The digital flight control system was compatible with a Research Flight Control System (RFCS) which could be installed when necessary. RFCS capability provided a flexible, reliable and safe means to modify the aircraft control system. The RFCS computer significantly increased computational speed and computer memory.
The XL-1 aircraft was previously used in NASA's Cranked-Arrow Wing Aerodynamics Project, or CAWAP, which provided aerodynamic data for NASA's High Speed Civil Transport (HSCT) research program. The unique cranked-arrow wing shape provided better low-speed lift and handling characteristics than the modified "double-delta" wing used on the Concorde supersonic transport (SST).
The XL-1 participated in NASA's 1995 sonic boom study, in which the aircraft flew 200 feet behind a NASA SR-71 to probe the boundary of the SR-71's supersonic shock wave. The studies helped HSCT engineers to better understand supersonic shock waves in order to reduce sonic boom intensity near populated areas.Fact Sheet Photos Graphics