Lockheed Martin’s version of the Hypersonic Air-breathing Weapon Concept missile demonstrator set a record for hypersonic flight under scramjet power in a just-revealed March flight test, the Defense Advanced Research Projects Agency confirmed.
The flight test likely achieved about 327 seconds of hypersonic flight under scramjet power, versus 200 seconds achieved by the Boeing
X-51 Waverider in 2010, based on figures provided by DARPA.
“DARPA, in partnership with the U.S. Air Force, recently completed a second successful test of a Hypersonic Air-breathing Concept, known as HAWC,” Stefanie Tompkins, head of DARPA, told the Senate Armed Services subcommittee on emerging threats and capabilities. “This test set a record for scramjet endurance, and we believe it’s an inflection point on the path to reclaiming U.S. leadership in hypersonic weapons.”
Tompkins did not provide details, but DARPA issued a release saying it had flown the Lockheed HAWC 300 miles at altitudes up to 65,000 feet. Scramjets require supersonic speeds to ignite, and are boosted to those speeds by a detachable rocket. Since hypersonic flight begins very quickly after the rocket fires, most of the 300 miles would be flown under scramjet power.
At 65,000 feet, the speed of sound is 660 mph. Hypersonic flight is considered above Mach 5, or five times the speed of sound, meaning the HAWC’s speed at that altitude would be at least 3,300 mph. At that speed, 300 miles would be covered in 1/11 of an hour, translating to a flight time of 5:45 minutes, or about 327 seconds.
“We were at hypersonic speeds for the majority of that distance, and it would be a longer flight than X-51,” a DARPA spokesman said in response to that calculation.
Tompkins’ testimony remark also suggests the duration of flight by the Lockheed HAWC bested the performance of the competing Raytheon HAWC, which made a free flight in September 2021. Few details of that test were revealed, although it was touted as a success by DARPA.