Northrop Grumman's Oblique Flying Wing (OFW) program will not proceed to an X-plane flight demonstrator. The U.S. Defense Advanced Research Projects Agency confirms that OFW has concluded following the preliminary design effort.

The OFW was a tailless variable-geometry flying wing designed to combine long subsonic loiter endurance with high supersonic dash speed. By increasing sweep as the aircraft accelerated, the leading edge always remained within the shock cone, reducing drag.

DARPA says the first phase built up an aerodynamic database from more than 1,000 subsonic and supersonic test runs using a dual-sting wind tunnel model to allow variable-sweep testing with force and moment balances in each of the stings, which hold up models in tunnel testing.

The proposed unmanned subscale X-plane demonstrator was to use trailing-edge and inlaid surfaces for flight control, and two afterburning J85 engines mounted in swiveling pods under the wing.

Northrop Grumman, meanwhile, has received a two-year, $5.7 million DARPA contract for the Advanced Technology Survivability Demonstrator. The research agency say it cannot provide any details on the program.

Artist's concept: DARPA