StevieB
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| posted on 22/10/06 at 04:49 PM |
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Designing a chassis
Now that my Indy is nowhere near complete and there's a long way to go, I'm thinking about the next project!
I'm planning for the next one to be done over a much longer period, and would like to design the chassis myself. I want to do the locost thing,
but I also like the idea of inboard damping etc.
Where's the best place to start, apart from the obvious reading lots of books, websites and threads on here (such as what software would be
useful etc.)
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MattCraneCustoms
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| posted on 22/10/06 at 05:50 PM |
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If you want a book to start reading, you want to get racing and sports car chassis design by Michael Costin, who I believe is the 'Cos' of
Cosworth. Thatll keep you busy and teach you the fundamentals that need to be considered in chassis design
Regards
Matt
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StevieB
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| posted on 22/10/06 at 06:47 PM |
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Tad privey that one - £130 on Amazon 
I have some ideas from doing mechanical engineering at A Level - I just need a way of assessing the suitability (CAD modelling or something?)
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DIY Si
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| posted on 22/10/06 at 06:53 PM |
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If you do find some cheap books on this let me know, as I'm looking into doing the same, but with a lola/canam type thing. As with you, I know
some/most of the basics, but only want to do it once.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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StevieB
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| posted on 22/10/06 at 07:19 PM |
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It's more a case of having a great idea, but wondering why it's not more commonly done.
I admire you going for something a bit ambitious - I'll be sticking to the se7en type and probably trying to have it conveniently sized to fit
standard bodywork from the mainstay suppliers 
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flak monkey
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| posted on 22/10/06 at 07:26 PM |
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Start with designing your suspension geometry then work on designing your chassis to connect the point up and be fully triangulated. Its not a black
art, once you know the rules, its pretty easy to design a chassis that will work. Where the skill comes is in designing a stiff chassis with very
little weight.
A good book on suspension was written by Miliken cant remember the title of the book now though.
David
Sera
http://www.motosera.com
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DIY Si
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| posted on 22/10/06 at 07:26 PM |
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I don't suppose you'd be willing to let us in on this "great idea"? Someone here should be able to help/advise on it.
And if it's really good, I might even be able to pinch it for use in mine!
Oh, having read the cymtriks plans for a stronger chassis, and how easy it would be to add most of them and double chassis stiffness, I'm
suprised more people don't use them.
[Edited on 22/10/06 by DIY Si]
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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Confused but excited.
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| posted on 22/10/06 at 07:28 PM |
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quote:
Originally posted by StevieB
Tad privey that one - £130 on Amazon
Do you mean that's a sh1t price?
Probably a bit uncool in these days of t' web, but have you ever thought of booking it out of a public library?
Tell them about the bent treacle edges!
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StevieB
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| posted on 22/10/06 at 07:56 PM |
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quote:
Originally posted by Confused but excited.
quote:
Originally posted by StevieB
Tad privey that one - £130 on Amazon
Do you mean that's a sh1t price?
Probably a bit uncool in these days of t' web, but have you ever thought of booking it out of a public library?
Would do, but I'm crap at taking things back!
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StevieB
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| posted on 22/10/06 at 07:59 PM |
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The big idea?
Inboard rear suspension. There's probably a reason we don't see it anywhere, but apart from the practicality of losing boot space
(bovered, me, am I?), I can't see what wouldn't work.
Apart from that, I want to use a lot more triangulation, round tube and structural panels (like the transmission tunnel - made with a small amount of
framing, but using thicker, one piece ali rather than thin panels).
Like I said, nothing that won't have been done before, but it'll be my own and different (and probably crap as well!).
Might even consider mid engine
[Edited on 22/10/06 by StevieB]
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StevieB
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| posted on 22/10/06 at 08:15 PM |
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Maybe something like this at the rear. The upper wishbone could be made using tube with threaded bits to give adjustability (if it'd be
safe/stong enough)
 
Rescued attachment Rear suspension.jpg
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DIY Si
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| posted on 22/10/06 at 08:39 PM |
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Certainly can't see why that wouldn't work. One reason for not manufacturing such a thing could be the extra expense/complication
involved. As a one off you already have to make everything so you can do what you wish. You could also adapt that slightly to have adjustable ride
height etc as you would at the front with inboard gear. As said, for a manufacturer, maybe not worth the effort, but for you......
