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  #41  
Old 11-01-2016, 05:45 PM
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Peter H Peter H is offline
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I have build my 4-link based on this article:
http://www.fourwheeler.com/how-to/su...ension-part-2/

Turned out great! Used the calculator only to verify.
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  #42  
Old 11-06-2016, 05:52 PM
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Quote:
Originally Posted by Peter H View Post
I have build my 4-link based on this article:
http://www.fourwheeler.com/how-to/su...ension-part-2/

Turned out great! Used the calculator only to verify.
Thanks Peter, have read that before and it does help with understanding the setup.
Well all in I had a fairly productive weekend. I picked up the axles from the blasting company on Fri, have to say I'm very pleased with how they turned out.

Before:


After:


I had a bit more grinding to do on these to get the what was left of the brackets off. Then gave them a lick of weld through zinc primer to stop any surface rust developing. I haven't used it before so we'll have to wait and see what it's like to weld over...

This is them ready for re assembly...


After that I drew up up a few sketches...




Then took a few photo's with a steel rule so I could scale them in the CAD software I use. This basically lets me trace over the photos to achieve the curves I can't measure accurately.




And finally drew up a 3D model in CAD.


I'll need to take a few check dimensions to make sure the model is accurate enough. The perspective in the photos can throw tings out a bit so it will need to be rechecked. The reason I have modelled the axle is so that I can design an axle truss, link brackets and shock mounts. Once I have that figures out I can send of the drawings to have parts laser cut and then weld the lot onto the axles.

Something like this practice model I did is what I want to achieve. Whats really cool with the CAD software is that you can actually cycle through the suspension to see how it moves and check for any clashes.

Cross axled:


Full bump:


Full droop:


Next up I need to model the rear axle.

Other than that I finished servicing a few bits on the motor and gave it a lick of some go fast paint...

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  #43  
Old 11-08-2016, 03:42 PM
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Peter H Peter H is offline
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Nice! CAD's are very impressive!
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  #44  
Old 11-13-2016, 06:59 AM
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Quote:
Originally Posted by Peter H View Post
Nice! CAD's are very impressive!
Thanks Peter

I semi put the axles back together this weekend, just enough to be able to mount the wheels so that I can put the axles under the 70 and locate them where I am planning to run them.





This is at 17.5" belly height and a Wheel base of 112.5". I have decided to pull the front axle forward as opposed to pushing the back axle backwards. Reason being I want to try and keep the weight distribution as 50/50 as feasible. It'll also give an awesome approach angle, I know it looks odd so I still need to think of how I can finish it whilst keeping it looking ok. Though i do still need to settle on a final wheel base, alot of folk are racing cars with 116" wheelbases...





I'm also thinking I may narrow the front end somewhat...



Anyway at least now I can start looking at the suspension and steering setup, of which I think the steering is going to be the hardest. I want to run a 4-link on the front but in order to stay class compliant I need a mechanical steering linkage. So I have been reading up on bell crank steering setups kind of like this...



But in order to do this I'll need to convert to LHD. Why go to this extent, well the suspensions going to be the most important element on the car. Being able to get rid of the panhard and run a 4-link will give me a superior setup to what most of the modified guys are running. It also allows me to ditch the drag link, unlike what is shown in the photo. If I use a double ended ram this will essentially be the drag link. Also steering boxes seem to take a huge amount of punishment especially from shock loading when a wheel hits and deflects off of something. Typical failures are stripped or snapped sector shafts. So if I can make this work I get a stronger and better performing setup than running radius arms with p/hard and std steering. That's my thinking, that and I like the challenge of trying something a but different to anything else I have seen on the UK & European trucks.
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  #45  
Old 11-13-2016, 10:57 AM
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Rather then a bell-crank and LHD.
Why not relocate and mount the box at an angle?
Point the steering arm to the front or back and not have the extra joint/pivot in the system.
Maybe not perfect but an idea.
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  #46  
Old 11-14-2016, 07:25 PM
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350 Vortec 350 Vortec is offline
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Great work ,patrol steering box is pretty durable,im with E (kinda)but just keep it simple and mount box as was on drivers side (knuckle steering arm is on LH side E),I guess your going to have a lot of bump steer though but can't see how you'd avoid it unless you mount box near suspension link ends
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  #47  
Old 11-15-2016, 12:51 PM
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1.
Go back to CAD and see just how much Bumpsteer you will generate and then decide if you can live with it, particularly considering you are running on dirt, the slip-angles will most often be large, as in, you will be sliding/drifting more then cornering like a street/track ride. Personally I'd sweat the Ackerman more then the Bumpsteer (up to a point).
2.
If you can't tolerate the Bumpsteer then Go back to a non-triangular 4 link and add the Panhard link. (My Choice)
3.
Do a drag link as you mention but I would figure out a way to run a steering arm of the knuckle rather then the Bellcrank even if that requires a bit of a bracket on the axle to clear the Coilover.
4.
Invent something
For example do the rules say the linkage has to actually work?
Why not a (limited) telescoping drag link that would allow the hydraulic ram to move faster then the Drag link and the springs would let the Bumpsteer happen only in the drag link rather then the tie rod
If you have to be able to have the linkage work then build so that the spring coil binds and you can get some steering but not full lock.

E
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  #48  
Old 01-10-2017, 01:32 PM
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Hey Guys,

Been a while and haven't made much progress on the truck with the holidays and all that, I did say this was going to be a slow build!

