Page 2 of 2
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 18:35
by DaveW
hardingfv32 wrote:2) This system does fail 10.2.2: powered elements. Power = Force X Distance The controlling valve moves because of inertia or force over a distance. Thus, the system is powered and in violation of 10.2.2. The rule states 'power', no restriction to the common electrical or hydraulic sources of power.
This type of shock has an orientation requirement. Disregarding packaging issue, do most racing shocks (gas chamber style) require a specific orientation?
Brian
A neat argument, but a false one I think. The accelerometer mass doesn't change position relative to the damper in the long term, & therefore doesn't consume power. The transient energy of displacement is stored in a spring which, ultimately, returns that energy.
The packaging of many (most?) dampers have an orientation requirement.
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 18:56
by hardingfv32
DaveW wrote: The "crude mass" controlling damper ports and restrained by a spring forms a mechanical accelerometer. The spring is normally preloaded to set the acceleration at which the control activates.
1) Surely force is required to overcome the preset spring and the valve must move to change the orifice opening? Power=force X distance
2) "The accelerometer mass doesn't change position relative to the damper in the long term, & therefore doesn't consume power. The transient energy of displacement is stored in a spring which, ultimately, returns that energy." But it does change position in the short term, thus the violation. The rule speaks to the use of power not the conservation of power.
3) Can you expand on the possible orientation requirements of a racing shock?
Brian
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 19:02
by gato azul
hardingfv32 wrote:
2) This system does fail 10.2.2: powered elements. Power = Force X Distance
Brian
Huhhh.............
I always thought Power =
dwork/
dtime or
F x
v
where is the time component in your formula?
Surely this forum, must be a sort of "parallel universe" where different physics apply.
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 19:39
by Jersey Tom
gato azul wrote:
Surely this forum, must be a sort of "parallel universe"
Sometimes, yes, I think so.
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 20:19
by hardingfv32
gato azul wrote:[where is the time component in your formula?
Feel free to add it. I'm always open to corrections.
I don't believe it changes anything. This system still does not comply with 10.2.2.
Brian
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 20:36
by gato azul
hardingfv32 wrote:
I don't believe it changes anything. This system still does not comply with 10.2.2.
Brian
I´m not here, to tell you what to "believe", it´s up to you to "believe" whatever you like.
I just wanted to point out that the "physics" you use to support your argument, are a bit "doggy", and I wouldn´t like to see some kid, somewhere in the world, fail at his physics exams, because it takes some things said one here, for the truth - that´s all.
“The whole problem with the world [and internet forums] is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts.”
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 20:41
by hardingfv32
Yes, I was too casual with the equation. Now that my hand has been slapped, I will TRY to be more through in the future.
Brian
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 21:55
by DaveW
hardingfv32 wrote:... But it does change position in the short term, thus the violation. The rule speaks to the use of power not the conservation of power....
The rule states :
Any powered device which is capable of altering the configuration or affecting the performance of any part of the suspension system is forbidden.
Note that the definition doesn't specify the source of the power. If your interpretation applies then damper control devices (shims stacks, etc.) that store energy temporally are also in violation.
hardingfv32 wrote:Can you expand on the possible orientation requirements of a racing shock?
Here is an example.
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 22:31
by hardingfv32
DaveW wrote: If your interpretation applies then damper control devices (shims stacks, etc.) that store energy temporally are also in violation.
1) I understand your position, but I am still comfortable when I say this system is illegal under this rule. 10..2.2 could very well fail to allow the current shock packages as written.
2) I do not understand the point of the shock photo in regard to orientation. What point is being illustrated? Could these shocks not be mounted vertically with a different rocker system. I noted in the beginning that packaging was not relevant to the question.
Just trying to weave the fact that you clock a shock, with this system in it, 90 deg and this function stops working. That is not the case with all the valves,etc. in a std racing shock.
Brian
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 23:34
by Richard
Perhaps Brian meant work done is force times distance?
It'll be interesting to see if these systems get more elaborate, and the FIA reaction.
The prevelence of g sensitive valves would also indicate that it would be OK to have a dumbell on a pendulum operating a valve. If that is OK then its not far off to exploit the properties of inertia, which leads us to a TMD?
Of course the McLaren J damper and the Renault inerter have attributes heading in that direction with their spinning mass.
Re: Swing in Lock mechanism
Posted: 02 Feb 2012, 23:45
by DaveW
hardingfv32 wrote:2) I do not understand the point of the shock photo in regard to orientation. What point is being illustrated? Could these shocks not be mounted vertically with a different rocker system. I noted in the beginning that packaging was not relevant to the question.
It is certainly true that dampers are not orientation specific in principle, but my example shows that they often become so once the package has been defined. In a similar way a g-sensitive housing can attached almost anywhere on the damper. After that has been selected, the element itself can be "clocked" to the correct direction, and the package likewise becomes orientation specific. There is a difference, I agree, but that is not usually too constraining.
Re: Swing in Lock mechanism
Posted: 03 Feb 2012, 00:37
by DaveW
richard_leeds wrote:The prevelence of g sensitive valves would also indicate that it would be OK to have a dumbell on a pendulum operating a valve. If that is OK then its not far off to exploit the properties of inertia, which leads us to a TMD?
I ought, perhaps, to explain the function of a g-sensitive damper.
Dampers are multifunctional devices. A major function is to dissipate disturbance energy, but they can also be used to control the rate at which the suspension responds to a single event.
For example, the braking event of an F1 vehicle generates (for a short time) a significant nose down pitching moment. This can cause the rear axle to lift, reducing rear downforce, & causing aero oversteer. There are several ways to control that problem, most of which will have a adverse effect on suspension performance for the remainder of a lap. A g-sensitive element attached to the rear centre damper can control aero-oversteer by slowing down the rear axle lift just for the time required to shed speed during the initial part of the braking event.
Typically, the g-sensitive element will be active for less than one second per braking event, and be inactive for the remainder of the lap, allowing the geometry, springs, bump rubbers, inerters, dampers, TMD, etc. to serve their function without compromise. The device is a very neat, simple, & low tech solution for a what is a persistent problem for F1 vehicles.
Re: Swing in Lock mechanism
Posted: 03 Feb 2012, 01:27
by thisisatest
inertia valve controlled low-speed-compression circuit used on mountain bikes. i have one, it works very, very well. it's also very different to just having a highly digressive damping curve.
http://www.facebook.com/photo.php?v=242 ... permPage=1
Re: Swing in Lock mechanism
Posted: 03 Feb 2012, 01:42
by hardingfv32
Not doubting your comments, but does Penske, etc. make something like this as a add-on feature? It does not seem very common.
Brian