Shoot 'Em Up
Sometimes you have to destroy the aircraft in order to save it.
- By Carl Hoffman
- Air & Space magazine, November 2002
(Page 4 of 4)
The day after my tour of the boneyard, I meet up with Manchor in the K-2 test pad control room. After the shot is fired, Manchor will try to run the helo at full power for 30 minutes—to simulate the time it would take for a pilot and crew to make it back to friendly territory.
“Okay, starting engine one,” says Chris Fisher, toggling a switch beneath a computer monitor displaying the helicopter engine’s vital signs. One of the five television screens shows the helo in full view, its rotors starting to spin. “Good start on one,” he says. “Moving to two.” The rotors spin faster, and Manchor watches oil pressure and engine temperature rise. Computers have already modeled the effects of this shot at the control link, and real shots have been fired at identical links under load in a static test stand, but those tests don’t show what this test will: what happens in response to a hit when all the forces are at work on the MH-60 in a hover. “We want to see if it fails, and if it fails gracefully or catastrophically,” says Manchor. A graceful failure means that even if it breaks, nothing else happens and the helicopter continues to fly.
The possibility of a catastrophic failure is the reason we’re hunkered down behind steel plates. The link could fail and start a cascade of other, far more deadly failures. Tests on the AH-1 Cobra are a classic example. Shots at the rotor blades and rotor drive controls under static load produced no surprises. But the results were very different when in 1996 the WSL conducted the first test of fast-moving rotor blades and rotor-drive train components while the Cobra was strapped under full power in a hover—a helicopter’s most stressful flight envelope. (The test was conducted not to teach the engineers how to improve the survivability of the helicopter but to develop methods for testing rotor components.) A video of the test shows shots at the end of the blades taking out chunks but affecting no other part of the helicopter; a shot near the rotor root, however, caused the rotor system to start vibrating, and in milliseconds the blades, traveling at 500 mph, sliced through the helo’s tail while the rotor mast transmission went flying 600 feet. One shot and the Cobra was dead.
In a few minutes Fisher pushes the helo to full power and lifts it off. Air bags atop and below four attach points deflate slightly, leaving the MH-60 in a hover. When Manchor sees the red dot of a gun-mounted laser reflecting off a piece of tape on the control link, which is spinning at some 250 revolutions per minute, he nods. “Start sequence,” says Tim Taylor, who is operating the firing system. “Five, four, three, two, one…”
Exactly what happened 0.0012 second later is classified, but Manchor will say that the tests showed “nothing unexpected,” and later, at the China Lake boneyard, I can see from a distance that the MH-60 is intact.
Over the next three years Manchor’s tests will grow potentially more destructive (when he starts shooting the rotors themselves, for example), and it seems hard to fault their realism. Then again, this is a helicopter, which is expected to fly into the kind of threats it’s being tested against. What worries people like Chuck Myers and Jim O’Bryon is that new stand-off precision weapons and low-observable technology may make people think they’ll never get hit, undermining the work at China Lake. “People on [the Joint Strike Fighter] say the plane will never have to fly lower than 15,000 feet,” says Myers. “But the day will come when it’s daylight and overcast, and you’ve got troops fighting other troops in jungles or forests or a city, and you’ll have to. In peace people think you’ll never get hit. But I flew B-25s in World War II and got hit. I flew F-9s off carriers in Korea and I got hit. If your testing causes improvements that extend the time you can stay with your aircraft for three to 10 minutes, man, that’s a big thing!”
Just how big was proven in early March, when U.S. and Afghan forces attacked al Qaeda and Taliban holdouts in one of the biggest battles of the Afghan war. Seven Apache helicopters provided close air support. The Apache had been subjected to—and redesigned based on—live-fire testing. All seven helicopters were hit. And all seven managed to limp home.