Spaceframe/suspension Design - update-27/03

[kee]

I'm in my final year of uni, studying a mechanical engineering degree, and instead of writing 10million word essay for the big marks in the final year, we get to design and sometimes manufacture stuff ;D

after talking with my tutor today, we have agree'd i'm going to design a spaceframe for the front of my fiesta, I doubt I will be able to have it made this year, but YAY.
actually looking forward to this, gonna be a hell of a lot of work, but if I do well and it works and I save up enough, I will have one beasty mk1 fiesta on my hands ;D

So, onto my questions
anybody on here know anything about spaceframing the front end of a car, or have any pointers/tips/info or resources I can use to get a lot of detailed info from.

this came about because I wanted to re-design my suspension, he suggested macpherson strut is curse word for a race car, so said to double wishbone it, but that can only be done with a spaceframed front end, then that was decided.

it also means I could fit a 16v engine a lot easier, but you can't beat the sound of a crossflow, so I need to decide on that aswell as my chosen suspension set up.

all info wil be gratefully received on suspension setups and the like also.
have some piccies, but I want more

[jikovron]

the main issue is to triangulate the suspension force to the body so that it puts pull/push forces into the bulk head,,,,,,,,,,,strongest places being the bottom area of the windscreen pillar and the front of the sill behind the front wheels (from my own non scientific tests in scrapyards),,,,,,,,,the load has to be spead across a wide area at the connection points on the bulhead or the frame has to extend into the body if the bulkhead is too weak

i reckon a design project on a spaceframe could produce a hefty design portfolio,,,,,,,,,,if you throw in a load of strain/stress/fatigue/poissons ratio/bending moments calculations based on parameters like tyre grip for braking/cornering forces,,,,,,vehicle weight,,for strengths and built in safety factor calculations
and basic destructive testing could be thrown in too on weld fatigue/tube deformation

i am doing a project too for my engineering degree,,,,,,,,,but its not car related:(

[stealthstylz]

For ultimate strenghth it'd need to tie into a rollcage. You could use the standard Fiesta stub axle for the double wishbone suspension, meaning you could keep the stock driveshafts and therefore track width.

Matt

[rustingdeathtrap]

Try not too concentrate too much on strength.
Remember for it to be safe you need to design in some sacrificial members so the the spaceframe will collapse in an accident rather than crushing the passenger compartment.
Also you need to allow for the natural flex of the bodyshell, make it too stiff and you'll find the rest of the car will start brake up around it, just ask nightmares racing as he has bitter experience of this.

[popuptoaster]

I was just gonna say that you don't want it to strong, fiesta shells are quite flimsy but still do an ok job of keeping stuff where its sposed to be, you want it light and rigid with some collapsable bits on the front to take energy out of a crash, if you look at lightweight low power race cars you'll see how thin the space frame can be and still do the job.

[SteB]

Nice simple example on a Mk2 Golf where the hoop supports the front engine mount

[Rich606]

Oct 14, 2008 19:00:10 GMT kee said:

it also means I could fit a 16v engine a lot easier, but you can't beat the sound of a crossflow, so I need to decide on that aswell as my chosen suspension set up.

Hmmmmmm, spaceframe - the world is your lobster. Imagine how your Fiesta would go with a VTEC. And Civics and Intergras have double wishbones at the front ;D

[sammm]

Shouldn't you start off small if this is your first spaceframe?



Seriously though Vtec seems to be engine of choice for FWDs.



Or you could put something in the back

[kee]

thanks for the advice,
it will be getting caged up aswell as i won't be able to race without it.

thanks for pointing out about the crush points being useful, its something i havent thought about so will look into that aswell.
great piccies.
still unsure on engine choice, problem is i will need measurements and i have just bought a 1600 xfow block ;D
at the moment its all research and learning, will have to keep you all updated as i go along with drawings and findings etc

[Andy Camaro]

go for it!

When i was at school I always tried to make the cdt projects to my benifit!

on another note - does this have enough cooling / cold air feed?

[CR500Dom]

Most if not all of those posted are Tube frames, they are not spaceframes.

A space frame by definition could have all the joints as flexible joints and still be a rigid structure, thats the key to it.

If you want a really good book on chassis design, there is one by "Costin and Phipps" as in Frank Costin, which goes into great detail on the different types of chassis structure, suspension design etc.....all older stuff Like Lotus 11`s, maseratis, lots of Lotus single seaters etc but very very interesting and will give you a good grounding for the project.



I`ll try and find some more proper spaceframe chassis pics, you will quickly see the difference

HTH
Dom

[kee]

cheers dom, i have seen that book and apparently its in our library so i'm off to get later

[CR500Dom]

Oct 15, 2008 10:02:33 GMT kee said:

cheers dom, I have seen that book and apparently its in our library so i'm off to get later

You wont regret it

Fantastic book

[HoTWire]

Oct 15, 2008 9:44:42 GMT CR500Dom said:

If you want a really good book on chassis design, there is one by "Costin and Phipps" as in Frank Costin

YAY! for Frank Costin!

[kee]

theres this one in our library
www.amazon.com/Racing-Sports-Car-Chassis-Design/dp/0837602963
but thats michael costin

[CR500Dom]

Oct 15, 2008 11:04:53 GMT kee said:

theres this one in our library
www.amazon.com/Racing-Sports-Car-Chassis-Design/dp/0837602963
but thats michael costin

Thats a good one too

Get it.... its out of print and has been for a long time as is the Costin and Phipps one as well I think

[garethj]

There's a good book by Allan Staniforth called "Race and Rally Car Source Book" which gives the basics for spaceframe chassis.

This subject came up here too and some useful comments: retrorides.proboards86.com/index.cgi?action=display&board=general&thread=43930&page=1

Don't just blindly follow what others have done, I wouldn't trust some people to assemble a deckchair

[Keefy]

i know a lot of the UK chassis builders swear by the boor 'Doorslammers'



secure.chassisshop.com/partlist/5607/

[CR500Dom]

Oct 15, 2008 12:21:29 GMT Keefy said:

I know a lot of the UK chassis builders swear by the boor 'Doorslammers'



secure.chassisshop.com/partlist/5607/

Good for straight lines

Not so good for roundy roundy

[kee]

thanks for the link gareth
this:
www.beardmorebros.co.uk/website%20pages/new_project.htm
looks like it will be a good read