Future Directions: Navy Essential Programs

1. AGENDA (PM) Future Directions: Navy Essential Programs, 12:30 - 2:30 PM - Smart Structures Based Nonthermal Anti-Icing - Rotor Flowfield / Ship Airwake Coupling During Shipboard DI - Active Rotors for Enhanced Shipboard DI Operations - Variable Geometry Compact Rotors for Sea-Based Missions - Active and Passive Mitigation of Rotor Blade Erosion - Lightweight, Ballistically Protected Rotor Blades - Robust Aero-Mechanical-Avionics HUMS Systems - Aeromechanics of Rotary Wing IED Sensor Platforms - Crashworthy Systems for High Mass Payload Items - Optimal Propulsion System Design for Variable Speed Rotors Wrap-Up and Adjourn, 2:30 - 3 PM

2. Navy Rotorcraft Missions • • Naval and Marine Corps missions present • numerous unique challenges • - All weather operations (icing, winds, sand, rain) • Dynamic interface with moving shipdeck • Ballistic threats in close air support in insertion • Limited deck space for stowage • Heavy lift for sea-based logistics support • Shipboard maintenance support • Emergency landings and crashes at sea • IED Detection for deployed USMC • Each challenge relates directly to safety, operating costs, and sustainment costs, and mission capability

3. Smart Structures Based Nonthermal Anti-Icing Technical Challenges: State-of-the-art (electrothermal heating blankets) requires high power (40+kVA), results in ice shedding of built-up ice (0.3 inches thick), can damage composite blades, heavy, and not compatible with polymer erosion coatings New Technologies - smart structures (piezo shear tubes And active macro fiber composite patches), ultrasonic And high frequency-based anti-icing, surface waves USN POC: M. Yu

4. Rotor Flowfield / Ship Airwake Coupling During Shipboard DI Operations Technical Challenges: Simulation for pilot training, design of ship landing areas, development of safe shipboard operating procedures requires accurate Prediction of rotor-ship airwake flowfields. Rotor downwash may alter gross ship airwake characteristics. Must capture transient fluid dynamics of flowfield. New Technologies - Advances in high performance computing, parallel processing algorithms, sub-scale Turbulence models and Lareg Eddy Simulations. USN POC: D. Findley, M. Fallon, B. Geyer, D. Gaublome

5. Active Rotors for Enhanced Shipboard DI Operations Technical Challenges: High pilot workload and degraded safety can limit flight operations in bad weather. Conventional FCS authority limited by swashplate and rotor blade response rates. High roll gains can destabilize modern rotor systems (air resonance) New Technologies - Active rotor technology has taken major steps forward. High authority resonant actuation systems, advanced fly-by-wire adaptive flight controllers, flight & wind tunnel tests for active rotors for vibration and noise suppression. USN POC: J. Milgram, B. Geyer, M. Fallon

6. Variable Geometry Compact Rotors for Sea-Based Missions Technical Challenges: Large rotor diameters for high Payloads are pushing the limits of sea base platforms. Elevator geometric limits, complex, heavy blade-fold Mechanisms. New Technologies - Variable geometry rotor programs have started to push the state-of-the-art in rotor design. Variable rotor speed can generate variable CF forces. Adaptive or morphing structures can change rotor diameter depending of flight RRM condition. USN POC: J. Vorwald, M. Yu

7. Active and Passive Mitigation of Rotor Blade Erosion Technical Challenges: Conventional metallic leading edge Coatings have not performed well in sand environments. Tiny sand particles entrain in rotor flowfield and score leading-edge surfaces. Contradictory requirements for mitigation of both rain and sand erosion physics. New Technologies - advanced layered materials to Protect against all type of erosion. Build on recent Navy programs for high temp erosion coatings. Active Flow control for leading edge blowing. Can impede sand particle entrainment by altering boundary layer. USN POC: M. Yu, S. Claus

8. Lightweight, Ballistically Protected Rotor Blades Technical Challenges: Low cost, low tech rifle fire and small arms fire can inflict serious damage to rotor blade structures. Aft blade skins and fuselage skins Can be repaired at low cost. Ballistic damage to rotor blade spar results in high cost blade replacement. Also, new designs for reduced weight (50%) result in loss of adequate torsional stiffness for flutter margins. New Technologies - Lightweight, segmented armor integrated on underside of blade spar. Shear thickening fluidic armor, nano-reinforced flexible matrix composites, and hybrid FMC-CE laminates for high damage tolerance. Grid-stiffened torsion wraps for high torsion stiffness. USN POC: M. Yu, S. Claus

9. Robust Aero-Mechanical-Avionics HUMS Systems Technical Challenges: First generation HUMS systems for drive system components and pilot controls have shown great potential. Reliable and integrated HUMS systems for rotor diagnostics and full-spectum loads monitoring still require substantial development. New Technologies - Active rotor damage detection using both embedded ultrasonic transducers and trailing edge Flaps (build on ONR MURI work and NSF programs). multi-function smart leading-edge mass for anti-icing And local damage detection. Extension of Neural-net loads monitoring methods developed by USN Carderock. Physics based simulation of gearbox diagnostics. USN POC: D. Haas, P. Bi, M. Yu, S. Claus, etc.

