Phil.S Posted April 22, 2008 Author Posted April 22, 2008 Blimey! You've made rapid progress with that phil! Hope you don't mind if I give some 'constructive critisism' with regards the wishbones? IMO the two triangles you've made, where the origonal bar went are across, now dont really do anything. Would you be better to have a curved bar that does from the origonal points and clears the sump still? Anyway you probably CBA to that now and it'll be fine anyway! No problems with a bit of constructive criticism!. I was trying to work out what the tie bar actually did being so close to the mounting points which really do the same thing. I worked out that if there was any twisting going on between the two points one would essentially go up and one down which is where the little triangles come in. Hopefully it will be OK it seems super strong!
dss123 Posted April 22, 2008 Posted April 22, 2008 Hey Phil, Great thread and great project - very jealous! Maybe worrying unnecessarily, but I also share Dave's thought's about the "modded" wishbone. The only bit that is contributing to the integrity of the structure is the cross bar. The remains of the old cross bar and the new "braces" aren't really doing anything. I'd maybe look at putting in two angled cross bars that cross in the middle of the wishbone or maybe even a piece of hefty steel plate, profiled to clear all the necessary bits and bobs?? (image below) Sort of thing that could be laser cut and welded on top of the wishbone? You seem pretty clued up though mate but just thought I'd bung my 2p in Hope you don't mind. Dunc
dss123 Posted April 22, 2008 Posted April 22, 2008 Spare moment at work Dunc! Loads on mate but just can't be arsed - feels like Friday for some reason? Dunc
Phil.S Posted April 22, 2008 Author Posted April 22, 2008 Spare moment at work Dunc! Loads on mate but just can't be arsed - feels like Friday for some reason? Dunc Dunc that looks the biz. May well have a crack at that
cmm_elise_s Posted April 22, 2008 Posted April 22, 2008 in theory this sounds good.......basically its a diagragm.....thus transfering the shear force.....however this needs to be something more robust than thin plate.......What material are you thinking of and how thick? also note the key to the strength with this solution is the position of the welding!!! Blimey! You've made rapid progress with that phil!Hope you don't mind if I give some 'constructive critisism' with regards the wishbones? IMO the two triangles you've made, where the origonal bar went are across, now dont really do anything. Would you be better to have a curved bar that does from the origonal points and clears the sump still?Anyway you probably CBA to that now and it'll be fine anyway! No problems with a bit of constructive criticism!. I was trying to work out what the tie bar actually did being so close to the mounting points which really do the same thing. I worked out that if there was any twisting going on between the two points one would essentially go up and one down which is where the little triangles come in. Hopefully it will be OK it seems super strong! Hey Phil,Great thread and great project - very jealous!Maybe worrying unnecessarily, but I also share Dave's thought's about the "modded" wishbone. The only bit that is contributing to the integrity of the structure is the cross bar. The remains of the old cross bar and the new "braces" aren't really doing anything.I'd maybe look at putting in two angled cross bars that cross in the middle of the wishbone or maybe even a piece of hefty steel plate, profiled to clear all the necessary bits and bobs?? (image below)Sort of thing that could be laser cut and welded on top of the wishbone?You seem pretty clued up though mate but just thought I'd bung my 2p in Hope you don't mind.Dunc
dss123 Posted April 22, 2008 Posted April 22, 2008 Reckon 4 -5 mm mild steel would be bomb proof. Dunc
dobbo Posted April 22, 2008 Posted April 22, 2008 Welding it on might be interesting - bound to distort and misalign the two existing bush holes. I'd suggest having a very tight fitting bar through the two existing bush holes whilst welding the plate, and heat-relieving it after welding (then remove the bar). / another 2p ;-)
Phil.S Posted April 23, 2008 Author Posted April 23, 2008 Heres another take on it: I'll probably switch to a remote takeoff further down the line then I can move the cross brace up some more. But for now this is my only option!
cmm_elise_s Posted April 23, 2008 Posted April 23, 2008 are you having a laugh?? replacing a tubular steel bar with some 4 mm plate?? Reckon 4 -5 mm mild steel would be bomb proof.Dunc if you are are a welder you should see some of the sh1t I have seen on site today!!I think you may well have a valid solution. Welding it on might be interesting - bound to distort and misalign the two existing bush holes.I'd suggest having a very tight fitting bar through the two existing bush holes whilst welding the plate, and heat-relieving it after welding (then remove the bar)./ another 2p ;-)
dss123 Posted April 24, 2008 Posted April 24, 2008 are you having a laugh?? replacing a tubular steel bar with some 4 mm plate?? Eh, no. Isn't the entire design ethos of the Elise chassis based on the notion of replacing as much tubular steel with plate?? It's how you use the mateial - Simplicate, then add lightness (CC). Looking at the original wishbone design, I'm inclined to agree with Phil that the cross bar in it's original position is largely redundant once fitted. Even if it was removed completely, I can't see how the wishbone would fail in normal operation? It certainly helps spread any side loading across both bushes and would therefore help reduce wear, but it isn't adding a great deal of strength. The cross bar helps to align the pivots, makes manufacture simpler / more accurate and gives the component added strength when being stored / transported / fitted. To this end, I would suggest a 4-5mm steel plate would be more than adequate. I'm interested to know how you think this would fail given that it's only ever going to loaded in compression or tension? (Let's assume it's fully welded) But hey, I'm no chassis designer so what would I know Dunc
Ladders Posted April 24, 2008 Posted April 24, 2008 I suppose at the end of the day it's how the loads and stresses are going through the wishbone. If it's a twisting force then yes, I suppose a plate wouldn't do that much, but if it's to give strength to the 'Triangle' of the wishbone, then yes it would be fine. The top front wishbone also uses a similar arrangement!
dss123 Posted April 24, 2008 Posted April 24, 2008 The top front wishbone also uses a similar arrangement! Quite so mate!
Reg Posted April 24, 2008 Posted April 24, 2008 Interesting project Phil, I have been watching it closely! Been bitting my lip (or fingers should it be?) though..... I'm not a professional welder, but I have done lots including building/designing a car chassis from scratch. May take on your wishbone is, if a weld looks shit it generally isn't very strong. Although bracing up what you have already have would undoubtedly make the wishbone stronger, 4-5mm plate is way over the top 1-1.5mm is all I would use. However, what I would suggest is have the sump modified to clear the original piece of wishbone (doesn't look like much needs removing), and use a shorter oil filter or better still like you said a remote one. As it stands I wouldn't be comfortable taking your wishbone on the road. Keep up the good work, Reg
Phil.S Posted April 24, 2008 Author Posted April 24, 2008 Interesting project Phil, I have been watching it closely! Been bitting my lip (or fingers should it be?) though..... I'm not a professional welder, but I have done lots including building/designing a car chassis from scratch. May take on your wishbone is, if a weld looks shit it generally isn't very strong. Although bracing up what you have already have would undoubtedly make the wishbone stronger, 4-5mm plate is way over the top 1-1.5mm is all I would use. However, what I would suggest is have the sump modified to clear the original piece of wishbone (doesn't look like much needs removing), and use a shorter oil filter or better still like you said a remote one. As it stands I wouldn't be comfortable taking your wishbone on the road. Keep up the good work, Reg Just out of interest Reg where do you think it would fail? - I really cant work it out!
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