Products and Design

How Warrior Racing Uses 3D Printing for Formula SAE

Recently we told you about how Brandon Horsch (a.k.a. AgentArrow) makes customized models for the T’au Empire in Warhammer 40,000. Brandon is also an engineering student at Wayne State University in Detroit, and an active member of the school’s Warrior Racing team. Here Brandon explains Formula SAE racing and the different ways his team uses 3D printing to compete, from bespoke parts to visual aids.

What is Warrior Racing?
Warrior Racing is the Formula SAE team for Wayne State University. Formula SAE is a STEM-based series which tasks teams of university students to design, build, test, and compete with a small-scale formula-style race car. We compete against other universities from around the world.

Steering wheel has a carbon fiber base with integrated quick-release and inset buttons for our shifting paddles into the base. Grips are printed in Elasto Plastic so that they have some flexibility and squish slightly when gripped, but still provide firm support.

How did you get involved in Warrior Racing?
I had just finished my final year in the FIRST Robotics Competition when I discovered the team during freshman orientation. I grew up loving cars and living near a racetrack, so Formula SAE seemed like a logical next step.

How do Formula SAE competitions work?
Each competition has a series of static and dynamic events. Static events are presentations about vehicle design, the team’s business structure, and the cost-effectiveness of the build.  Dynamic events include a short drag race, a figure 8 skid pad, a timed autocross, and a combination endurance race and fuel economy evaluation.  Final team rankings are determined based on cumulative scores across all of the events.

How big are Formula SAE cars?
Smaller than Formula Ford or Formula 1, but still large enough that up to a 95th-percentile American male can fit in one and drive it. They have an approximately 60-inch wheelbase and are typically 80 to 100 inches in total length.

Throttle pulleys printed in Stainless Steel to test multiple cam profiles.

What is your role on the team? 
I wear a variety of hats. I’m the head of our frame, body, and ergonomics subsystems as well as our CAD lead, PDM server manager, and 3D designer. My responsibilities include designing our tube frame and testing its chassis stiffness, designing and manufacturing our body, seat, headrest, steering wheel, and safety harness mounts.

I’m also in charge of modeling, exporting, and doing any finishing work or painting of 3D printed components and creating any computer generated animations we use to promote the team.

Lastly, I was the first in our team’s history to instate a CAD standard and a required competency level for all students designing parts for the car, and I constructed the team’s first ever complete vehicle 3D model. As a result, I am now responsible for creating and maintaining the master model of our vehicle and solving any issues we have with file management throughout the season.

How did you learn how to design in 3D?
I started in high school when I joined the FIRST Robotics Competition team. I started learning how to create models of robot components and then combine them into complete assemblies in Solidworks. We would then use drawings created from those models to machine finished parts. By my senior year I had fallen in love with the virtual side of the process and had progressed to become the team’s CAD lead. From there I taught myself some of the other features Solidworks offers which are more applicable to design and less so to the kinds of machining we would do for our robots.

What was the most difficult challenge for you when delving into 3d modeling?
The transition from basic features like extrusions and cuts into complex geometric features like lofts and surfaces was my most challenging obstacle.  There are so many degrees of freedom when working with surfaces, lofts, and the like which can lead to very undesirable results if constraints and guides are improperly defined or overconstraining.

You 3D printed scale models of different chassis designs for Warrior Racing. Why were those useful to your team?
One of the places we earn points at competition is the design event, where students bring their car before a panel of industry professionals and motorsports experts and proceed to justify every decision, from initial goals to final vehicle.

Each 3D printed is a scale model of the frame for a vehicle we used in competition, going as far back as 2014. I have served as our frame lead for five years now, and I use the printed frames to display the progression of our designs across the years as the team refined its analysis methods and better defined its quantitative goals, and as I grew as a designer.

One key metric of a vehicle’s frame is its torsional stiffness, or the vehicle’s resistance to twisting in a corner or while hitting a bump. Weight is always the enemy, and the frame becomes a balancing act of trying to make a structure which is sufficiently stiff while also not excessively heavy. During the event, I can hand these to a design judge and they can feel the relative stiffness difference from year to year by twisting the models in their hands.

As part of my presentation I also have load path visualizations of a surface model of our chassis. It is the same size as the model, allowing me to set the model on top of the surface visualizations to display how effectively our frame tubes are placed to efficiently distribute expected loads.

How many parts of your race cars do you fabricate with Shapeways? With other forms of 3D printing? What other ways do you make these parts?
We use Shapeways for a variety of bespoke and prototype components, including but not limited to: Dashboards, steering wheel electrical covers and shifter paddles, throttle pulleys and axles, transmission-side shift levers, oddly shaped mounts and brackets, and relay/fusebox enclosures.

Intake restrictor printed in White Strong & Flexible plastic.

We have a league-regulated intake restrictor diameter and use White Strong & Flexible plastic, which we then finish and smooth on the inside to reduce boundary effects. This allows us to design a restrictor which has ideal converging and diverging cones to meet the restrictor rather than just a simple restrictor plate, which is the standard in motorsport. We can also integrate our throttle body into the restrictor and include brackets for mounting the throttle pulley, return springs, and throttle position sensor along with cable management for the throttle cable all in a single part. This reduces manufacturing time and combines multiple difficult to manufacture parts into a single component.

One of our sponsors, DynamikIllu51ons, custom fabricates a brake light for us that features a housing and lens from Shapeways.

By printing the housing in black Black Strong & Flexible plastic and the lens in Transparent Acrylic plastic, we have a custom light housing solution which snaps together easily, secures with four M3 flathead bolts, and is watertight. It also mounts to our intake manifold with just two bolts.

We have one major component which is frequently made with the use of 3D printing but not through Shapeways: our intake manifold, printed using a proprietary plastic from Synergeering. This season, we have also begun to acquire our own ABS/PLA printers to help speed up low-volume prototyping.

Steering column gearbox printed in black PLA.

Are you still a student, or have you graduated?
I’m still a student for a few more months — I’m about to graduate.

Do for work? What kind of work do you want to do?
I work in the design engineering department of Pratt & Miller, a company most famous for its racing heritage. Pratt & Miller is the factory outfit for Corvette Racing and Cadillac Racing, and is heavily involved in every facet of GM’s motorsport programs.

In the future I would like to move into our aerodynamics division to help craft the intricate aero packages featured on our race cars.

Racing is in my blood, and I don’t envision it ever disappearing from my life. I will always be involved in some form or another. To me, building race cars is building my future. It’s my passion, my drive, and a constant learning experience.

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