Solar Car Aeroshell

Team: Erica Francis, Samantha Fronk, Rachel Lee, and Garrett Nagel

Sponsor: Aggie Solar Racing Team

Project Description

Problem: To increase their performance and competitive edge in the American Solar Challenge (ASC), the Aggie Solar Racing Team needs a new aeroshell that is an improvement over the previous shell design, Astra 2020.

ASC Constraints:

  • >4m2 solar panel space
  • Must not exceed 5 m x 2.2 m x 1.6 m in size
  • Allows greater than 100 mm of ground clearance
  • Allows 100 degrees of driver visibility
  • Windshield has an impact strength greater than or equal to 30 kJ/m²
  • Canopy must be positively latched

Functional Requirements:

  • Decrease drag force experienced by car
  • Excess top area for optimal solar panel placement
  • Minimize weight
  • Fit current chassis design
  • Easy to construct

Design Description

Fig. 1 James Bond Design

Fig. 1 James Bond Design

The aeroshell design features four major sub-assemblies: the canopy, the collar, the airfoil, and the oval (see Fig. 1).

Additionally, to improve aerodynamics and manufacturability, the aeroshell is constructed from pre-preg carbon fiber composite panels. The panels are joined together to form the aeroshell as shown in Fig. 2.

Fig. 2 Aeroshell Composite Panels

Fig. 2 Aeroshell Composite Panels

Performance Review

Fig. 3 Solar Panel Inspection

Fig. 3 Solar Panel Inspection

Fig. 4 Wind Tunnel Testing

Fig. 4 Wind Tunnel Testing

Fig. 5 CFD Simulation

Fig. 5 CFD Simulation

Requirement/Constraint Target Threshold Predicted Performance Actual Performance
Solar Panel Surface Area 5 m2 4 m2 5 m2 5.4 m2
Reduced CdA 0.2377 0.2641 0.2377 0.2308
Minimal Weight 69 lb 70 lb 60 lb 66.2 lb
Compliant with ASC Regulations
  • Sizing requirements
 5.0 m L x 2.2 m W x 1.6 m H 5.0 m L x 2.2 m W x 1.6 m H 4.6 m L x 1.6 m W x 1.3 m H
  • Ground Clearance
 > 100 mm 100 mm 197 mm
Manufacturable
  • Manufacturing takes a minimal amount of time
 85 working days 150 working days 85 working days 150+ working days
  • Smooth Finish: 16 μin
 16 μin 32 μin 16 μin 16 μin

Conclusion

Requirements/Constraints Fulfillment

  • The aeroshell design meets all requirements and constraints as outlined in the performance review with exception to being manufacturable within Spring semester.

Lessons Learned

  • Start the build process earlier
  • Plan for when things go wrong
  • Presenting the Aggie Solar Team with a finished, functional product is more important than a complicated design

Recommended Future Work

  • Formula Sun recommends the Aggie Solar Racing Team finish putting the aeroshell together using the constructed composite panels and build plan.
Fig. 6 Autoclave Composite Curing

Fig. 6 Autoclave Composite Curing

Fig. 7 Assembled Aeroshell Bottom

Fig. 7 Assembled Aeroshell Bottom