Patent ID: 7669796

Claim:
A system for reducing hoop stresses in an airship, comprising an enclosed vessel, said vessel having a fore portion and a rear portion and further having an axis running from said fore portion to said rear portion; and said vessel comprising a flexible skin having an inside surface and an outside surface, said vessel further comprising a plurality of membranes disposed along said fore to aft axis each of which said membranes is attached to a respective perimeter of said skin normal to said fore to aft axis thereby defining a sequence of chambers each of which is defined by a portion of the said flexible skin and at least one membrane; and wherein said chambers are vented chambers and wherein each vented chamber has a bi-directional controllable valve disposed between the inside of said vented chamber and the outside surface of the said flexible skin defining the said vented chamber and said valve being operable to equalize gas pressure between the said inside of said vented chamber and said portion of the outside surface of said flexible skin surrounding said chamber at the said valve.