Gulfstream Aerospace hosted a NASA F-15 in Savannah, Ga., on February 14 for an aerial demonstration of its Quite Spike telescopic nose spike installation. If Gulfstream were ever to decide to launch a supersonic business jet, it would have to employ some means of suppressing the sonic boom while flying over land.
Instead of building an airplane that could exceed Mach 1 only away from land, Gulfstream envisions a design with a retractable spike on the nose that extends to change the shape of the nose and alter the impact of the sonic boom. Lab testing has shown that the spike can reduce the sound of the boom, resulting in a boom that is quieter than that of the Concorde supersonic airliner by a factor of 10,000.
The spike testing on the F-15 was done to verify the structural integrity of the system, not its sonic boom suppression capability. There was some testing of the shock wave created by the spike, said a Gulfstream spokesman, but the F-15 installation won’t have much of an effect on its sonic boom. Funds for the Quiet Spike come from Gulfstream’s research and development budget, the spokesman said, but until and if the FAA changes the regulations that prohibit sonic booms in the U.S., “there’s no case for us being involved in a supersonic business jet.”