Lotus E21 Renault

[PhillipM]

And whilst we're at it, hydraulic fluid CAN be compressed, slightly.

[nlehoullier]

I've been waiting for someone to say it

[Crucial_Xtreme]

E21 Barcelona updates coming next week.

Speaking about what the team intended to bring to Barcelona, technical director James Allison said: "Nothing revolutionary, but plenty which should help us go faster.

"We have new front wing endplate detailing, new aero around the rear drums, modifications to the diffuser and a different top rear wing so there's plenty to help keep us in the hunt."

Link

[Blackout]

And Allison updates listings are rarely exhaustive... : P

[shelly]

I am curious to see the new rear drums (maybe we have already seen them in the spyshots from the last aero test) and the new rear wing.
Will Lotus test DRD again? Barcelona seems idela for at least a friday trial, given that the teams have plenty of references for setup

[ringo]

Hydraulic fluid per se, cannot compress, so therefore there just cannot be any spring in its use. Imagine, if hydraulic fluid could compress or spring, then we would have no JCBs etc or any other machinery using hp oil. Yes, the ancilliaries could be used to provide some give, but the oil itself, CANNOT provide any springing.

It's not the fluid that is being compressed.

If you have a reservoir with pressure diaphragm, you control the volume of the system. If you can do that, you can make a hydraulic "spring".

Have a look at this fine arcticle by scarbs:

http://scarbsf1.com/blog1/2011/11/29/lo ... d-inerter/

With Mercury having a high coefficient of thermal expansion, the patent suggests using a relief valve emptying into another chamber is used to ensure the system has a constant volume of fluid.

That's not a spring, you know that?
Any how, believe what you'd like. As incorrect as it may be. Can't say i never tried.

[ebare]

Hydraulic fluid cannot behave like a spring Off course it can, and without the need of a compressible fluid. Exploiting its compressibility, for itself it can’t, however, exploiting its viscosity, it can, like Lancia Delta’s “old” central differential, where the viscosity actually pushed de discs against each other just like a spring. What puzzles me is the time they took to go this path after the ban of the mass dampers.

[ringo]

Hydraulics are used to support loads in orders of Tonnes of force, with almost non existent deformation and we are here convincing ourselves a 640kg vehicle is going to compress a column of hydraulic oil by centimeters?

I'm trying to understand what you are saying. Apparently the car will compress an in-compressible fluid before the tyres filled with air (a compressible fluid) even considers imploding. Ponder that one...

Ok ok, lets discuss..
The wheel pushes the oil through an orifice. There is a reaction force to the wheel from the damper, as long as the wheel is moving. (Newtons per meter per second) Answer these questions:

In a system with no air springs, no coil springs, just oil and orifices.

What causes the oil to return and push back the wheel after the compression stroke is complete (after system reaches steady state) ?

Why should the oil compress (reduce in volume) when all it has to do is send that volume through an orifice?

Finally a trick question:

If energy stored in a spring is 1/2 spring rate * displacement squared. What, if any, is stored in the fluid. And what, if any, is "stored" by the fluid passing through the orifice.

I'll be looking for the air springs on the e21 while you work on that. If we find no air springs then it's using conventional corner springs.

[henra]

Hydraulic fluid cannot behave like a spring Off course it can, and without the need of a compressible fluid.

The problem with that is that before a fluid compresses everything else around it will compress. Starting with the tyres as @Ringo rightly commented. Then the hydraulic lines and cylinders will start to expand. The amount of compression of the fluid at the same time will still be negligeable. Having hydraulic lines or cylinders expand is not an hydraulic spring. It is solid materials deforming. In doing so they will have strange spring characteristics (i.e. non-linear/degressive).
There might be potential for tricky solutions but more likely potential for setup trouble with such characteristics especially since there are many things that will start deforming. And you have to calculate/control them all.
I'm with @Ringo on this one. I doubt anyone would go on this expedition with lots of uncertainties/risks and very vague prospects for benefits.

[RB7ate9]

This was found in the Caterham CT-03 thread.

It looks like the 2013 Lotus with a new nose update (vanity panel).

http://www.diablomotor.com/wp-content/u ... 1-2011.jpg

[wesley123]

Nope it looks nothing like it. It is the 2011 Renault R31

[RB7ate9]

Absolutely correct. I'm a bit fuzzy in the head this morning

[PlatinumZealot]

Hydraulics do not a good spring make. Do the maths.
Might as well u use a real spring than hydraulics, because you are gonna need humungous housings to contain a hydraulic spring. Use your God given brains people.

you better tell Andre Citroën about that!

See the above posts.. Hydrualic fluid? Spring?!! Craziness. lol

[ebare]

The problem with that is that before a fluid compresses everything else around it will compress. Starting with the tyres as @Ringo rightly commented. Then the hydraulic lines and cylinders will start to expand. The amount of compression of the fluid at the same time will still be negligeable. Having hydraulic lines or cylinders expand is not an hydraulic spring. It is solid materials deforming. In doing so they will have strange spring characteristics (i.e. non-linear/degressive).
There might be potential for tricky solutions but more likely potential for setup trouble with such characteristics especially since there are many things that will start deforming. And you have to calculate/control them all.
I'm with @Ringo on this one. I doubt anyone would go on this expedition with lots of uncertainties/risks and very vague prospects for benefits.

As you can read in my original post, i agree that the hidraulic fluid cannot work for itself as spring in a compression manner (or it won't be easy to do so), hence the use of one elastic element. Sadly i didn't make mayself clear. By "this path" i didn't mean "hidraulic spring", i meant interconnecting the four wheels, trying to emulate mechanically the electronic suspension.
However, i think that saying hydraulic fluid cannot beave as spring, period, is not totally accurate, because in Lancias's central diff example, its the viscosity of the fluid that pushes or releases the discs according to the demand, and that seems to me pretty much what a spring would do.

[miguelalvesreis]

Hydraulics do not a good spring make. Do the maths.
Might as well u use a real spring than hydraulics, because you are gonna need humungous housings to contain a hydraulic spring. Use your God given brains people.

you better tell Andre Citroën about that!

See the above posts.. Hydrualic fluid? Spring?!! Craziness. lol

You are assuming that the fluid is hydraulic oil on all parts of the system? I didn't assume that at all by the article.
I agree with your point (and other's) that the spring effect can't come from elasticity from the pipes. There are too much variables in action there, from temperature to phisical properties of the pipe materials. I would believe that they have chosen materials with stabler behaviour with temperature and pressure variations and would rely on different materials on a contained area to have the spring effect.

Not that I'm deffending that they really have an hydraulic suspension but only assuming that it's not impossible that they have it. Perhaps hydraulic was a term used with a broader scoap than it should have been. Nevertheless, with proper containers/reservoirs where they might have a compressible fluid, than it would be feasible.
Advantages? Cons? Well, I could only think of layout and CoG. They can put such containers in advantageous location. If this is really a pro feature, I'm not sure since I don't really know how small and light are the F1 springs nowadays. They might have found the weight to be in excess but the interconnection an advantage and due to the fact that they might be able to locate it on a better (for CoG) location....