Using 2″ thick H35 foam obtaining this piece and cutting it to size was quite a task. I first had to disassemble my 2 axis full size flight simulator to make room for the tub on saw horses.

After a trial fit, I laid out all the inside measurements and cut outsides of the foam. It takes quite a lot of weight at this stage to bend it to the fuselage bottom shape.

Any weights do the job

Expensive foam slab

Getting a fit