Northrop Grumman unveils quiet, supersonic aircraft

Flight Journal, Feb 2003 by Pace, Steve

n late 2002, Integrated Systems sector of Northrop Grumman Corp. unveiled a design for "an efficient and capable longrange supersonic cruise aircraft that would operate with a less intense supersonic boom."

The design, or "preferred system concept," which includes variants for a long-range military-- strike aircraft and a civil-business jet, is part of Northrop Grumman's work under the Defense Advanced Research Project Agency's (DARPA) Quiet Supersonic Platform (QSP) program.

The concept calls for a joined-wing air vehicle that is 156 feet long with a 58-foot wingspan. It features a dorsal (top-mounted), active, isentropic engine air-inlet system, extensive laminar-flow aerodynamics and wings with an adaptive leading edge. The preferred concept meets DARPA's QSP goals of 0.3 pound per square foot initial [sonic] boom overpressure (approximately seven times lower that that of the Concorde), a speed greater than 2.0 Mach number (about 1,480 miles per hour) and a range of 6,900 miles.

Northrop Grumman worked with Raytheon Aircraft Co., its principal subcontractor during Phase I, to explore synergies with the civil sector. To evaluate the dual relevance of these technologies, Raytheon designed the variant for the civil-business jet, while Northrop Grumman designed the military long-range strike variant.

In Phase II, a Northrop Grumman F-5E Tiger 11 with a modified fuselage will demonstrate sonic-boom flight at NASA Dryden Flight Research Center at Edwards Air Force Base in California. The modified F-5E is expected to produce a specially "shaped" sonic-boom signature with significantly less intensity than the conventional signature produced minutes earlier by an unmodified F-5E. -Steve Pace