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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StevieB
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| posted on 22/10/06 at 09:10 PM |
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You'd make the wishbone in 3 pieces, and but a threaded adjuster on the red bar (as shown). It'll be 3 dimentional as well for
strenght/stability (but I don't have the patience to sketch that bit out yet!)
The only thing I'd worry about would be extra weight, but there are places to save that and, if it works, the benefits should outweigh the, er,
weight.
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StevieB
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| posted on 22/10/06 at 09:10 PM |
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Forgot the piccy version 2
 
Rescued attachment Rear suspension.jpg
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DIY Si
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| posted on 22/10/06 at 09:55 PM |
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You'd have to be careful adjusting that too much, as you'll lose some of the pre-load on the springs. Otherwise look good, if it an be
made strong enough.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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NS Dev
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| posted on 23/10/06 at 08:56 AM |
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there's always the question of why???
(as there is also the one of why not!!! )
Inboard give much scope for cock up as well as gain!
rather than just doing boggo inboard like that I would look at some good handling race cars and get some ideas from there.
I looked at the back of my mate's Ducati (guess a lot of bikes are the same though) at the double acting rear shock and thought it would be a
great way of improving damping using cheap shocks, patting myself on the back at the good idea, then looked at a Radical and realised they did it
years ago!!! lol !!!!
Seriously though, pushrodded double acting shocks are nifty engineering that is worth having if you are saving on the shocker budget.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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StevieB
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| posted on 23/10/06 at 09:02 AM |
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The answer to the question is the 'why not' option.
I'm half way through an Indy build and the ideas keep coming while I'm working on the chassis, looking at parts and deciding that a better
way must be possible.
The idea is just to do something a little different. The idea in the sketch above is just a basic one - that's why I was asking about research
sources and aftware to do some modelling.
I'd already decided that a pushrod set-up allows a bit more freedom in placing the shockers.
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iank
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| posted on 23/10/06 at 12:26 PM |
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Looks like you've re-invented the Sylva inboard suspension.
Here it is on the R1ot
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kb58
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| posted on 23/10/06 at 01:23 PM |
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As far as books go, check out my list: Kurt's book list
If there's one book I recommend most it's Staniforth's "Competition Car Suspension."
That front suspension above is very similar to that on my Mini.
[Edited on 10/23/06 by kb58]
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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Alan B
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| posted on 23/10/06 at 02:10 PM |
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quote:
Originally posted by iank
Looks like you've re-invented the Sylva inboard suspension.
Or mine......
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StevieB
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| posted on 23/10/06 at 02:59 PM |
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I know it's been done before - I fully confess to being a rip off artist!
I just thought it would be a bit different to do it in the rear (oo-er!) of a se7en as well as the front.
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iank
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| posted on 23/10/06 at 03:31 PM |
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Well with suspension everyone has been a rip off artist for decades 
Not seen rockers on rear suspension, but I suspect that is more of a packaging issue (in that it will eat any boot space) than anything else.
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Alan B
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| posted on 23/10/06 at 03:36 PM |
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quote:
Originally posted by iank
Well with suspension everyone has been a rip off artist for decades
Not seen rockers on rear suspension, but I suspect that is more of a packaging issue (in that it will eat any boot space) than anything else.
There you go....
From a sports racer....
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Syd Bridge
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| posted on 23/10/06 at 03:45 PM |
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quote:
Originally posted by iank.............
Not seen rockers on rear suspension, but I suspect that is more of a packaging issue ...............
Open wheelers and sportscars have been doing it for 20 years and more. So have Ferrari on some of their road cars.
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StevieB
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| posted on 23/10/06 at 03:56 PM |
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I'm not really bothered about boot space -planning it to be a sprint/hillclimb/race car, so just want a good chassis and lightweight thta
handles
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