February 04, 2013
Credit: Photo Credit: Chinese Internet
Bill Sweetman Washington and Bradley Perrett Beijing
If ever there were an aircraft that should grow in capability, China's newly flown Y-20 airlifter would be it. The prototype that took to the air on Jan. 26 mates what looks like a modern airframe with obsolete 1960s-technology engines. Together, they probably represent no more than a serviceable design standard, offering only modest advances in capability over the Ilyushin Il-76 that China already operates.
But a better engine is under development for the Y-20. If and when China's technologically challenged aero-engine industry can get that high-bypass turbofan ready, then the airlifter should surge in performance. More distantly, a truly modern engine under development for the Comac C919 airliner could also be available.
Successful development of the Y-20 airframe is in itself an important accomplishment for the Chinese industry, which in more than six decades of Communist history has been only slowly and haltingly weaning itself from copying foreign types, mostly Soviet-era Russian designs. Underscoring this point, the Y-20 is the largest indigenous Chinese aircraft built so far, exceeding the unsuccessful Y-10 airliner tested in the early 1980s.
The Y-20 will not enter service before 2017, according to two Chinese military academics, Zhang He and Li Wei, writing in China Youth Daily, a major national newspaper. They also say that the Y-20 airframe incorporates composite materials (although most of it appears to be aluminum) and a “supercritical” wing. It is not clear whether the objective is to have a new engine ready by service entry.
The Y-20 is an entirely new design, even though it is close in size and shape to the Il-76, which uses the same Saturn D-30KP medium-bypass engine as the Chinese airlifter's prototype. Compared with the Il-76, the Y-20 has a shorter wingspan and a shorter, but slightly wider, fuselage. The Y-20 is larger than the Airbus A400M and has about the same fuselage diameter, but is much smaller than the Boeing C-17.
Specifications estimated by Aviation Week (see table) and including dimensions determined photometrically, vary from figures quoted by Zhang and Li. The academics say the Y-20's span is 45 meters (148 ft.), length 47 meters, height 15 meters, gross weight “over 200 tons” and payload 66 tons. They give no source, but their figures could be preliminary numbers estimated in 2006, when the project was launched after about 15 years of study. Comparison with the Il-76 suggests that the published weight and payload figures are too high for a version fitted with the D-30KP.