sharky47

I am ordering the material to make a prototype set for myself. I want to guage the interest in something like this, basically an affordable alternative to the "Charlie Arms" type stuff that is out there already. And they would be kept in-stock.....

So here's what I am thinking:

4130 square tubing, same type of steel airplanes are made of.

Modular ball joint system i.e. - you could bolt up off-the-shelf joints like the early 944's and save a ton of money chaning them. Or you could use specialty-built 19mm type joints for hardcore racing.

You could use stock bushings/caster blocks, or use aftermarket delrin/aluminum stuff.

And most importantly - they will be AFFORDABLE! - well under 1k!


Discuss.......

Airflite40

Can you machine a turbo for me?

Better yet, you better just machine a whole 951 for me, I don't wanna **** people off.

great job BTW keep it up!

schwank

I take it that price would be per PAIR?

I would likely be interested but would wait til the current ball joints are obliterated.

How about wheel hubs... can those things be made cheaper than $375/piece that Racer's Edge gets?

M758

Don't use a rod end for ball joint end. Really bad loading for the rod end.

I will tell you that the load these arms sees in mostly in plane and would occur underbraking. Remember underbrakes the tires pull back while the car goes forward. So it is classic triangle of loading with the length of the arm causing a bending moment about the crossmember. If you need to I can make a very simple load diagram. Think about this loading when you design these arms so that you can minimize their weight and maximize strength. The problem however is allowing clearance for the tires. Otherwise they all would be a simple triangle.

OriginalSterm

I agree with Joe, proper engineering must go into designing control arms. Not just "connecting the dots" for mounting the arms. FEA on your design would be helpful as well, if you have that capability.

sharky47

I can do simulated loads in Solidworks.

As well as beating the ever living hell out of the prototypes.......

Darwantae951

I'm pretty sure Sharky has an idea of what itll take to make these things hold up. Plus we all know he'll test them out on his own car first. Good luck with this, I might be interested if you can keep the cost down.

-Darwin

M758

Great
testing should be as follows.

Accelerate to 170 MPH. Get hard on the brakes down to 40 mph. Turn and bash over curbs at 40 mph 3" high on left and thern right side. Repeat 50 times.

Oh... must do on a 3300lbs car using big red brakes and 10" wide front slicks.

inactiveuser92616

A mechanical engineering grad student that I work with in my advanced engines class said that he designed and analyzed a set of A-arms for the 944 (company never got off the ground); I will talk to him if you are interested in skipping a step.

sharky47

Haha, Joe - I'll get right on that......

Seriously though, I was already going to have an engineer involved......

M758

I said that in jest, but it is realility in many ways. Good to see you have an engineer involved. I too am an engineer (jet engines) and I have spend hours doing FEA on parts. Anyway the key is to make sure the engineer knows the loads involved or a good way to estimate them. In correct boundry conditions can result in perfect accurate, but useless results. I think the biggest loads will be from a super high hp car with rapid braking and then boucning off curb. Those kind of loads can break stuff. Also scan the Racer's Edge control arm breakage thread. Apparently some welds were causing problems in batch of arms. I am certain there is something to learn from that experinece.

Good Luck

alordofchaos

Better stuff is always good
shiney is good, too

GodSpeed

Perhaps posting some technical drawings would help. Well I just want to see them anyway.

Rock

Just make them pretty. Ill buy. I love eye candy!

sharky47

The engineer I am using is a Designated Airworthiness Representative.

Arms will be powdercoated.......