I am in the planning phase for an RC aircraft which will include a helium envelope, and I'm having some trouble researching the optimal materials and adhesives to build it.The envelope will be a prolate spheroid (football shape) with a length of 2 meters and a diameter at the widest point of 0.4 meters. The envelope, meant to hold helium, will be pressurized and not rigid. I have decided on maybe using mylar foil from hardware stores or using a space blanket. The problem is, mylar can't be heat sealed with a household iron. I'll have to find an adhesive that will leak helium as slowly as possible. Maybe some sort of epoxy?Otherwise, I'd like suggestions for materials with lower density than mylar and that are heat sealable and helium resistant.Also, I have no idea how I would inflate/deflate the envelope or make/find reliable valves. via /r/DIY https://ift.tt/2lWv3hG
