Designing a Race Car with Open Source Tools
Channel: linux conf au 2017 - Hobart, Australia
Date: 2017-01-23

Dave Chinner
http://linux.conf.au/schedule/presentation/45/
After I ran out of talent and had a high speed encounter with an immovable object in May 2016, I needed to build a new race car. The car I crashed is
somewhat unique for many reasons - it's a Locost Clubman. The car has a space frame chassis, based on the original 1957 Lotus 7 designed by Colin Chapman. In the early 1990s, Ron Champion published a Haynes manual titled "Build your own sports car for as little as £250" which was a step by step guide to fabricating and building the entire car. Essentially, it was the source code for the car.

To Locost enthusiasts, this is known as the "book chassis". It is simple, and very similar to design of the original Lotus 7.  Over the past 20 years, many people have built, broken, analysed and improved on the chassis design. Mechanical engineers have published PhDs using finite element analysis to identify weak points and model stronger chassis designs. There are interweb forums full of people who have built these cars and they share mods, designs, fabrication techniques, etc. In the car world, it's a microcosm of open development and improvement.

In analysing the corpse of my car - mostly based on the book chassis - I realised that I needed to make something far stronger. Not just for safety reasons, but also to handle the suspension loads generated by modern race tyres and ludicrous power and torque of my race spec engine. The challenge I face is whether I can design a chassis with open source tools on my laptop and then build it in my workshop.

Are the open source 3D cad tools capable of building a complex space frame
chassis? Can I get an open source finite element analysis software to perform strength and failure analysis and get sane results? Can I design all the parts I need and send them to 3rd parties to get them laser cut, bent, fabricated and delivered to my door? Can I integrate my little CNC milling machine into these tools (i.e. CAM) so I can rapidly fabricate prototypes and iterate designs? If the open source tools exist, is it even possible to make them work together in a sane way? What tools have I had to write myself? What landmines will I step on?

I really don't know - by the time January and LCA rolls around I might have a car built, or I might have a pile of scrap metal and broken, twisted dreams. All I know is that I'm going on an adventure in open source land and I will have fun finding out where it takes me. Maybe you will, too.