I have a question about these people who buy a car and then build their own chassis for the car which weighs less (space frame chassis)

Basically my question is, if you put all mounting points in the right place and make the chassis strong enough with good welds can anyone make a chassis without going college/uni?

Everything is self teachable so I am wondering how hard it will be to teach yourself. There is a guy on Street Stylers Southwest who is building a viper kit car which is going to be used as a track car and he has built his own chassis for it and he is self taught.

What other things do you have to take into consideration when building chassis's?

Quote from sam93 :

I have a question about these people who buy a car and then build their own chassis for the car which weighs less (space frame chassis)

Basically my question is, if you put all mounting points in the right place and make the chassis strong enough with good welds can anyone make a chassis without going college/uni?

Everything is self teachable so I am wondering how hard it will be to teach yourself. There is a guy on Street Stylers Southwest who is building a viper kit car which is going to be used as a track car and he has built his own chassis for it and he is self taught.

What other things do you have to take into consideration when building chassis's?

the risk that if you make a mistake during welding and it breaks up... then your life is ..cked

Quote from el pibe :

the risk that if you make a mistake during welding and it breaks up... then your life is ..cked

Spot on.

Don't build your own "lightweight chassis", you'll just end up fail welding one of the joints and end up dead wrapped around a tree.

I wasn't implying that I am going to build one, I was just curious, welding isn't exactly hard once you obviously learn how to do it lol.

Doing it correctly is another thing...

Too much welding can distort the frame because of the heat.

There are three main approaches to building a chassis available to anybody with a bit of common sense. Firstly there's the old fashioned approach of using common sense and doing what seems right, a hard skill to master but in reality all good chassises still have a lot of this going on. You could take the first approach then do some FEA on it (or get someone else to do it) and tune it a bit from there. Or the most common approach is just to make a wild guess and then wonder why your super lightweight special with geometry as refined as an AC Cobra's spits you off the track.

The majority of small scale specialist car design is largely based upon guess work and experimentation, nothing wrong with this but look how many duff cars Colin Chapman produced for every great one. Very few cars are just designed on a computer and work out of the box, it is changing though, for example the JCB Dieselmax had no wind tunnel testing and was largely produced by CNC, very impressive but unreachable at the moment for the hobbyist.

Quote from Scrabby :

Doing it correctly is another thing...

this is extremly true, some amny people say oh welding is hard and i usually say the same but i always say that being able to weld properly and reliably is another thing altogether, my grandad is a welder he used to work as a welder/fabricator on cat buldozer buckets and rippers and also has done decrative wrought iron and steel work for many year but even he takes alot of encouraging when it comes to working on cars or karts etc

unless you have someone who can check every single weld using ultrasound and over engineer everything building your own high performance chassis is a very dodgy thing

Welding looks easy. In fact it IS easy to join two bits of metal by welding - I can do it.

But to make a good weld; one that can withstand cyclic loading, bending, shear, some tension, without inducing stress raisers is very difficult. It's not just a case of turning on the welder, pointing the nozzle at the joint area and pressing a button.

Making a chassis light is quite easy - just use less metal.
Making a chassis strong is quite easy - just use lots of larger tubing and thicker walls.
Making a chassis stiff is never that easy, but just try to maximise the second moment of inertia.

However, making a chassis that is stiff, strong and light all at the same time is very, very difficult. Whilst most 'kitcar' builders probably reduce weight, I'd doubt they manage to maintain stiffness, resulting in a lightweight but soggy car.

Finite Element Analysis. Coupled with the ability to interpret the outcome and the ability and experience to translate it in to an actual engineered chasis.

That's how it's done properly. Of course first of all you have to have someone who even knows how a chasis should be designed initially. Most people just copy exisiting known good designs and try and improve it with use of different materials and engineering techniques obviously adapting it as they go along to account for differences in materials properties etc.

All of which is way out of the grasp of a hobyist. Of course assuming you have the basic skills you can easily knock up something that will hold all four wheels in the right place and allow you to drive it around a track, (anyone that has ever watched scrapheap challenge knows that), but as Tristan has stated making something that is safe and will perform reliably and well is something else entirely.

