USU Mini Baja 2025
Team: Tony Daniels, Eric Lapray, Alan Merritt, Travis Kunzler, Spencer Lorrigan, Brock Nielson, Kale Vorwaller, Victoria Kemeny, Ben Johnson, Henry Shaw, Will Loveland, Matthew Hope, and Benjamin Shunn
Sponsor: USU COE
Project Description
The purpose of this project is to design a competitive off-roading buggy to compete in the Baja SAE Arizona 2025 competition. Competition success is determined by a combined score from the dynamic and static competition events including a cost reduction report, design review, acceleration test, sled pulling capabilities, and overall endurance.
Design Description
Frame
The frame was designed with a tilted rear roll hoop, flared-out side members, and a symmetrical rear frame.
Hubs and Spindles
The hubs and spindles were redesigned to remove rear outboard brakes and accept ATV ball joints.
Drivetrain
The drivetrain was edited for better CVT spacing and ratios and featured a limited slip differential and dog clutch to improve/ engage or disengage 4WD.
Brakes and Ergonomics
The rear brake was redesigned to incorporate a single, center-mounted rear brake. A new seat design allow for more lateral support to the driver.
Suspension
The Baja Buggy suspension consists of shocks, control arms, bushings, and ball joint connectors. The design focus this year was to redesign the suspension to utilize a double wishbone geometry, mount the shocks to the lower control arms, and remove Heim join connections.
Performance Review
| Requirement | Target | Threshold | Method | Predicted Performance | Actual Performance |
|---|---|---|---|---|---|
| Time to accelerate ot 100 ft | 3.9s | 4.4s | ΣF = ma | 4.7 s | 5.4 s |
| Wehicle Weight | 380 lb | 435 lb | Solidworks Scale |
419 lb | 435 lb |
| Turn Radius | 85 in. | 100 in. | Solidworks | 95.5 in. | 95 in. |
| Ground Clearance | 10 in. | 8.5 in. | Solidworks | 10 in. | 11 in. |
| Suspension Total Travel | 12 in. | 9.5 in. | Solidworks | 10 in. | 12.75 in. (limited to 11.5 in.) |
| Number of repairs required | 0 | 3 | FEA | 3 | TBD |
Conclusion
Although, we did not meet every goal set, the vehicle was completed with sufficient time to perform test driving which allowed us to optimally tune subsystems and improve weak points. Overall, the team produced a quality vehicle that handles well and behaves as predicted.
Lessons learned include integrating early with other sub-teams to ensure that everything fits together. Recommendations for future work would be to make minimal changes to successful subsystems (chassis and suspension). Focus your early design efforts on the drive train and CVT. Work hard to make time for testing.