Quarantine downtime has me no less busy, but I've set aside some time to design and build a deflector for the vertical face of the cap. This will be an intermediate solution to keep in place until more elaborate plans are executed. Basic design goals are:
-Lightweight
-Attach to existing roof rack tracks
-Use as much recycled material as possible.
My recycled material of choice is aluminum, as I have various panels of .040 sign faces and thicker street signs left over from my years in a sign shop. Some manner of angled box-type thing would be an improvement over the flat vertical surface, but I wanted to incorporate a curve for a hopefully better transition to the horizontal roof of the cap. I found a workable solution in an old 700c bicycle rim that was too worn to justify re-lacing for wheel service.
The 622mm bead seat diameter works out to a tick over 12" radius at the outermost edge. They tuck nicely into some 1" U-channel from the hardware store, with .040 aluminum gussets making for a snug fit. 3/16" pop rivets connect the 3-layer (or otherwise thick) junctions, with 1/8" pop rivets doing the job elsewhere. I made three trusses thusly, with center truss 3/4" shorter (from the bottom) to follow the cab roof curvature. I laid them on the .040 sheet to plot out the curve.
