[Fubeca]

Hi everyone,

I'm pretty new to the site but have been reading every thread I could find regarding aero caps and tonneau covers.

I have a 2006 Chevy Silverado 1500 4x4 and since winter is coming would like to keep the snow out of the bed and off my stuff. I've been considering a regular flat tonneau cover, but would love to be able to increase the truck's aerodynamic efficiency at the same time.

So, when reading through everything, it seems that the design of the cap is important to ensure that it actually improves the airflow.

Initially I was planning on making something fairly straight (easy to make). But am concerned that the transition would be too abrupt between the roof of the truck and the cap.

So the three questions I have are:

1) How much of a radius is required to allow the air to transition smoothly down the "ramp" of the cap - would the image attached be sufficient?

2) Can the transition from the sides to the top of the cap be abrupt, or must this also have a radius?

3) At the end of the day - am I only going to be able to figure out the optimal design by building a mock up and testing it? Or can reasonable assumptions be taken from design images?

Thanks in advance! I am so impressed with all of the knowledge on this site!