NASA crash tests polka-dot chopper to study safety

Monday - 9/2/2013, 12:59pm EDT

NASA's Martin Annett on the Federal Drive with Tom Temin and Emily Kopp.

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"Three...two...one...release."

Those words were heard Aug. 28, at the NASA Langley Research Center in Hampton, Va., as researchers crashed a helicopter from a height of 30 feet to the ground.

Researchers used a 45-foot CH-46 helicopter for the crash, outfitted with 13 crash test dummies and several high speed cameras.

"NASA is focused on the crashworthiness of the airframe — what can you do to the airframe to improve it, as we change materials and go into new technologies and different designs for the future," said NASA's Martin Annett on the Federal Drive with Tom Temin and Emily Kopp. Annett was the lead test engineer for the fuselage crash.

The original intent of the crash was to test the crashworthiness of just the aircraft itself, Annett said. Researchers chose the particular model of helicopter because it had an airframe typical of many civilian and military rotary crafts, making it a good baseline for the test.

But the Navy and Army wanted in on the test, too. They provided prototypes and new designs of restraints and seats. NASA researchers installed the systems into the helicopter and strapped in some of the dummies.

"What we tried to do as best as possible was set up comparative experiments. For instance, if there was a seat that had a specialized restraint, we put it against a standard restraint that's used in the military," Annett said. "We don't get a chance to do something this large with this much data too often."

The researchers at Langley also painted the helicopter with several black polka dots, and not just for decoration.

"We had about 8,000 dots that were an inch in diameter," Annett said. "We wanted to use that to measure the deformation of the airframe as it hit the ground."

Using high speed cameras, the engineers were able to record and track the dots, to determine the relative motion at each point. The cameras film at 500 images per second, allowing researchers to "see exactly how the fuselage buckled, bent, cracked or collapsed under crash loads," according to a press release from NASA.

The cameras inside the helicopter were able to provide a detailed account of what happened on board.

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"It's pretty amazing to look at some of the video and what happened during the impact," Annett said. From their preliminary observations, the researchers found that some dummies had fallen on top of each other, while the energy absorbent seats seemed to bare the impact well. They will continue to investigate and further analyze the data.

Annett said NASA's goal from this test is to "get [the new] systems on board and have them optimized for crashworthiness." This ultimately will make helicopters quieter, safer and able to carry more passengers and cargo. The improvements may also allow helicopters to be used more extensively in the airspace system.

Another helicopter crash test is planned for next year.

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