The Blended Wing Body (BWB) concept in aircraft involves just that - fixed wing elements contoured finely with the fuselage, this producing a "flying wing" of sorts as there is no defined break between the body and the wing mainplanes and the aircraft lacks a true tail unit. The concept features many of the benefits of a flying wing in that greater internal space means larger fuel stores and more surface area helps to create inherent lift. Collectively, these qualities increase operational range and fuel efficiency compared to more traditionally arranged aircraft. However, as with any other design venture, BWB aircraft hold technological challenges all their own which leads prominent defense contractors to pursue the merits of such aircraft through developmental platforms like the Boeing "X-48B".
BWB aircraft have been on the minds of aeronautical engineers since the early 1920s as the world recovered from The Great War, a war which saw the aircraft become a viable military component in monoplane, biplane, and triplane forms. From there, the concept evolved through great thinkers in the field and as technology allowed - straight wings gave way to swept wings and flush, all-metal skinning became the norm. In the new century, Boeing's "Phantom Works", its special projects division, began looking into furthering what was already known about BWBs and this begat the X-48.
Earlier work was completed by McDonnell Douglas and this was absorbed into Boeing records after the merger of the two powerhouses in 1997. Boeing then teamed up with engineers at NASA Langley Research Center to develop what would become the X-48. A prop-driven, remotely-controlled scale model of a BWB aircraft was flown in 1997 to prove the concept sound. However, the X-48A initiative, to include a wingspan of 35 feet, fell to naught - the product was cancelled before any physical work had taken place.
Next came the X-48B and this featured a more modest span of 20.4 feet. Dimensionally smaller than the intended A-model, the B-model was given large-area mainplanes with sweep along the leading edges. Its surface area was such that it negated use of a true tail unit. Vertical planes were instead seated at the mainplane wingtips. A mock cockpit was painted into the nose of the fuselage and three engine nacelles were affixed along the extreme aft of the aircraft's body, these housing JetCat P200 turbojets of 52 pounds thrust each. A full tricycle undercarriage was installed and the finalized design's gross weight reached about 500 pounds. Composites were used through where possible and Cranfield Aerospace of Britain was charged with its construction.
The X-48B began its testing phase in 2007 and recorded a first flight on July 20th. Cranfield Aerospace was commissioned for two demonstrators which were delivered ("Ship 1" and "Ship 2"). The X-48B was able to achieve a maximum speed of 136 miles per hour, an endurance window of 40 minutes and a service ceiling up to 10,000 feet. Since it became airborne, the X-48B has become a crucial component to Boeing Phantom Works regarding its research into BWBs.
The future prospects of the X-48B are interesting - it is intended as a scale-model version of a full-sized aircraft still to come. BWB designs could serve both military and civilian markets well if certain technical aspects can be solved and - perhaps more importantly - these two services are not averse to something completely different that traditionally-arranged aircraft. The inherent benefits of BWB aircraft are intriguing to say the least but it may take much convincing to pull off serial production commitments from entities such as the United States Air Force and major global passenger carriers. It is seen that such aircraft could effectively fulfill the role of heavy-lift transport in military service and long-haul airliner in civilian service.
Since the X-48B entered its test phase, yet another in the series was introduced - the X-48C. This entry became a modification of the X-48B before it but had been given a two-engine arrangement and was intended to test low-noise capability - a good quality for a civilian passenger hauler to be sure. The X-48C had its first flight in August of 2012 and wrapped up its test phase in April of the following year.
There are noted plans by Boeing for a dimensionally larger aircraft in the series still to come to continue research into their BWB design.