In my case the panels would be placed on a small vehicle that has roof space for one panel. The second panel would be placed directly above the first. Going down the road I would have power from the top panel thru an mppt solar controller to the battery. Parked, I would slide the top panel out, exposing the bottom panel to the sun. Providing 2x power compared to driving. Providing a small shaded area adjacent to the vehicle.
Cassones RV in Mesa Arizona had a Winne Travato on the lot with a slick two panel side mount system using German gas shocks to hold and stabilize in the up and down position. The mounting was done with piano hinge. This appears in a youtube video by AZ expert. I'm damned if I can find the video without watching everything on the channel but the videographer James is a good mechanic and takes on some interesting projects.
Also, Everlanders on youtube has this setup. 4 normally visible, expands out to 8 visible. Not sure if they have any videos that directly talk about it.
Figured I'd use drawer sliders. Have been using a set for the ARB fridge pullout the rear for years. Have not failed me yet, and they are loaded heavy when the fridge is loaded. I'll have to find the original invoice and see if they are still available. Thanks for all the comments.
I have a few ot these racks on my vans.
They are designed to tuck ladders flat on top of the van, but swing them down to the side for easy ladder removal.
Not sure how they would work with panels...