UMD - Heavy Lift Helicopter Alfred Gessow Rotorcraft Center Department of Aerospace Engineering University of Maryland, College Park College Park, MD 20742 June 1, 2005 University of Maryland Alfred Gessow Rotorcraft Center Department of Aerospace Engineering University of Maryland, College Park College Park, MD 20742 UMD - Atlas Design Proposal In response to the 2005 Annual AHS International Student Design Competition - Graduate Category June 1, 2005 _______________________________ _______________________________ Benjamin Hein Dr. Inderjit Chopra - Faculty Advisor _______________________________ _______________________________ Eric Schroeder Dr. V.T. Nagaraj - Faculty Advisor _______________________________ _______________________________ Anne Brindejonc Eric Parsons _______________________________ _______________________________ Anirban Chaudhuri Tim Beasman _______________________________ _______________________________ Nicholas Rosenfeld Eric Silberg Acknowledgements The Atlas design team would like to acknowledge the following people and thank them for their valuable assistance and guidance. Dr. Vengalattore T. Nagaraj - Research Scientist, Dept. of Aerospace Engineering, University of Maryland, College Park. Dr. Marat Tishchenko - Former Chief Designer, Mil Design Bureau. Dr. Inderjit Chopra – Professor and Director of the Alfred Gessow Rotorcraft Center, Dept. of Aerospace Engineering, University of Maryland, College Park. The Honorable Jacques S. Gansler, former Under Secretary of Defense for Acquisition, University of Maryland, Technology and Logistics, Roger C. Lipitz Chair in Public Policy and Private Enterprise. Mark Robuck, Associate Technical Fellow, Drive systems, Boeing Rotorcraft. Dr. J. Gordon Leishman - Minta Martin Professor of Engineering, Dept. of Aerospace Engineering, University of Maryland, College Park. Dr. Fredric Schmitz - Martin Professor of Rotorcraft Acoustics, Dept. of Aerospace Engineering, University of Maryland, College Park. LT Rich Whitfield, Squardon Quality Assurance Officer HSL41, SH-60B Instructor Pilot, USN. Dr. Jayant Sirohi - Research Associate, Dept. of Aerospace Engineering, University of Maryland, College Park. Paul Samuel, Joseph Conroy, Jinsong Bao, Anubhav Datta, Maria Ribera, - Graduate Students, Department of Aerospace Engineering, University of Maryland, College Park. i Table of Contents ACKNOWLEDGEMENTS ......................................................................................................................................................i LIST OF FIGURES ..................................................................................................................................................................v LIST OF TABLES...................................................................................................................................................................vii LIST OF SYMBOLS / ABBREVIATIONS .........................................................................................................................viii RFP COMPLIANCE ...............................................................................................................................................................ix PERFORMANCE SUMMARY AND DESIGN FEATURES............................................................................................... 1 SECTION 1: INTRODUCTION. .............................................................................................................................................3 1.1- Historical Considerations SECTION 2: IDENTIFICATION OF DESIGN DRIVERS ...................................................................................................4 2.1 FCS Transport Performance Capabilities 2.2 FCS Logistics Mission Requirements: 2.2 Mission Profile 2.3 Configuration Selection Drivers SECTION 3: CONFIGURATION SELECTION ....................................................................................................................7 SECTION 4: PRELIMINARY SIZING ..................................................................................................................................12 4.1 Design Requirements 4.2 Method of Analysis 4.3 Initial Sizing 4.4 Trade Studies 4.5 Mission Timeline Prediction 4.6 Preliminary Design Cost Analysis SECTION 5: MAIN ROTOR AND HUB DESIGN................................................................................................................18 5.1 Blade Aerodynamic Characteristics 5.2 Blade Structural Design: 5.2.1 Material Selection: 5.2.2 D-Spar: 5.2.3 Torsion Wrap: 5.2.4 Core and Skin: 5.2.5 Abrasion Guard: 5.2.6 Balance Weights: 5.2.7 Lighting: 5.2.8 Lightning Protection: 5.2.9 Survivability: 5.3 Hub Design 5.3.1 Hub Operation: 5.3.2 Hub Construction: 