LocostUSA.com

Since Mallock tells us the trailing arms should be at least 30" while the change in rise should be 1" on both links, we know the maximum angle will be inverse sin(1/30) = 1.9102° or ~2°, which fits in decently with your experiment, Cheapy. This will be the maximum because the angle(s) will diminish from the above as the trailing arms get longer.

Of course, we don't have the benefit of asking Sir Aurthur what problems were solved in his view, but it looks like binding may have been one of them. There will be other steering effects from his recommended configuration too, but to understand those we'd have to know much more about the car the 4-link above was mounted on to calculate them. In his case the links converge towards the front of the car.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

I need some help in this area. Where are you putting 30" trailing arms? I only have room for about 14 or 15 for my live axle mustang diff. I am trying to find some details in how to install it.
I have the Haynes book, but that is IRS. With the 4 link, wont you need a trackbar? What is going to stop the diff from lateral movement?

There are some examples of long trailing arms on this site, but none as far as I know with the Haynes Roadster as the basis. You can take a look at the Car9 design process for the general reasoning and to see where they ended up being anchored up front in that case. There was an old-time version of the Lotus 7 that had them. They called it the Lotus 7-1/2, I believe.

Here's a more modern take on it ==> http://www.lotustalk.com/forums/f94/uti ... ger-95687/

Yes, you'll need some kind of lateral locator. The most popular, and simplest, is the Panhard rod. However, there is also the Watts linkage, J-bar, Mumford Link and WOBLINK alternatives, to name a few.

You can make a 4-link work with 14" or 15" trailing arms. I'm in the process of designing a 4-link for my bespoke version of the Haynes roadster with a 1994 Mustang 7.5 rear axle. You can check out the last couple pages of my build log to view my (incomplete) setup thus far. PM me if you like too.

Cheers,

Lonnie

EDIT: Spelling error correction

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

Great write up, thanks for sharing. Have you tried to make videos before? If you hold the camera and narrate what is happening it is much easier, clearer and quicker to get the information you need. You can also show the motion and how it starts to bind. Also making a 2 minute video takes 2 minutes. A great write up like this probably took over 30 minutes. Once you have the video upload it to youtube and share the link.

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2015 & 2016 EMod Florida State Autocross Champion
2013 & 2014 DSP Florida State Autocross Champion

Scrap Metal Build Log viewtopic.php?f=35&t=14558

Thanks, I will look. I am using a 90 mustang 7.5 diff LSD. I am not using the haynes chassis, I am using McSorley 442+. I just dont know where to place the diff and what wheelbase to use.

I'm not familiar specifically with the McSorley designs and what they traditionally run for wheel base, but here are a couple of others:

Caterham CSR 91.14"
Champion 92"
Haynes Roadster 94.1" (2390mm)

I'm aiming for 95" myself because it gives the best package for me. If you're between 91"-95", I'd think you're in good range. Probably the biggest thing to look out for is possible collisions between the center unit of the axle and the seatback on bump and the lower rails on droop. Side to side movement will depend on your lateral locator, but should be less than 1/2".

In my opinion, having good packaging relationships is more important that if the wheelbase turns out to be 92" or 93" or 95".

Cheers,

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886

If it helps, I've used the 7.5" mustang rear as well with longer than "book" links. It's why I have fake brake duct scoops in front of my rear fenders (to hide the links). I'm running a 3-links setup so only have the lower links on the sides. Didn't see the point of a (potentially) binding 4-link on a low torque car.

Cheers.

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Build log: viewtopic.php?t=9291

bevins"][quote="Lonnie-S"][quote="bevins"]
I need some help in this area. Where are you putting 30" trailing arms? I only have room for about 14 or 15 for my live axle mustang diff. I am trying to find some details in how to install it.[quote]


Hi Bob !
Hey, I took a glance at your picks here, Man
You are goin'to be our future Enzo Ferr here in
Canada. My guess is that diff ought to be
located in the back of McSorley frame, with
proviso that it could bounce up'nd down only.
Automotive geeks call it "bounce and rebound
movement in perfect vertical line (so they say).

As for other things, I look forward with
patience to see beautiful emblems carved
on alu 2X8 plate with "LOTUS ARTIS" sign.

ewhen