Why would NASA engineers deliberately crash a helicopter? To test a safety shield, of course -- one that could someday be used to make the cars we drive safer.
A small helicopter, donated by the U.S. Army for NASA's research program survived a 35-foot plunge to the ground intact, thanks to a lightweight honeycomb structure that bore the brunt of the impact.
The honeycomb shield, made of Kevlar 129 -- the same material used to make bulletproof vests -- was attached to the underside of a 3,000-pound MD-500 helicopter at NASA's Langley Research Center in Hampton, Va.
The shields can be made of any material, as it is the structure of the honeycomb that provides the strength and flexibility to cushion the impact.
"The beauty of the honeycomb is that it will allow you to customize," Kellas said. "We like composites because we have more options for tailoring, but they can be made out of any material you want."
For the test, which took place earlier this month, the craft was suspended in the air with cables. Restraints were released, allowing the helicopter to fall, and just before it hit the ground, explosive devices fired to break the cable. Four crash dummies, including one with simulated internal organs, were seated inside.
The impact was equal to what would be considered a relatively severe crash at about 33 miles per hour.
"(Without the shield) we know that the occupants would have severe injuries, or death, and the helicopter would be severely damaged," project engineer Sotiris Kellas told Discovery News.
"Even the helicopter skids survived," Kellas said. "We thought they would snap off."
The team will learn exactly what would have happened without the shield when they crash the same helicopter -- san honeycombs -- early next year.
"We did the (shield) test first because we wanted the helicopter to survive," Kellas said.
More work remains on a system to deploy the structure, as well as sensors to detect when a crash is imminent.
Kellas hopes the shield will one day be incorporated into cars, particularly small vehicles that have little material for crunching in case of collisions.
"What's available today is not enough protection for a side impact," Kellas said. "There isn't anything that an internal structure (like an airbag) can do for you."
He also points out that an airbag is only good for a single impact, while many collisions involve multiple strikes.
"In the scheme of things, there's a lot of time for front airbags to do their thing (as the front of a car is crushed) but there isn't a lot of time for side airbags to deploy," said Russ Rader, with the Insurance Institute for Highway Safety. "There's always room for improving these systems."