choosing a roll center height.

Shocks, Springs, Brakes, Frame, Body Work, etc

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Olefud
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Re: choosing a roll center height.

Post by Olefud » Thu May 30, 2013 11:22 am

MadBill wrote:It's worth noting that an SLA front suspension can be arranged to maintain a RC fixed Vs. either the ground or the CG, as required to match an axle or chassis-mounted Watts pivot.
Point taken. Still, my thought was that there’s a lot going on with a SLA so it may be the better course to not fixate on the RC parameter alone. It’s good to have a well thought out setup but compromises will be made.

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Re: choosing a roll center height.

Post by Warpspeed » Thu May 30, 2013 6:30 pm

My approach to initially establishing some roll centre heights on a new project would be to begin by shamelessly copying an existing car that is known to work well.

That might be a consistent winner in your class.
Or a car of similar size, weight distribution, power, tire size, and usage that some multinational company has spent millions of dollars on R&D developing over a long period.
Make as much as possible adjustable, and use the template car the starting point for your new design.

The original poster is building a tube framed front (mid) engined car for road racing with strong aero.
This has been done many times before, and it is just a case of tracking down a few famous past winners and figuring out what they did and why they did it that way.
Cheers, Tony.

redliner
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Re: choosing a roll center height.

Post by redliner » Mon Sep 09, 2013 8:26 pm

Warpspeed wrote:More than one way to skin a cat.
It's a bit clearer with a Watts linkage, you can do it both ways.
Image
I am interested in installing a watts linkage on my 4-link drag/street car and your picture of the linkage with the pivot mounted on the chassis looks like the better way to do it on my car because of room constraints. I think I can run a mount down from my upper shock mounting bar ( but how far down? to center of pumpkin at ride height?) and mount the outer ends of the bars to the backbrace(bolts centered?) on my rearend housing...follow? Feasable?

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Re: choosing a roll center height.

Post by Warpspeed » Mon Sep 09, 2013 9:36 pm

Certainly feasible, I have done it this way myself in the past.

One point to be a bit careful of is ground clearance at full bump.
If the lower end of your Watts linkage ever digs into a speed hump, or concrete curb, the damage could be pretty major.
Cheers, Tony.

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Re: choosing a roll center height.

Post by redliner » Tue Sep 10, 2013 5:44 am

Warpspeed wrote:Certainly feasible, I have done it this way myself in the past.

One point to be a bit careful of is ground clearance at full bump.
If the lower end of your Watts linkage ever digs into a speed hump, or concrete curb, the damage could be pretty major.
Thanks Tony!

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