Formula SAE Executive Summary 2nd draft
Formula SAE Executive Summary final draft
Executive Summary
The Formula SAE project started nearly 25 years ago as an informal “mini Indy” competition between college design groups. Today over two hundred universities participate in yearly competitions held in six different countries. The University of Utah design team will be entering the Fontana, CA competition in June 2007. The premise of the competition is that student teams have been hired to build a prototype car which will be marketed to the weekend amateur autocross racer for under $25,000. Scoring will be based on marketability to the target consumer group, racing performance, merits of the design, cost, and ease of manufacturing and maintenance. This report will cover the details and rationale for the team’s design, the specifications of the prototype?, and the research done into the methods that are being employed to complete the design. Because the car will be built for autocross racing the team chose weight, handling, and acceleration as the most important design factors.
The first main design goal is to keep the car as light as possible. To accomplish this, the team has decided to build the chassis and body out of carbon-fiber. Using carbon fiber will permit the chassis to be structurally equivalent to a standard steel tube frame at a fraction of the weight. The team’s chosen design will look similar to monocoque designs used by most universities including previous University of Utah team designs. A monocoque design, comparable to a fuselage, integrates the body and chassis, and carries the major part of the stresses in the outer skin. In contrast, the 2007 University of Utah car will have a separate chassis with a detachable body panel.
The chassis will provide the main support structure and side impact protection similar to a boat hull. The front and rear roll hoops, which are required to be made from steel tube, will be integrated into the chassis and will also provide additional support for the suspension and spring mounts. The body will protect the driver from external exposure but will require much less material to fabricate than the chassis. It will also be detachable to offer easy maintenance access to internal components. This two-piece design will provide the required side impact and rollover protections and structural support but will be much lighter than typical monocoque designs since less material will be utilized. Less material will also mean less cost which, as previously mentioned, will be an important part of the judging.
According to the competition rules, the engine is limited to a 610cc, four-stroke, piston engine with a restrictor on the air intake to limit horsepower. The restrictor also makes it more difficult to maintain a smooth airflow necessary for a consistent air-fuel mixture at different engine speeds. The team has purchased a 599cc, four-cylinder motorcycle engine and will be building a new throttle body and air intake to meet these restrictions. This engine was selected because it is compact in size, light-weight and is designed to provide a broad powerband. The race focuses on acceleration rather than top speed, and this engine will provide the low-end torque necessary for both the autocross courses and acceleration events. In addition, a four cylinder engine, compared to a one cylinder engine with a similar displacement, can pull in air more smoothly through the restrictor and will not require the addition of a supercharger. Keeping the engine normally aspirated will reduce the complexity, weight and cost of the intake design.
The suspension, steering, and wheelbase designs will all be optimized for quick and responsive handling through the winding autocross course. The team has chosen to use an unequal length, non-parallel, A-arm suspension layout. This concept is the most commonly utilized design in open wheel racing. The team decided that this layout would provide the most adjustability in camber changes and roll centers.
Because of the collaborative effort required to complete this project, every team member is expected to have a general understanding of the entire project as well specialized knowledge of a specific portion of the project. Scoring of the competition will not only be based on how well the drivers do in the various races. Members of the team will also be required to defend the decision making process for each aspect of the car and will have to present the marketing strategy to the competition judges. To accomplish our overall goal of winning the competition our strategy is to build a racecar that is light-weight, quick, and responsive in the curves, while being low cost to manufacture and maintain.