scooter Posted June 21, 2007 Share Posted June 21, 2007 I was looking at my De-Dion set-up and it struck me that it wouldn't necessarily be all that difficult to modify the rear chassis to take IRS. The question is would the modifications maintain the necessary rigidity? I have already done away with the 'boot shelf' so I have the space. Has anyone attempted this? Link to comment Share on other sites More sharing options...
Mark Durrant Posted June 21, 2007 Share Posted June 21, 2007 Scooter I suggest you take a look at the rear chassis tubes on the CSR and this will give you an indication of the work involved. I have seen a bare chassis at both Arch and at Caterham and the difference is significant. Mark D Comp Sec Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted June 21, 2007 Share Posted June 21, 2007 wouldn't necessarily be all that difficult Has been done - search for Sugino's website - but I suspect on a scale of 1 to 10 for difficulty, it would score 11 for me! Edited by - Alex Wong on 21 Jun 2007 10:11:06 Link to comment Share on other sites More sharing options...
Irrelevant Posted June 21, 2007 Share Posted June 21, 2007 I suggest you take a look at the rear chassis tubes on the CSR and this will give you an indication of the work involved Afraid I'd disagree on that . . .. the CSR rear end is the outcome of a design that was required to use as many of the de dion rear end components as possible. When the first design didn't work it had to be re-engineered . .. . that's why the CSR is so complex. If you started with a clean sheet and didn't have the constraints Caterhan had, an IRS back can be very simple . . . . many people have done it in the past. Look at Sugino's IRS . .. it was very simple. Thing is . . .. the hard thing is to beat the performance of the de dion rear end . . .. it really is quite good, especially on a track (where the CSR rear end is still arguably no better). Link to comment Share on other sites More sharing options...
Colin Mill Posted June 21, 2007 Share Posted June 21, 2007 I think you would be better off to apply the same amount of effort to unsprung weight reduction of the existing de-dion setup. Alloy brake components and an alloy or composite tube would do a lot in that direction. Link to comment Share on other sites More sharing options...
Jason Plato Posted June 21, 2007 Share Posted June 21, 2007 simply take a look at a Westfield or a birkin or quite a few other Kit cars that run IRS I imagine Bruce @ Arch has already done the thinking on this ( probably in 1972 or something 😬) so he may be worth calling to discuss. Link to comment Share on other sites More sharing options...
chris perry 1 Posted June 21, 2007 Share Posted June 21, 2007 Hello, I found this a while ago. Now my car is in to gooder condition to try it on. Anyone feeling brave?! http://www.locost7.info/files/suspension/RortyLocostIRSAssembly.pdf Chris P Edited by - chris perry on 21 Jun 2007 13:33:33 Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted June 21, 2007 Leadership Team Share Posted June 21, 2007 Sugino's rear end This is one serious car! Stu. www.superse7ens.co.uk..........the rebuild 😬 Link to comment Share on other sites More sharing options...
Jason Plato Posted June 21, 2007 Share Posted June 21, 2007 trouble is - all these designs look good and "should" improve the handling. If the design actually works is another matter I expect. Caterham spent a fortune on chassis design for the CSR and yet there were rumours abound that Arch determined the final design with a 12 foot length of scaffold pole and 2 x 15 stone blokes hanging off the end of it 😬 Link to comment Share on other sites More sharing options...
elie boone Posted June 21, 2007 Share Posted June 21, 2007 I think that a Jaguar style rear IRS can't be to difficult, with some extra bracing to the outher sides of the chassis. On a super smooth track it does'nt make much difference what type of axle you have, LA, DD or IRS a more important factor are the dampers. Link to comment Share on other sites More sharing options...
