May 19 2004
A team led by The Boeing Company has successfully used advanced materials in the design, development and testing of a revolutionary new helicopter rotor that could benefit all rotorcraft.
The Smart Material Actuated Rotor Technology (SMART) system offers an 80 percent vibration reduction, a jet-smooth ride and other benefits. It employs existing materials to drive on-blade trailing edge flaps to reduce vibration and noise and improve aerodynamic performance. Whirl tower testing was conducted by Boeing at its Mesa, Ariz., rotorcraft facility. The $10 million joint program teaming Boeing with the Defense Advanced Research Projects Agency (DARPA), NASA, the U.S. Army and three universities achieves unprecedented aerodynamic flow control.
The goal of DARPA’s Smart Materials and Structures Demonstration program is to create a shift in the design of undersea vehicles and torpedoes, aircraft wings, engine inlets, and helicopter rotor blades.
The rotor system is now ready for forward flight testing to quantify significant improvements in vibration, noise, and aerodynamic performance expected. With completion of wind tunnel and/or flight testing, commercial, military, and unmanned helicopters could incorporate this technology within five years.
The SMART active flap rotor system used for the whirl tower tests is a modified five-bladed, bearingless MD 900 Explorer helicopter rotor. Each 17-foot long blade incorporates actuator assemblies that move a single flap on its trailing edge. During 13 hours of whirl tower testing, the flap actuators operated for seven hours under a full range of conditions.
“These successful whirl tower tests demonstrated that the active flap system works in full scale, confirming it meets the requirement,” said Friedrich Straub, Boeing principal investigator in Mesa. “This can provide up to 80 percent vibration reduction and reduce noise for a helicopter passing overhead.”
The vibration reduction and performance improvement should provide a jet-smooth ride, significantly reducing helicopter life cycle costs, increase productivity and fleet readiness. Proving the integration, robust operation, and authority of the flap system was the key objective met by the whirl tower tests.
“This technology development program evaluates the potential of dynamically morphing blade structures to achieve revolutionary improvements in rotorcraft performance and mission capability,” said William Warmbrodt, chief of the Aeromechanics Branch at NASA Ames.
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