10. Aeromechanics of Rotary Wing IED Sensor Platforms Technical Challenges: Advances have been made in development of explosive detection sensors for IEDs. Integration of these sensors with Rotary Wing UAVs involves many critical aerodynamic interactions. Task tailored UAV flight controllers also required for simplified use in the field. New Technologies - Wind tunnel testing, combined with CFD simulation for prediction of flowfield in IED detection operational roles. Particle simulation using high Performance computing algorithms developed under NSF IGERT programs. PIV Flow vizualization methods. USN POC: P. Bi, M. Fallon, D. Findley

11. Crashworthy Systems for High Mass Payload Items Technical Challenges: Crash loadings (20-20-10 g) present worst case design loads for many high-mass items (palettes, engines, fuel). Crashes into water or soft soil dramatically reduce the effectiveness of landing gear shock absorbers. Current technology results in high weight penalties and compromised crew safety. New Technologies - Nastic structures based on Flexible Matrix composites (DARPA), high energy dissipation tearing structures, fuselage design to exploit external Airbag deployment, USN POC: M. Yu, S. Claus

12. Optimal Propulsion System Design for Variable Speed Rotors Technical Challenges: Power transmission design for heavy lift rotorcraft (15000 HP+) requires substantial technical risk. Variable speed rotors, large gearboxes, extensive shafting, excessive noise generation, and High weight all pose challenges to Joint Heavy Lift. New Technologies - New pericyclic, planetary, and conical, and transmission concepts have been introduced. Potential For Multidisciplinary Design Optimization (MDO) in rotary- wing-drive system design, multi-phase flow via CFD for windage loss predictions, active-passive noise control For light-weight composite gearbox housings. USN POC: C. Neubert, M. Yu

13. Tasks Under Development • Application of Reynolds Stress Models of Turbulence to Rotorcraft Problems - (fuselage drag, etc) • Wake Capturing and Interaction with Rotors for Acoustic Prediction • Dynamics and Aeromechanics of High Advance Ratio Rotorcraft • Rotor Rig test/PIV Flow Vizualization - Anti-Erosion Active Flow Control • Tip loss Control in Ducted-Fan Rotary Wing UAVs

14. Tasks Under Development • Adjoint Methods for Minimum Noise Design • Advanced Configuration Rotorcraft Acoustics • Maneuver Noise Prediction and Reduction through Flight Path Optimization • Segmented Rotor with Semi-Active Control for Vibration and Noise Reduction and Performance Improvement • Prediction Methods and Optimal Design for Low Noise Hovering Micro Air Vehicles

15. Tasks Under Development • A Semi-Autonomous Micro Quad-Rotor Unmanned Air Vehicle • Simulation and Control of Rotary Wing UAV's Operating in Shipbaord and Urban Environments • Intelligent Controllers for Multiple Cooperating Rotorcraft UAVs • Intelligent Control for Life Extension and Damage Mitigation on Rotorcraft

16. Tasks Under Development • Rotor load control and gust rejection via active control and passive tailoring • Distributed Actuation for Adaptive Airframe Vibration Reduction (actuators & transient control algorithms) • Active and Passive Vibration Suppression Concepts for Rotorcraft Power Transmission and Driveline Systems • Coherent (Time-Domain) Planetary Gear-Health Monitoring for Damage Detection and Prognosis

17. Tasks Under Development • Distributed Miniature Trailing-Edge Effectors for Rotorcraft Applications • Morphing Rotors Using Bi-stable Mechanisms • Rotor Lag Damping via Advanced FluidLastic Dampers • Rotor Lag Damping with Radial Absorber and Coriolis Coupling

18. Tasks Under Development • Lightweight, Ballistically Protected Rotor Blades • Nonthermal Anti-Icing Systems Based on Smart Embedded Actuators and Sensors

19. Nano-Reinforced Flexible Matrix Composites for Rotor Systems and Airframes • • FMC materials have shown potential for application to highly flexible driveshaft ccomponents. • - Other applications include: • -elastically tailored rotor blades (extension-twist, bending twist) • Conformable airfoil skins • Hybrid graphite/epoxy & FMC laminates for improved damage tolerance • High strain-capable bearingless rotor flexbeams • Each application involves new design, material characterization, and proof testing

20. Shock Isolation of Large Mass Items Using Nastic Structures • Crash safety requirements (20-20-10 g) results in substantial weight additions. • • Crew safety cannot be compromised • • Nastic structures based on flexible matrix • composites may offer combination of high • shock isolation, small stowed volume, and light • weight.

21. Shock Isolation of Large Mass Items Using Nastic Structures • Crash safety requirements (20-20-10 g) results in substantial weight additions. • • Crew safety cannot be compromised • • Nastic structures based on flexible matrix • composites may offer combination of high • shock isolation, small stowed volume, and light • weight.

22. Lightweight Blade Armor System to Prevent Ballistic Damage Current rotor blades vulnerable to expensive damage from small arms fire • Low speed + low altitude increase exposure time to small arms ground fire • Blades must be designed to be damage tolerant = heavy • After spar is damaged, blade must be removed from service = $$ and down time Proposed RCOE Research Contribution • Frangible lower-surface armor segments • Combination of ceramic type plate and flexible matrix or substrate • Segmented into removable pieces along underside of rotor blade • High energy dissipation without appreciable mass loss Transition Plan • Team with industry blade design and materials communities • Team with US Army at Aberdeen • Weight reduction and survivability implications for Heavy Lift Glaze Ice Encountered During Test (Icing Research Tunnel NASA Glenn)

23. Grid-Stiffened Composite Rotor blade Structures for Light Weight and High Torsional Stiffness • - Light Weight heavy Lift rotor designs require extremely high torsional stiffness • - Integral stiffeners have been utilized to carry bending loads in large structures • - Composite materials and processing capabilities have developed consderably Proposed RCOE Research Contribution - Investigation of discrete helicoidal torsional stiffeners - Development and validation of suitable design analysis - Selection of material systems and development of fabrication methods - Design study to determine weight savings potential and torsional stiffness limits Transition Plan - Builds on current NASA/DoD heavy Lift Rotor Blade Design studies - Team with industry and ARL at Langley FMC (+/-45)