Lotus 99T, McLaren MP4-5 front pushrods; how do they work?

[newyorkkopter]

So I was looking at the 99T and MP4-5's front suspension and what I don't get it how the pushrod pushes against the shock absorber

pic found at forums.vwvortex.com/showthread.php?3438832/page64

It goes from the lower part of the chassis to the upper part of the upright
So if the wheel goes up, to me it seems like it would pull the shock absorber rather than push against it.

However, I do get how the pushrods work on a 641

The wheel goes up, causing the pushrod to push against the shock; makes sense

But, I don't get the setup used in the MP4-5
Can someone explain?

[dumrick]

The MP4/5 setup wasn't pushrod, but pullrod, like the recent rear setups from the Red Bulls. It doesn't push against the shock, but pulls it.

It allows for a smaller diameter of the rod and, in some cases, to place the shocks lower, lowering the CG of the car.

[newyorkkopter]

oh okay that makes sense. Thanks
So does the shock get pulled from the top downward by the pullrod?
Is that why there's something on top of the shock? to pull the shock from the top?

[marcush.]

the lower shockmount is attached to a lever that lever can move vertically up and down and is attached to the pullrod ,straightforward:

example:
http://www.flickr.com/photos/32975211@N05/3245667390/

[gridwalker]

Slightly off topic here, but I've gone through the photostream and that Lego BT46B is just beautiful!

[marcush.]

Slightly off topic here, but I've gone through the photostream and that Lego BT46B is just beautiful!

I thought the same ..and posted the link hoping someone would have the same feelings

[newyorkkopter]

Alright I think I got it.
Thanks!
so when the pullrod pulls the shock, the shock body moves outward towards the upright as it compresses, right?

If yes, then how does it work on the McLaren(doesn't seem to be much room for moevement in that area)

Also is there a cutaway of some car that uses this setup I could checkout?
I don't want to keep on pestering

And btw, nice work with the fan car!

[marcush.]

the shockmovement for the Mclaren layout is mainly vertical ,as the shock is positioned upright and the pullrod attachment point and lower shockmount are very close to one another and the turnaxis of the lever is on the same plane or close to it ,here some early examples :

http://www.gurneyflap.com/Resources/P1000342.jpg
http://www.gurneyflap.com/Resources/DSC_4255.jpg
http://www.gurneyflap.com/Resources/76-023.jpg

the very best i could find is a rear layout ,Lotus:
http://www.gurneyflap.com/Resources/Lotus-underside.jpg

[747heavy]

some more examples, and a drawing of the (rough) working principle

[747heavy]

pull rod in old Indy car (March86):
front:

rear:


Minardi F1 front:

[mep]

Push- and pullrod has nothing to do if your damper gets pushed or pulled.
Both is possible. It only depends where the damper is mounted on the bellcranck.

[747heavy]

maybe this explains the principle best:
[youtube]http://www.youtube.com/watch?v=MrFKPejn ... re=related[/youtube]

[wesley123]

such an device wouldnt even work anymore on current F1 cars, the nose is simply too high to create the desired pick up points, with thelowest allowed nose these points would even be too high(the BGP001 was on the lowest allowed point), thus an pushrod would be the way to go.

[imightbewrong]

maybe this explains the principle best:
[youtube]http://www.youtube.com/watch?v=MrFKPejn ... re=related[/youtube]

Is this video really suggesting that they are not running a third damper?

[747heavy]

I think this video just explains in basic terms how a pull rod suspension works in general.
I don´t think that anything else can/should be taken from it.
If you look, the angle and position of the pull rod if totally different from the real car.
It neither shows the correct position of the parts (pull rod/dampers) nor does it include inerters or 3rd spring/damper elements.
I still feel, that it shows the basic function of a pull rod suspension rather nicely, and that was the question in the OP.
I don´t think that it is a true/valid representation of the actual RB6 layout.