Who would need ARBs ?!!!

[Lemon Lime]

Hello Mates , Warm greetings and afterward . I had a silly idea about compensating ARBs for mechanical motion to prevent excessive body rolling in corners .. The motion mechanism works well in heave and rolling " OR AT LEAST THAT IS WHAT I THINK " .. but might disappoint you due to one wheel bumps ... Never the less .. The track doesn't contain one wheel bumps . P.S : Feedbacks are extremely welcomed . Thanks everyone , And good luck to all who are going to FS UK in few days . Oh yes .. And here is the picture explaining what I was thinking of ---> [IMG]Picture (https://www.facebook.com/photo.php?fbid=137060186498801&l=abafaaed45)

[Tim.Wright]

I think some of the arrows are in the wrong direction if they are representing roll.

The green links are in a bit of a strange location on the bellcrank. When the bellcrank rotates, they aren't really going to move at all.

But anyway, why do you want to replace the anti roll bars with this system? One thing to remember is that while roll movement is generally unwanted, it is necessary to get the correct wheel loads. In terms of body control, the suspension has 2 jobs:
1. Controlling the body movements
2. Controlling the wheel loads

Your system seems to be only addressing the first point not the second. But I do admit, I don't really understand how it works or what problem it is trying to solve.

[Lemon Lime]

Mr.Tim Wright Sir,

Warm greetings and afterward ; The system hopes to deliver roll resistance in cornering .. My humble idea is as follow .. Rather than making one spring to resist the roll motion " compressing one spring " ... Two springs will to resist the roll motion ... And about the location of the green rods ... Well the drawing isn't really that accurate to judge on " PARDON MY HUMBLE WAY FOR EXPLAINING MY IDEA VIA USING MS. PAINT " And I think Sir that you're right considering the wheel loads .. Thanks for your reply Mr.Wright ... Really appreciated .

[TurboTom]

Lemon lime,

That looks very similar to a system that RMIT ran last year on the rear of their car at fsae Australasia. I'm sure there was at least a couple photos taken of it, so have a look on the interweb.
I believe that system worked by bending the two blades as the car rolled, as one blade would want to move up, and the other one move down, putting that centre link in either tension or compression. Is that how your system is supposed to work?
The main two issues with that system were adjustability for roll moment distribution as mentioned before, and you need a large, empty space below and above for the blades to move in bump/ heave.

[Lemon Lime]

TurboTom,

First thank you for your reply ... Afterward ; My system was supposed to work by making 2 springs in compression due rolling rather than 1 spring . About RMIT ... I looked over the interweb for some pics but I couldn't find a clue . Again Thank you for your time .

[Z]

Lemon,

As Tim says, your picture's arrows show heave motion rather than roll, and the green-links-to-grey-rocker-connections will result in the centre section not doing much at all.

However, I do understand what you are trying to do, which is to stiffen the axle-roll-mode with the centre section (green links + yellow rocker). But you have made it TOO COMPLICATED!

IT CAN BE MUCH SIMPLER! http://fsae.com/groupee_common/emoticons/icon_smile.gif

Hints:
1. Get rid of the central yellow rocker.
2. Think about how a single green link can connect to the two main rockers (= grey "bell cranks"). Ie., above or below the rocker "mounting point" (black)?
3. Can this single green link be used to stiffen either axle-heave or axle-roll?
4. Can you give that single green link some controlled axial springy-ness, and thus add controlled stiffness to heave or roll?
5. Can you use two similar-but-different central springy-green-links to give independent control of both heave and roll?
6. Do you now need the two main springs (blue)...?

Z

[Lemon Lime]

Z,

I've been looking forward for your comment Sir , You always inspire me .. Specially when you posted about the Semi-Leading & Trailing Swing-Arms .. Just terrific .

Although I'm confused bit about a thing .. In your design you've used 4 bearings ... I guess 32006J ?! Well I do understand that 2 of those bearings are for wheel rolling friction cancellation .. The other 2 for the steering axis yawing cancellation .. Am I right ? .. Well why Sir you've used 2 bearings on the steering axis rather than 1 single bearing ... I mean that the 2 dedicated bearings for rolling friction will supply axial and radial support for the shaft . Again .. I have such a small amount of knowledge Sir and I'm trying to learn .

About your hints ... Thank you a lot Sir for your reply ... I guess your hints are pretty much similar to what TurboTom was trying to say .. Although Sir you've clarified it more ... Thank you ... But pardon me again ; I have one last question ; If I left the system as it is and configured the mounting point ( black ) on the middle rocker ( yellow ) to make it a torsion rod and also removed the blue springs would that be convenient ? Sorry for my ignorance .. I'm just 18 years old trying to learn ! .. Again Sir thank you for your time .

