Things With Wings

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  • Do Airliners Have to be Boring?
    Posted by Graham Warwick 3:58 PM on Sep 12, 2012

    With both Airbus and Boeing choosing to pass up the opportunity to design all-new next-generation single-aisles, in favor of minimum-change re-engining of their current narrowbodies, we could be forgiven for thinking creativity is dead in commercial aviation. But to paraphrase Monty Python, "its not dead yet."

    Concept: Bauhaus Luftfahrt

    Take the example of Munich-based aviation think-tank Bauhaus Luftfahrt's (BHL) Ce-Liner concept, unveiled at this week's ILA airshow in Berlin (see Aviation Week's show coverage here). The Ce-Liner is an all-electric, zero-emissions design for a 190-passenger, 900nm-range airliner that could enter service in 2035-2040.

    Power for the superconducting motors driving the ducted-fan engines, as well as the electric actuators and other aircraft systems, comes from advanced lithium-ion batteries housed in up to 16 modified LD3 cargo containers. With a capacity of 2,000Wh/kg, these battery packs are exchanged between flights, to save time, and not recharged in situ.


    The C-wing planform increases aerodynamic efficiency by extending effective span while staying within airport-gate size limits; reducing wingtip vortex generation; and eliminating the need for a horizontal tail (as the upper wing sections are behind the main wing to provide balance).

    The widebody fuselage has twin-aisle, 2-3-2, seating, with a center door and seats that fold sideways to speed boarding and de-boarding of the aircraft, says BHL. The windows are continuous bands of transparent, load-bearing structure that run the length of the cabin.

    Concept: Airbus

    Or take Airbus' Smarter Skies concepts to reduce fuel consumption and emissions with new ways to operate aircraft that could be in place by 2050. These include using an electromagnetically propelled ground trolley to accelerate the aircraft along a track and into a steep "eco-climb". Requiring smaller engines and less fuel, and reaching an efficient cruise altitude more quickly, the aircraft would have lower emissions.

    Once in the cruise, aircraft would "self-organize" to select the most efficient route based on weather. By rendezvousing then flying in formation, autonomously keeping station 20 wingspans apart, aircraft would be able to surf the wingtip vortices of others to reduce fuel burn by 10-12% and emissions by 25%, says Airbus. Air traffic control would be able to treat each formation as a single "flock", streamlining airspace management.

    Concept: Airbus

    On arrival, the aircraft would make a steep, gliding approach to the runway, slowing earlier and landing in less distance - with an accuracy that allows an autonomous taxiing carriage to be waiting to tow the aircraft to its gate. Combined, assisted take-offs and free-glide approaches could reduce required runway length by a third, says Airbus, increasing the capacity of existing airports or enabling smaller "micro-airports" to be built near to large cities.

    Or take German Aerospace Center DLR's LamAIR research project. This centers on a concept for a narrowbody airliner with a forward-swept wing and flexible "droop nose" leading edges to promote drag-reducing natural laminar flow and a tail with boundary-layer suction for hybrid laminar flow control.

    Concept: DLR

    With a conventional aft-swept wing, the maximum leading-edge sweep for natural laminar flow is limited to 20° to prevent cross-flow instabilities causing airflow over the wing to become turbulent, says DLR. This limits cruise speed to Mach 0.75. With a forward-swept wing, leading-edge sweep for laminar flow can be increased to 25°, and design M0.78 - 0.80 without out too much of a penalty.

    So there is creativity out there - we just have to get it off the computer screens and show floors and into the air...


    Photo: DLR

    Tags: tw99, Airbus, DLR

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