ACCA first flight breaks new ground

Lockheed Martin will work through November to expand the flight envelope of an experimental aircraft testing new composite materials that could revolutionise aerospace manufacturing.

The Advanced Composite Cargo Aircraft (ACCA), which is likely to receive the X-55 designation, also tests a new collaboration arrangement between Lockheed's Skunk Works division and the US Air Force Research Laboratory (AFRL) that may spark a wave of new flying technology demonstrators, programme officials say.

The envelope expansion phase began after a successful test flight on 2 June of the ACCA platform, a heavily modified and widened Dornier 328Jet, says Barth Shenk, the AFRL's programme manager.


© Sgt Shannon Collins/USAF

The 87min sortie launched from Palmdale, California, validated the basic flying qualities of the cargo aircraft, made mostly from out-of-autoclave composite materials, programme officials say.

The ACCA adds a cargo door and ramp to the 328Jet, which also is modified with a slightly widened and extended fuselage to accommodate military-standard 463L pallets. A newly designed vertical fin also features integrally stiffened skin.

The programme's goal is to show that out-of-autoclave composite resins can be cured at strengths that could eventually meet airworthiness standards.

However, the programme was delayed by several months after learning that its original "recipe" for the curing process had failed, says Michael Swanson, Lockheed's ACCA programme manager.

Swanson compares the learning process on ACCA with the Lockheed SR-71 Blackbird's problems with introducing titanium metals into airframes. But the programme "came out of that process with several well-documented, repeatable processes" for out-of-autoclave composites, he says.

Such resins are expected to dramatically streamline the aircraft manufacturing process by removing the need to cure composite structures in autoclaves. Instead, the resins could be cured in low-temperature ovens built around tooling on a standard assembly line, Swanson says.


© David Henry

Sir Richard Branson guest edited Flightglobal.com on June 8^th. He chose this story because

Sir Richard Branson: It’s encouraging that Lockheed Martin and others are putting so much resource into aircraft made from composite materials. As Steve Fossett showed with the Virgin Atlantic Global Flyer, the aircraft of the future will be lighter, cheaper and far more environmentally friendly.