb.

And as for flexures, they do contribute to the ride rate of the car but it's surprisingly low. I have an old, steel flexure ChampCar a-arm around somewhere. When the chassis-side mounts are clamped down, you can get a lot of travel out of the wheel-side point with very little effort.

[DaveW]

I'm told that some engineers don't warm to the idea, wanting to keep the individual wheel rates under seperate control from pitch. Also it seems the dynamics of soft rear and stiff front roll rates don't suit every driver\car\aero package. Lastly the set up doesn't suit all tracks.

Scarbs: I have no issue with your second sentence. However, & with apologies, I do with your first.

I think that, if installation stiffnesses are sufficiently high, any combination of bars, corner springs & 3rd spring that yields the same values of Kh & Kr (see my earlier post) will, if all else remains the same, cause a vehicle to respond identically to a disturbance, whatever the source. The problem with a "decoupled" spring layout is often fitting the elements into an envelope (high stiffness bars with sufficient linear stroke are a particular problem, I think). Achieving an adequate installation stiffness for all elements can also be difficult.

[timbo]

I think that, if installation stiffnesses are sufficiently high, any combination of bars, corner springs & 3rd spring that yields the same values of Kh & Kr (see my earlier post) will, if all else remains the same, cause a vehicle to respond identically to a disturbance, whatever the source. The problem with a "decoupled" spring layout is often fitting the elements into an envelope (high stiffness bars with sufficient linear stroke are a particular problem, I think). Achieving an adequate installation stiffness can also be difficult.

Maybe some guys just don't want to commit optimizing their setup for another design?

[scarbs]

I'm told that some engineers don't warm to the idea, wanting to keep the individual wheel rates under seperate control from pitch. Also it seems the dynamics of soft rear and stiff front roll rates don't suit every driver\car\aero package. Lastly the set up doesn't suit all tracks.

Scarbs: I have no issue with your second sentence. However, & with apologies, I do with your first.

I think that, if installation stiffnesses are sufficiently high, any combination of bars, corner springs & 3rd spring that yields the same values of Kh & Kr (see my earlier post) will, if all else remains the same, cause a vehicle to respond identically to a disturbance, whatever the source. The problem with a "decoupled" spring layout is often fitting the elements into an envelope (high stiffness bars with sufficient linear stroke are a particular problem, I think). Achieving an adequate installation stiffness can also be difficult.

You may be right. As I understand its not the specifc rate of the different spring elements they want to control, rather than differing rising rate between the wheel springs and the heave spring.

[scarbs]

I think that, if installation stiffnesses are sufficiently high, any combination of bars, corner springs & 3rd spring that yields the same values of Kh & Kr (see my earlier post) will, if all else remains the same, cause a vehicle to respond identically to a disturbance, whatever the source. The problem with a "decoupled" spring layout is often fitting the elements into an envelope (high stiffness bars with sufficient linear stroke are a particular problem, I think). Achieving an adequate installation stiffness can also be difficult.

Maybe some guys just don't want to commit optimizing their setup for another design?

This is a quote from my source within F1, I think it echoes your comment perfectly "Some 'engineers' I have worked with can't get their heads around this for some reason, perhaps they can't think from first principles"

[bettonracing]

And as for flexures, they do contribute to the ride rate of the car but it's surprisingly low. I have an old, steel flexure ChampCar a-arm around somewhere. When the chassis-side mounts are clamped down, you can get a lot of travel out of the wheel-side point with very little effort.

Requirements (no corner springs), materials & geometry have all matured since then. With the larger diffusers of recent years (and the resulting decreased pushrod angles) I wouldn't be surprised that flexures are being used to absorb more of the spring rate to minimize rocker arm loads & friction.

I've also heard of teams using different flexure spring rates for different siuations (presumably different tracks) indicating that they contribute some useful portion of the net spring rate.

Regards,
Kurt

[747heavy]

While what you say is possible and makes sense Kurt,
it´s maybe worth to note, that some teams (at least at the rear)
have gone away from using flexures.

As can be seen here with the McLaren, and also if you look at the rear wishbones
of the F10 in the Ferrari thread.

[marcush.]

on top of that such a layout will alter springpreload on the system if you change the ride right and go away from the neutral -not bended a-armposition. ...it does not seem to be something you would really want to have as an added variable...so to rely on spring rates added by the flexures adds complexity to the system .But who knows ...F1 boffins seem to like maths .. so why bother

[bettonracing]

Well. Scratch that thought. Thanks for the update. Out of curiosity, anybody know what type of inboard joint Williams is using in their 'corner-spring-less' suspension?

The ride height issue can be remedied by using shims at the inboard joint.

Regards,

Kurt