I have some ideas from doing mechanical engineering at A Level - I just need a way of assessing the suitability (CAD modelling or something?)
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.)
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
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?)
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.
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 
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
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]
quote:
Originally posted by StevieB
Tad privey that one - £130 on Amazon
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?
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]
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
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......
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.
Forgot the piccy version 2
Rescued attachment Rear suspension.jpg
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.
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.
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.
Looks like you've re-invented the Sylva inboard suspension.
Here it is on the R1ot
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]
quote:
Originally posted by iank
Looks like you've re-invented the Sylva inboard suspension.
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.
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.
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.
quote:
Originally posted by iank.............
Not seen rockers on rear suspension, but I suspect that is more of a packaging issue ...............
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
Ha haaa...
IRS 3
Did it pretty much cos it was already designed for the front, and i wanted the same choice of shock mounting positions to play around with different
wheelrates (without changing springs) on the rear.
Liam
[Edited on 23/10/06 by Liam]
Liam - it was reading through your post the other day that got me thinking about doing something the same but different to all the other sevens around.
quote:
Originally posted by NS Dev
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
lots of people use yamaha bike shocks - i have 3 in the garage. They are no lighter than normal ones, but they are adjustable and cheap.
See - I wasn't going to post anything about my idea because then I could sit and think it's original, not find out it's been done in a
dozen ways.
Right - Plan B. It'll be another Indy but painted pink with yellow dots and blue racing stripes. Bet no-ones done that before!
Doh! I was thinking of doing the same too! Maybe not so original anymore but worth investigating! On our formula student car we used fox racing shocks off a mountain bike...not ideal for something that weighs 400-500 Kgs but perfect for an R6 powered single seater weighing 204Kg!