The advanced composite cargo aircraft (ACCA), developed by the US Air Force research laboratory and supported by Lockheed, has received the air force designation X-55A.
The X-55A, which is used as a technology demonstrator for the design and manufacturing of future aircraft through the use of advanced composite materials, has evolved from the Dornier328J aircraft by replacing the fuselage aft of the crew station and the vertical tail with new structural designs.
The fuselage was constructed in two large half-sections featuring Nomex core sandwiched by MTM-45 skins, which are bonded together with adhesive and ply overlays along the longitudinal seam, while the vertical tail was designed using tailored stiffness technology.
The composite structure uses approximately 300 structural parts compare to 3,000 metallic parts for the original components, while about 4,000 mechanical fasteners as against 40,000 in the original aircraft.
Air Force Research Laboratory's air vehicle directorate X-55A programme manager Barth Shenk said that strength, light weight, ease of manufacture and corrosion resistance were just some of the composite materials characteristics that air force officials want to use the X-55A to explore.
Test flights of the ACCA were conducted on 13 July and 8 August 2009, which expanded the aircraft's manoeuvre envelope and recorded external aerodynamic flow data.