Dave-M
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| posted on 5/2/09 at 01:41 PM |
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trailing arms and anti-squat
Regarding the post below, I thought a new post might be better rather than a hijack.
I am in the process of 5 linking an escort axle and would like to get it right.
It was said that incorporating anti-squat will introduce bending loads into the trailing links, for the lfe of me I can't see how this would be
the case.
The load along the tube should be the same but it would be resolved into a vertical and a horizontal component at the chassis end of the rod, rather
than just a horizontal load when anti-squat is not used.
By way of explaining why I have come to this conclusion, if there is a rose joint at each end of the trailing link, how can any force be transmitted
into the link to create a bending load?
Is this right or wrong?
If it is wrong I will have to redo my trailing links in 2mm instead of 1.5mm
Dave
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JoelP
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| posted on 5/2/09 at 02:26 PM |
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i would agree with you dave. Unless there is some binding effect and we havent thought it through to the end, but i cant see it as they would all
still be parallel.
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procomp
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| posted on 5/2/09 at 02:49 PM |
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Hi
There are no real problems with extra loading on the arms as long as they are 2-3 mm wall.
However when running anti squat you have the arms angled to each other and NOT parallel to each other. This means that when the axle is moving you
need to have compliance in the bushes to enable the free movement to take place. If using rose joints it will simply not have the freedom of movement
and bind up due to there being no compliance for the arms to change length.
Cheers Matt
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Dave-M
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| posted on 5/2/09 at 04:15 PM |
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quote:
Originally posted by procomp
Hi
However when running anti squat you have the arms angled to each other and NOT parallel to each other. This means that when the axle is moving you
need to have compliance in the bushes to enable the free movement to take place. If using rose joints it will simply not have the freedom of movement
and bind up due to there being no compliance for the arms to change length.
Cheers Matt
Not true Matt, by your logic double wishbone front suspension would not work, consider the front view of the front suspension the same as the side
view of the trailing arm/axle.
All that happens is that the axle casing rotates from it's original position (equivalent to camber change at the front.
Dave
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procomp
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| posted on 5/2/09 at 04:27 PM |
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Hi
Your only thinking 2D with the axle moving up and down squarely. Think 3d and roll the axle in the chassis also.
Cheers Matt
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Dave-M
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| posted on 5/2/09 at 05:19 PM |
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You are dead right Matt, I had overlooked that. It will try to twist the axle case.
As the roll angle is so small I guess one compliant bush on each side will be enough, not that I am using Rose joints anyway.
I am incorporating 25-30% anti dive and wanted to understand if the loading would be greater on the trailing links than had if I had not.
Dave
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multanen
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| posted on 5/2/09 at 05:45 PM |
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quote:
Originally posted by procomp
However when running anti squat you have the arms angled to each other and NOT parallel to each other.
But wouldn't it be possible to have anti-squat with equal length parallel arms too? (But not parallel with ground of course.).
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Dave-M
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| posted on 5/2/09 at 06:25 PM |
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How would you do that?
Dave
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MikeRJ
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| posted on 5/2/09 at 07:39 PM |
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quote:
Originally posted by procomp
Hi
There are no real problems with extra loading on the arms as long as they are 2-3 mm wall.
Are cars in the Locost race series permitted to run anti-squat? If so, does anyone do this?
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C10CoryM
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| posted on 6/2/09 at 01:39 AM |
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5 link (4+ panhard) only works w/o bind if all arms are the same length and angle. If you want antisquat and no bind you should look into 3 or 4
link.
I have 4 link (3+ panhard) so if I ever get my car done I will let you know how it works 
"Our watchword evermore shall be: The Maple Leaf Forever!"
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Dave-M
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| posted on 6/2/09 at 09:24 AM |
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quote:
Originally posted by C10CoryM
5 link (4+ panhard) only works w/o bind if all arms are the same length and angle. If you want antisquat and no bind you should look into 3 or 4
link.
I have 4 link (3+ panhard) so if I ever get my car done I will let you know how it works
Interesting
Where would you fit the third trailing link on the axle?
Dave
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alistairolsen
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| posted on 6/2/09 at 10:14 AM |
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I assume one radius arm each side and an a frame in the centre like old landrovers
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C10CoryM
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| posted on 6/2/09 at 03:01 PM |
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Basically remove the 2 upper links of the 5link, and install one on top in the middle of the axle going fore or aft.
Suzuki sidekick/tracker axles are 3 link. 2 lower outer links, then one A-arm in the middle with a balljoint on the diff. They are almost perfect
for a locost and will be what I use if I build another.
In theory, you could just leave out one of your upper links on the 5-link and all would be well. 5-link came to be used because high power drag cars
needed more links to deal with the torque. Locosts...... not so much
"Our watchword evermore shall be: The Maple Leaf Forever!"
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procomp
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| posted on 6/2/09 at 03:16 PM |
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Hi
The LOCOST race cars are not allowed to run true anti squat as the dimensions for the rear pickup positions on the chassis are effectivly fixed.
However the other car i produce the LA gold comes as standard with fully inbuilt adjustable anti squat. I believe it is the only live axle kitcar that
comes from a manufacturer with this facility in the UK . Having spent 10+ years passionately playing with various settings dampers and corner weight
settings we have got it to a point where we can give the driver exactly what he need with a bit of work. It is capable of propelling a 500 kg +drivers
weight car without a LSD to do 0-60 mph in 2.7 and the 0-64Ft time in 1.9 pulling just over 1 G off the line. Once you have it dialed in it can be
very effective.
Cheers Matt
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Dave-M
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| posted on 7/2/09 at 11:57 AM |
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Impressive! My car is not a locost but the front and rear end are based on the locost, they are just held apart with a GRP monocoque instead of a
chassis.
The car weighs 100kg more than a locost and will be used for hillclimb/sprints.
I would be more than happy to have the performance you quote so I guess what I am asking is, would you be prepared to share some of your hard earned
knowledge regarding % squat settings and anti dive at the front as well.
Regards
dave
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