I believe that Colin Chapman was forever skirting the boundaries involving the critical elements in chassis construction as mentioned by Tristan, hence his race cars being known as 'not very much of very little held together with f***all'
Or suchlike!

Triangles, build lots of traingles, one thing I know is that triangles = good.

5haz is correct, a triangular shaped structure is one of the strongest structures if you know what i mean, im shite at explaining stuff, especially geometry!

yahoo answers agrees as well! http://answers.yahoo.com/quest ... qid=20090212163623AA5yza1

I know loads of people go on about engineering and how you have to know about it before building say a race car, but it must all be self teachable because the first person to discover this stuff had to self teach himself lol.

True but that person probably was very smart (not offending you )

Quote from Scrabby :

True but that person probably was very smart (not offending you )

He probably was, but he may have also been very thick lol.

Like a lot of things, its easy to do, but not easy to do well.

But whats wrong with welding yourself a crude spaceframe from some old iron for a laugh, the result may not be race or roadworthy, but it would be fun and a learning experience, everyone has to start somewhere.

If everybody had the attitude 'its best left to the professionals', then there would be no professionals.

Quote from sam93 :

I know loads of people go on about engineering and how you have to know about it before building say a race car, but it must all be self teachable because the first person to discover this stuff had to self teach himself lol.

The first person to discover this stuff wasn't the first at all. He built on the knowledge accumulated by everyone that went before him. You don't concoct ideas out of thin air. You research and understand what's been done before and then use your newfound knowledge to find a better way to solve the problem at hand. It's called education.

The alternative is to reinvent all of modern engineering from scratch through trial and error, which I'm going to assume right now you won't have the noodle to do. Very few people do.

Quote from sam93 :

I know loads of people go on about engineering and how you have to know about it before building say a race car, but it must all be self teachable because the first person to discover this stuff had to self teach himself lol.

Everything and anything is self teachable. Engineers just think they are something special, that they are far more special than everyone else.

People who are educated properly are different.....because they have access to more updated information, more systematic training and the standard they are expect to deliver are higher, that's why they get better.

"everything can be self taught" is correct if you have unlimited time and money, however it isn't usually the case.

You can't jump from zero to hero and overtake generations of accumulated knowledge in one leap, at least I haver never seen that happen.

simple things are easy to learn your self, just start small build a model of of kebab sticks. then make your own go cart learn how to keep everything strieght even if by chance you get all the welds strong will be no good if you have a small twist in it.......


aim small then slowly get bigger its not something you will learn in a day.

I designed not long ago a V8 Bug one but even my model was a little off so i never made anything bigger.

Quote from sam93 :

I know loads of people go on about engineering and how you have to know about it before building say a race car, but it must all be self teachable because the first person to discover this stuff had to self teach himself lol.

Go the engineering section of your local library.

Read about materials, stress/strain, 2nd moment of areas, stress analysis of simple frames, bending, buckling, tension, loading, fatigue...

If you self teach yourself you'll be ready in about 2015.

Why is there ... at the end of fatigue, is there more lol?

I don't even know where my local library is, wait, oh yes I do, it's next to co-op lol.

Or, I could just download the ebooks about it and not have to bother about the library.

Yes, someone made the first chassis - But have you seen how shit the first cars were? Modern cars have had over 100 years of evolution in them...

Quote from sam93 :

Why is there ... at the end of fatigue, is there more lol?

I don't even know where my local library is, wait, oh yes I do, it's next to co-op lol.

Or, I could just download the ebooks about it and not have to bother about the library.

The ellipsis (...) were indeed because there is more. But there is enough topic material there to keep you busy for a couple of years, and the reading and research will naturally lead to further topics.

ebooks just aren't the same. You can't flick between pages, or have several open right in front of you. You can stick a couple of fingers in other pages so you can flick between them quickly. You can't make notes on them. They are rarely formatted in a way that makes digestion of the content easy (and I don't mean eating them). ebooks (and e-catalogues) are rubbish.

For an example - if you're choosing a birthday present for someone from Argos, is the paper catalogue or the e-catalogue easier to browse through and find suggestions? The digital revolution has not managed to make paper books, magazines or catalogues redundant yet, as they have not been bettered.