3 link for my 65 falcon

[Bryce]

i have a car in my garage called an intermeccanica omega. It has a 3 link rear suspension with a panhard it has a offset upper link.



this was a holman moody deigned suspension from the 60's it has a italian body and ford running gear. I will try to get a picture today.

[Bryce]

JR

Its not that the bars need to be horizontal. They need to be the same length and parralel at some point during the suspension travel. I think the only way this is possible is to have the arms horizontal at some point.

for my application a long panhard will be easier to package. It will be 42" long.

[BillyShope]

Billy Im hard pressed to find a pic of the rear suspension of a c-class You have a pic.

Third post down:
http://www.hotrodders.com/forum/home...made+truck+arm

http://www.racetec.cc/shope

[LowBuckX]

Thant answers some questions. I found pics on individual parts but not assembled.

[Norm Peterson]

Third post down:
http://www.hotrodders.com/forum/home...made+truck+arm

The PHB in that C-Jag picture is certainly . . . ummm . . . unusual.


Norm

[BillyShope]

The PHB in that C-Jag picture is certainly . . . ummm . . . unusual.


Norm

It IS that. But, whatcha gonna do when there are no frame rails extending back to a big chrome rear bumper? It's essentially what dragracers do with their triangulation of the lower links of a 4link. Whatever works, I guess.
http://www.racetec.cc/shope

[Norm Peterson]

Leaving the bending of the PHB aside, I think that one of Mark Ortiz's fairly recent Chassis Newsletters addressed the topic of a lateral location link with plan view skew. From memory, I think it introduced some asymmetries of its own, which I wonder how they combine with the asymmetry of the upper longitudinal link. No opinion if good or bad, though I guess the C-Jag designers were mainly looking for a low roll center, and the overall result had to be at least better than somewhere between poor and evil.

Somebody over on Corner-Carvers has got the Chassis Newsletters hosted (or at least used to), and a search on that term should find the thread.


Norm

[BillyShope]

Leaving the bending of the PHB aside, I think that one of Mark Ortiz's fairly recent Chassis Newsletters addressed the topic of a lateral location link with plan view skew. From memory, I think it introduced some asymmetries of its own, which I wonder how they combine with the asymmetry of the upper longitudinal link. No opinion if good or bad, though I guess the C-Jag designers were mainly looking for a low roll center, and the overall result had to be at least better than somewhere between poor and evil.

Somebody over on Corner-Carvers has got the Chassis Newsletters hosted (or at least used to), and a search on that term should find the thread.


Norm

I get Mark's newsletters, but I must have neglected to read that one. (Hope he doesn't read this and stop sending them.) In a dragracing application, there would be no effect, so I must assume that Mark was considering the case when lateral loads are present.

As for the C-Type, it is my understanding...from communication with a Jaguar engineer...that very little analytical work went into the design's asymmetry. As the sketch indicates, they provided for a great deal of latitude as far as upper link offset was concerned. In discussing this with the Millikens, it would appear that mine was the first work to establish the analytical relationships between link positions and angles and the corresponding antisquat. This is not to minimize the work at Jaguar. As with the development of any project car, I'm certain they were pressed for time and felt that the proper solution could be achieved more reliably and quickly through testing.
http://www.racetec.cc/shope

[LowBuckX]

Billy could you take a look at my project at the link in my sig and tell me what you think. You did inspire me in part to do the offset upper link.

[BillyShope]

Billy could you take a look at my project at the link in my sig and tell me what you think. You did inspire me in part to do the offset upper link.

Looks good. Keep in mind that you can use the spreadsheet at Page 40 to adjust the lower links for equal tire loading.
http://www.racetec.cc/shope

[Bjkadron]

I'm still slightly confused, so another question. theoretically you could use the rear roll center height to control the oversteer/understeer characteristics like you can with a swaybar? And could you do this with a softly sprung car(for maximum mechanical grip) that uses swaybars to control the side forces?

When determining the distribution of the lateral inertial force during cornering, BOTH the roll center height and the roll stiffness must be taken into consideration. But, when considering the fore-and-aft distribution of the driveshaft reaction torque, ONLY the roll stiffness distribution need be considered.

The asymmetric adjustment of the lower links has nothing to do with either the roll stiffness or the roll center height. That portion of the weight transfer taken through the lower links has a vertical force component. With an asymmetric adjustment, the vertical force at the right link is greater than that at the left, resulting in a torque on the axle housing which is both proportional to the driveshaft torque and opposite in sense. So, with the proper link forces (and, with the help of that portion of the driveshaft reaction torque which is fed back through the springs), it is possible to achieve full cancellation of the driveshaft torque for dragracing.

(Actually, for dragracing, you'd want 100% antisquat, so all of the torque necessary for cancellation would be by the link forces. The 100% antisquat would be an average of the left and right link adjustments.)
http://www.racetec.cc/shope

[BillyShope]

...theoretically you could use the rear roll center height to control the oversteer/understeer characteristics....

No "theory" to it. Watch the NASCAR pit crews as they adjust the Panhard height to do exactly this.
http://www.racetec.cc/shope

[Bjkadron]

I hadn't thought about that... I think you just changed my plans..

No "theory" to it. Watch the NASCAR pit crews as they adjust the Panhard height to do exactly this.
http://www.racetec.cc/shope

[Bryce]

what a great direction this thread is going, i like all this suspension design discussion.

[Bryce]

So I got my heidts subframe connectors (thanks route66, 10% discounts are nice) this will be my last building block for the 3-link. i have teh design done. Now I need to create a triangulated mount for the chassis mount for the upper link. It will tie into the SFC and the rear frame rails. This will be a very strong piece while adding minimal weight.

Packaging the panhard and the shocks behind the rear end and in front of the gas tank will be slightly challenging.

[PhillipM]

Old thread I know but this has really helped me on my rear 3 link design. Thanks guys!

[Bryce]

Phillip,

This was a good thread. I just need to start working on the 3-link for my car. Hopefully life will get out of the way for a little bit.

[PhillipM]

I decided to follow Billy's suggestions and am going to offset the upper link to the passanger side to cancel the torque of the driveshaft. Looking forward to seeing how it works.

[Bryce]

Hows it going Phillip?

Im officially starting the build design is done.

[Bryce]

FYI, I finished the 3-link. Its a bolt in design with A/S adjustment 70% to 150%. See my build thread for updated pictures.