kaBOOM's, uh, project?

well that testing was done without the body on ;) Ala like this....

Image111.jpg


Image112.jpg


Sorry I'm having major body issues with the plastic forming process atm....I'll try to put some more pics up
 
why the need of a body. i'd drive it as is. :D looks awesome :thumbsup:
 
Why would you buy it? (car nut)

.. lots of good reasons ...
$30,000 AUD sale cost, for a car that will hit 100km/h in around 4 seconds. For that price there is simply nothing else around....

:shock: OMFGWTFBBQ!?! Are you taking orders? :p

Seriously dude ... you could put that into production, charge TWICE that amount and still have a decent waiting list. If there's something that Australia needs right now, it's a low-rent 'man-in-a-shed' sportscar company. Sort of like a poor man's Elfin.
 
Amazing to see something like this come together!

It's a standard wrx engine right? What model year is it from?
 
MY98 WRX, stock as a rock.....I mean it doesn't need anymore power as it is!

I'm thinking about putting a water to air intercooler on it, and running a side radiator etc

But the current project is a better set of body molds.....molds that don't explode is the vac former machine >:
 
Sounds like a good plan.

Was just thinking with my99 > it's easy to do a flash tune on the ecu but it sounds like you don't need it.
 
Good work kaBoomn. I'm often interested to know with these home brew projects how much theoretical engineering has gone into it? I'm not trying to start some fruitless forum argument here by the way, just interested how much you did through pure spannering experience and how much was calculated etc.

For instance:

  • What did you use to define the chassis hardpoints?
  • At what point did you design the suspension? Before the chassis or after?
  • Do you know your roll centre and how did you decide on the suspension geometry?
  • How did you spec your various bearings and rose joints?
  • Did you do any computer modelling to package the components or design the chassis?
  • Do you know what the installed chassis stiffness is in Nm/Deg?

I'd say you've done an amazing job. The overall finish seems really good. The only thing I would say, is perhaps the side members could do with a bit more triangulation. I'm not sure the little cross member going from the front bulkhead to the lower tube will do a great deal as it's feeding the load from and to two unsupported tubes. You're always better to try and terminate all tubes in common 'nodes'. You'd be amazed how much material you can take out just by getting load paths spot on. It might be worth making your own wishbones at some point too since you could save quite a bit of weight if you really do the design work on them. You could probably use 1/2in tube for most of it if you get rid of the rod ends in bending on the outboard side.

If you want any help with what calculations to use and some good engineering fundamental books for race car design, I can perhaps point you in the right direction. I've had experience designing a number of Formula Student cars and currently work for an automotive manufacturer here in the UK, so I've got an idea of what helps to tune some of the inevitable teething problems out.
 
This thread needs moar videos.

  • Did you do any computer modelling to package the components or design the chassis?

If you want any help with what calculations to use and some good engineering fundamental books for race car design, I can perhaps point you in the right direction. I've had experience designing a number of Formula Student cars and currently work for an automotive manufacturer here in the UK, so I've got an idea of what helps to tune some of the inevitable teething problems out.

Mainly w.r.t the computer modelling side of stuff, I like to design cars in my free time and any resources there are to aid in making them more "realistic" would be nice to know about. Are you referring to an Aliastools kinda thing or a more hardcore engineering based simulation, like say...Inventor and the FEM tools inside of that?
 
Hey man thanks for the interest :) Before we start please bear this in mind (if I sound like I'm talking down a bit, I'm not. You probably know a hell of a lot more than I do...but anyway:

- I've worked for a kit car maker/alfa romeo service/weird car shop since 2003
- This car project was used as a final project for my industrial design degree which I started in 2003...

..and a few things about the car...

- Its designed around economical production and ergonomic features

[*]What did you use to define the chassis hardpoints?

The initial hard points where designed around the ergonomic setup of the vehicle. Vehicle seating, the ideal references of various parts from one to another -- eg the steering column to the steering rack, with minimal amount of universals for steering "feel" and also making sure that the steering will decouple in a front end accident situation.

From here came the basic vehicle proportion design: Basically what we are doing here are doing a basic development of the vehicles visual aesthetics. Good visuals always depend on good visual proportions. Check out the Golden section. There are various rules of car proportioning if you want it to look correct.

These two "requirements" (for want of a better word?) have to be juggled back and forth to get your packaging spot on.

[*]At what point did you design the suspension? Before the chassis or after?

The suspension and chassis have to be designed together. The chassis give you your arm offsets relative to your suspension track and the type/geometry you use.

