Air Force officials have approved X-55A as the new
designation for the Advanced Composite Cargo Aircraft.
The X-55A is a technology demonstrator for the design and
manufacture of future aircraft using advanced composite materials. The X-55A is
a modified Dornier 328J aircraft with the fuselage aft of the crew station and
the vertical tail removed and replaced with completely new structural designs
made from composites using new out-of-autoclave curing techniques. The test
platform contains some 600 accelerometers and stress gauges. Its first flight
was June 2, 2009 at Air Force Plant 42 in Palmdale,
Calif.
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The Advanced Composite Cargo Aircraft makes its first test flight June 2 from Air Force Plant 42 in Palmdale, Calif. AIr Force officials have designated the aircraft X-55A. The ACCA is a modified Dornier 328J aircraft. The fuselage aft of the crew station and the vertical tail were removed and replaced with completely new structural designs made of advanced composite materials fabricated using out-of-autoclave curing. It was developed by Air Force Research Laboratory and Lockheed Martin. (Lockheed Martin photo)
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"We're extremely proud to have been awarded
X-designation," said Barth Shenk, X-55A program manager with AFRL's Air
Vehicle Directorate. "We hope to take this testing to the next phase to
further mature our understanding of composite materials, how they behave in
flight and how they age. This effort may drastically change the way we
manufacture future military and civilian aircraft."
The strength, light weight, ease of manufacture and
corrosion resistance are just some of the composite materials characteristics
Air Force officials want to use the X-55A to explore, Mr. Shenk said.
The X-55A was made possible by a 10-year Air Force Research
Laboratory-led research and development investment called the Composite Affordability
Initiative. Government labs including NASA worked collaboratively with industry
to develop advanced materials and manufacturing technologies, Shenk said.
The ACCA was conceived by AFRL as a fast-track, low-cost
development effort. Working with Lockheed Martin's Skunk Works, it was designed
in 5 months, then built and flown 20 months after the go-ahead. Shenk said it
was built at half the estimated cost of a conventional design of the same size.
Test flights on July 13 and August 8 expanded the aircraft's
maneuver envelope and recorded external aerodynamic flow data.
Phase III of the program was awarded on Sept. 17, to
Lockheed Martin and plans to include fully expand the flight envelope and
characterize the structure, examine reliability and longevity of the design,
and baseline the X-55A as a test-bed for other technologies.
According to Shenk, the X-55A program already has
demonstrated the feasibility of designing and manufacturing large, bonded
unitized structures featuring low-temperature, out-of-autoclave curing. The
fuselage was constructed in two large half-sections (upper-lower) featuring
sandwich construction with MTM-45 skins and Nomex core, bonded together with
adhesive and ply overlays along the longitudinal seam rather than numerous
frames, stiffeners and metal fasteners used commonly in traditional aircraft.
The vertical tail was designed using tailored stiffness technology. These were
joined with an existing Dornier 328J cockpit, wing, engines and horizontal
tail.
Compared to the original metallic components, the composite
structure uses approximately 300 structural parts versus 3,000 metallic parts
for the original components and approximately 4,000 mechanical fasteners
compared to 40,000.
Robyn Dinwiddie of the Air Force Research Laboratory
contributed to this article.
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