1. Vehicle Dynamics Part I: An Aerodynamic Odyssey
Jeremy Losaw
Advised by Professor Ann Anderson

2. Introduction Purpose How did I do it?
Characterize the flow over a radio controlled vehicle with a NASCAR style body
How did I do it?
3 Methods
Force balance
Pressure taps
PIV (Particle Image Velocimetry)

3. Lift - Dr. Jekyll
Lift
Downforce (negative lift) increases a tires capability to produce cornering force
Down force stabilizes vehicles at high speed
Improves braking performance

4. Drag - Mr. Hyde Reduces top speed
Helps chasing cars to draft and catch up
Reduces effective power of engine

5. Why RC Cars Perfect size for the Union wind tunnel
Can outfit with many body styles
Fast enough that aerodynamics can have an impact on their handling

6. Juxtaposition
Make changes to spoilers each to see effects
4 spoiler configurations
full spoiler
no spoiler
2 alternate geometries
Characterize flow over cars and analyze the results based on the needs for each vehicle

7. Tools Force Balance Pressure Taps PIV Cumulative lift and drag
Local performance characterization
PIV
Full field validation

8. Spoiler Geometries
Regular Spoiler
Spoiler A
Spoiler B

9. The Inspiration

10. Lift Coefficient
Cl = Fl/ (.5 AV2 )

11. Drag Coefficient
Cd = Fd/ (.5 AV2 )

12. NASCAR Pressure Distribution
High pressure at the front and over the trunk
Local flow acceleration at the front of the roof

13. Spoiler Comparison Higher upstream pressures with full spoiler
Low pressure with no spoiler
Spoiler B has less of and effect on upstream pressure i.e. less drag

14. PIV Local acceleration consistent with pressure data
Stagnation point on nose
Recirculation zone behind car

15. Conclusions
RC racecars are suitable for generating qualitative results of the full scale
Each of the three methods served to validate each other
There is only a slight difference in performance for the different spoiler geometries, but Spoiler B seems to have a slight performance edge

16. Special Thanks
Professor Anderson
Stan Gorski
Pat Tuccillo
Jim Howard