Monthly Archives: December 2012

Mazda Miata Consultation

The first cfd consultation of Hancha Group. A Mazda Miata that races in SCCA Solo and track days wants to know whether aerodynamic changes actually helped performance.  He also wants to look into other aerodynamic performance changes.

actualPictureActual Picture of Car

s_2_cfd_modelCFD Model (No front splitter and no wing)

meshQuality_2Mesh Quality on Surface

The first analysis is of a stock Miata at stock ride height.   This was just for shear curiosity and to compare to the rest of the runs.

cd = 0.36

cl = 0.27

s_1_pressure_plot_1

Pressure Plot of Stock Miata

s_1_velocity_plot_1

Velocity Plot of Stock Miata

The next analysis was of a stock Miata lowered to have a 4 in ride height.  This was how the looked before the additional aero.

cd = 0.41

cl = 0.08

The results were as expected.  Lowering a vehicle will increase the downforce by increasing the velocity below the vehicle.  This does however increase drag.  The aero balance did not change between the runs.

s_2_pressure_plot_1

Pressure Plot of Lowered Miata

s_2_velocity_plot_1

Velocity Plot of Lowered Miata

This is all for now….currently running the current setup on the car to compare to it to the lowered Miata.  Stay tuned for more on this project.

Update on 01.14.2013

This project has been done for a little while. I am just now getting to the finished results.  The project was successful.

The next analysis was on the current cars setup.  The current car has a front splitter and a dual element rear wing. This setup did increase drag, as expected because of the rear wing. The big benefit that can be seen is the coefficient of lift.  The Miata is now making downforce!  Good news since drag currently isn’t the big concern.

cd = 0.51

cl = -0.93

s_3_pressure_plot_1

Pressure Plot of Current Setup

s_3_pressure_plot_4

Pressure Plot Under Rear Wing

s_3_velocity_plot_1

Velocity Plot of Current Setup

To improve this setup, the Hancha Single Element Wing was used instead of the dual element wing.  Single element wings are better to use if you can meet the downforce required because they will have less drag.  Now if you cannot meet the downforce required, duel element wings would have to be used. This setup improved the performance by lowering drag and increasing the downforce.  This is a double win by increasing the efficiency!

cd = 0.48

cl = -1.00

s_5_pressure_plot_1

Pressure Plot Improved Car

s_5_pressure_plot_6

Pressure Plot Under Rear Wing

s_4_velocity_plot_1

Velocity Plot of Improved Car

This setup still isn’t perfect.  The wing is stalled in the center, which can be seen in the pressure plots of the car and the wing.  The picture below shows the deadwater behind this section of the wing.  Improvements are still in the process.  This car will be getting one of the prototype single element wings!

s_5_stream_3

Deadwater in the Center of the Wing