Description: In Phase I we demonstrated methods to optimize the stitched structure and characterized the permeability of a stitched conformal tank. In Phase II the Phase I results will be applied to a representative X-33 tank. For the Phase II Enhancement we intend to apply all the lessons learned and develop a conformal tank for atmospheric aircraft, specifically a blended wing body. To do this, the tank volume will be sized to meet the target vehicles mission requirements. The structural sizing will consider a full vehicle airframe to account for flight, pressure and crash loads at the interface between the tank and airframe. Using the sized vehicle and tank structure a representative section of the tank will be selected for manufacturing. The section will include complex curvature, frames, stringers and means of attachment to bulkheads and close out ribs. A detailed design of the manufacturing article will be generated from which stitching and cure tooling will be designed. With a finalized design, the Manufacturing Demonstrator Article will be fabricated. This work will advance the state of the art in stitched composites by creating methods to create non-cylindrical pressure vessels that conform to complex aircraft interior volumes, thereby allowing for more efficient aircraft.

Benefits: This technology is intended to enable the use of LH2 for atmospheric flight. The ability to shape a fuel tank to an optimized structure enables the designer to create more efficient flight structures and aerodynamic profiles. With NASA’s policy for Sustainability, this technology is a significant step towards zero-emission flight.

This technology is intended to enable the use of LH2 for atmospheric flight. The ability to shape a fuel tank to an optimized structure enables the designer to create more efficient flight structures and aerodynamic profiles. The global aviation industry has announced the goal of being carbon neutral by 2050. This technology could greatly help that goal.