pnichols wrote:
Below is a link to the Winnebago brochure for our 2005 Itasca Class C.
The last page shows the layout of the internal aluminum framing within the coach walls. Looking closely to see the aluminum framing of the cab overhead, I do not see how the cab overhead structure is going to move up or down, or left or right ... in any motions separate to those of the coach's main living area structure.
Hence, how is the cab overhead going to get jostled around any more, or differently, than the whole coach when traveling?
https://www.winnebago.com/Files/Images/Winnebago/brochures/2005/05-Spirit-bro.pdf
(However, a forward facing cabover window is really going to get blasted by water when traveling in a rain storm - along with the cabover clearance lights!)
When I worked for an Aircraft company I used to watch computer models that the stress engineers would develop and was very surprised at the movement of the aircraft when under load. A 737 model actually looked like a bird flapping its wings several feet at the wing tips. I would imagine that a short class C has a lot less movement but vibration would still be there. From the brochure you posted it looks like your Spirit has corner seams. The 2021 Spirit 22R looks like a partial wrap around and no front window which would prevent the water from hitting that front seam directly. It also has a nice big storage bay in the rear.