Scott Hayden, Team Lead – Chief Engineer, Performance & Structures Specialist Dana Pugh – Trade Studies and Propulsion Specialist Dany Fahmy – 3-D designer, Aerodynamicist Court Groves – Stability and Control Specialist Morphing Aircraft Design MAE 155B, Aerospace Engineering Design II University of California, San Diego Jacobs School of Engineering June 7, 2004 Charles Chase, Lockheed Martin Dr. James Lang, Project Advisor

  Goals, Schedule and Project Cost   Design Drivers   Initial Morphing Aircraft Concepts   Delta Wing   Jive   Straight Jacket   Final Design Concept   Straight Jacket   Method of Morphing   System Design   Configuration   Aerodynamics   Propulsion   Stability and Control   Materials and Structures   Performance   Trade Studies   Cost Estimates   Conclusions   References and Acknowledgments Morphing Aircraft Project Outline

Goals, Schedule and Project Cost

Project Description   Design a Strike Aircraft with morphing capabilities   Maximize the Strike Mission performance.   Ingress and Egress demand supersonic cruising at Mach 2   Carry a 2,000 pound internal weapons payload   Three morphing variations to maximize flight performance and Minimize project costs:   “Swing" wing concept   Fan wing concept   Switchblade wing concept   Trade studies varying T/W, W/S, and Aspect Ratio up to 20%   Perform preliminary design analysis on final aircraft choice

 Climb from Sea Level to Best Cruise Altitude ( ≥ 55,000 feet )  Ingress for 1,200 nautical miles at Mach 2.0 and BCA  “Strike Patrol” for 4 hours at subsonic velocity ( ≥ 55,000 feet )  Return to base at Mach 2.0 and BCA  Carry Reserve fuel for additional 20 minute loiter  Descend to Sea Level and Land  SUBsonic Configuration:  Make TEN sustained 360° turns at M=0.7  Withstand a 3g sustained load ( ≥ 55,000 feet )  SUPERsonic Configuration:  Make ONE sustained 180° turn at M=2.0 Mission Requirements

Design Drivers Supercruise at Mach 2   Aerodynamics   Wave Drag   Area-Ruling   Stability and Control   Yaw and Pitch Stability are critical   Propulsion   Utilize only military thrust to reach and maintain cruise velocity of Mach 2

Design Drivers (cont…) Subsonic to Supersonic and vice versa   Maximize performance for BOTH supersonic cruise and subsonic loiter   Feasibly morph between optimal operating configurations   Recognize this HUGE change   Aerodynamics   Stability and Control Systems   Optimize!

Mission Phase Breakdown 0 – 1 Take-off and accelerate 1 – 2 Climb from sea level to BCA and M = – 3 Ingress at M = 2.0 and BCA for 1200nm 3 – 4 “Strike Patrol” for 4 hours at subsonic speed for maximum endurance and optimum altitude (at or above 55,000 ft) 4 – 5 Combat allowance 5 – 6 Climb and acceleration allowance (to BCA and M = 2.0) 6 – 7 Egress at M = 2.0 and BCA for 1200nm 7 – 8 Descend 8 – 9 Reserves: Fuel for 20 minutes at optimum speed and altitude for maximum endurance Landing Strike Mission Profile Subsonic Supersonic

Spring Break Milestones Final Schedule Final Presentation Preliminary Design Switchblade concept Fan concept Swing wing design Trade Studies Conceptual Design Objectives and Success Criteria June 7th Weeks During Spring Quarter 2004 (March 22 – June 7)

Project Costs   Engineering (4 engineers, $92/hour, 12 hours/week, 11 weeks): $48,576   Travel to Lockheed Martin Sponsor (food/gas): $95   Miscellaneous Design Tools: $150   Total - Pay up! Design Project Cost Estimates

Initial Morphing Aircraft Concepts

Conceptual Design Approach  Individually design three different morphing aircraft  Each satisfying the mission requirements  Highlight design drivers – Supercruise at M=2, Morph to optimize performance  Develop method to compare each individual design  Fair  Systematic  Same set of assumptions and design restrictions  Use subjective and objective comparisons to downsize to a final design  Measures of Merit  Weight!  Pugh Chart

Conceptual Design Approach (cont…)

Delta Wing SupersonicSubsonic

Delta Wing  TOGW: 90000lbs.  W f =46967lbs W e =41287lbs  Subsonic / supersonic aspect ratio: 8 / 2.91  C do subsonic / supersonic:.0105 /  Span subsonic / supersonic: / 52.16ft  L/D loiter / supercruise: /  W/S loiter / supercruise: /  T/W loiter / supercruise: / 0.377

Jive Supersonic Subsonic Inlets Pivot Points 2 Engines 1 Vertical Tail Rotates Inside Fuselage