Anyway back to what I have actually managed to achieve. I went ahead and played around in cad to work out what the bumpsteer would be like with the bell crank setup. These are a few shots of the front axle flexed out, I put in links to where the steering wheel will be approx. I get around 15" of bump steer input, but this will be damped sound in the steering so I am thinking in reality it will be negligible. The green indicator shows the bumpsteer generated by cycling through the range of the suspension travel.




So I am going to continue pursuing this steering setup. Worst case if I can't get it to work I'll race in Legends class with full Hydro until the next season.

So that has led me to start playing around with links. I mate of mine had to abandon his build due to a change in circumstances. He bought a roller and parted it out. So i had the opportunity to pick up a set of 2.5" 7075 Aluminium links with 2.5" Johnny Joints. His wheelbase was going to be 116" so I figured why not try give it a shot with his link lengths and see what I can come up with. worst case I may need to trim his links down or cut longer ones.

So this just a little test fitting to see roughly where things can fit after which I took measurements and plugged them into the Triaged 4-link calculator.







As the links are fitted in the pics above the numbers turned to not be great. The diff pinion angle change was in excess of 20' and put the pinion pointing into the motor at full compression. But it was a starting point. So I played around in the Triaged calculator and in CAD to figure out what was feasible and have come out with the following numbers, Ignore the rear I haven't started on that yet.



What do you guys think? I decided not going for 100%AD would probably be beneficial with regards to keeping the suspension supple in the rough stuff when under braking.

So from that I have gone on to start the design for the truss, Ram mount, Bellcrank and link mounts. I still need to do the chassis mounts. This is where I am at.





I need to still do the shock mounts and bump stop pads and then tidy up a few of the tabs. I like using a slot and tab setup, it saves me having to rely on a tape measure too much and helps keep things symmetric.

Other than that the shocks are ordered and should be with me at the end of the month. I went for the King 2.5"x14" RR coil overs. So looking forward to getting those in. By then I should have all the laser cutting done for the front truss and chassis mounts.
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  #49  
Old 01-15-2017, 10:57 AM
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Looks nice but heavy. That's a lot of unsprung weight!
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  #50  
Old 01-15-2017, 01:57 PM
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Looks nice but heavy. That's a lot of unsprung weight!
Hey Peter, Thanks.

Weight wise, other than the weight of the ram and links, i'll be adding around 18kg to the axle. Do you think that's too much? This is based on doing everything in 5mm plate, if I went 3mm plate it would be around 11kg.

Are you going to be competing in the Ultra4 Europe events this year?
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  #51  
Old 01-15-2017, 03:59 PM
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18 Kg is not bad, but you should take it in consideration when choosing shocks and springs.

No, I'm not competing in Ultra4. My rollcage is not compliant to the regulations of ultra4. I'm going to the Morocco desert challenge as staff member, I'm competing in the BRR rally France and maybe the wild boar challenge in Croatia.
I will come to the king of France ultra4 as spectator and maybe king of Italy.
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  #52  
Old 01-15-2017, 04:21 PM
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Originally Posted by Peter H View Post
18 Kg is not bad, but you should take it in consideration when choosing shocks and springs.

No, I'm not competing in Ultra4. My rollcage is not compliant to the regulations of ultra4. I'm going to the Morocco desert challenge as staff member, I'm competing in the BRR rally France and maybe the wild boar challenge in Croatia.
I will come to the king of France ultra4 as spectator and maybe king of Italy.
That Morocco Challenge looks awesome. I have an 80 series I'd be very temped to build up for something like that.

You should check with the U4E tech guys, Richard Crossland I think has the main say, as they seem to have relaxed the rules in order to try and tempt more racers from other offroad disciplines into the U4E events. There seem to be a fair few of the challenge event guys crossing over who's cages are technically not compliant with U4E but are compliant with other bodies.

The Italy race also seems to be off the cards for this year. Apparently there were too few entrants last year to justify a race this year so they have substituted it with a race in Wales but next year they will be having a King of Spain which should be interesting. Hopefully a king of Italy too.
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  #53  
Old 02-01-2017, 06:02 PM
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Ok, So still not much physical progress but the parts for the front axle truss and chassis link mounts are cut and waiting to be welded up. So all being well I should have a fairly productive weekend ahead of me.

In the meantime an early birthday present arrived...

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  #54  
Old 02-05-2017, 06:04 AM
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Ok, so thanks to a mate of mine it was a really productive day in the workshop yesterday.

These are the puzzle pieces for the front axle and chassis mounts.



We tacked up the truss assembly on the bench


Afterwhich I found I had made a mistake with the axle tube outside diameter which made the entire assembly sit too high on the axle due to the front and rear profiles not being far apart enough. The bottom of the from profile should sit just above the weld at the centre of the axle.
https://dl.dropboxusercontent.com/u/...4/IMG_4268.JPG

I'm a bit confused as to how I managed to cock that up but hey ho we moved on and made a plan...







Top link mounts going in.



Skid plate and Ram mount going on



1omm gussets going onto the knuckles, apparently a bit of a weak spot on these axles when you start abusing them.



And a little comparison of the Cad and end product. Next I need to fabricate the chassis mounts and then finally the lower link mounts on the axle. After that I'll need to cycle the suspension to check clearances and see if I need to tweak anything. After that then on to the bell crank.

Looking at it as it stands I think I'll need to raise the ride height a couple of inches, given I was shooting for a fairly low height (17.5") the impact should hopefully not be too detrimental.
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