Hello everyone. I have been trying to think of some practical and cheap airship designs. I have done some calculating, and if you were to have an airship's envelope in a cylindrical shape that is 300' long and 75' in diameter, it would be able to lift approximately around 45 tons if filled with hydrogen as a lifting gas (Not factoring in the atmospheric affects on the hydrogen's density) (Not including the weight of the envelope nor gonadal). Question: If you were to have an envelope of this design, would it require a frame, and if so, what would be the best material to make it out of (Factoring in the weight and cost of said material)? *Note* I do not actually intend on constructing a lighter-than-air aircraft. This is just an interest of mine.