X-48B downscaled test plane (NASA/ Boeing), anticipation crossing Siberia (WS)

In 1989 the Northrop B-2A stealth bomber had its maiden flight, but “Flying Wings” were confined to military purposes. Immediately speculations arose about using the Blended Wing Body (BWB) concept also for very large passenger aircraft. Normen Bel Geddes had proposed a fanciful air-cruiser concept already in 1932, without doubt influenced by the ocean liners’ top-deck lounges. Not a ‘flying wing’, but an equally luxurious idea was the “Lieutenant-de-Vaisseau Paris” concept by Caillard et Mauny of 1935. Also Junkers showed fantasy with the never-built J 1000.

Junkers J 1000 anticipation (Deutsches Museum Munich)

A design by Caillard et Mauny of 1935: Hydravion ‘Lieutenant-de-Vaissau Paris’ (archives Deutsches Museum Munich)

As the early pioneer in blended wing technology, the American aircraft engineer William Bushnell Stout was praised (by Wikipedia) for his Stout Batwing study around 1926. An anticipation of the Blended Wing Body was the Junkers G.38, introduced in 1929. “Flying Wing” bombers were developed during WWII by “Jack” Northrop in the USA and by the Horten brothers in Germany. A test forerunner of the Horten VIII was half finished at Goettingen when the US forces discovered it. Plans of the Ho VIII were brought to the USA and the ‘UFO’ rumors arose. In Germany before its defeat, also Arado, BMW, Junkers and Messerschmitt had studied ‘Flying Wing’ bombers (see the book ‘Geheimprojekte der Luftwaffe’ by Dieter Herwig and Heinz Rode). In Russia, Boris Ivanovich Cheranovskii has tested already in 1924 his BICh-1 ‘Parabola’ glider, “considered to have been world’s first successful flying wing”, according to Yefim Gordon and Bill Gunston (‘Soviet X-Planes’). This renowned source showed Cheranovskii’s studies culminating in jet fighter projects, not realized and kept secret. Development of ‘Flying Wings’ took place mainly in the USA by Northrop with the prop-driven bomber XB-35 of 1941, reaching the highlight in 1947 with the jet-powered successor YB-49. Due to the hazardous stall conditions of tail-less aircraft, the USAAF abandoned the project and scrapped the planes in 1949. Blended wing body designs by V.J. Burnelli were another option, but in the seventies the Boeing 754 project, based on Burnelli’s ideas, was abandoned due to various technical reasons. Concerning Russian researches at the Central Aerohydrodynamics Institute, Bratukhin’s book ‘Russian Aircraft’ reported: “The preliminary design studies resulted in an aircraft accommodating about 900 passengers. The passenger cabins were located on two decks in the center of the aircraft and one deck along the wing center section. The takeoff mass of the aircraft is 560t (…), the wing span (…) more than 100m.”

NASA directed a commercial BWB development, cooperating initially with McDonnell Douglas. In 1999 Boeing published a BWB design with 289ft (c.88m) span, showing two full passenger decks, sitting 800 persons in parallel compartments, with cargo bays being located between the cabins in the centerbody and the fuel tanks in the outboard portion of the wing. Three 60,000-lb-class turbofan engines with a high bypass ratio, mounted on top of the wing in the rear, would make the BWB more fuel efficient than the smaller 747 with four engines of this class. Facing questions about stability and control, making the BWB completely dependent on a sophisticated computerized steering system, Gerry Janicki, director of the Boeing Phantom works, said: “So if we actually build this aircraft in 20 or 30 years, it may or may not look like the models we’re building today” (AIAA, April 2000). Cranfield Aerospace of the UK completed two 8.5%-scale flight demonstrators X-48B for tests at Edwards Base. In 2007 Boeing published the possibility of building a BWB freighter towards 2020 and also a military BWB or HWB. Under NASA label the MIT Hybrid Wing Body was published, a HWB, the H Series being described for 350 passengers, a range of 7,600 miles and a reduction in fuel consumption by 54%. An Airbus study showed engines not placed in the rear. Aerospace America (July 2013) described NASA’s Phase I work “by three industry teams using different advanced vehicle concepts: Boeing’s blended wing body, Lockheed’s box wing and Northrop Grumman’s flying wing (…). Project manager Fay Collier was quoted, stating: “We are more likely to see them on the military side than on the civil aviation side.

Northrop YB-49 (via Wikipedia)

The military “Spirit of Arizona”: Northrop B-2A (USAF, via Eddy)

OFW
An extremely daring concept was the “oblique flying-wing” or OFW. Already in 1943 Richard Vogt of Germany’s Blohm & Voss had proposed a jet fighter P-202 with a pivoting oblique wing and a fuselage. In the USA R.T. Jones, since 1945 specialized in swept-back wing development, studied for Boeing a supersonic transport aircraft with an oblique wing, also in a twin-fuselage configuration. In 2005 the U.S. Defense Advanced Research Projects Agency (DARPA) announced a different variable-sweep flying wing Mach 1.2 long-range OFW bomber without any fuselage, targeting a 2025-timeframe. Considering the aerodynamic and control issues of the unstable OFW, DARPA’s project manager Thomas Beutner called the program “extremely challenging”. Nevertheless fanciful and unrealistic speculations arose about using that “switchblade” concept also for future supersonic passenger aircraft with a cabin layout comparable to the BWB.

Comment
Half a century ago, delta-wing pioneer Alexander Lippisch had a completely different idea of a “flying fuselage”, powered by VTOL (vertical take-off) technology, too uneconomic. And who would board a plane which can fall down from the sky like a stone? When the “Flying Wing” stealth bomber B-2A was presented, Newsweek wrote: “The B-2 bomber is run almost wholly on computerized adjustments. Hundreds of thousands, maybe millions of adjustments that are going on all the time keep the plane stable” (Newsweek Sep24, 2007). An additional problem is every engine arrangement in the rear. The German magazine Der Spiegel (33/2010) wrote about the problems once with the MD-11: “Its high landing-speed and the centre of gravity positioned far in the rear make steering very pretentious…” When the McDonnell-Douglas BWB design was published, Newsweek uttered concerns about the passengers’ comfort: “Unfortunately only a few passengers would get a direct view. Everyone else will have to settle for images from outside beamed to seat back monitors …” Remember that the experimental windowless lounge on a TriStar cargo deck and a similar proposal for the 747 were unsuccessful. Flight Intl quoted George Muellner, head of the Boeing Integrated Defense System, saying about Boeing Commercial Airplane’s attitude towards passenger BWBs: “BCA is scared because it has no windows”. If ever a BWB should be commercially viable, it must be attractive for standard airlines’ clients – not only with virtual displays, but also with viewing-points or standup-bars for everybody close to the (few) windows. After the YB-49 was built, Jack Northrop envisaged the use of that concept for passenger aircraft, equipped with viewing lounges. In the 21th century, the German magazine Aero (4/2003) reported: “In order to raise acceptance of the unusual BWB concept by the passengers, a team of the Technical University Munich and Hochschule fuer Angewandte Wissenschaften Hamburg concentrated its studies on the aspects of view and perception. A solution should be big virtual reality displays in side and partition walls (…) completed by a direct window view in so-called motion zones”. It’s difficult to realize in consideration of the BWB’s envisioned structure. And airlines possibly would not allow passengers to leave their economy-class cabin. For freight, the BWB was praised, but the stagnating orders for the proposed A380F have dampened optimism also for freighters.