Adjustable blade ARB's

[Jeffer]

lol

[Fat Audi 80]

Wadda guy!

Cheers Steve

Jon

That was easy!

[zlobo]

nice Jeffery

[quattro84]

Hi guys,

I'm trying to help Jeffer on this part.
Since i'm becoming an Automotive Engineer this is a nice challenge for me.
Cut the crap, here are some pictures of the stress & displacement tests i did with CosmosWorks. These are just some tests i tried with an force of 500kg applied normally to the bolthole. Clearly it's easy to spot the difference.





But, i need some info. For instance the maximum perversion-angle under hard cornering. Otherwise the blades will be much to stiff or vice versa. I guess this will take some testwork.

And i need to figure out a way to calculate how much force the blades have to resist under hard cornering (has got something with the bodyroll,impression of the springs&dampers, internal relations of the parts).

I used Spring-steel on these blades and they don't seem to be elastic enough. What i need is a material with a high yield strength and a big elastic deformation boundary.
And for the rod on which both the blades attach to, well that has to be torsionproof as f*ck. CrMo4340 would do the job.

clever comments are

[quattro84]

Little update.

Did some calculations considering it to be CrMo4130-steel.
Critical points are the connection to the uniball, and the fatique in the blades.

I did find some early pics of some Norwegian and Swedish rallycross-cars with a same setup.


Aren't there any forumers living next door to some Rallycrossers like Sverre Isachsen? Some dimensions of the blades would be very nice.. Also some more pictures of ARB-setups.

Cheers

[Rusty]

Nice work, love to see some FEA plots on the forum! 0.35mm vs 1.8mm deflection is quite a large change!

No idea how you'd measure corner loads other than measuring spring rate then using deflection (from photographs) and thus making a best guess. From pics of my car (on standard rear springs) around the ring, 3" (76mm) deflection would seem to represent HIGH cornering loads (exiting mini-Karussel in mid air) so if you can measure the rear springs then thats a good start (I have data on a previous thread where I calculated that the rear springs are stiffer than the fronts, do a search, this uses helix spring theory and you'll have to guess the material and temper as as interested in relative stiffness).

HTH

[shortsport]

Found a in car adjustable system

http://www.genesisparts.com/index.cfm?form_pic_id=43_2&action=product_picture&form_cat_id=1

http://www.genesisparts.com/index.cfm?form_pic_id=43_1&action=product_picture&form_cat_id=1

http://www.genesisparts.com/index.cfm?form_cat_id=6

[G60Rallye]

Thought i would bring this topic back to the top as its very interesting!

Have you seen the price of the genesis set up!!!!

[stiglet]

Would love to have one of these in my Coupe

[WabTheKing]

why do u need 2 blades??

look at a 997 gt3 cup car set up, only has one blade, the other side just has a drop link

the bar will deflect at its weakest point and will be the same both ways so you dont need it adjustable at both ends

assuming this is why this works on the cup car, will try and get some photos this week

[stiglet]

Pic i found on another forum of an E36 racecar, has two adjustable blades rigidly connected so there is only one adjustment but it adjusts both blades symetrically. I dunno why you would need that, perhaps just to keep the whole thing balanced? If one blade bends and deforms and the other doesn't, maybe that leads to funky rates at different deflections or something?

[Keeper of The Kitten]

No. You only need one blade to flex. If you have two then the flexing is doubled and this might be too great a variation. Depends on arm lengths and relative thickness of the waisted part.

[Keeper of The Kitten]

(And the very short bar in the BMW here would be relatively stiff of course)

[Keeper of The Kitten]

Extraordinary to see such elaborate bell cranks just for the ARB function too!

[stiglet]

Greater adjustability is the only reason i can see for having both

People do seem to use both singles and doubles though so i guess there is a reason.