Chinese and Russian Widebody takes shape: Part 2.

Discussion
The CR929-600 data

The project company, CRAIC (China-Russia Commercial Aircraft International Corporation), has presented the key dimensions for the CR929-600, the base aircraft for the project.

In Figure 1 the data is compared to the data for the nearest competitors, Boeing’s 787-9 and Airbus’ A330-900.

Figure 1. Key data for CR929-600, 787-9 and A330-900. Source: Leeham Co.

The CR929-600 is close in key dimensions to Boeing’s 787-9. The A330-900 is different in all key dimensions except for the range of the 242t version.

Differences to 787-9

The main differences compared to the 787-9 are:

  • A wider fuselage. The 787 was designed with a comfortable eight-abreast cabin in economy or for higher density applications as a nine-abreast cabin. The latter presumed 18-inch aisles and 17.3-inch seat width. The CR929 has a 0.17m wider fuselage, allowing a nine-abreast cabin with 18-inch seat widths.
  • A one-meter wider wing. This lowers induced drag, especially as the Maximum Take-Off Weight (MTOW) of the CR929-600 is 20 tonnes lower than the 787-9. This results in a lower weight aircraft, everything else being equal.
  • The lower MTOW of the CR929 base variant opens the possibility to design the aircraft with a lower wing area than the 787-9. This lowers empty weight and friction drag because of a lower wetted area. The gives the CR929 a high wingloading, however.
  • The likely decision for a base variant (which is the base for a future stretch version) is to stay with a moderate wingloading. The likely result is a wing area about equal to the 787, giving a wingloading of 650kg/m2. The higher span then gives the CR929 a 1% higher aspect ratio at 9.82.
  • The wider fuselage only increases the wetted area (the driver for friction drag) by less than 1%. It’s a price worth paying for avoiding the debate about 17-inch wide economy seats.
Similarities to 787-9

Figure 2. Planform of CR929-600 (magenta) versus 787-9 (blue). Source: Leeham Co.

The similarities between the CR929-600 and Boeing’s 787-9 are striking, Figure 2:

  • Both have fuselages of 62m length. The CR929 is wider to avoid the 17-inch seat debate, but otherwise, they have almost identical dimensions. The difference in fuselage perimeter (driving weight and drag per meter fuselage) for the two designs is less than 1%.
  • The CR929 structure shall contain over 50% composites according to preliminary information. By necessity, this means the CR929 has a CFRP (Carbon Fiber Reinforced Polymer) fuselage (otherwise the fraction of CFRP for the aircraft would be lover). This is similar to the 787, also at 50%. While this is good for weight and maintenance costs, it will force the inexperienced Chinese part of the project to develop, certify and produce a CFRP fuselage, something it has never done before. We will discuss this more in Part 3 of the article series.
  • The wings have almost identical dimensions. It’s left to see if CR929 uses the same modern adaptive spoiler-flap arrangement as the 787 and Airbus A350. It enables the wing to be flown with an adaptable profile, by it enabling lower aircraft drag as the weight of the aircraft changes during flight.
  • The propulsion systems have similar thrust rating. The CR929-600 is projected to have 75klbf Static Sea Level thrust per engine with the 787-9 at 76.9klbf thrust. The CR929-600 in its first version is likely to use one or both of the 787 engines. There are hints the CR929 is planned as a more electric aircraft. This would remove the need for GE Aviation to remap its GEnx-1 engine to a customer bleed version, should it be chosen for the aircraft. Rolls-Royce Trent 1000 is already available in a customer bleed version, the Trent 7000 for the A330-900/800.

Passenger capacity

With a fuselage of the same length and similar diameter, the cabin capacity of the CR929-600 and 787-9 is close. COMAC has been showing the CR929-600 cabin in a three-class version at an exhibition in China. Based on this information, we could design our standardized two-class cabin with its normalized rule-set for the aircraft, Figure 3.

Figure 3. Cabin for CR929-600 in a normalized two class version. Source: Leeham Co.

The capacity is then 291 seats, compared with 290 seats for the 787-9. The arrangement of door areas, galleys and access to the overhead crew-rests are similar. The aft galley area is a bit shallower, but otherwise, there are no principal differences in how the space of the fuselage is used between the aircraft.

A different range class

The lower Maximum Take-Off Weight (MTOW) of the CR929-600 restricts its range to 6,500nm with the nominal payload of 280 passengers, flown in a three-class cabin. The lower MTOW is set to optimize the design for the primary markets China and Russia. It is the same range as the 242t version of the A330-900.

It allows Chinese and Russian airlines operating the CR929-600 to fly to all destinations in Asia and Europe and most in Africa. It will also allow them to cross the Pacific Ocean when going from Central and East China/Russia to the US West Coast. But it will now allow routes like Hong Kong – West Coast of the USA to be flown reliably. We will dwell more on the range capability when we analyze the CR929 performance.

Next step

The achieved performance level for the CR929 will depend on how well the Joint venture can realize an aircraft of the CR929 class. This will be the subject of our next article. Once the probable realization is analyzed, we can continue with a performance analysis.

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