[murpia]

Originally posted by Z:
Lemon,

As Tim says, your picture's arrows show heave motion rather than roll, and the green-links-to-grey-rocker-connections will result in the centre section not doing much at all.

However, I do understand what you are trying to do, which is to stiffen the axle-roll-mode with the centre section (green links + yellow rocker). But you have made it TOO COMPLICATED!

IT CAN BE MUCH SIMPLER! http://fsae.com/groupee_common/emoticons/icon_smile.gif

Hints:
1. Get rid of the central yellow rocker.
2. Think about how a single green link can connect to the two main rockers (= grey "bell cranks"). Ie., above or below the rocker "mounting point" (black)?
3. Can this single green link be used to stiffen either axle-heave or axle-roll?
4. Can you give that single green link some controlled axial springy-ness, and thus add controlled stiffness to heave or roll?
5. Can you use two similar-but-different central springy-green-links to give independent control of both heave and roll?
6. Do you now need the two main springs (blue)...?

Z

If you take a look here: http://scarbsf1.com/blog1/2013...-up-sheet-explained/ (http://scarbsf1.com/blog1/2013/06/04/analysis-set-up-sheet-explained/) you can see some variations on rocker-activated elements.

Anything that's a just damper, or gap-to-rubber in the above, could also be a spring. See the roll damper...

I have also seen heave dampers operating in the axle-droop-closes-damper mode, i.e. opposite to typical, which allowed for a droop stop on the coupled-heave mode.

Regards, Ian

[Z]

Originally posted by Lemon Lime:
Although I'm confused bit about a thing .. In your design you've used 4 bearings ... I guess 32006J ?! Well I do understand that 2 of those bearings are for wheel rolling friction cancellation .. The other 2 for the steering axis yawing cancellation .. Am I right ? .. Well why Sir you've used 2 bearings on the steering axis rather than 1 single bearing ...
Lemon,

Yes, there are a pair of E32006J bearings for the wheel-axle, and another pair for the steering-axis. Tapered-roller bearings work best in pairs, although other layouts are possible. The configuration in the sketch is quite common, and IMO well suited to FSAE type loads, costs, general conditions, etc.


About your hints ... I have one last question ; If I left the system as it is and configured the mounting point ( black ) on the middle rocker ( yellow ) to make it a torsion rod and also removed the blue springs would that be convenient ?
First, let's assume your green-links attach to the two main-grey-rockers somewhere above their black-mounting-points, perhaps near where the blue/orange-spring-dampers attach.

Then, yes, having a torsion bar on the central-yellow-rocker will allow it to carry all heave loads of the car, and (to a degree) you can then remove the blue-springs. But you can achieve the same result more simply by having a single springy-green-link (or spring-damper) interconnecting the two main-grey-rockers. This sort of heave-spring (aka a "third spring") is shown on Ian's link

If you want independent springing of the roll-mode, then you can interconnect the top of one main-grey-rocker with the bottom of the other main-grey-rocker, via a springy-green-link (shown as roll-damper in Ian's link). Note that this "roll-mode-spring" normally has very little, or no load on it, and only carries a relatively small tensile or compressive load when the car corners one way or the other. By comparison, the heave-spring (above paragraph) is always in compression from the relatively large load of the car's weight (+ any aero DF), although this compressive load fluctuates a bit from bumps, increased aero DF, etc.

If you want even more simplicity, then it is possible to toss the above roll-mode-spring and get a similar anti-roll effect from the heave-mode-spring alone. I call this "pendulum springing" and it involves nothing more than a small adjustment to the geometry of the main-rockers, pushrods, and heave-spring.

Hint 1: Think "rising-rate geometry".
Hint 2: Think of a pendulum consisting of a weight (the car) hanging from a spring (its heave-spring). Why does the overall geometry of a pendulum keep bringing the weight back to the central position? Can some similar sort of geometry be used to bring the car body back to the no-roll position?

Keep unlocking those locks. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Z

[M. Nader]

Similar idea

https://pbs.twimg.com/media/BOZbAqMCYAAdzaH.jpg:large

[Markus]

That is just a "conventional" ARB, a type what at least we call copter-ARB or heli-ARB, and on a side note it looks Zürich has gas springs?

Lemon Lime is (was?) trying to figure out how to interconnect the springs to double the spring rate in roll or something along those lines, but the first sketch just showed a locked roll-mode.

[Lemon Lime]

Z,

Many thanks again Sir .. And sorry for the late reply , I've been really busy . Again you inspired my and you're a great teacher Sir ... Thanks again And Of course I'll take your amazing advices into considerations .