Hancha Rear Toe Link

[Hancha Group]

Originally Posted by Dimman

I your blog you mention going for stiffness to weight as a priority. But then you chose aluminum over chrome-moly. Why, when aluminium has much lower E modulus? (It's hard to see how much of a diameter change on your part vs stock.)

Also, why bother with a nonstandard aluminum alloy (26xx?) when the rod-ends are 7075?

SubieNate hit the nail on the head. You can use thin wall steel or titanium, but then the stress goes up as well. But then you have to use bigger rod ends as well, in order or use some sort of insert. If you use a thicker walled steel or titanium, the weight goes up. You typically need to get the hole extruded from bar stock, which significantly increase manufacturing time and cost. By using a solid aluminum piece, it reduces stress while increasing stiffness. Our turnbuckle is 1.125" vs OEM 3/4"

The stiffness, K, is equal to area, A, times the modulus, E, divided by L or the length. So K = AE/L

OEM: A = (.019m/2)^2*Pi, E = 210 GPa, L = .254m
Hancha: A = (.028m/2)^2*Pi, E = 70 GPa, L = .165

OEM stifness: 2.34 x 10^8 N/m
Hancha stiffness: 2.61 x 10^8 N/m

That's about 11% stiffer. Solidworks says our final piece will weigh under 1.5 lbs. I'm not sure if that's less than OEM. If someone could let me know the weight of the OEM link, it'd be greatly appreciated.

6061-T6 is difficult to machine and a bit weak. 7075-T6 is expensive and isn't very good against corrosion. That's why I selected a non-typical alloy. Aluminum rod ends are less than $20, a lot cheaper to replace if you need to vs the turnbuckle.

Originally Posted by robispec

pricing?

I should have the finalized price today so please check back. The initial GB price will offer significant savings though. Everything is made in Indiana so once I place the order, the lead time is typically 3 weeks or less, add a day for shipping to us.

[Hancha Group]

Originally Posted by Dimman

I understand the shape/size aspect to stiffness, but in the side by side with the original steel part there looks like very minimal diameter increase.

You have to remember, it's the area, so even though the diameter grows minimally, the area grows exponentially. A = Pi*r^2

Originally Posted by Dimman

http://www.qa1.net/qa1_motorsports/c...-aluminum.html

'Red as standard' Not exclusively red. (If they are QA1 ends.)

If you ask nicely, and pay a few more dollars you can probably get any of the normal anodizing colours. Blue, black, clear, red, purple, gold, off the top of my head.

The rod ends are QA1 for this application. It may not always be QA1 for future products. The rod end is selected depending on the application and the material it will mate with. Strength and weight are also considered. I'm a stickler for attention to detail. If someone wants to select a rod end from a different manufacturer, arrangements can be made.

[DriftEightSix]

Keen to see the pricing as well as shipping to Aust.

[Dimman]

Originally Posted by Hancha Group

You have to remember, it's the area, so even though the diameter grows minimally, the area grows exponentially. A = Pi*r^2



The rod ends are QA1 for this application. It may not always be QA1 for future products. The rod end is selected depending on the application and the material it will mate with. Strength and weight are also considered. I'm a stickler for attention to detail. If someone wants to select a rod end from a different manufacturer, arrangements can be made.

That stiffness formula doesn't look complete, since load isn't distributed equally throughout the part. Isn't the whole point of using tubing structurally all about removing a bunch of weight that only contributes very slightly to overall stiffness and strength?

The QA1 example was to show Orbital that though they come in red, you can special order different colours. He was just being a smartass though. Colour isn't exactly what you should make your suspension buying decisions on...

Finally, as a machinist, I swear that '6061-T6 is difficult to machine' is put into engineering texts (do they really even say that?) to see if students are just parroting the book or paying attention to the real world. It is not difficult at all. I can machine it with carbide, high speed steel, even unhardened mild steel. Either that or unscrupulous machine shops use that line on the uninformed to charge more money. I just don't understand why I see that statement all the time.

[Hancha Group]

Originally Posted by Dimman

That stiffness formula doesn't look complete, since load isn't distributed equally throughout the part. Isn't the whole point of using tubing structurally all about removing a bunch of weight that only contributes very slightly to overall stiffness and strength?

The QA1 example was to show Orbital that though they come in red, you can special order different colours. He was just being a smartass though. Colour isn't exactly what you should make your suspension buying decisions on...

Finally, as a machinist, I swear that '6061-T6 is difficult to machine' is put into engineering texts (do they really even say that?) to see if students are just parroting the book or paying attention to the real world. It is not difficult at all. I can machine it with carbide, high speed steel, even unhardened mild steel. Either that or unscrupulous machine shops use that line on the uninformed to charge more money. I just don't understand why I see that statement all the time.

You are correct in the case of bending. The increase in the moment of inertia increases its stiffness, but in this case it's to a power of 4. So you can get a part that's exponentially stiffer while removing mass when it's hollow. However, the load in the toe link is transmitted in tension/compression.

I am not a machinist, so you may very well be correct. However, we found an alloy that's stronger by 25% for a competitive price, the same weight, corrosion resistance, and it's claimed to be easier to machine. That is why we chose the alloy over 6061-T6.

Unfortunately, I know how this industry works and how companies will just copy our alloy without doing their own research, that is why we have chosen to keep this a trade secret.

[OrbitalEllipses]

Originally Posted by Dimman

The QA1 example was to show Orbital that though they come in red, you can special order different colours. He was just being a smartass though. Colour isn't exactly what you should make your suspension buying decisions on...

Precisely my point.

