Quiet Supersonic Transport or QSST is the name of a project by Supersonic Aerospace International (SAI) to develop a private supersonic business-class jet.
Lockheed Martin's Skunk Works has been developing the project for six years under a $25-million contract from SAI. Designed to fly between Mach 1.6 and 1.8 (1,056 to 1,188 miles per hour), the two-engine gull-wing aircraft would leave a sonic wake that's only one hundredth the strength of the Mach 2-capable Concorde.
Another concept aircraft being designed by the Skunk Works is the QSP or Quiet Supersonic Plane with a single engine, single tail, and long slender fuselage. This design is to eliminate the sonic boom problem of Mach 1 plus aircraft. The QSP version is for both military and commercial usage.
When an aircraft travels faster than the speed of sound, it creates pressure waves in the air that collide with one another faster than they can dissipate, resulting in a loud crack, or sonic boom. The QSST, though it shares its general shape with Concorde, it is less than half the size and uses fine-tuned aerodynamics to control the pressure generated as the plane displaces air at supersonic speeds. With air disturbances along the craft evened out, the QSST generates more shockwaves of smaller magnitude rather than two explosive reports. Tom Hartmann, the program manager at Lockheed, expects the boom to be imperceptible—quieter than a kite flying overhead.
Another key to quiet flight is its broad distribution of lift-generating surfaces. The QSST's canards—the small wings near the front of the fuselage—and swept-V tail provide substantial lift, preventing the sharp, sonic-boom-generating pressure change typical of larger, wider wings.
Future of QSST
SAI is evaluating engine designs from General Electric, Pratt & Whitney and Rolls-Royce for a unit that produces 33,000 pounds of thrust (on par with a midsize airliner), for 66,000 pounds of total thrust from two engines. Michael Paulson, the founder of SAI plans to settle on a design in the next year, assemble an international consortium to manufacture the jet, and put it on the market by 2014 for about $80 million. He'd like to roll out a fleet of 300 to 400 in the next 20 years.