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Feb 18, 2009 22:55:13 GMT
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nice, used to love proEngineer at uni. be careful with your datums in sketcher tho, looks like you have dimensions referencing other dimensions rather than fixed datums, that can screw it up, and changing one thing will change something else without you realising it. btw that red golf on the first page has both a supercharger and a turbo, hence the mega amount of cooling  |
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kee
Posted a lot
Posts: 4,991
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Feb 18, 2009 23:21:13 GMT
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all the dims are fine, it had some other datum lines i deleted to make the picture clearer.
the centre line is the centre of the car
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Feb 18, 2009 23:25:03 GMT
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all the dims are fine, it had some other datum lines I deleted to make the picture clearer. the centre line is the centre of the car fair play  look forward to seeing more development of the design ;D |
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kee
Posted a lot
Posts: 4,991
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Mar 27, 2009 21:28:36 GMT
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well the draft report deadline is fast approaching and i am way behind  should have finished everything and started writing up my 8000 word report on it. here it is at the mo after a big re design   not happy with the frame to be honest but i can't think of any other way to do it. i'm having to go push/pull rod as there is nowhere to fit a coilover apart from where they are. thats at the bulkhead by the way  and its really REALLY awkward trying to sort the pushrod placement out aswell. comments, help and general cheering welcome ;D |
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Mar 27, 2009 23:21:16 GMT
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So where does the frame link into the car? Rocker setup = good, means you can set the preload and ride height independently!
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1997 TVR Chimaera
2009 Westfield Megabusa
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kee
Posted a lot
Posts: 4,991
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Mar 27, 2009 23:29:25 GMT
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still working on that Adam, gonna have a load of tube coming off that which would be welded to the bulkhead and roll cage etc.
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kee
Posted a lot
Posts: 4,991
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Mar 27, 2009 23:34:17 GMT
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tidied the frame up a bit, starting to think it may be ok   thats tonights work.  less welds should also make it easier to assemble, looks much better than the square version and a million times better than my first effort. i reckon so anyway  |
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tycho
Part of things
Posts: 151
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How do the bones attach to the springs/dampers? sorry if I am being thick but I can''t see it in the pic. Is there really that much room in a fiesta engine bay or will it be tighter IRL?
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looks good but you will need two tubes to run front to back underneath it.just below bottom suspension points in the corners.
as its drawn now theres no strenght to it
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Have you checked for interferance between wheels and wishbones? To me it looks like any serious lock will cause the tyres to hit the wishbones
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kee
Posted a lot
Posts: 4,991
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tycho: there will be some pushrods attatched to the top rocker arms, pro/engineer isn't making my life easy at the moment hence why they aren't there. Nobody: Thanks for the advice, i kind of thought it might but didn't really want to, should only take a couple of minutes to throw it on though Mskinner: not yet, again pro/engineer makes life difficult. once the frame is finished I'm going to draw the assembly again in a different order and it should be easier. thanks everybody |
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kee
Posted a lot
Posts: 4,991
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Mar 28, 2009 20:16:07 GMT
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added some more bracing and some pretty colours ;D also trying to sort a perch for the rocker, am sure this would be easier to do with some steel and a welder in hand  also, tycho, theres not that much room surprisingly. the gearbox is a lot bigger than that, my drawing is just a quick mockup of length basically. also no ancillaries such as carbs, exhaust and alternator etc. and no cylinder head ;D keeping it fwd makes it much more difficult, damn my silly ideas. heres todays progress   |
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filmidget
East Midlands
Mostly Lurking
Posts: 1,652
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Mar 28, 2009 21:30:52 GMT
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A few things stand out to a totally uneducated sub-amateur: Front frame uprights - couldn't they be straight tubes set at an angle (removing need for that nasty kink) The upper cross brace - why is it offset downwards? (feeding loads mid-member) Lower bars running front-back - why are they feeding to the front bar mid-member instead of corners? I assume you are going to add triangulation later? Uprights - liking the adapter for the top wishbone, but have you checked the geometry? The inclination between the spherical bearings looks a bit steep? Wishbones - leaving aside the lock problem somebody mentioned, surely even real strong tubing is going to have problems not bending, twisting, etc, especially the tube to the lower rod end. The pushrod for the suspension rocker arm - where will that run to? Where does the rack mount on a fiesta? Learning the software makes previous attempts I have made in AutoCAD look very poor though |
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'79 MG Midget 1500 - Still patiently awaiting attention
'02 Vauxhall Astra 1.8 Elegance(!) - Better than you might think
'03 Mazda MX5 - All new and shiny looking (thanks to Antony at Rust Republic)
'09 Renault Clio - Needs to go.
