This thread is special case of this one : https://www.homebuiltairplanes.com/forums/threads/devfus-foam.32338/ and one special persone I was asked, to design and help build an fuselage of ul class high wing. Now, as a prototype do come fk-9 Happy part - front will be combined - metal tube frame for structural / crash protection. Tail - only composite. So - all from door rear edge to tail - is composite. And yes - it is with some pros and cons. For pros - it is a perfect part to be made in a foil-on-foam mold, possible to mold in one piece. For cons - you have 4 point to connect it to tube frame. But tube frame itself is "main connector for all main/heavy parts". Pros - connector in composite aircraft is a hard thing to design and build Question - which kind of data is necessary for calculations ? Should it be done as stressed skin with some support walls later added ? Or all could be incorporated in a single step using precutted \_/ pieces of foam in one single process ? Like this : As i see it - biggest isuue here would be wall buckling under load. Inspiration/design philosophy - do it nice on both sides, and as fast as possible, by using clever/smart solutions. Should i add here some vision on possible wing building ? I can call it as a corrugated plastic construction, with non-load bearing foam formers.