Roof Rack Drag Coefficient

The best position for a short roof rack is at the most rear position on a vehicle.

Roof rack drag coefficient.

Use of roof racks requires vehicles to expend more energy due to aerodynamic drag. While roof racks are very useful in carrying extra storage on a vehicle they also increase the frontal area of the vehicle and increase the drag coefficient. As you get ready to hit the road this summer with the kids loaded inside and the bikes strapped to the roof of your car you may want to stop and consider that the roof rack on your car may be. 39 mpg thus the cargo box on the roof increased fuel consumption by about 5 compared to the baseline.

Defender decreases the vehicle s aerodynamic drag by roughly 8. The secret to reducing the noise from a roof rack is by either diverting or disturbing the airflow around the cross bar. 40 mpg roof mounted thule xtender 739 ski carrier with skis. According to message boards across the internet that s a rather conservative estimate.

6 0 l 100 km approx. According to the epa a good rule of thumb is that a loaded roof rack reduces fuel economy by five percent. The net drag coefficient yes there s a formula for that naturally depends on your vehicle and what you re carrying but the effect on fuel economy is unequivocally negative. Acting on the bottom surface of the overhang in combination with pressures acting on the top surface.

While roof racks are very useful in carrying extra storage on a vehicle they also increase the frontal area of the vehicle and increase the drag coefficient. 5 9 l 100 km approx. Leeward roof p 23 psf 0 85 0 6 11 8 mwfrs roof overhang pressures asce 7 only addresses the windward overhang specifying the use of a positive pressure coefficient of c p 0 8. The use of roof racks and roof top tents require vehicles to use more energy due to aerodynamic drag.

The addition of an unloaded roof rack can increase fuel consumption with roughly 21 for the land rover defender and 26 for the toyota hilux bakkie. While there have been studies of their impact on individual vehicles depending on the configuration the fuel consumption penalty can be 0 to 25 percent on passenger cars this is the first study to estimate impacts at the national level. While there have been studies of their impact on individual vehicles depending on the configuration the fuel consumption penalty can be 0 to 25 plus. This is because as the air flows over the top of the vehicle following the smooth lines of the hood and windshield then collides with the roof rack and causes turbulence.

For the leeward overhang the coefficient for the leeward. 5 6 l 100 km approx.