[SubieNate]

With the Heim joints at both ends of the rod there will be very little (read: basically none) bending force put into the rod.

That said, have you done any simple compressive buckling calculations compared to the stock part? What type of FEA analysis did you do? Just curious.

6061-T6 is stupid easy to machine. I really don't know where that comes from. Difficult compared to what? Now 4130 chromoly, that's a PITA. A lot of stainless steels are a pain as well.

[Hancha Group]

Originally Posted by SubieNate

With the Heim joints at both ends of the rod there will be very little (read: basically none) bending force put into the rod.

That said, have you done any simple compressive buckling calculations compared to the stock part? What type of FEA analysis did you do? Just curious.

6061-T6 is stupid easy to machine. I really don't know where that comes from. Difficult compared to what? Now 4130 chromoly, that's a PITA. A lot of stainless steels are a pain as well.

I use Solidworks and Solidworks Simulation. I have done tension/compression FEA on our part. For the OEM, I've just done a quick model making it 19mm round extruded 9" with alloy steel as the material. Loading condition is 8000 lbs both ways. That's roughly the equivalent of setting 3 cars on the turnbuckle! I debated making it lighter, but I wanted to try and beat the OEM performance in strength, stiffness, and weight.

Hancha turnbuckle in tension:



OEM turnbuckle in tension:



The OEM has less stress, but it's negligible. We're not even halfway to the yield point with our turnbuckle. The Hancha turnbuckle in compression:



The OEM link in compression:



My quick hand calcs were pretty close, eh? FEA says our link is actually closer to 14% stiffer than OEM. And we're not even to the good stuff yet! We just got the finished solid model for the FR-S that we're going to start using to develop an aero kit. But first, we've got to finish up some CFD work for a GTI that's competing in One Lap of America. Then we'll start working on the FR-S aero. This is a quick rendering I did with our wing design. Paul's going to start a thread in the cosmetic section soon so keep an eye out. You can check out our blog for more info.

[Huehuecoyotl]

Tell me more about hanchagroup, its previous successes with stuff like this. You have my attention. I get I should be comfy trusting my life to this part, has it been yield/failure tested? realworld? I got axles for my truck, it was relevant to know the vendor knew precisely when they would break, at what force, and where they'd fail. This matters more to me than color. Now fatigue is something you have to make sure the proprietary alloy will live up to, but that too I rather that you disclose the metalurgy

[Hancha Group]

Originally Posted by Huehuecoyotl

Tell me more about hanchagroup, its previous successes with stuff like this. You have my attention. I get I should be comfy trusting my life to this part, has it been yield/failure tested? realworld? I got axles for my truck, it was relevant to know the vendor knew precisely when they would break, at what force, and where they'd fail. This matters more to me than color. Now fatigue is something you have to make sure the proprietary alloy will live up to, but that too I rather that you disclose the metalurgy

Hi, we have not done physical destruction testing, as we don't have the financial resources to do so at this time, but I take safety very seriously. Fatigue resistance was taken into consideration and in SolidWorks I did a simulation of 10^9 cycles at a 2G loading condition. The fatigue strength is a little lower than that of 6061-T6. It is 90 MPa vs. 96.5 MPa at 5e8 cycles. I have omitted the alloy and temper, but you can see some of the data for yourself, directly from Alcoa's brochure:





I'm not trying to pull a fast one or hide anything from anyone. I'm just trying to protect a trade secret so our design doesn't get knocked off right away. I hope you can understand. I also hope you can see I do my proper due diligence.

We're a very new company but we've had some experience individually. I have worked in the aftermarket industry and have interned with a SCCA World Challenge team. Paul has interned with a Top Fuel Dragster team and currently develops radiators for NASCAR Sprint Cup Cars for a day job.

Don't let that deter you though, we are greater than the sum of our parts. We have an incredibly knowledgeable and diverse network we can reach out to. My roommate was the lead DAG (Data Acquisition Guy) for an IndyCar team last year, I have a close friend that is a damper engineer for Penske Racing, I keep in contact with our old professors, one of which consults for an ALMS team, and one that works in F1. Paul learned aerodynamics from a former F1 Chief Development Aerodynamicist. So if we ever run across something we don't know, we can find the right answer.

You can read more about our background in our intro thread here

[Calum]

Is there anything built into your design to counter bump steer due to lowering?

[Huehuecoyotl]

great responsiveness and appears the vendor has a handle what they are doing, so thats good. I'm game to hear and see more.

Originally Posted by Calum

Is there anything built into your design to counter bump steer due to lowering?

is that what the factory bend helps with, that bit of offset?

for those of us needing to put strength 1st and weight second, is there an HD end link option? I mean, this thing made of steel would likely be fine by me, for my needs, I just need unbreakable. this is not a high priority part for weight shave for me

[Hancha Group]

Originally Posted by Calum

Is there anything built into your design to counter bump steer due to lowering?

Originally I wanted to design the shank longer to allow for 10mm of bump steer adjustment, but because of the trailing arm and e-brake cable I decided to scrap that idea. With our prototype version, it touches the e-brake cable as you can see here (our production version is 5mm shorter with a thin nylon lock nut so it won't touch).



I will keep an eye out with the prototype and see what happens over time. I am not 100% comfortable with releasing an extended shank at this time. I'm sorry I couldn't find a solution for this, I really wanted to make it happen. However, if we find there aren't any ill effects, in the future, we will offer an extended shank for bump steer adjustment as an option. The nice thing about our design is if you want the bump steer shank in the future, you can just change the shank and buy a few extra shims rather than having to buy a new toe rod or ball joint.

[robispec]

I have a no ebrake car....tester?on the extended shank???