FridgeFreezer Posted January 7, 2009 Share Posted January 7, 2009 What you have drawn is just a more complicated version of a hockey stick with different mounting points on the axle. Thank god for that, I was beginning to wonder if I was missing something Quote Link to comment Share on other sites More sharing options...
muddy Posted January 7, 2009 Share Posted January 7, 2009 Yh but if you go over a jump then your axle will droop more so the wheels contact the ground earlier so you actualy get more traction and go faster ennit. if this thing has as much articulation as you presume then i reckon those top like would get mighty close to the chassis/springs/spring seats. Will. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted January 7, 2009 Share Posted January 7, 2009 Consider the axle separate from the body. With an axle and hockey sticks on the ground in front of you, when the car cross-axles it's the same as your lardy mate pushing the chassis end of one arm towards the floor while you try to lift the other one up. The standard hockey sticks are overcontstrained and it's only the movement in the bush that gives rotational suspension travel (roll travel). Your system would have much more constraint because of the increased separation of the axle mounts and the reduced movement in the Johnny joints. Now, if you could make one of the diagonals incorporate a variable length, then you could be cooking on gas but in plain metal, not a goer I don't think (even for marks in a Uni project). Quote Link to comment Share on other sites More sharing options...
Timmy511 Posted January 7, 2009 Author Share Posted January 7, 2009 Consider the axle separate from the body. With an axle and hockey sticks on the ground in front of you, when the car cross-axles it's the same as your lardy mate pushing the chassis end of one arm towards the floor while you try to lift the other one up. The standard hockey sticks are overcontstrained and it's only the movement in the bush that gives rotational suspension travel (roll travel). Your system would have much more constraint because of the increased separation of the axle mounts and the reduced movement in the Johnny joints. Now, if you could make one of the diagonals incorporate a variable length, then you could be cooking on gas but in plain metal, not a goer I don't think (even for marks in a Uni project). youve got me thinking, but i dont know how to make it work and how to make it small enough, yet. Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted January 9, 2009 Share Posted January 9, 2009 if anyone has built a home made front suspension kit (like plastic badgers disco) and they dont mind me using it as an example in my research please could you post up a few pictures and a very brief write up as to how much you think it has improved you vehicles abilities. I'm about to tear apart the Toy Rover for a full rebuild into a Range Rover, so I can take some better photos of the three link under and out of the car. I've been updating the CAD drawings to 'as built' too which I'll post when done. The concept was to remove the binding of the original hockey stick set up. In theory my front axle has around 24" of vertical drop travel and 45 degrees of articulation each way before any kind of mechainical bind in the joints or brackets. The mods to the rear suspension again offer about 18" of vertical drop travel and 30 degrees of articlation. All in theory as it's currently restricted by shock length, whel arch clearance and prop shaft angles. Quote Link to comment Share on other sites More sharing options...
HoggyN Posted January 10, 2009 Share Posted January 10, 2009 I worry that if whoever marks your project has a decent understanding of mechanics, they may not be as impressed with your efforts as they could be? If I were marking the project I would be expecting to see a working scale model - as well as the CAD simulations. Quote Link to comment Share on other sites More sharing options...
Troddenmasses Posted January 10, 2009 Share Posted January 10, 2009 If I were marking the project I would be expecting to see a working scale model - as well as the CAD simulations. How very 20th century... Quote Link to comment Share on other sites More sharing options...
T1G UP Posted January 10, 2009 Share Posted January 10, 2009 Timmy, This link explains where the problems are in a radius arm set up and where they can be improved. As Jez has said this is where i'd spend my time analysing and engineering a solution to the problem. http://forums.lr4x4.com/index.php?showtopi...dius+arm+bushes Quote Link to comment Share on other sites More sharing options...
Daan Posted January 10, 2009 Share Posted January 10, 2009 I you run the lower arms to the centre of the axle, bolted to the diff flange, and remove the panhard, you get better articulation. Just an idea. Daan Quote Link to comment Share on other sites More sharing options...
HoggyN Posted January 11, 2009 Share Posted January 11, 2009 How very 20th century... Maybe, but they like it, I like it, the IMechE like it, and the students learn a whole lot more that way Quote Link to comment Share on other sites More sharing options...
jacks906 Posted January 11, 2009 Share Posted January 11, 2009 why not have arms going to the rear bush on the axle bush mount then from the centre of the arms bar made togo to the top of the diff (same as on the rear were the ball joint mounts) as long as its all guseted well enough will increase the articulation when i did me enginnering project weather the project works or doesnt it didnt matter as long as the paper work is correct you can get full marks dave Quote Link to comment Share on other sites More sharing options...
HoggyN Posted January 11, 2009 Share Posted January 11, 2009 why not have arms going to the rear bush on the axle bush mount then from the centre of the arms bar made togo to the top of the diff (same as on the rear were the ball joint mounts) as long as its all guseted well enough will increase the articulation I think you mean a three link setup like this when i did me enginnering project weather the project works or doesnt it didnt matter as long as the paper work is correct you can get full marks Absolutely, proving that something doesn't work is as valuable as proving that something does. If you publish your work it can save others loads of time and effort. Quote Link to comment Share on other sites More sharing options...
jacks906 Posted January 12, 2009 Share Posted January 12, 2009 see the second bit confused me as if you know its not going to work why start the fab etc to prove it doesnt anyway back on what i was on about is totally different that but it wouldnt be strong enough my idea dave Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 12, 2009 Share Posted January 12, 2009 Absolutely, proving that something doesn't work is as valuable as proving that something does. If you publish your work it can save others loads of time and effort. I'd say the caveat is that proving something that looks like it might work doesn't, is valuable. IMHO this doesn't fall into that category. Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted January 12, 2009 Share Posted January 12, 2009 I cant understand why the idea wont work. The bronco guys seem to think it's very succesfull. Is it because it's different in pickup on the axle? http://www.rmftc.com/howtos/extendedradius...radiusarms.html Quote Link to comment Share on other sites More sharing options...
HoggyN Posted January 12, 2009 Share Posted January 12, 2009 I'd say the caveat is that proving something that looks like it might work doesn't, is valuable. IMHO this doesn't fall into that category. Good point - I should have said 'can be as valuable' Normally the project would have be deemed worthwhile before work begins. Unfortunately, unless one has an intimate knowledge of Land Rover front suspension, this might look like a goer and be worth further research. Nevertheless, a student can still gain a lot of valuable knowledge - even chasing a red herring. I cant understand why the idea wont work. The bronco guys seem to think it's very succesfull. Is it because it's different in pickup on the axle? If I'm not mistaken, the reason that those Bronco guys get increased articulation is that the extra long radius arms have less angular movement than the standard arms therefore twist the axle less per degree of articulaton. You could get the same effect by lengthening standard RR hockey sticks. EDIT: Apologies. I see what you mean. You are talking about moving the rear mounts closer together to create a kind of 'torque tube' or 'A frame' type of suspension system. Which is more or less what I've been pondering over - moving the trailing end of the hockey sticks together to a single pivot together with replacing the panhard rod with a watts linkage. I think it should work but I suspect there are issues I haven't thought of - packaging etc. Anybody tried it? Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted January 12, 2009 Share Posted January 12, 2009 Moving the trailing end of the hockey sticks together gets around the overconstraint of the factory setup, but I think the chassis rails and engine start to get in the way - not necessarily an issue if you can shape the arms to fit into the required loci, but we've seen recently why straight forged arms might be a sensible factory solution. Quote Link to comment Share on other sites More sharing options...
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