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kee
Posted a lot
Posts: 4,991
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Mar 28, 2009 21:46:20 GMT
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All very good points, i'll answer as best i can. Front frame uprights - couldn't they be straight tubes set at an angle (removing need for that nasty kink)the wishbones need to be different lengths, when looking at them straight on, the top needs to be shorter from upright to frame, than the bottom in order to gain camber during body roll. the kink should'nt be any weaker than a straight bar, just a bit of extra cost. The upper cross brace - why is it offset downwards? (feeding loads mid-member)mainly because i'm lazy and ditn actually think. i did the rear and front in one 'part' on pro/e, the rears are lower down to allow room for the rockers, i'll change the front and raise it up Lower bars running front-back - why are they feeding to the front bar mid-member instead of corners?sump is in the way, i want the engine relatively low, i've already raised it 50mm to put those in. i initally put radiused bars in but they ran below the scrub line. I assume you are going to add triangulation later?yes ;D Uprights - liking the adapter for the top wishbone, but have you checked the geometry? The inclination between the spherical bearings looks a bit steep?not sure which bit you mean on this one? Wishbones - leaving aside the lock problem somebody mentioned, surely even real strong tubing is going to have problems not bending, twisting, etc, especially the tube to the lower rod end.there aren't any bending forces at the moment, i think i have some of my dimensions wrong so i need to take my wheel of my actual car to have a look. The pushrod for the suspension rocker arm - where will that run to?dunno yet, want to run it as close to the upright, on the lower wishbone, as possible, difficult becuase of the awkward softwar and the driveshaft that is likely to be in the way. Where does the rack mount on a fiesta?rack mounts at the bulkhead, not though about that one though  thanks for the help, pointed a few things out, this is why i like people to check. some of the things like steering rack may not be important for my report, it's more a point of showing my 'academic skills' which i lack greatly ;D i'd rather just get designing and building i hate reports. thanks again |
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John
Part of things
Posts: 347
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Mar 29, 2009 19:49:22 GMT
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A few space frame RULES....
Always feed loads (ie engine mounts, coil over mounts, wishbone mounts) into junctions of tubes NEVER in the centre of an unsupported tube.
Keep tubes straight.
Triangulate.
To achieve all of the above will take some thought, but basically the spaveframe is a bracket to connect all the components together. So decide where everything is going (ie suspension pick up points, coil overs, engine mounts etc) THEN design to connect these points together.
Aim for good torsional (twisting) rigidity between the spring mounts. The easiest way to do this is to triangulate everything and build a small wooden model of your proposed design and twist it in your hands. You will be amazed at what you learn. You will quickly learn that ANY open square will be an area of twisting and a single diagonal will have amazing results.
Unfortunately your design breaks nearly every rule. Loads in to the middle of tubes, bent tubes and no triangulation. Your design will work but with some repositioned tubes it could be made lighter and stiffer.
Study the frame on my space frame Minor which someone has already linked to.
John
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kee
Posted a lot
Posts: 4,991
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Mar 29, 2009 19:54:08 GMT
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thanks John, i have studied it, i was the one that linked it and your minor inspired me to do this |
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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Mar 29, 2009 20:14:02 GMT
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don't quit the day job The kink sticks out like a sore thumb, why not just run the tube at an angle? it solves your sump clearance offset tube problem too. Insted of having those top tubes as a curve around the engine they should go straight back to the corners of the a pillar with a tube running across the bulkhead to link them. Maybe a braced cross at the bulkhead to get your wishbone mounts closer the where they nees to be. The coilovers would be better off on top of the top wishbones, more or less where the struts would have been. It simplifys the design by miles and you know they will fit. The wishbones don't really need to be that shape. If you angle the inner rosejoints and put a pivot in their you will gain bags of strength, clearance and make castor adjustement alot easier Just think of a big trapeziod shape for the frame really. Keep it simple!! |
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kee
Posted a lot
Posts: 4,991
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Mar 29, 2009 22:01:36 GMT
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i like the top brace idea slater thought about having the coilies on the top wishbones too, being stubborn though and don't really want to do that I have designed thw wishbones like that as if i where to do it as you say, and keep the rod ends vertical, the wishbone would be under way too much stress and snap or prevent the wheel articulating, i did it like that originally but my tutor pointed me in the direction I'm in now. |
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kee
Posted a lot
Posts: 4,991
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Mar 30, 2009 15:03:16 GMT
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another massive change to the frame then, thanks for the advice word of warning people, never try to spaceframe and double wishbone a fwd car will defo chuck that engine further back for the proper one ;D todays and last nights progress, better frame, I know there was something about that last frame but couldnt get my head around it, so much stress recently and little sleep, doing work till midnight plus and having my daughter get me up early in the morning is a killer. thank the lord this will be over in a few weeks ;D have a piccie.  there will be more triangulation added to the back of it and tubing to connect it to the bulkhead edit to add the picture |
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Last Edit: Mar 30, 2009 15:03:44 GMT by kee
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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Mar 30, 2009 15:20:02 GMT
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much better
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