[*]Do you know your roll centre and how did you decide on the suspension geometry?

The front and rear roll centers are almost the same.

The front suspension is a classic double wishbone setup. Custom chrome molly/mild steel arms, Cortina stubaxle. Car specific geometry, include my ackerman angle, anti dive and castor.

The rear suspension is a 5 link "multilink" Independent system, which I'm still not happy with. While the front end was essentially copied from works lotus 7 replica project (as far as arms go, no pickups) then rear end was my own.

Two subaru lateral links, a track arm for toe adjustment and a adjustable amount of antisquat....well that was the idea. The problem is that it pounds the crap out of the lower coil over bush...ah well.

The upper rear upright and top links are my own...this rear end is a work-in-progress at the moment. It performs well but there are a few other problems..

[*]How did you spec your various bearings and rose joints?

The ball joints at the front are just generic Ford parts....

...however the suspension bush's are custom ones that where made at work for the clubman project. They are a poured poly bush with a mild steel inner.

The rear does have some rose joints, however I'm intent on getting rid of them. This is a road car, designed for Australian roads and it will spend quite a bit of time on dirt roads. Its just our local conditions.

Rose joints have far too much shock transmission and cause cracking on the suspension pickups in my experience. I still have 3 rose joints on my rear suspension design, I'm intent on getting rid of them.

[*]Did you do any computer modelling to package the components or design the chassis?

Solidworks.

[*]Do you know what the installed chassis stiffness is in Nm/Deg?

Local rules demand a rigidity of 3000nm/degree for a 4cyl kit car. Mine was designed around the idea of 3800nm/degree. I'm almost up to the point of doing a full scale test.

I'd say you've done an amazing job. The overall finish seems really good. The only thing I would say, is perhaps the side members could do with a bit more triangulation. I'm not sure the little cross member going from the front bulkhead to the lower tube will do a great deal as it's feeding the load from and to two unsupported tubes. You're always better to try and terminate all tubes in common 'nodes'. You'd be amazed how much material you can take out just by getting load paths spot on. It might be worth making your own wishbones at some point too since you could save quite a bit of weight if you really do the design work on them. You could probably use 1/2in tube for most of it if you get rid of the rod ends in bending on the outboard side.

The side members are opening doors, the horizontal bars are compliant side intrusion bars, that also hold up the power window mech. Doors are the second hardest thing on a car to design in my experience...

That front tube, goes from the front coil over upper mount (point of action) to the main firewall. I loose a lot of strengh if I take that out. The whole frame is designed around the idea of ergonomics and fabrication time. It's not as good as it could be, but remember this project was not intented to be a awesome dynamic supercar: The car is a GT, a tourer. I could easily double the build time to get a extra 10% of grip etc out of it and less weight, but whats the point?

Anyway I'm not sure that 90% percent of the driving public could honestly tell the difference between the two. In its place I've used ergonomics to compensate -- This is a nasty area that engineers fear to tread, car journo's will ignore because they are getting duped and car fanboys like to think doesn't exist.

Most of the wishbones I made myself. The only two are the rear lower paralell links....

.
..
...

Not as good as my first post that I lost but it will do!
 
If you want any help with what calculations to use and some good engineering fundamental books for race car design, I can perhaps point you in the right direction. I've had experience designing a number of Formula Student cars and currently work for an automotive manufacturer here in the UK, so I've got an idea of what helps to tune some of the inevitable teething problems out.

Not a problem, when I get into the swing of road testing another brain is always good :)

I still have to work on my body shell process....damn exploding formers...
 
And that sir....is the correct answer :)

I was interested to see what design process you'd gone through and what you'd understood to be the important things! I figured you did indeed know what you were on about, but it really does amaze me how many people build project cars with very little understanding. The Autosport show here in the UK is a classic place to see this.

There are a lot of really nice cars out there in production where the designers who are supposedly highly qualified have just copied what other people have done with little or no understanding of why! Sometimes, what they've copied is not even good in the first place.....a classic example being Lotus 7 replicas. Caterhams are fantastic to drive, but there is a lot of stuff on it which could be greatly improved, but all these companies like MK Sportscars copy bad design without any understanding.

Another fatal mistake is when people just design the chassis and then the suspension....or the other way round. I think a classic example of this is the Aerial Atom. Admittedly, there's a lot of styling in the car, but the thing just didn't handle in the first place because they'd just fitted the suspension in once the chassis had been designed! They've sorted it now and it's actually a really good car, but really, with a clean sheet design like that where all the suspension was bespoke, they could have hit it bang on first time.

