Light business jet safely concludes high-speed flights without flutter at up to M0.9
Sino Swearingen Aircraft (SSAC) has completed dive testing of the SJ30-2 light business jet to speeds of Mach 0.9, clearing the aircraft for its level-flight maximum Mach number of 0.83. Dive testing confirmed the aircraft does not encounter flutter at speeds up to M0.9, and follows the fatal crash of an SJ30-2 prototype in April 2003 during high-speed flutter testing.
San Antonio, Texas-based SSAC says the second of two conforming prototypes, aircraft 0004, completed 60h of high-speed testing to confirm the M0.83 maximum operating Mach number. Tests were conducted with and without the yaw damper, which is mounted on the ventral fin.
In the 2003 crash, in which the test pilot was killed, the aircraft was seen to roll right after reaching M0.884 in a shallow dive. The pilot said he could not stop the roll, which continued to ground impact with the aircraft appearing to remain intact throughout. The accident is still under investigation.
SSAC says it has "a lot of flight testing still to do" before achieving US certification, planned for the second half of next year, but believes it has completed all the critical tests.
These include wing ultimate load testing and pressurisation tests to the ultimate limit of 2.35bar (31.4lb/in2), confirming the SJ30-2 fuselage meets the design requirements of 0.82bar cabin pressurisation to 49,000ft (15,000m).
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