5.4 Rotor Control 5.4.1 Trailing Edge Flaps: 5.4.2 Swashplate Design: 5.5 Active Trim Tab 5.6 Vibration Control 5.7 Rotor Dynamics 5.7.1 Dynamic Analysis ii 5.7.2 Aeroelastic Analysis: 5.7.3 Ground & Air Resonance: 5.7.4 Autorotation SECTION 6: ANTI-TORQUE SYSTEM ................................................................................................................................33 6.1 Anti-torque comparison 6.2 Tail Rotor Detailed Design 6.3 Tail Rotor Structure 6.4 Tail Rotor Performance SECTION 7: AIRFRAME AND LANDING GEAR DESIGN ...............................................................................................34 7.1 Cargo Bay Cross-Section 7.2 Airframe Design 7.2.1 Structural Details: 7.3 Airframe Layout 7.3.1 Cockpit: 7.3.2 Cabin and Cargo Bay: 7.3.3 Doors and safety exits: 7.3.4 Sponsons: 7.3.5 Empennage: 7.4 Cargo Loading 7.4.1 Loading Considerations: 7.4.2: Airframe Loading Structures: 7.5 Manufacturing 7.5.1 Airframe Materials: 7.6 Landing Gear Design 7.6.1 Tires and wheels: 7.6.2 Magnetorheological (MR) Fluid Based Landing Gear: 7.6.3 Shock strut sizing: 7.6.4 Retraction scheme: SECTION 8: FOLDING SYSTEMS........................................................................................................................................43 8.1 Overview 8.2 Automatic Main Rotor Blade Folding 8.2 Automatic Tail Boom Folding SECTION 9 - HANDLING QUALITIES AND STABILITY ...............................................................................................49 9.1 Stability 9.2 Effect of Design Elements 9.2.1 Hinge Offset: 9.2.2 Horizontal Tail: SECTION 10 - FLIGHT CONTROL SYSTEM ....................................................................................................................51 10.1 Primary Flight Control System (PFCS) 10.2 Automatic Flight Control System (AFCS) SECTION 11 - COCKPIT AND CABIN SYSTEMS..............................................................................................................52 11.1 Flight Crew Station and Controls 11.1.1 Primary Flight Controls: 11.1.2 Cockpit Systems and Avionics: 11.2 Cabin and Cargo Area Systems iii SECTION 12 - FAULT DETECTION AND HEALTH AND USAGE MONITORING SYSTEM (HUMS)....................56 12.1 Main Rotor and Rotating Components 12.2 Engines and Main Gearbox 12.3 Flight Control System and Avionics 12.4 Tail Rotor and Tail Gearbox 12.4 Structure SECTION 13 - SELF-DEFENSE EQUIPMENT/COUNTERMEASURES.........................................................................58 SECTION 14 – MECHANICAL SUBSYSTEMS (ENGINE / TRANSMISSION)..............................................................58 14.1 Engine Design 14.1.1 Current Engine Technology: 14.1.2 Evaluation of Technology Initiatives: 14.1.3 Gross Engine Sizing: 14.1.4 Power Ratings: 14.1.5 Temperature and Altitude Losses: 14.1.6 Specific Fuel Consumption 14.1.7 Number of Engines: 14.1.8 Structural Integration: 14.1.9 Engine Installation: 14.1.10 Engine Subsystems: 14.1.11 Auxiliary Power Unit: 14.2 Transmission Design 14.2.1 Design Considerations: 14.2.2 Transmission Configuration: 14.2.3 Weight Estimation: 14.2.4 Stress Calculations: 14.2.5 Structural Integration: 14.2.6 Transmission Losses: 14.2.7 Oil System: 14.2.8 Tail Rotor Drive System: SECTION 15 - PERFORMANCE ANALYSIS......................................................................................................................67 15.1 Drag Estimation 15.2 Hover Performance 15.3 Forward Flight Performance 15.3.1 Return trip (Without FCS) SECTION 16: ADDITIONAL APPLICATIONS AND CAPABILITIES ...........................................................................71 SECTION 17: CONCLUSIONS..............................................................................................................................................72 APPENDIX A: MIL-STD-1374 WEIGHT SUMMARY.......................................................................................................73 REFERENCES iv List of Figures Figure 2.1 – Timeline for One Aircraft to deliver (4) FCS Vehicles to Objective and Return to Base Figure 2.2 – Load Factor required to Sustain Twice the Standard Turn Rate at Cruise Speed in Level Flight Figure 4.9 – Acquisition cost for Heavy Lift – high speed VTOL aircraft Figure 4.10 – Mission Time Reduction per unit Increase in Speed for RFP Mission Figure 4.1 – Variation of Cruise Velocity with Blade Loading Figure 4.2 – Empty Weight as a function of Blade Loading Figure 4.3 – Takeoff Power required as a function of Blade Loading Figure 4.4 – Cost as a function of Blade Loading Figure 4.5 – Cruise Velocity as a function of Blade Loading Figure 4.6 – Aircraft Acquisition Cost vs. Cruise Speed Figure 4.7 – Denominator of Productivity vs. Cruise Velocity Figure 4.8 – Variation in