The Vehicle Technology Directorate of the Army Research Laboratory (ARL) led a workshop with Defense Advanced Research Projects Agency (DARPA) recently to develop a cohesive plan that incorporates government, industry and academic interests in maturing plasma actuation into a new technology that will advance the Department of Defense rotorcraft performance beyond current capabilities.

ARL is looking into the use of plasma-actuation, which could impact DARPA’s Mission Adaptive Rotor (MAR) programme’s ongoing investigation of smart structures and aerodynamic flow control approaches to improve rotorcraft capabilities.

Workshop planner Dr Bryan J. Glaz, an ARL research aerospace engineer, said that plasma actuators appear to immediately address some key attributes of onblade actuation. “They’re lightweight, have low to no volume, and are durable. These are critical aspects since technologies that add too much weight interfere with blade structural dynamic design, or that cannot survive the loads that rotor blades are subjected to will not buy their way onto mainstream fleet vehicles. In addition to enhancing rotor thrust, they could also potentially be used to reduce vibratory loads or acoustic signature since they have high bandwidth performance far above rotor rpm, or revolutions per minute.

According to DARPA’s website, the MAR programme seeks to dramatically improve system performance, operational availability, sustainability, and survivability of rotorcraft, including reduction in acoustic susceptibility and rotor vibration while increasing useful payload fraction and range. The goal is to develop and demonstrate the capability to achieve these improvements through the use of technologies that enable adaptation of the rotor throughout military missions and/or mission segments.

Glaz said: “Although aerodynamic flow control has long been recognised as necessary for achieving substantial breakthroughs in rotor blade aerodynamic performance, no on-blade flow control technologies are currently fielded because they weigh too much, consume too much power, and/or are ineffective at full-scale aerodynamic conditions.”

ARL’s Vehicle Technology Directorate is interested in a new way of using plasma actuators that shows potential for working under the aerodynamic flow conditions associated with full-scale rotor blades.

“The ideas that VTD is interested in are new and have not yet been fully investigated. There is substantial work that needs to be done in order to determine if plasma will be a new active rotor technology,” Glaz said. “So we are working with DARPA and other government agencies (Army, Navy and NASA) to determine how we can combine resources to mature this technology. There is substantial interest from the other government agencies, industry, and academia because everyone recognises the impact to future rotorcraft capabilities if successful.”