Engineers from the Naval Air Warfare Center Aircraft Division , collaborating with NASA, the Federal Aviation Administration, the U.S. Arm...
Using 13 dummies and two manikins simulating crew and passengers, information was collected from onboard computers with 350 channels of data and from 40 cameras located inside and outside a retired CH-46 Sea Knight helicopter, once used as a medium-lift rotorcraft for the U.S. Marine Corps.
The Transport Rotorcraft Airframe Crash Testbed full-scale crash test program was conducted at NASA Langley's Landing and Impact Research (LandIR) Facility.
LandIR, a 240-foot high, 400-foot long gantry, has an almost 50-year history. It started out as the Lunar Landing Research Facility, where Neil Armstrong and other astronauts learned to land on the moon. Then it became a crash test facility where engineers could simulate aircraft accidents. And recently it added a big pool where NASA is testing Orion space capsule mock-ups in anticipation of water landings.
Accelerometers, instruments used to measure speed and motion, recorded the effect of the crash on the dummies.
The helicopter was dropped by cable off a metal super-structure from a height of 31 feet, hitting a bed of soil on the ground at 30 mph. The combined vertical and horizontal impact simulated a realistically severe, but survivable condition for both civilian and military helicopter occupants.
“While we have increased the crash standards for military helicopters, we now fly faster and crash harder as a result of higher performance aircraft design,” said Lindley Bark, Naval Air Systems Command (NAVAIR) crash safety engineer and lead NAVAIR engineer for the test. “The results of this test will be studied and applied to the Navy’s next generation of rotorcraft.”
Several seat designs were tested representing standard troop benches to modern civilian aircraft passenger seats. Crash dummies were also used to test different types of restraints, from lap belts to the new pretensioning aircrew restraint systems. Engineers are particularly interested in how the seats and restraints will work with composite material helicopter designs, officials said.
“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, NASA-Langley's lead engineer for the test. “The data from the instrumentation on the crash dummies recorded reaction before, during and after the impact.”
The CH-46 Sea Knight was one of two helicopters transferred to NASA from NAVAIR’s Specialized and Proven Aircraft Program office (PMA-226) for testing.
The Navy provided the CH-46 Sea Knight helicopter fuselages, seats, a number of crash test dummies and other experiments for the test. The Army contributed a crash test dummy that is lying down similar to a patient on a medical evacuation litter. The FAA provided a side facing specialized crash test dummy and part of the data acquisition system. A private company, CONAX Florida Corporation DBA Cobham Life Support in St. Petersburg, Fla., also contributed an active restraint system for the cockpit.
NASA will use the results of both tests to try to improve rotorcraft performance and efficiency, in part by assessing the reliability of high performance, lightweight composite materials. Researchers also want to increase industry knowledge and create more complete computer models that can be used to design better helicopters.
The ultimate goal of NASA rotary wing research is to help make helicopters and other vertical take off and landing vehicles more serviceable – able to carry more passengers and cargo – quicker, quieter, safer and greener. Improved designs might allow helicopters to be used more extensively in the airspace system.
Another crash test of a similar helicopter equipped with additional technology, including composite airframe retrofits, is planned for next year. Both tests are part of the NASA Aeronautics Research Mission Directorate's Fundamental Aeronautics Program Rotary Wing Project.
