From this moment, Northrop would regularly adapt the flying wing characteristics to the needs expressed by its new client (the XB-35 and the XB-49 bombers, the XP-79 fighter jet, and even some drones such as the JB-1 and JB-10) but failed to win any contract.

The Northrop YB-49 (Credit: U.S. Air Force photo)

However, in a perfect example of serendipity, it is said that the manufacturer discovered the stealth capabilities of the flying wing during the flight tests of the XB-49, as its small radar cross-section made it hard for airports to see the approaching aircraft.

In 1975, Northrop competed against Lockheed and McDonnell Douglas in the Experimental Survivable Testbed (XST) stealth bomber program, but fell short to Lockheed’s Have Blue concept that would become the legendary F-117 Nighthawk.

Fortunately, Northrop did not give up, and it went on to participate in the Advanced Technology Bomber (ATB) program, which was supposed to provide a new generation bomber. Flying for the first time in 1989, the B-2A Spirit strategic bomber would become one of the backbones of the United States nuclear deterrence to this day.

In 2015, the USAF trusted Northrop again to develop its first bomber of the XXI century, the B-21 Raider. After the success of the B-2A, other manufacturers would develop their own flying wings: Boeing with its MQ-25 Stingray refueler drone, Dassault with the nEUROn demonstrator, and even startups such as the Swiss senseFly (a subsidiary of Parrot) with the miniature eBee, a fully autonomous mapping drone.

A flying wing airliner?

If the stealth capability of the design is irrelevant to passenger transport, the low drag and increased lift surface of the flying wing could significantly save on fuel consumption by as much as 20%, marking a step forward towards a more sustainable aviation. Moreover, by giving the ability to place the engines on top of the airframe, the noise perceived on the ground could be reduced.

But if the concept has been mastered for 30 years, its application to commercial aviation raises several problems. The main one is passenger experience. By moving away the seats from the plane’s center of gravity, it increasingly subjects passengers to yaw and rolling movements and could induce some discomfort. The tailless design also proves to be rather unstable and difficult to control due to the scarcity of yaw control surfaces.

Another issue is modularity. The classic “tube and wing” configuration allows for easy derivations: by extending or reducing the fuselage, a manufacturer can create a whole family of aircraft. But the calculations behind the Blended Wing Body are more complex, and any modification to the cabin would have consequences for the wings, making each design unique.  

Nonetheless, with the same persistence as their military counterparts, commercial aircraft manufacturers and airlines have been trying to outweigh the cons. McDonnell Douglas was the first to seriously study the concept of the Blended Wing Body, a hybrid between a conventional fuselage and a flying wing, as early as the 1990s. However, after it was acquired by Boeing in 1997, the aircraft stayed on the drawing-board.

The same year, a model developed by Boeing Phantom Works, in collaboration with NASA and the USAF, took to the skies. It was turned into a full-size aircraft named the X-48A, with a wingspan of 10.7 meters (35 feet) but was eventually abandoned in 2004. 

Two smaller versions of only 6.4 meters (21 feet), the X-48Bs, were assembled by UK-based Cranfield Aerospace, a division of the Cranfield University, and were successfully tested in flight between 2007 and 2010. 

 

The X-48B during its first test flight (Credit: NASA)

An ultimate version, the X-48C Hybrid Wing Body aircraft, flew between 2012 and 2013, before the program came to an end. “Our team at NASA Dryden has done what we do best, flight test a unique aircraft and repeatedly collect data that will be used to design future ‘green’ airliners,” Heather Maliska, NASA Dryden’s X-48C project manager, said at the time. Boeing is reportedly working on a bigger version, but it has yet to be unveiled to the public.

On June 2, 2019, KLM Royal Dutch Airlines showed interest in the concept. During the IATA Annual General Meeting in Seoul, South Korea, the airline signed a cooperative agreement with Delft University of Technology (TU Delft) to work together on the “Flying-V”, a wide-fuselage long-haul aircraft that integrates the passenger cabin, cargo hold and fuel tanks in the wing structure. The first flight test is expected to take place in 2020.

Last but not least, Airbus lifted the veil on one of its secret projects named MAVERIC during the 2020 edition of the Singapore Airshow 2020. Started in 2017, the 2-meter long and 3.2-meter wide model completed its maiden flight in June 2019. The flight-test campaign should continue until the middle of 2020.

All in all, 2020 could be the year when we finally know if the flying wings are the way of the future for commercial aviation.

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During the Singapore Airshow 2020, Airbus lifted the curtain on one of its secret projects named MAVERIC. The flying wing technological demonstrator offers a glimpse into the commercial aircraft of the future.