Designed to cruise at an altitude of 60,000 feet at speeds of Mach 1.6 to 1.8 (approximately 1,218 to 1,370 statute miles per hour) with a range of 4,600 statute miles, the two-engine gull-wing aircraft was designed to create a sonic boom only 1% as strong as that generated by the Concorde.
SAI invited engine proposals from General Electric, Pratt & Whitney and Rolls-Royce. Each of the QSST's two engines must generate 33,000 pounds of thrust, comparable to the power of engines for midsize airliners. SAI had planned to select an engine once an international consortium to manufacture the jet was completed, achieve first flight in 2017, and begin customer deliveries by 2018. The price per aircraft was expected to be about $80 million.
The QSST was designed to generate a much quieter sonic boom than previous supersonic aircraft, claimed to be 1/100 that of the Concorde. This result is achieved by increasing the ratio of length to wingspan, using canards, and ensuring that the individual pressure waves generated by each part of the aircraft structure reinforce each other less significantly, producing a light rumble on the ground without an objectionable sonic boom like conventional supersonic aircraft.