Supersonic business aviation took a step closer to reality this week after NASA began flight testing Gulfstream’s patented Quiet Spike sonic-boom mitigation device on a Boeing F-15.
The Quiet Spike is designed as part the design for Gulfstream's proposed Supersonic Business Jet (SSBJ), which also features wings that sweep back and centreline engines (see animation below). On an operational SSBJ, Quiet Spike will probably have four sections. It has yet to be determined whether a tail spike is needed to deal with the aft sonic shock.
Image: © Gulfstream
Animation: Justin Wastnage/ flightglobal.com
| The Gulfstream SSBJ will transform from subsonic configuration to supersonic configuration |
The initial shake-down flight from NASA Dryden at Edwards AFB in California was conducted with the three-section boom retracted. It will telescope in flight from 4.3m (14ft) to 7.3m in length, and is designed to reduce sonic boom overpressure by splitting the bow shockwave into a series of weaker shocks.
A second aircraft will probe the supersonic signature in the near field, to see if the wave system is as predicted. The Quiet Spike is designed to divide the bow shock into several less-intense pressure waves, turning the characteristic N-wave sonic boom into a softer S-shaped signature.