Resumen de Hushed up
Powell considers on the possibility of quiet supersonic airliners. NASA now has a design called the Quiet Supersonic Technology X-plane, which it reckons will produce a boom that sounds about 40% quieter than Concorde's. A real test flight of the X-plane is now being planned for. In softening the boom at frequencies they can hear, it will shift more shock waves to inaudible frequencies.
