Teardrops n Tiny Travel Trailers

Can someone please explain how someone gets curves like this for their frame? Is it similiar to the hatch on a teardrop?

It can be done with plywood, by fitting sawn pieces of dimensional lumber together, or by laminating thin strips of wood together.

In your photo it appears that the frame was sawn from lumber and placed on a laminated strip.
The joinery is unclear overall. It may be two sets of pieces overlapping and screwed together, or it could be they used splines or lap joints.

Rob

I like cutting the curved framing and half lapping the joints.

A lot of older campers have plywood strips veneered around the curve and some just have short blocks scrapped in along the curve. A lot of the wood seems to be there just for nailing because the structure of the camper is carried by the interior sheeting, cabinets, outer skin... it's more of a composite structure.

Yep, it's important to recognise that a camper is not a house - the framing does not need to be self-supporting since all the strength is in the continuous plywood. The framing is just there to connect two bits of plywood together. If the framing can stand up on its own, like the photo above, it's overbuilt.

If you could get 20x40ft sheets of plywood, houses wouldn't need self-supporting framing either.