NASA engineers used a former Marine helicopter on Wednesday to conduct what they say is one of the most ambitious aircraft crash experiments they’ve ever attempted at Langley Research Center, which will ultimately help design better and safer helicopters.
The 45-foot-long fuselage of a CH-46 Sea Knight was hoisted 30 feet in the air before its cables were released, allowing the helicopter full of test dummies to free fall at a slight angle and slam into a pile of soil at 30 miles per hour.
NASA officials say the impact conditions represented a severe but survivable crash. Upon impact, there was no explosion and the helicopter remained intact. There was a brief thud after the helicopter hit the ground and skipped along the surface for a few feet before coming to a rest. Still, NASA officials say they weren’t looking for Hollywood-style drama. They just needed data, and the amount of data they’ll have to sort through from the crash test is striking.
There were almost 40 cameras inside and outside the helicopter recording how 15 test dummies reacted before, during and after the crash. Some of the occupants were standing for the crash, while others were placed in side-and forward-facing seats. Others were on a patient litter that would carry wounded troops.
The helicopter itself was painted with black polka dots over a white background, which allowed cameras filming 500 images per second to record each dot. That allows researchers to examine exactly how the fuselage moved under crash loads. Onboard computers also recorded 350 channels of data, and technicians installed an XBox Kinect video game motion sensor in the helicopter to see how it fared recording data.
“I think it’s the most ambitious test we’ve done in terms of the instrumentation and in terms of the video coverage we have on board,” said Martin Annett, the crash test’s lead test engineer.
To qualify as an ambitious test at Langley isn’t easy, considering the research facility gantry’s nearly 50-year history. Langley served as the host to the Lunar Landing Research Facility, where Neil Armstrong and other astronauts learned to land on the moon. Numerous other aircraft crash tests have also been conducted on the facility’s gantry, a 265-foot-wide, 400-foot- long A-frame steel structure that’s used to lift and drop heavy objects. Langley’s gantry has recently been used to conduct water-landing tests for the Orion space capsule, which will eventually take astronauts to deep space.
Wednesday’s test was a joint effort of NASA, the Navy, Army and the Federal Aviation Administration. While NASA is primarily interested in improving the airframe of a helicopter, the military expressed interest beyond that.
“The Navy was interested in virtually every aspect of this particular crash test, from the fuselage structure to the cockpit seating,” said Lindley Bark, a crash safety engineer at Naval Air Systems Command on hand for the test. “Even the passenger airplane seats in there were important to us because we fly large aircraft that have the same type of seating.”
Among other things, the crash tested out how improved seatbelts in the cockpit and a different type of gunner’s belt would fare. While the Marines are phasing out the Sea Knight helicopter, Bark said the information gathered from the crash test would be valuable to apply to other helicopters.
“It’s extraordinarily useful information. … If my career lasts another 20 years, I will use this information for the next 20 years,” Bark said.
NASA plans to test crash a similar helicopter next year that has different technology, including composite airframe retrofits.
Original article: www.marinecorpstimes.com