USM: Choosing The Right Fasteners To Build An Electric Race Car
How do motorsport engineers find the best fasteners needed to build their race cars?
That’s the question Accu posed to the young engineering students competing in the iMechE Formula Student competition.
The University of Strathclyde Motorsport (USM) team duly responded, giving us a detailed insight at the ‘behind the scenes’ of designing, procuring and integrating the precision fasteners needed to assemble their brand new race car - often needing to find innovative solutions to problems faced as they build a fully electric vehicle for the first time.
Making Connections
Fasteners play a crucial role in any Formula Student team’s build each year, connecting the hundreds of unique parts that all go together to create a working race car. Therefore, it is very important for us to choose the right fastener to fit the application.
At USM, we have been utilising fasteners from Accu for many years after being impressed by the quality, variety, and value offered.
As such, we are keen to share some different uses of Accu fasteners over the years that will hopefully give a small insight behind the thought process of designing and building an electric Formula Student race car.
In this piece, we’re going to discuss five innovative applications where we use different types of fasteners on our car and how we choose the right ones.
Nylon Screws, Nuts & Bolts: Non-Electrically Conductive Fastening Solutions
With the industry wide push for sustainable solutions to engineering challenges - and most relevant in the automotive sector, sustainable powertrain solutions - here at USM we have recently transitioned to an electric powertrain after a period of over 20 years running a combustion engine powered car.
One of the biggest challenges is keeping the electric battery casing electrically and thermally insulated to keep our drivers and engineers safe.
As such, we were in need of a type of fastener that was non-electrically conductive to be used within our battery casing.
Accu have a wide selection of nuts and bolts made from nylon, which fits this application perfectly. These fasteners play a key part in mounting our non-structural parts within the battery case.
We choose a range of M3 and M4 Nylon Nuts and Bolts which are used to hold our PCBs securely in place. The precision and quality of Accu’s specialist plastic fasteners were impressive - with their plastic parts having withstood wear and tear from continuous adjusting, even whilst tweaks were made to our electric powertrain all through its year of testing!
“The electrically insulating nylon fasteners from Accu are imperative for mounting safety critical components in our high voltage battery. As they're insulating, they allow us to secure everything safely without the risk of short circuits, protecting the driver and everyone involved.” - Taylor Phillips (Head of Accumulator)
Imperial Fasteners: Securing The Steering Rack To The Race Car
Being based in a country that uses the metric system as standard, you may be wondering why imperial fasteners are on this list.
Although we stick with the metric system throughout the majority of our race car, there is one area where this isn’t the case for our team – the steering rack.
Through our design phase we found that transitioning to a new steering rack provided a host of packaging and performance benefits. There was only one snag; the rack is designed to be used with Imperial Fasteners.
This added a slight complication in securing the steering rack using our boxes of metric fasteners… Fortunately, Accu stock a range of imperial fasteners which we were able to select the correct size, length and strength very easily through their website – even with the imperial units that we aren’t too used to!
"Being able to streamline our supply lines to fewer suppliers has benefitted the team massively, as less time is spent tracking packages. This frees up labour allowing us to push ahead with the manufacture of USM23. Due to the need for imperial fasteners for OEM parts, Accu being able to cater to all our requirements with their wide range of fasteners is perfect." - Cameron Douglas (Head of Suspension)
Socket Head Cap Screws: From Drivetrain Mounting To Jigging Assemblies
Maybe not as ‘innovative’ in its use case throughout the car, however Socket Head Cap Screws are an integral part of not only our car build, but every Formula Student team’s car build.
You’ll find these types of fasteners on everything from our drivetrain mounting and dashboard to floor panels and aerodynamics devices due to their quick and easy fitment using a standard socket set.
These aren’t just used through the finished car, they are also used extensively in our jigging assemblies to keep the chassis and mechanical systems securely in position while being welded or fitted.
Having access to a range of sizes and quantities to fit each application's exact need has been highly beneficial throughout our car build phase.
Locking Nuts: Avoiding Unwanted Loosening From Vibrations
Although our car isn’t experiencing the jarring vibrations from a combustion engine anymore, there are still harsh bumps and slides that our car endures whilst it's running.
Over time this results in unwanted loosening of our nuts and bolts, so to combat this, we use an abundance of Nylon Locking Nuts.
These components work through the addition of a nylon insert within the nut, preventing any unintentional loosening caused by these vibrations.
We use a variety of sizes of nylon locking nuts on the car from M3 to hold our shock absorber potentiometers in place to M8 to securely mount our electric battery to the chassis.
For specific high-temperature applications, we also make use of Aerotight Locking Nuts. These are made solely of stainless steel and lock by deforming slightly when tightened which increases friction between the Nut and Bolt.
Due to the all-stainless-steel nature of Aerotight Nuts, these components are an excellent variant of locking nut for use in high-temperature locations on the car, such as our wheel assemblies.
Here, the Aerotight Nuts are used to connect our brake rotors to the rotor carriers. After continuous running on track these can reach temperatures of up to 350 degrees Celsius!
We’re confident in saying locking nuts are a must for any Formula Student team so, to have Accu supporting us with hundreds of these for our car is a massive help!
High Tensile Steel: Critical Fasteners For Critical Areas Of The Car
The Formula Student competition hosts a variety of challenges and design criteria all laid out within an extensive 100+ page rule book that every team must comply with to go racing at the competitions!
One of the most relevant rules with our partnership with Accu is the use of “Critical Fasteners” within our race car.
A critical fastener in Formula Student is one which is used within all of the – you guessed it – critical areas of the car; such as suspension and steering systems, chassis primary structure and certain powertrain mounting.
These fasteners must meet specific standards and diameters and must be manufactured from specific grades of material.
"The critical grade, high tensile steel fasteners Accu provides are crucial in order to safely mount our Tractive System and Drivetrain as these components carry high load and are crucial to the performance of the car." - Jamie Kerr (Head of Mechanical Integration)
Although the stainless steel used in most of Accu’s bolts and screws is excellent in almost all use cases, for these critical applications we require high tensile steel fasteners.
These fasteners can take very high loads and are proven to be very durable through all the harsh environments and high loads experienced by the car’s critical parts. Most importantly, these fasteners keep our car legal, safe and ready to race!
Current Progress Update
Hopefully this article has highlighted the crucial nature of fasteners in a Formula Student Race Car as well as bringing to light some interesting and novel features and challenges with our design that call for the broad selection of components that Accu provides.
At the time of writing, our most recent electric Formula Student Race Car - USM23 - is almost complete.
Final alignment work on our aerodynamics package and tuning of our electric powertrain are currently in progress in preparation for our Launch Event on Friday 30th June 2023.
After which, we have two very exciting and competitive competitions we are competing in this summer; Formula Student UK and Formula Student Germany.
The team is fired up and ready to compete and we can’t wait to get our car out on track alongside Accu as a key partner!
Learn More About USM
Want to learn more about the team? Check out their website here:
https://www.usmformulastudent.co.uk/
A huge thanks to the University of Strathclyde Motorsport team for the fascinating insights into how they’ve been using our components to build their electric race car USM23.
We wish the team the best of luck for the two Formula Student events they’re competing in over the coming months.