Lockheed Martin and Northrop Grumman receive funding boost to continue systems research and refine their designs

Boeing and Pratt &Whitney have been eliminated from the US Defense Advanced Research Agency's (DARPA) Quiet Supersonic Platform (QSP) programme as the effort to develop technology for a long-range, low-boom strike aircraft enters its second phase. DARPA has also narrowed the missions and technologies to be investigated.

Lockheed Martin has received $2.4 million, and Northrop Grumman $2.7 million, to continue systems studies conducted during the year-long first phase of QSP. Both will be refining their designs to meet revised programme goals, which now focus on a long-range, rapid-response supersonic strike aircraft. Phase I studies under the two-year, $35 million, QSP programme were also relevant to a supersonic business jet.

Phase I focused on reducing sonic boom and demonstrated that "high efficiency and low boom could be achieved simultaneously in a properly integrated vehicle", says DARPA. In the year-long Phase II, vehicle designs "will be optimised to meet revised sonic boom goals while maximising range and payload performance", the agency says. The QSP is a 45,000kg (100,000lb) gross-weight aircraft capable of cruising at Mach 2.0-2.4 with an 11,000km (6,000nm) range and payload fraction of 20%.

Lockheed Martin and Northrop Grumman will work with engine manufacturer General Electric to quantify the desirable propulsion system performance, size and weight. GE is studying the QSP propulsion system and maturing advanced fan and high-performance nozzle technology, under a $3.4 million Phase II contract. Phase I showed that highly integrated inlets and nozzles are required to reduce boom and increase efficiency.

Arizona State University has received $700,000 to demonstrate that distributed roughness promotes drag-reducing natural laminar flow on swept wings. Phase I studies showed that micro-scale roughness can inhibit cross-flow instabilities and delay the transition from laminar to turbulent flow on a swept wing. Supersonic natural laminar flow using thin unswept wings and offboard energy addition to reduce boom did not make it into Phase II.

Source: Flight International