Video feature: Boeing's X-48C proving BWB concept

7 June 2013 Liam Stoker - aerospace-technology.com

Developed as part of a collaborative effort involving Boeing Phantom Works and Nasa, the X-48C hopes to prove that blended wing body aircraft can deliver on fuel efficiency promises.

Having completed its flight testing campaign in late April, Boeing's X-48C experimental aircraft can only be considered a successful first foray into blended wing body (BWB) aircraft. Having been first conceptualised in the 1990s, the BWB finally looks like taking off.

Boeing acquired the concept as part of the company's merger with McDonnell Douglas in 1997, with the latter's Project Redwood certain of providing fuel efficiency advantages over traditionally designed aircraft. The concept relies on the aircraft designed as one entire part, combining the fuselage and wings into a more triangular design.

By reducing the number of parts that are pieced together and creating a design that is more streamlined, it is expected that the aircraft will provide greater fuel efficiency through being more aerodynamic.

In an age where airliners are increasingly at odds with spiralling fuel prices, any way in which fuel efficiency can be drastically boosted has to be considered worth persevering.

BWB goes into development

Having been developed through a collaboration involving Nasa's Langley Research Center and Boeing Phantom Works, the aircraft's initial entity - the X-48B - completed wind tunnel testing in May 2006, before progressing to taxi and ground testing.

Boeing X-48 chief engineer Norman Prince said: "Earlier wind-tunnel testing and the upcoming flight testing are focused on learning more about the BWB's low-speed flight-control characteristics, especially during takeoffs and landings. Knowing how accurately our models predict these characteristics is an important step in the further development of this concept."

The X-48B first flew in July 2007, reaching an altitude of 7,500ft during a 31 minute flight, before completing its initial flight testing phase in March 2010. Just over two years later the latest incarnation of the aircraft, the X-48C, commenced flight testing.

Featuring a new flight computer, new engines and a slight re-design, which saw the vertical stabilisers moved inboard, the aircraft completed 30 further test flights, finishing in April 2013.

The future for BWB aircraft

With two successful flight test regimes under its belt, the X-48 programme is edging ever closer towards proving the BWB concept as a manageable, fuel-efficient alternative to fuselage-and-wing aircraft.

Boeing and Nasa now intend to developer a larger BWB capable of transonic flight based upon the X-48C concept.

BWB aircraft are now also interesting the US Army and Air Force, with their improved fuel efficiency likely to be highly applicable for air-to-air refueling and cargo delivery missions.

Thought to be between 15 and 20 years away from development, blended wing body aircraft could become a cornerstone of not just civilian airliners, but non-combat military aircraft too.