Racecars are finely tuned machines designed to be driven on the edge. The performance goal for a racecar is to produce the maximum usable horsepower and translate it efficiently through the drivetrain and onto the soft racing tires gripping the track. At speed, the racecar must use the wings, ground effects, and other aerodynamic techniques to produce the desired amount of grip. The suspension must optimally balance all varying applied loads to each tire, which enables the driver to push the car to its limit. A racecar must be compatible, functionable, and responsive to perform well at high speeds. Overall, the compatibility of the car is measured by our use of system integration. The overall goal for each system leader is to consider their system and how its design affects other systems of the car. All systems depend on one another.
Project Management
Designing a competitive racecar is challenging, but even more challenging is completing every bit of manufacturing, testing, and iteration before competition in May. Throughout the year team leaders must layout a project timeline, meet team deadlines, then execute their goals. Project Management is one of the best attributes of Formula SAE, because it can be applied to all industries.
Computer Modeling, Simulation, and Analysis
A pivotal piece of the design process is first creating a 3-D computer model of the car in Solidworks. We spend an extensive amount of time accurately modeling the car within Solidworks. The allows us to save time during manufacturing while ensuring a higher quality finished product. The use of a 3-D model allows for much more dynamic iterations in the design phase, since changes are just a few clicks away. To optimize component structures, finite element analysis (FEA) software is used. Finite element analysis helps us determine how designs will hold up to mechanical stress and vibration, fatigue, motion, heat transfer, and more factors. Another form of analysis used by the team is computational fluid dynamics (CFD), which allows us to simulate fluid flows for our aerodynamics package.
Aerodynamics
The amount of available grip has many factors; One of the trickiest factors is the optimization of aerodynamic elements. The purpose of using aerodynamics is to maximize the traction with high speeds and during cornering. A sleek, efficient, light, low drag, high downforce package is ideal. The greater amount of downforce available, the faster the lap times will be. Throughout each year, the Aerodynamics team refines the wing elements, making modifications using data from our CFD software STAR-CCM+, on-track testing, and other forms of verification. Additionally, the downforce must be translated in the form of mounting, so the mounts also receive analysis to ensure translation of downforce is at a maximum.
Chassis
A racecar's chassis is essentially a large mounting bracket, made to hold all other systems in place. Our car utilizes a complete carbon fiber monocoque with honeycomb core. Being the main structure of the car, the chassis team works with all other systems to integrate their needs as easily as possible. When designing the chassis, safety requirements, driver comfort, workability, minimizing weight, and performance goals are main considerations. Performance goals of the chassis relate to its stiffness and compliance under loading. To validate performance and safety, many tests are conducted. These include destructive tests to representative test pieces as well as non-destructive tests such as testing for torsional stiffness. The overall goal of the chassis is to connect the driver to the car and allow them to push the car to the limit.
Drivetrain
The drivetrain is the middle man between the engine and the suspension, as it must effectively transmit the engine's power onto the tires. Our means of transmitting the engine's power is with a chain-sprocket system connected to a Torsen T1 differential with a custom aluminum housing. The differential allows for limited slip which is an essential characteristic for our car to equalize the varying wheel speeds throughout the varying road course. Once the power is transferred from the differential, it is then carried to the wheels by along a half shaft. Finally, the half shaft is connected to the rear wheel hubs and wheel centers which spin the tires. Drivetrain components see dynamic loading throughout use, meaning custom parts must factor in all possible load cases.
Electronics
The electrical system encompasses the wiring harness, the ECU (engine control unit), PDM (power distribution module), and battery. The electrical leader is in charge of designing and building a durable, neat and modular wiring harness connecting the ECU and the PDM to the car's sensors and data acquisition module. The harness has to allow for easy troubleshooting and withstand wet conditions. We run a Motec M130 ECU and a C185 Data Logging Display. Any software changes in the ECU are another important part of the electrical system. To ensure the best performance at competition, we can implement launch control and no lift shift when desired. Below, you will see a lie...electrical is really what brings life to the beast.
Engine
An engine is the heart of a racecar, it brings life to the beast. Formula SAE has a maximum displacement of 710cc, so there are many options to choose from like 450cc, 500cc, 600cc, 636cc, and 675cc engines. We currently run a 675cc Triumph Street Triple. When beginning to choose an engine, we look into it's stock horsepower and torque, weight, fuel efficiency, tunability, and size. The first design requirement for the engine begins by restricting all intake air to one 19-20mm washer. Because of the intake restriction, this allows us to design a custom carbon fiber intake which utilizes a 3D mold. Another design consideration is choosing between E85 or 100 Octane fuel. Due to the restriction of air and the high performance we require from the engine, modifications to the cooling and oiling systems are necessary. We developed our own dry sump oiling system which increases engine life and creates additional power. Our Triumph Street Triple also has custom piston with a 16:1 compression ratio, as well as a custom exhaust and muffler system. To optimize performance, we test it on our in house dyno and the engine gets tuned during testing days.
Ergonomics
The ergonomics team designs each component that directly interfaces with the driver such as the steering wheel, pedals, clutch system, seat, safety belts, the braking system, and the steering shaft. To brake it down by each component: the steering wheel must have a logical and appropriate arrangement for the buttons and paddle-shifter, as well as maximum comfort. The steering shaft design should transfer all steering input truly with minimum sloppiness in the steering wheel. A quality pedal design allows the driver to precisely modulate throttle response and effectively give a solid brake pedal feeling. Additionally the braking system must be effective at all temperatures, and be designed around the car's weight. To shift between gears we use the paddle shifting system, but at low speeds we must use the clutch so the engine doesn't shut off. The clutch lever for our car is designed to be usable in a quick fashion. Our seat is made with foam beads to mold to the shape of the driver. Overall, the ergonomics team is responsible for providing the driver the upmost comfort while performing.
Suspension
When designing the suspension of a racecar, you must first start with the tires. Tire testing data is analyzed and then the suspension is designed to maximize the potential of the tires. A key factor the suspension interfaces with is the driver. The suspension must allow the driver to receive feedback and be comfortable to push the car to the limit. The performance goals of the suspension system are primarily related to cornering capability and our car utilizes unequal length, non-parallel control arms with pushrod actuated dampers to achieve these goals. Many of the suspension points on the car are adjustable to tune the car to the track and driver’s needs.
