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Rotary Racer Wind Tunnel Testing
This page lists the results of performing wind tunnel tests of 4 quater scale models of different car designs at the UWE wind tunnel on 2006-12-08.
- Car 1: This was the original Rotary Racer car.
- Car 2: A streamlined car
- Car 3: Gareths teardrop like car
- Car 4: A modified version of the original Rotary Racer car with more rounder and tapered front.
Date: 2006-12-08
Ground Plane alone (To be taken way from all other readings)
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | 0.24 | 2.22 | 0.53 |
| 25.0 | -0.03 | 5.6 | 1.55 |
| DragCoeficient |
|
Car 1: Original body, no canopy, steering king-pins.
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -0.73 | 4.03 | 0.92 |
| 24.9 | -2.2 | 10.6 | 2.47 |
| Area |
| ||
| DragCoeficient |
|
Car 1: Original body, no canopy, no steering king-pins.
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -0.68 | 3.77 | 0.94 |
| 25.0 | -2.41 | 9.97 | 2.50 |
| Area |
| ||
| DragCoeficient |
|
Car 1: Original body, no canopy, no steering king-pins, wheels spaced out double the distance (8inches).
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -0.50 | 3.74 | 1.04 |
| 25.0 | -2.10 | 9.92 | 3.07 |
| Area |
| ||
| DragCoeficient |
|
Car 1: Original body, with canopy, no steering king-pins.
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -1.17 | 4.03 | 0.97 |
| 25.0 | -3.55 | 10.75 | 2.48 |
| Area |
| ||
| DragCoeficient |
|
Car 1: Original body, with longer canopy, no steering king-pins.
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -0.09 ? | 3.92 | 0.9 |
| 25.0 | -2.2 | 10.20 | 2.63 |
| Area |
| ||
| DragCoeficient |
|
Car 2: No canopy
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -7.85 | 3.33 | 0.75 |
| 25.0 | -9.3 | 8.8 | 2.32 |
| Area |
| ||
| DragCoeficient |
|
Car 3: Gareths car
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -7.16 | 3.33 | 0.76 |
| 25.0 | -8.90 | 8.75 | 1.75 |
| Area | 0.0171 m square | ||
| DragCoeficient | 0.50 ? |
Car 4: Rounded and tapered front, with canopy
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -6.11 | 3.44 | 1.1 |
| 25.0 | -7.08 | 9.04 | 2.97 |
| Area | 0.0193 m square | ||
| DragCoeficient | 0.49 ? |
Car 4: Rounded and tapered front, with slotted canopy
| Velocity m/s | L (N) | D (N) | S (N) |
| 15.0 | -6.9 | 3.38 | 0.48 |
| 25.0 | -8.24 | 8.91 | 1.31 |
| Area | 0.0193 m square | ||
| DragCoeficient | 0.47 ? |
Results
Car 4's air drag was: 3.3N. Car 1's air drag was: 4.37N. This is a 32% improvement. The kingpins made about a 15% difference on the old car. Car 4 has a larger gap between the front wheel and body and so the kingpins will probably make less difference on this car, but we can probably improve on the 32% by doing something with the kingpins.
It would have been good to have been able to test the following in the wind tunnel:
- Cars at a 10 degreen angle of incidence tio the wind.
- Cars higher above the ground.
- Cars having a concave rear section.
- Different canopy designs.
- How much difference the external motor made on the original car.