Three-dimensional gore design concept for high-pressure balloons

A new design concept, named three-dimensional gore design, is investigated for the development of a large super-pressure balloon capable of carrying a heavy payload. The theoretical and experimental studies are contrasted wit h the conventional natural shape balloon design. Each gore of the three-dim ensional gore balloon has a bulge of small local radius between adjacent lo ad tapes. This bulge is obtained not by film elongation but by adding exces s film in both the circumferential and meridional directions. The longer ed ge of the gore is attached to the shorter load tape in a controlled shorten ing ratio. The film tension is zero in the meridian and extremely low in th e circumferential direction in proportion to small local radius of a bulge. In addition, the maximum pressure of this balloon does not depend on the b alloon volume. Test balloons of several sizes have been manufactured to con firm the feasibility of the three-dimensional design concept. Indoor full i nflation tests and a flight test of these balloons have been performed succ essfully.