related, hendirk posted over on cdf
China reveals the shape of things that may come in air travel
China has flown a scale model of an airliner that exploits design elements not found in Western passenger jets
Ben Sandilands — Editor of Plane Talking
Ben Sandilands
Editor of Plane Talking
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COMAC’s intriguing model jet will be closely studied in Toulouse and Seattle
There were two developments in China in recent days that point to serious intentions to innovate in the design of airliners that could break the Airbus and Boeing duopoly in larger scale aviation.
And neither relate to the imminent first flight of the COMAC c919 single aisle jet, which has been doing taxying trials in Shanghai, and is imitative rather than innovative in seeking to join the huge market in such jets which is divided between the A320 and 737 families.
Development Number One is about the starting of work on a ten year Sino-Russian project to build an A330 sized twin engined wide body jet that would be able to fly non-stop between China cities and those in the US.
Or for that matter, fly the likes of Sydney or Melbourne non-stops to Los Angeles or Dubai.
There is no hint in the China Aviation Daily report about #1 having anything to do with Development Number Two which is reported in the most detail in French on the East Pendulum site, but seems to survive Google translate without any major errors.
For a teaser, you can also pick up the intriguing photos of the flight of a scaled model of future blended wing body or BWB Chinese airliner here.
If however #1 and #2 are aspects of the same wide-body 280 seat airliner ambition, there may be a lot more excitement in Airbus and Boeing than would be the case if China is sticking with the c919 strategy of producing an A320 or 737 clone (using western engines and other key components) that appears to be initially optimised for relatively short routes between PRC cities.
Look closely at the photos of the model that actually flew in the East Pendulum site and you will see that this a blended wing body or fuselage intégré en français which needn’t be any such thing, but a delta plan wing similar in construction to that seen on Concorde or its TU-144 emulator. The engines remain in a conventional under wing location, not on struts above the ovaloid wing as seen in many other BWB studies.
There is no attempt in the COMAC LingQue-B model to spill the passenger accommodation into the vastly increased wing area as often seen in western BWB design studies. Which is smart on the part of the Chinese designers, since anyone seated that far from the centreline of the cabin would experience wildly exaggerated angular momentum forces in light turbulence or slight changes in heading even while taxying on the ground.
The COMAC design is a thin wing, which doesn’t present any opportunity to build a true BWB monocoque type structure in which much of the internal loading bearing components of a conventional design are replaced by an outer structure sufficiently strong to counter the stresses of ‘ovalisation’ which occur in pressurized fuselages and would be another serious obstacle to building a full fuselage intégré airliner.
Instead the function of the delta shaped wing in this model seems to be to create space for more fuel, or perhaps, avoid the width requirements of conventional wings and thus make it easier to fit the airliner inside the gates at existing airports and be compatible with those taking nothing larger than an A321 today.
All this means that, except for one glaring anomaly, the LingQue-B design represents a serious attempt to pack more range into a future airliner while keeping it sufficiently compact not to be incompatible with many existing airport gates or taxiyways.
These are two issues that Airbus and Boeing engineers have identified in various studies dating back to the last century, yet which have not been addressed in their jets, apart from the inclusion of a folding wing tip in the design of the forthcoming Boeing 777-X family.
The anomaly in the COMAC model is the V-shaped tail. Most of the technical commentary on the LingQue-B underlines the inherent aerodynamic risks of diminished if not loss of control in a configuration like this if such an aircraft begins to yaw from side to side. If a V-tail was to be a serious part of such a design it would presumably need continuous computer driven massaging of the control surfaces of the jet to prevent such a crisis developing.
But whatever the reasons for the appearance of the model that flew in China in recent days, it signals an intention to do more than build replicas of existing western designs.