I feel for you on the bodywork front. I spent about 8 months making the bodywork for the last FSAE car I worked on. I never want to work with expanding foam, body filler or fiberglass ever again!

As I said before, I didn't want to start any kind of argument. I appreciate that some questions are a bit argumentative perhaps, but I was hoping you'd justify your decisions, which indeed you did! I'm certainly no master engineer, but judging FSAE in particular has showed me the value of having someone question your design. I really wish people had done more of that when I was a student as I really feel I might have understood what the real priorities were. As an engineer, it's very easy to get stuck on the detail. One classic question by one of the FSAE judges is:

'Do you know what the elastic modulus of your brake pads is?'

It's a fairly arseholey question and many get quite defensive and resort to 'I don't know'. Ummm let me see if I can find out'

The one's who understand the real meaning of the question answer correctly showing they really do understand the whole system. What the judge is looking for is.

'I don't know, but it's irrelevant compared to the elastic modulus of the brake lines. You're limited by the braided hose as it's impossible not to have at least some.'

I'm not sure I agree with his attitude, but there is method in his madness!

I'll be really interested to see how things go and I wish you the very best of luck with the rest of the development. It seems like you've really got some good fundamental aims to achieve, and I'd say you're not far off. I look forward to reading about it in EVO magazine in a few years ;)
 
My main goal with the whole project was a larger feature set that suits the current kit car market better, and is far more time and cost effective to build. Remember at the end of the day cars only exist to make money for their designers so they can eat. End of.

You are totally spot on about knowing whole systems. On brakes I've noted a lot of people getting things like pedal ratios all messed up and ending up in all sorts of trouble (end up trying to compensate with boosters and weird master cylinder sizes). A little research goes a long way...

...on the other hand you get people that over research and end up in a big mess with way too many design requirements. A similar lower tech solution in some cases may be "better" but a lot of peoples pride gets in the way --> This is a reference to the endless live axle vs IRS debate. Dammit it depends on your vehicle requirements, not what is better technically in every dynamic position. :lol:

---------------

As for the FSAE world. I started a mechanical Engineering degree, I'm still not sure that I'll finish it. There is a FSAE program at UniSA, but after looking into it I wasn't too impressed....

...however I do realize it really isn't aimed at the slightly older student (27) who has experience building cars. I think my main problem was the lack of creativity in some vehicles and the adoption of "cool" solutions over cold hard pragmatic ones....but then again, it really isn't intended for me.

.
..
...

Anyway thanks for the nice words. :) This plastic bodyshell design is a bit of a pain atm....*sigh*
 
Yeah I completely agree. There are cars out there that are a complete orgasm of engineering, but it's not IMO true engineering. The Caparo is an example of F1 engineers thinking they can make a road car. Lot's of amazing engineering detail, but all done with no eye on cost. Someone like Gordon Murray is one of the few who has an eye for both engineering design and the practicalities of engineering. Admittedly, the F1 was ludicrously expensive, but it fullfills the brief perfectly and doesn't really have anything that's just engineering bling. It's functional.

As for FSAE. I know what you mean. I think the experience you get out of it is massively dependent on the University. Some have stacks of money and like you say, just make overly complicated stuff with little or no understanding. Others (like the university of Stuttgart in Germany) are very, very good and you look at the way everyone in their team is utilised and how all designs are so fantastically well justified and you can really see how it should be and you can see the benefits. What I got out of it though, was ultimately a good understanding of the fundamentals and also how important it is to just get stuff done sometimes. A well tested OK idea is 1000x better than an untested great one.
 
It's awesome to think you have constructed a complete car from nothing. I like to dream about building a tube frame race car but in reality i would never have the time, patience and engineering skill to do it. Modifying production cars is about my limit.

It would be cool to catch up with you sometime, i would love to see this thing in the flesh and pick your brain about automotive engineering.

Let me know if you ever need to use a chassis dyno. I have use of the dynapak hub dyno (no wheelspin or frictional losses) at AMMR and it's down your side of town. Or you can drive it down to turbotune and use the dyno-dynamics, either way. :)
 
That's absolutely insane. I'm a complete technical numbskull, but I can recognise this as some really fantastic work. Would love to see it one day.
 
^^^I'd have to agree with all that. This is a simply amazing project, and I think I speak for everyone when I say I can't wait to see the finished product. The amount of thought and consideration you've put into it just seems impossible to me. And, with that I have endless respect for you and your car.
 
Top