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Not quite three link.....


simonr

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No worries Si,

Saley - how long do you find the bushes last with your setup? looks cool - sort of torsion tube meets landrover B)

exactly, got the idea straight from the mog set up and the bushes have lasted and not been changed yet but not as much weight on the front as the engine is in the back

on the mods list are watts linkage front and rear instead of panhard rods and hydaulic steering so will need some advice on the steering if possible

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yeah sorry Fridge - forgot, was nice having experts explaining I was going to die when the pas belt snaps.......even when cycling the steering with the engine off to show them and they still dont understand.... bless, they are old and from the clan luddite

Adrian and Saley - could you guys please post up an "A" frame front end thread in the tools and fab forum - its gonna save us hijacking Si's thread (soz Si) and Im really interested to see how you guys have done it, probs encountered, driving experience etc B)

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its gonna save us hijacking Si's thread (soz Si) and Im really interested to see how you guys have done it, probs encountered, driving experience etc B)

I don't mind being hijacked - at least it's interesting! Prob time for a new thread anyways. This one is getting a bit long.

Si

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Si, Saley et al - it's good to see some real innovation here.

To extend the passive damping idea, could you add a little electronic control and force articulation through the link with an active ram (and the software which I know Si has already written!) in a similar way to the Disco2 ACE system?

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To extend the passive damping idea, could you add a little electronic control and force articulation through the link with an active ram (and the software which I know Si has already written!) in a similar way to the Disco2 ACE system?

What I (or was it Jez ;) ) had figured was by locking the ram it would do a reasonable job of limiting vehicle roll on corners, particularly with solid bushes on the other side.

You can then get some of the effect of air suspension, by unlocking the ram, sticking it in forward or reverse with the brakes on - which will cause the vehicle to torque-roll, then locking the ram again.

This will give you a fixed lean to the left or right - which could be good for side slopes - or getting you a couple of inches closer to that elusive punch!

This is the design for the variable damper I've sent to Steerforth's. I'll machine the piston & rods. They'll supply the other standard bits:

54717.jpg

The left hand rod connects to the axle and the body to the hockey stick. The right hand rod is not connected (directly). The right hand rod means that the swept volume is the same on either side of the piston.

There is a pointy bit machined on to the end of the right hand rod which forms part of a needle valve inside the piston. When you screw in the right hand rod, it reduces the flow through the piston and vice versa.

If the rod were connected via say a speedo cable to a knob in the cab - you could remotely adjust the damping and/or lock the ram.

Clever huh?

Si

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Hinged radius arms, slotted bushings. Both have their handling issues IMO. Three link it if you can find the room for the upper 3rd. Or move the crossmember back 5'' so that the front bolt holes in the crossmember line up with the rear bolt holes in the chassis rails.Drill another 2 holes each side through chassis, fit crush tubes etc. Fabricate an ''A'' frame as saley has done. You don't need flexible bushings at the axle. only one is required at the crossmember.You could make the'' A'' from 2''x2''x1/4 '' square tubing, and use a large metalastic bushing from a torque rod off a large truck for the single pivot.You end up with near standard castor variation and antidive geometry throughout the range of suspension travel. You will have almost 100% positive axle location under brakes or accelleration. and you should have no clearance issues re exhausts, oil filters etc etc. The technology is as old as the motorcar itself and has been well proven on over 15 million T model Fords, many tractors and thousands of Unimogs.

Bill.

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Bill,

I totally agree that this is about the best way to go. It refuces the stress on the cross-member, compared to regular 3 link and is pretty easy to fabricate.

However, it's not the only way to go. Like a lot of my buildings, this is just an experiment. It has one, significant advantage over all the above however - being able to lock it - and reduce roll on or off road.

That's the main reason I'm persuing it.

Top90, yes I have read Sam's post VERY carefully - and a dozen or so others (pirate, outer limits etc) but I've read similar about most of the things I've built. The fact that it has not worked for one person is a lesson in what the problems are likely to be and an invitation to think up a solution.

It may be that the solution I've proposed above is rubbish - but trying it is the only way to find out! (unless you have a rather more expensive cad system than mine!).

Also, the cylinder I'm using at the moment is exactly as you describe. It has a shortcoming in that the swept volume on either side of the piston is different (cos one side has the volume of the rod subtracted). A double ended cylinder solves that - and if one is making a custom cylinder, putting the valve in the piston makes the most sense (no leaks, no matter how bad my machining!).

Si

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Bill,

I totally agree that this is about the best way to go. It refuces the stress on the cross-member, compared to regular 3 link and is pretty easy to fabricate.

However, it's not the only way to go. Like a lot of my buildings, this is just an experiment. It has one, significant advantage over all the above however - being able to lock it - and reduce roll on or off road.

That's the main reason I'm persuing it.

Top90, yes I have read Sam's post VERY carefully - and a dozen or so others (pirate, outer limits etc) but I've read similar about most of the things I've built. The fact that it has not worked for one person is a lesson in what the problems are likely to be and an invitation to think up a solution.

It may be that the solution I've proposed above is rubbish - but trying it is the only way to find out! (unless you have a rather more expensive cad system than mine!).

Also, the cylinder I'm using at the moment is exactly as you describe. It has a shortcoming in that the swept volume on either side of the piston is different (cos one side has the volume of the rod subtracted). A double ended cylinder solves that - and if one is making a custom cylinder, putting the valve in the piston makes the most sense (no leaks, no matter how bad my machining!).

Si

I am certainly interested in the outcome of your experiment Simon. If it works I may adopt it and claim it as one of my own to non LR4x4.com readers. :):)

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  • 2 weeks later...

After a day slaving over a hot lathe:

54751.jpg

54752.jpg

It appears to work rather well - at least on the bench. The valve is controlled by rotating the bolt which passes through one rod. 90 degrees takes it from fully open to fully closed.

The ram is filled with EP90 at the moment - which might be too viscose - but we'll see!

Si

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umm can you genuises come down here and join us mortals for a bit to explain what the hell you are talking about? it all sounds very interesting, if i could just understand what it all means.

ta

James,

You know how you get anti-roll bars on cars & stuff? These limit the roll while you are cornering and thus improve handling a bit.

On an off-roader, you want max articulation so you don't really want a device which limits it.

What this is, is a "have your cake AND eat it" solution. An anti roll device you can switch on & off.

Even off road, a vehicle with very free suspension can be a bit frightening because of how fast the body can roll from side to side. This device does not restrict the total roll, but slows it down so you have time to react safely. That's the idea.

Si

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the rule of "All visitors must bring biscuits" has been modified slightly Si, "All visitors must bring dog biscuits as well as normal biscuits" its not inflation....... merely bribery for the bull mastiff thats taken up residence and thinks its a bouncer :huh:

more than welcome, let me know and I'll put the kettle on :)

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umm can you genuises come down here and join us mortals for a bit to explain what the hell you are talking about? it all sounds very interesting, if i could just understand what it all means.

ta

Sort of re-inventing the ACE system on Disco 2 - one of the few really clever, well built things LR have ever done

Fascinating post though

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  • 2 months later...
the rule of "All visitors must bring biscuits" has been modified slightly Si, "All visitors must bring dog biscuits as well as normal biscuits" its not inflation....... merely bribery for the bull mastiff thats taken up residence and thinks its a bouncer :huh:

more than welcome, let me know and I'll put the kettle on :)

Wonder how your Mastiff would get on with my Ernie the Sicilian Mastiff :o

He is 3 years old and 60kilos just now. Stands about 33" at the shoulder

post-2593-1169884984_thumb.jpg

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