Low cost fabrication of HOPE-X all-composite prototype structure

Two strict requirements were to be adhered to in the development of HOPE-X: to shorten the manufacturing lead-time and to reduce the fabrication cost for the lightweight prototype structure of HOPE-X. To meet these requirements, the design team adopted an all-composite monocoque structure instead of a conventional aluminum skin, stringer-frame structure. The all-composite structure was made of several large parts in order to reduce the total number of parts. These large parts were made by using the non-autoclave curing technique and assembled by bonding into a monocoque structure. The high-accuracy large lay-up tool and the custom-made oven played important roles particularly during these manufacturing processes, leading to reduction in both lead-time and cost. The structural design and the manufacturing strategy for the prototype structure are described in this paper. The development of the lay-up tool and the oven, which helped to realize low fabrication cost, is described here.