Colin Mill Posted June 21, 2007 Share Posted June 21, 2007 Caterham spent a fortune on chassis design for the CSR and yet there were rumours abound that Arch determined the final design with a 12 foot length of scaffold pole and 2 x 15 stone blokes hanging off the end of it There is a lot going for the "2 x 15 stone" approach. I had a minor involvement with the Huygens lander (that is now sat on the surface of Titan). They spent ages using finite element analysis to design the structure but part of the instrument mounting broke on the vibration test rig causing a bit of last-minute beefing up to be applied. Link to comment Share on other sites More sharing options...
scooter Posted June 21, 2007 Author Share Posted June 21, 2007 Just been looking at the De-Dion set-up. Sure the tube is a substantial b*gger, but there's not a great deal of engineering connecting it (and therefore the wheels, etc.) to the chassis... Are we getting slightly carried away by the need to carry out mega-bracing for IRS? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted June 21, 2007 Share Posted June 21, 2007 I reckon you can get IRS using a multi-link setup (including the use of woblinks, which is always good for linkage tomfoolery) without any further outrigger type chassis tube stuff. i.e. tunable IRS using the same suspension pickup points as already exist on the chassis. I'm sure I've got a sketch here somewhere. Link to comment Share on other sites More sharing options...
k80rum Posted June 21, 2007 Share Posted June 21, 2007 woblinks gets my vote.. Every time I hear the word it makes me 😬 PC's idea sounds full of promise, since as Adam mentioned, anything else is likely to be a lot of work for very little on-track gain (other than the engineering exercise). If anyone's mad enough to want try and graft a CSR-type rear end onto their existing chassis, rumour has it that Arch have a lot of the old prototypes sitting around. The difficuly there may be getting them to part with one though 🙆🏻 Darren E Website and Emerald maps library Superlight R #54 Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted June 22, 2007 Share Posted June 22, 2007 Looking at the pic of Sugino's car - I wonder how he got the diff in? It looks like it was positioned then had a load of tubes brazed around it! Link to comment Share on other sites More sharing options...
Irrelevant Posted June 22, 2007 Share Posted June 22, 2007 I wonder how he got the diff in? Probably via the diff shaped hole at the back The chassis is nickel coated remember so the diff must have some way of getting in and out when necessary. It looks like it was positioned then had a load of tubes brazed around it! Daresay this is exactly what was done, using an old diff casing . Possibly all bolted down onto a flat welding platform or even in a jig. Link to comment Share on other sites More sharing options...
Molecular--Bob Posted June 22, 2007 Share Posted June 22, 2007 What would the woblink do in an IRS? I thought they were for lateral location of beam axles. Link to comment Share on other sites More sharing options...
Peter Carmichael Posted June 22, 2007 Share Posted June 22, 2007 The term "woblink" refers to a linkage which is to all intents an inside-out Watts linkage. It allows you to articulate a locus approximating a straight line relative to two rigidly joined mounting points, where the mounting points are close together. For instance, you could approximate Caterham's implementation of the watts linkage fore-aft location of the de-dion tube by mounting a woblink on the upper and lower radius arm holes at the front edge of the wheelarch. I worked out a few years ago the number and type of links you would need to articulate independent rear suspension using no pickup points further aft than the rear bulkhead. I worked on the principle that the geometry could be fine tuned with the individual linkage design (I did the maths to suggest that this was feasible). All I did was work on the basis of the required degrees of freedom to achieve independent suspension articulation from the known strong points on the chassis. Link to comment Share on other sites More sharing options...
Molecular--Bob Posted June 22, 2007 Share Posted June 22, 2007 A little explanation goes a long way, i was trying to figure out a lateral aplication of the link in an irs and my little brain couldn't make it fit. Is this style of irs a realistic option? Link to comment Share on other sites More sharing options...
Peter Carmichael Posted June 22, 2007 Share Posted June 22, 2007 Is this style of irs a realistic option? Does anybody want to sponsor some research...? Link to comment Share on other sites More sharing options...
scooter Posted June 22, 2007 Author Share Posted June 22, 2007 I'll donate the chassis Mr Carmichael and pay for all materials (I want it all back though... in one piece!). Link to comment Share on other sites More sharing options...
scooter Posted June 23, 2007 Author Share Posted June 23, 2007 I take it that's a 'no' then!!!! ☹️ Link to comment Share on other sites More sharing options...
Phil Posted June 23, 2007 Share Posted June 23, 2007 Just think, if only someone somewhere could make a carbon fibre DD tube? X/FLOW 1700 DD 1990 ROAD USE ONLY..SO FAR Link to comment Share on other sites More sharing options...
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