It appears there is still interest at Boeing in high-speed airliners, at least within its advanced projects organization. The company has been granted a US patent
for a design that is remininscent of both its high-speed Sonic Cruiser and high-capacity Blended Wing Body (BWB), if that's not too odd-sounding a concept.All patent images via USPTO
The design is intended to increase passenger and cargo capacity, so reducing cost per passenger and container, without incurring all of the weight and drag penalties normally associated with simply making the aircraft bigger. The configuration combines features of the high-speed Sonic Cruiser, particularly the engine installation, with those of the BWB, particularly housing the passengers in the broad constant-section aft fuselage.
To explain its advantages, Boeing's patent compares the new configuration with a 1970s-vintage concept for a transonic widebody twinjet (left, above). To reduce wave drag at speeds above Mach 0.85, this design is aggressively area-ruled
, with the fuselage "waisted" at the wing/body join to offset the increase in cross-sectional area caused by the wing.
Among the disadvantages of this configuration, the patent explains, is the overall size resulting from its elongated fuselage and wing, which increases weight and makes it unweildy on the ground. The unfavorable "dumbbell" weight distribution, with most passengers and cargo in the fatter sections fore and aft of the waist, is also a problem - as is the narrowing of the airframe just where the main load-carrying wing structure passes through the fuselage.
Although it is not obvious at first glance, the new blended wing-body design has a better distribution of cross-sectional area than the more obviously area-ruled dumbbell twinjet, reducing transonic wave drag, as the patent illustrates (older design is dotted line):
The patent claims other advantages for the new design, including the constant-width passenger cabin with its four seating sections and three parallel aisles. The engines are also located aft of the passenger cabin, reducing noise and improving safety.