Teardrops n Tiny Travel Trailers

Hi Guys, still doing some designing here, just got a couple of quick questions.

Ive designed my teardrop so it can be skinned with 4 4x8 sheets of aluminium (1 for each side, 1 for roof, one for hatch) . As a result my hatch will have a curved length of 5ft ish. Its a standard 4ft wide TD.

I intend the ribs to be 3/4 ply, 1 1/2" deep. It'll have 1/8 ply top and bottom of the sandwich and alu top.

Will inch and a half ribs be beefy enough to support 5ft length 4ft width?

The math says it will. Seen many hatches made to those specs.

That is how I constructed my hatch. The "ribs" are 1-1/2" deep. On the sides I used two thickness of 3/4" plywood. The interior ribs are one thickness. The framing is skinned with 1/8" plywood. I can't say exactly, but my hatch is 6' to 6-1/2' in length.