goin2fast52
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 posted on 17/7/05 at 03:30 AM |
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Single control arm?
So I was playing Gran Turismo 4, and I got that crazy Nike concept car (http://www.granturismo.no/images/gran_turismo/gt4/review/nike_one_2022.jpg),
and I was looking at it and wondered, "How does the suspension work?"
Now I know that usually you have and upper and a lower control arm, with the shock going inbetween, but why can't you only have a lower control
arm, using the shock as the upper part? Sort of an A-arm/ McPherson strut hybrid sort of thing.
Or you could go inboard and use a pushrod as the upper link...?
Thanks in advance,
Andrew
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scoobyis2cool
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| posted on 17/7/05 at 09:27 AM |
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I think you could probably have just one arm by mounting the shock inboard and pivoting the suspension at the vehicle body, like in my drawing
below.
The problem you'd get would be you'd have to fix the wheel solid to the axle, which would give you no control over camber, giving poor
handling and roadholding. Does look nice and futuristic though 
Pete
 
Rescued attachment suspension.gif
It's not that I'm lazy, it's that I just don't care...
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JoelP
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| posted on 17/7/05 at 09:33 AM |
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there is a name for this type of suspension, is it swing arm or something? Pretty crap anyway, odd in roll, camber change in bump etc.
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scoobyis2cool
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| posted on 17/7/05 at 09:39 AM |
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quote:
Originally posted by JoelP
there is a name for this type of suspension, is it swing arm or something? Pretty crap anyway, odd in roll, camber change in bump etc.
You're right Joel, it is swing arm, I didn't recognise it because the attachment is at the bottom of the wheel rather than the centre.
It's been used as rear suspension on cars such as the old VW Beetle because of its simplicity and cheap manufacturing costs. Not sure how it
would work at the front because you obviously have to have some movement in there for steering...
Pete
[Edited on 17/7/05 by scoobyis2cool]
It's not that I'm lazy, it's that I just don't care...
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goin2fast52
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| posted on 17/7/05 at 07:51 PM |
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What if you did it like this? You could put a sterring rod in there somewhere, and still have enough pivots for the wheel not to fall over.
So basically it is just like a regular suspension with no top a-arm and a low mounted shock. Or am I still missing something?
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JoelP
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| posted on 17/7/05 at 08:23 PM |
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i think so, though maybe i am!
whats wrong with using two arms?! this would give you control of camber change in bump, and also relieve a lot of the excess forces that would be put
through a single lower arm.
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scoobyis2cool
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| posted on 17/7/05 at 09:56 PM |
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I agree, unless you've got a very good reason for doing this I'd stick to the tried and tested method of two arms
Pete
It's not that I'm lazy, it's that I just don't care...
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goin2fast52
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| posted on 17/7/05 at 10:14 PM |
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There is no reason :-)
That crazy car on GT4 just made me wonder if it was possible.
Thanks for the replies.
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Bob C
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| posted on 17/7/05 at 10:44 PM |
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Swing arm IFS, patented by bellamy in the '50s was a highly respected front suspension system used in many formulae right up to the beginnings
of formula 1. When Lotus first did wishbone systems they were at pains to copy the gemetry and behaviour from the successful swing axle IFS systems
they had used before.
The drawing above clearly has very short swing axle length (giving camber control problems) and the roll centre would be relatively high. Why not have
the swing axles "cross over" so each actually pivots at the far side of the chassis.... I reckon that would be feasible and could work
quite well.
Practical difficulty would be the need for massive strength at the hub end & consequent unsprung weight savings would not be so great: dead easy
to do a 'geared up' inboard suspension though!
I'd do a picture but it's too late.....
cheers
Bob
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Bob C
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| posted on 17/7/05 at 10:46 PM |
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You'd have to take the track rods from the far end of the rack too
Ouch.....
Bob
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crbrlfrost
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| posted on 19/7/05 at 02:04 AM |
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The I-beam front suspension off a ford truck might be what you're thinking. Cheers
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NS Dev
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| posted on 19/7/05 at 02:32 PM |
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Just going to say, F150 trophy truck racers use that full width crossover swingaxle setup at the front (and quarter elliptics at the back don't
they?)
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Rorty
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| posted on 20/7/05 at 05:09 AM |
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Actually all the F-Trucks use those damned cross-over arms. I had F150 XLT for years which I used as a tow truck for my two-car race trailer.
AFAIK, the off-road race trucks mostly all use aftermarket wishbone front suspension (except maybe for some of the entry level classes).
This is the front end of Rob Herman's Ford Trophy Truck:
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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