Scratch Build: 1/43 Roadster

Hey all,

I thought i'd share this little project with you. It's a project that i've had to do for one of my pieces of coursework at University. The brief was to design and machine a 2-seater open-top sports car that fits into a block 50mmx50mmx100mm using 3D CAD software and a 3-axis CNC machine. It could only be a single piece, and did not have to include wheels. It was also supposed to be 'thin walled' with a thickness of around 3-5mm.

So first i did a quick design sketch of the car that was in my head. I decided to do a wind deflector instead of a full windscreen because with 3-axis machining, a raked windscreen would have become a big wedge of material and look very un realistic.

http://img511.imageshack.us/img511/2930/dsc00183ig9.jpg

I then started doing the CAD model. This took a few weeks and was very difficult. It would have been easy to do a car, but very tricky to get it to resemble the sketch. A few things had to become thicker because we were told that we couldn't make the model any thinner than 3mm as it would probably break.

I also decided that i should add some wheels to it. I found some perfect ones in a lego kit and tried to figure out how to fit them. I settled for a single post of the same diameter as the diagonal distance between the lego pimples. I also modelled the wheels in the CAD software to ensure that i could get them to fit correctly. My lecturer was impressed because no one had ever tried to fit wheels to their car in the 7 years that the course had been running! He was also dubious as to whether it would work though.

http://img138.imageshack.us/img138/5398/dsc00232yl5.jpg

And this is the finished car design in the Cad software complete with wheels. This took several weeks to get to this standard and i'm quite proud of it :)

http://img249.imageshack.us/img249/3647/trial13vw1.png

http://img104.imageshack.us/img104/1270/trial12cs3.jpg

I'll post the results of the machining later. At the moment the machined model is encased in latex which will become the production mould. i'll then have 2 copies of it made out of plastic. one for me to keep, the other to hand in. I'll be breaking out the airbrush to paint it as soon as the plastic part is ready!!

wow, thats gonna be awesome to see when all done, hope it all goes well for you and you get a good grade on it.

You better copyright the design before Gio et al nick it for Scuderia Labs :)

You better copyright the design before Gio et al nick it for Scuderia Labs :)

I wonder what motivated you to post this remark.

Nice work! I'm an engineering student too, where are you going to school? I haven't gotten to take a CAD class yet, but should be next year. I'm looking forward to seeing how your project works out!

I wonder what motivated you to post this remark. Nothing, it was just a joke (as I indicated). I remember Gio showing us some of his amazing looking designs and how they can be fabricated, and this one reminded me of that story. Sorry if I gave the wrong impression. Like you guys I love edgy designs, and actually, it would be really cool to see someone turn one of these into an exotic kit.

looks great! do you get to keep the mold? if so, there may be a resin kit, no?

Thanks for the great comments guys :-)

Joe, I go to University of Birmingham in england. I'm only getting to do a project as exciting as this because in my 4th and final year and a took this as a specialist option. Only 7 of us are in the class!

rsxse240, I get to keep a resin copy of the car, so i could quite easily repeat the moulding process with latex. Unfortunately i dont get to keep the latex mould made at university though. My lecturer is very keen to keep hold of this one beacuse it's a bit different. As for a resin kit... i cant imagine many people would want to buy something like this!!!!

...Update time.

This is pretty image intensive, so here goes.


This is the model being machined on the milling machine.
http://img137.imageshack.us/img137/4128/dsc00212sk9.jpg


This is the finished bottom half...
http://img84.imageshack.us/img84/9153/dsc00217od9.jpg

...which was glued onto a sacrificial block to have the top machined.
http://img233.imageshack.us/img233/513/dsc00221tj7.jpg


The car after it had been machined
http://img131.imageshack.us/img131/2453/dsc00224ws0.jpg


And sitting on its wheels after light sanding
http://img263.imageshack.us/img263/2061/dsc00228hq1.jpg


and the rear
http://img221.imageshack.us/img221/7254/dsc00229nf4.jpg


and the bottom (complete with bodged lego at the rear. I knew this would happen when i was doing the CAD model, but i preferred to have to cut the lego than lose the diffuser at the back)
http://img263.imageshack.us/img263/6609/dsc00230oi9.jpg


I’m very, VERY pleased that the lego fits as well as it does. It literally pops on and stays on without glue or excessive force. Just like a real lego part!

Hope you like it :)

That is awesome. You have done a great job integrating the Lego wheels. Well done!

Kurz