AMRDEC Public Affairs
REDSTONE ARSENAL, Ala. — Army rotorcraft of the future will depend on the imaginations and engineering prowess of scientists, researchers and aviators at the U.S. Army Research, Development and Engineering Center.
AMRDEC’s Aviation Development Directorate maintains a deep portfolio of science and technology project looking at current and future rotorcraft, including survivability, performance and affordability.
Rusty Graves, the directorate’s acting chief engineer, hopes to use science and technology to enhance the legacy fleet while supporting Future Vertical Lift until it transitions to the Program Executive Office Aviation.
“We manage and conduct basic and applied research, and advanced technology development to provide one-stop life cycle engineering and scientific support for aviation systems and platforms,” Graves said.
AMRDEC divides the directorate’s S&T efforts into six focus areas.
Basic Research develops the fundamental understanding of vertical-lift phenomena that is the foundation of the more applied research in the other aviation focus areas. Understanding rotor aerodynamics and aeromechanics is our toughest challenge, said Dr. Mahendra Bhagwat, focus area lead.
Experimental work in the focus area involves investigations of rotor wakes and their interactional aerodynamics effects. Novel flow-control techniques are developed using plasma and fluidic actuators in order to reduce fuselage drag to eventually allow the aircraft to fly faster. The focus area also helps to validate advanced flow control and diagnostics through experimentation.
Computational work in the basic research focus area is the theoretical basis for S&T modeling and simulation capabilities. “Our computational aeromechanics team,” Bhagwat said, “is developing a new grid-generation paradigm with strand grids. These grids allow the users to easily generate complete aircraft simulation models with sufficient resolution that is required to achieve the accurate and high-fidelity simulation that is essential to good design.”
External research is supported through the Vertical Lift Research Centers of Excellence at the Georgia Institute of Technology, Pennsylvania State University and the University of Maryland. The centers do cutting-edge research in aeromechanics, structures, flight dynamics and control, design, concepts, vibration, noise control, propulsion, affordability and safety, while training future rotorcraft scientists and engineers.
DESIGN & ASSESSMENT
Bruce Tenney’s Concept Design & Assessment focus area uses research from Bhagwat’s focus area and its own tools and data to examine new conceptual designs from industry, brokering these with Army requirements staff. The focus area is now concentrating on medium, light and heavy versions of FVL, working with the joint FVL requirements team, which includes the services that would operate FVL.
For example, the focus area translates requirements for troops carried, speed, operating radius and takeoff capabilities into conceptual FVL designs. It has helped the Army understand that its desired capabilities may result in a very large aircraft.
Tenney’s focus area will lay out the FVL family for the FVL requirements team in April.
“This focus area is also developing better computer-modelling tools to simulate unconventional configurations, for which there is no data,” Tenney said. “This streamlines design, allowing adjustments earlier and more economically, and expands design options for all rotorcraft. Besides FVL, modelling can investigate legacy options such as putting a wing on the UH-60 Black Hawk.”
The Platform focus area hunts for improvements in aeromechanics, rotors, structures, vehicle management, flight controls and subsystems, all while decreasing vulnerability.
Lead researcher Jon Schuck’s first priority is advanced configurations to reduce drag for future higher-speed rotorcraft. Active drag-reduction technologies will be tested by Computational Fluid Dynamics in wind tunnels and eventually flight.
Reliability is next, for which Schuck anticipates that certification methods for fixed-wing aircraft will be applied to rotorcraft. Using fly-by-wire techniques in rotorcraft should improve handling, reduce structural loads and lengthen useful lives.
“We seek survivability through internal and external airbags and advanced occupant restraints,” Schuck said. “The Army will move toward crash prediction by using data that senses when a crash is unavoidable to pull crew into safer positions.”
Schuck’s ultimate objective is to ensure that, unless destroyed by superior force, a helicopter can continue the fight.
These innovations are much easier for new aircraft, but the Armament Research, Development and Engineering Center’s Combat Tempered Platform Demonstrator intends to apply improvements to the next major Black Hawk upgrade.
The Power focus area works with engines and drive systems. Lead researcher Kevin Kerner seeks versatile, intelligent engines and drives that improve performance over wide operating ranges, enhance durability and reduce maintenance.
