Remote third spring

[hardingfv32]

Can this be called a remote third spring system? It is found on the Caterham.

http://i.imgur.com/5mwomXm.jpg

The line at the very top of the assembly: Is it a hydraulic line or a drive cable for a mechanical adjuster?

Would the output of this assembly go to a slave cylinder near the suspension rocker assemblies, front and/or rear?

Brian

[Tim.Wright]

Probably a pitch spring actuated via hydraulics

[mep]

Interesting,
I am looking forward to hear what people think about that.

[McMrocks]

I thought this has something to do with the front and rear connected suspension

[Lycoming]

Interesting. If it is indeed a heave spring remotely activated via hydraulics, its a good way to drop the center of gravity, but you pay for it with a rather hefty weight penalty. Wonder how much there really is to gain in that regard, assuming of course that that is what it is.

[xpensive]

I wonder if there is another one on the other side of the car, that would make it most interesting?

[hardingfv32]

The assembly is only on the one side.

Brian

[marcush.]

let´s not forget Gascoyne was at Tyrrell when they played around with their Hydrolink suspension...
No pictures around of that system apart from the words:"hydraulic rocker"

[DaveW]

The assembly is only on the one side.

This might help, perhaps....

[marcush.]

penske offered a remote third spring setp for their shocks a while ago..

[DaveW]

penske offered a remote third spring setp for their shocks a while ago..

1997 Ferrari 333 (but not as polished as your image). The Audi R8 (the proper one) also used a similar system made by Ohlins. Ferrari on both axles, Audi on the front axle only, I recall.

[hardingfv32]

In these types of systems how does the hydraulic force get converted to a linear motion at the shock? Wouldn't there have to be some kind of slave cylinder associated with the spring perch or shock body?

On the Penske unit shown above, the center spring unit feeds into what would normally be the location of a remote oil reservoir for a std shock. These small cylinders on the suspension shocks do not look like the normal remote reservoir. What are they about?

Brian

[DaveW]

In these types of systems....

Personally, I don't think the image posted by Marcus is related to your Caterham image (in a functional sense, anyway). GA's explanation suggests that is part of a "FRIC" system, rather than an hydraulically coupled (remote) 3rd spring.

On the Penske unit shown above, the center spring unit feeds into what would normally be the location of a remote oil reservoir for a std shock. These small cylinders on the suspension shocks do not look like the normal remote reservoir. What are they about?

All hydraulic dampers have a reservoir. The reservoir of a "single sided" (non-through rod) damper is complicated. It normally contains a gas accumulator separated from the oil with a sliding piston. The volume of gas must be large enough to accommodate the fluid ejected from the damper by the damper shaft without a significant increase in damper spring rate. The displaced fluid is then used to generate some or all of the compression load/velocity characteristic by a valve or valves also housed in the reservoir.

In Marcus' image, the two corner dampers share a reservoir. In this case the compression control valves are separated from the reservoir (& housed in the small cylinders you mentioned). The reservoir is the central element, but the gas spring is supplemented by an internal 3rd spring compressed by the sliding piston. The (often negative) preload of the 3rd spring is set by adjusters mounted in the end of the reservoir. Hence an hydraulically coupled 3rd spring.

[scarbs]

I can say for certain its part of the team’s interlinked (front to rear only) suspension. I can be sure as Mark Smith told me so at Monza, but he declined to explain it any further. Caterham said when they tested this at Lurcy Levis that it was a hydraulic\mechanical system, hence the coil spring that other teams do not employ.

[hardingfv32]

So, the shock the spring force is modified by changing the internal pressure in the main shock body. This pressure is acting on the cross sectional area of shock's main shaft. I am familiar with this principle, as this is a common variable when sitting the reservoir pressure.

1) May I assume that this type of use of the shocks would be applicable to the 'FRIC' systems?

The 10-15 year old Williams F1 shock I own is very small. The main body is the size of the general purpose Penske remote reservoir. The shaft is correspondently small.

2) How can you generate any useful force with such a same shaft cross section? What force might be required for a 'FRIC' system?

3) What kind of internal pressure might necessary to generate a useful force? What happens to the issue of seal drag?

Brian