Aerodynamic Coefficients
C_D: 0.331 +/- 0.011
C_L: -0.249 +/- 0.003

Results: It was surprising that this configuration increased the drag of the base model more than any other addition. We believe that this increase in drag was caused by the redirected airflow around the sloping extension. As the flow follows the extension downward toward the bed of the truck, the air impedes upon the tailgate, causing the increase in drag. This theory has been left untested and we recommend a flow visualization study to confirm this hypothesis.

The top image is a picture of the truck with the new sloped cab addition. The graph below shows the convergence of the drag coefficient as Reynolds number is increased.