J-20 Stealth Fighter Design Balances Speed And Agility
Unique J-20 could fit anti-access role
Nov 10, 2014 Bill Sweetman | Aviation Week & Space Technology
Chengdu’s J-20 stealth fighter represents the pinnacle of China’s aerospace engineering, but its existence and development have posed mysteries since the unexpected appearance of the first prototype at the end of 2010, followed in May 2012 by the debut of a second, similar aircraft. The past few months, however, have seen the first flights of a pair of significantly different J-20s, identified by the serial Nos. 2011 and 2012.
The most substantial design change in the new aircraft appears to be that the fuselage aft of the main landing gear is a bit more slender, with a deeper tunnel in the undersurface between the engines. The tailbooms that extend aft of the all-moving vertical tails are longer, and the lower fixed stabilizers are moved aft. The trailing-edge tips of the vertical tails and canards are cropped, and the leading-edge root extensions are straight rather than curved.
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The top line of the outer wall of the diverterless supersonic inlet has been drooped, and the landing gear doors changed: The main doors now close after the gear has extended and the nose landing gear door has been reshaped. The F-22-style one-piece frameless canopy on the early aircraft has given way to a separate windshield and canopy, the latter with detonation cord to shatter the canopy for ejection. What appears to be a housing for an infrared search and track system has been added below the nose, and a missile-warning sensor fairing installed below the aft fuselage.
The new variant aircraft appeared slightly more than three years after the first flight of No. 2001, so some of the changes may reflect lessons from flight testing. Other changes represent a move toward a production or pre-production design. So far, there have been few indications as to when the J-20 will enter service: The Pentagon, in its latest annual report to Congress, says it is unlikely to be operational before 2018.
However, the appearance of the new aircraft tends to confirm that the design has proved sound so far; all four prototypes are now reported to be at Yanliang air base in Xian, the Chinese air force’s main test site. The question now is what role the J-20—which is not only the first Chinese stealth fighter but the largest tactical aircraft built in China—will perform in the future force.
Close examination of the J-20 shows it has no direct analogue in the West or in Russia. The dimensions can be estimated accurately from open-source satellite images, but its characteristics are sometimes mis-assessed through a focus on overall size. Details of avionics and materials remain uncertain.................................