“We are looking at engines and drives with variable-output speed capability,” Kerner said. “These will enable rotor speeds to vary so new aircraft configurations can perform better at high speed. Another initiative is investigating smart filtration, which would improve the reduce the impact of sand and dust on engines.”
Smart filtration is operational when needed against sandy operating environments, but can be turned off for better engine performance when sand is not threatening.
The focus area also works on better diagnostics and prognostics to track engine and drive system health. By extending the maintenance intervals, these tools would increase aircraft availability and reduce maintenance cost, while still preventing catastrophic maintenance surprises.
Kerner said the variable speed technology is more easily appliedto engine designs for new airframes. The other two areas, smart filtration and improved prognostics, could be retrofitted on current airframes.
The directorate recently transitioned Advanced Affordable Turbine Engine technology to the Improved Turbine Engine Program, Kerner said.
The Missions Systems focus area is responsible for five areas:
● Human-systems interface
● Engagements and effects (weapons and sensors)
● Avionics and networking
● Teaming, autonomy and information management
“Information management includes software that runs in the background, assisting pilots in their decision making and making recommendations for pilot actions,” said lead researcher Ray Wall.
This last area involves both manned and unmanned aircraft, he said.
The team is emphasizing handling degraded visual environments, or the brownouts or blackouts that can cause pilots to hit unseen obstacles or roll over after losing orientation due to lack of visual clues.
“To mitigate these sorts of danger, we’re working in three areas, modernized flight controls; advanced sensors for low visibility; and symbology, which would provide visual cues to pilots,” Wall said.
Wall likened symbology to the modern automobile dashboards that give drivers necessary data in a quickly comprehensible format or to the equipment for instrument flight rule flying on aircraft.
The Missions Systems focus area is now concentrating on FVL, but Wall said he also seeks to upgrade legacy aircraft, for example by enabling unmanned aircraft to fly as wingmen to manned rotorcraft.
The major current project is Autonomous System Technology for Rotorcraft Operations, known as ASTRO, which seeks the best technologies for Enhanced Condition Based Maintenance.
“ASTRO is a total-system approach, using automated data “reasoners” to assess system health of engines, drives, structures, rotors and electrical systems,” said lead researcher Brad Miller.
Miller collaborates closely with Kerner on power-train diagnostics and Schuck’s platform technical areas.
“Current health monitoring collects data for analysis by engineers,” he said. “ASTRO will tell mechanics or pilots what is going on in aircraft and recommend actions before failure. It would translate temperature spikes, pressure changes, noises and vibrations into defects and remedies. The concept would be easier to design into FVL, but elements might be retrofitted on legacy aircraft.”
Miller’s goal for the second generation of FVL is zero maintenance, combining ultra-reliable, fatigue-free design, and next generation predictive health monitoring and assessment, to enable significant periods of maintenance-free operation.
“It would be hugely beneficial if maneuver commanders could deploy for 30 to 90 days without worrying about maintenance, except for battle damage,” Miller said.
Today’s deployed rotorcraft may spend hours being inspected and maintained after each day’s operations. Parts like turbine blades require inspection every couple hundred hours. Miller seeks at least 300 hours of no maintenance and, ideally, synchronized with the planned upgrade schedule.
Miller works with the Army Research Laboratory to integrate their fatigue-free platform concept with zero-maintenance. ARL is developing techniques to detect micro-cracks and other damage pre-cursors before they become problems. They are building a better understanding of fatigue so planners can modify how aircraft are flown to extend their remaining useful life. ARL is also developing a concept for Virtual Risk-informed Agile Maneuver Sustainment, or VRAMS, to provide real-time predictive health monitoring and assessment to the crews and the commander.
Researchers said there is a good deal of collaboration among the six focus areas, especially in basic science and the tools for simulating and predicting performance of rotorcraft and systems.
“We are maturing technologies to maintain the relevance of our current fleet and develop technologies to support the future fleet,” Graves said. “Our goal is to provide the Army with the decisive edge and support our Soldiers.”
This article appears in the March/April 2015 issue of Army Technology Magazine, which focuses on aviation research. The magazine is available as an electronic download, or print publication. The magazine is an authorized, unofficial publication published under Army Regulation 360-1, for all members of the Department of Defense and the general public.
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