Aerodynamic Design and Analysis

The aerodynamic package was designed to be relatively simple, because of limited time for both design and manufacturing. The main aim of implementing an aero package was to enlarge the boundaries of the G-G diagram, i.e. to generate downforce, which would result in lower lap times. Other goals were cooling enhancement and achievement of aerodynamic balance (i.e. neutral behavior in terms of car handling).

Car Model with Aerodynamics

Lap Simulations:

Lap Simulation Data Comparison with and without Aerodynamics

The concept of Aerodynamics was initialized by validating the need for an aero package. Lap simulations were performed on Optimum Lap which showed an improvement of 1.8 sec in each lap when compared to the car without an aero package. Limiting value of coefficient of drag was calculated to be 1.33, considering the engine power. The aim was set to design the components to produce -3 coefficient of lift within the limited value of drag.

Aerodynamic Component Design and Analysis:

Airfoils producing high lift and high Reynolds number were selected. Various airfoils were simulated and E423 airfoil was chosen. Designing was started with the rear wing and iterated to reach the optimum value of forces. The front wing was simulated in three sections, where the sections were designed to enhance cooling, increase the efficiency of the rear wing and under-tray and the outermost section to reduce the drag of the wheels. The undertray has side skirts which give downforce as well as reduce drag of the rear wheel. The side-pods were modelled to collect air from the nose and front wing to enhance engine cooling and provide a high pressure region for the air intake.

E423 Airfoil Model​
Rear Wing Geometry
Rear Wing CFD Analysis
Front Wing CAD Model
Front Wing CFD Analysis (Top)
Front Wing CFD Analysis (Bottom)
Undertray CFD Analysis (Bottom)
Undertray CFD Analysis (Top)

Complete Model Simulation:

Center of pressure position was determined such that it balanced the Center of gravity of the car to yield a balance of 50:50.The components were further iterated and optimized to achieve an aero balance of 57% in the front and 43% in the rear. The aerodynamic CAD model was analyzed at different yaw angles, ride heights and pitch angles to determine the changes in the forces which will be acting during dynamic conditions and, minimize their effect. Coefficient of drag of 1.149 and coefficient of lift of -2.86 was achieved from the final simulations

Aerodynamic simulation CAD
Virtual Wind Tunnel

Mesh of the Model (Trimmer)

Result: (1) Pressure Variation
Result: (2) Velocity Magnitude
Result: (3) Streamline

Drag Reduction System:

To further improve the timings and not limit the engine power on straights, a drag reduction system has been implemented. Drag reduction system on the rear wing has been designed to increase the car acceleration and speed on the straights. The change of angle of attack was calculated such that, the center of pressure balanced the shift of center of gravity at 1g acceleration. Reduction of 90N of drag is achieved through the drag reduction system when CFD analysis was done at 20m/s. Aerodynamic effect is validated on the track using linear potentiometer sensors, which were used to measure the ride height of the car and calculate downforce from it.

Pneumatic Circuit Diagram of Drag Reduction System​
Drag Reduction System Geometry​

Manufacturing:

The manufacturing process chosen was vacuum bagging. The parts produced were light in weight due to all the excess resin being drawn out and an optimum fiber to resin ratio was obtained. Core material was used in parts where stiffness was required. This ensured stiffness without increasing the weight of the part. Three point bend test was done on laminate samples varying in resin content and using different core materials. Manufacturing was done based on the results obtained from the tests. Accuracy of parts was obtained by using CNC machined molds. This also reduced the finishing time required for the molds.

Vacuum Bagging of Aerodynamic Components

Get in Touch

shakshi_himmatramka@berkeley.edu

+1 (510) 990 1432