First supersonic weapon release system tested at Holloman

  • Published
  • By Staff Sgt. David Wagstaff
  • 49th Fighter Wing Public Affairs
HOLLOMAN AIR FORCE BASE, N.M. --  Members of the 846th Test Squadron and the Boeing Corporation have successfully demonstrated how an innovative application of a technology called active flow control enables - for the first time - munitions to be safely released from a weapons bay at high supersonic speeds. 

During a recent test at the High-Speed Test Track at Holloman, researchers from the Air Force Research Laboratory and Boeing Phantom Works used a rocket sled and active flow control to successfully release a MK-82 Joint Direct Attack Munition Standard Test Vehicle at a speed of about Mach 2 (twice the speed of sound) from a weapons bay with a size approximating that of the Air Force B-1 bomber. 

"This technology will enable future war fighters to safely dispense weapons at supersonic speeds around Mach 2," said John Leslie, 846 Test Squadron Test Manager. 

The active flow control configuration used in the High Frequency Excitation Active Flow Control for Supersonic Weapon Release (HIFEX) rocket sled test is a tandem array of microjets upstream of the weapons bay. Wind tunnel testing indicated that, without active flow control, the JDAM test vehicle would have returned to the bay. 

"Sled track testing is the only viable means of performing this type of test," said Kamal Shouman, 846 Test Squadron Test Engineer. "There is no aircraft in the current Air Force inventory capable of performing this test. And if there was, no one would be willing to risk that asset and the pilot to perform this test." 

The sled used in the HIFEX test was designed by the U. S. Air Force 846th Test Squadron and the Support Systems unit of Boeing Integrated Defense Systems. At 65,700 pounds, it was 26,000 pounds heavier than any sled tested in more than 10 years but was faster by 400 feet per second. In the 57-year history of the Holloman High-Speed Test Track, it was the heaviest sled train to reach Mach 2. 

Powered by two pusher sleds, the HIFEX sled achieved thrusts of 438,000 pounds for about 5.9 seconds on the first stage, 575,000 pounds for about 3 seconds on the second stage, and 115,000 pounds for about 3.6 seconds on the third stage. The JDAM test vehicle was dispensed during peak velocity, which was about 2,000 feet per second. The sled train accelerated to more than 13 g's to get to peak velocity, then decelerated at 7.5 g's for more than a mile to stop. 

"Accelerating a 65,700 lb sled train to mach 2 (approximately 2250 ft/sec at Holloman AFB) and stopping it on track was an engineering challenge, but thanks to the foresight of our predecessors we had two high thrust pusher sleds available for this task," said Shouman. "The biggest engineering challenge of this program for us was the design and fabrication of the unique forebody sled. This sled had to be a scaled up version of the wind tunnel model so that data could be compared, and, due to its shape it had a huge lift load at Mach 2." 

The 846th Test Squadron, Boeing, Waveflows, and EPIC Systems will conduct additional testing of the full-scale HIFEX system in 2008. Air Force Research Laboratory intends to use active flow control technology from HIFEX to develop full-envelope weapon release systems for future Air Force Global Strike aircraft. 

(additional information for this story was supplied by the Boeing Corporation)