X-51A Achieves Successful Combustion on JP-7

  • Published
  • By Propulsion Directorate
  • AFRL/PR
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  AFRL engineers began tests on the SJX61-1 engine using the National Aeronautics and Space Administration Langley Research Center's 8-foot high-temperature tunnel. 

The Pratt & Whitney Rocketdyne SJX61-1 (or X-1) is a hydrocarbon-fueled scramjet [supersonic combustion ramjet] engine featuring full X-51A flight hardware: flowpath, F-119 full-authority digital engine control/fuel control, and closed-loop thermal management system. 

The X-1 successfully completed its first ignition on ethylene fuel and transition to JP-7-only operation at Mach 5 simulated flight conditions. This successful effort is a critical step in the development of the X-51A integrated propulsion system and marks the first time the AFRL HyTech scramjet engine has been tested in a simulated "full flight" integrated propulsion configuration (which includes both a full vehicle forebody/inlet and nozzle).

The X-51A Flight Test program plans to demonstrate the AFRL HyTech scramjet engine within the Mach 4.5 to 6.5 range with four flight tests, beginning in Fiscal Year 2009. 

The X-51A program is a collaborative effort between the Air Force; the Defense Advanced Research Projects Agency; Boeing (Huntington Beach, California); and X-1 builder Pratt & Whitney Rocketdyne. The flexibility of the X-1 control system and the hard work of the joint NASA/Pratt & Whitney Rocketdyne test team made the successful test a reality. 

Subsequent tests will verify engine performance and operability across the X-51A flight envelope and characterize the closed-loop thermal management system. The X-1 is the first of two ground engines planned in the X-51A Flight Test program.