 Swings in from a pivot point  The swing motion follows a designed track within the fuselage  From subsonic configuration to supersonic configuration, only about 70% of the wing swings in  Latches into supersonic configuration with clamps creating a smaller aspect ratio Jive - How it Morphs

Jive – Weight & Characteristics

Straight Jacket   High Aspect Ratio Subsonic Wings   Maximize L/D for loiter   Low Aspect Ratio Supersonic Wings   Reduce Drag   Maximize Range   Increase Maneuverability   Combine wings to simplify Morph   Reduce mechanical/electrical/control costs and complications   Utilize long slender subsonic wings to shape slender body   Achieve something never seen before Aim of Design

Straight Jacket - Subsonic

Straight Jacket - Supersonic

Straight Jacket – Method of Morphing

Comparison

Measures of Merit  Every aircraft meets project requirements  TOGW

Final Design Concept and the winner is…

STRAIGHT JACKET

Straight Jacket

Subsonic 3-View

Vertical Tails Payload Engines Wing Structure Inlets Nose Gear Main Gear Fuel Tanks Electrical System Tailpipe Engine & Oil Cooling Instruments Engine Controls Anti-ice Gear Avionics Sub Configuration

Supersonic 3-View

Method of Morphing Concept: Wing design incorporating single subsonic and supersonic wing into ONE structure   Takeoff and climb to BCA in subsonic formation   Morph to Supersonic formation for Mach 2 ingress   Accelerate in subsonic formation to M=0.7   Cervos/mechanisms “pop” wings down   Large gears simultaneously rotate wings forward   Mach 0.7  Mach 1   Use advanced controls systems   Utilize seamless elevons and ailerons on BOTH wings   Create lift and stability   Cervos/mechanisms bring wings back into fuselage and secure into place   And away we go… accelerate to M=2

Method of Morphing Cross Section of Fuselage in Supersonic Formation  Reach Strike destination and slow to Mach 1  Cervos/mechanisms “pop” down wings  Slowly draw subsonic wings from forward fuselage  Allow aerodynamic forces to deploy wings  Only apply resistive force with gears

Method of Morphing Front view of Straight Jacket in Subsonic Formation  Reduce lift and drag on forked wings  Use seamless elevons and ailerons to minimize lift  drag  Advanced feedback control systems  Allow drag forces to pull back wings  Natural Aerodynamic forces will slow aircraft from M=1 to M=0.7  Wings rotate out  Cervos/mechanisms bring wings back into fuselage and secure into place  Survey and drop payload if necessary… Morph back and RTB

Method of Morphing Top View of Wing Planform Bottom View of Wing Planform Back View of Wing Planform Master Morph Control Gear Simultaneously controlled wing gears Subsonic Wings Supersonic Wing Large Steel / Titanium Strut Re-lubricating Bearings Titanium Circular Shafts Bottom Shaft Brace

Method of Morphing   Use tooth to stabilize hidden wings   Bring wings up and down   Controlled by same servos and mechanisms, simultaneously   Used to catch wings bring brought in   Helps guide back into fuselage pocket Hidden Wing Support – The Tooth Tooth

Method of Morphing   New Belly material (IN RED)   “Smart” material - Polymer that forms to wings and tooth when collapsed   Stiffens and reduces surface area when wings are out   Able to take Mach 2 airload from skin friction drag Drag Reduction Technology

System Design

Aerodynamic Characteristics SubsonicSupersonic Aspect Ratio146 AirfoilNACA 4412NACA t/c Wing Span Wing Area Sweep828 Cl max (L/D)max Cdo Oswald efficiency Swet/Sref410 Taper Ratio Aerodynamics

  TOGW = 83,939 Lbs   We = 49,063 Lbs   Wf = 34,876 Lbs   Wf/W = 0.43   W/S to = Lb/ft 2   T/W to = 0.4 Fuel burn by mission segment (lb) 1) take off / acceleration ) Climb ) Ingress ) Strike Patrol ) Combat allowance ) Accel/Climb Allowance ) Egress ) Descend ) Reserves ) Land142.5 Weight Summary – Strike Mission

C DO vs Mach Number

K vs Mach Number

  Pressure drag due to shock formation   It is greater than all the other drag together   D/q(wave) = 4.5*pi()*(A/L)^2   L=longitudinal dimension   A= max cross-sectional area   To minimize the wave drag, we tried to minimize the cross sectional area and maximize the longitudinal dimension and this is how we came up with the fuselage shape. Wave Drag – Area Ruling

  Engine Type: F119- PW- 100 (F-22)   Scale Factor: 1.39   Includes 16.7% improvement   -10% installation   Engine sized up from 35,000 lb of Thrust to 43,750 lb Max Thrust   Number of Engines: 2   Engine Characteristics: Propulsion

Propulsion – F119 2 Engine PerformanceThrust Sea-Level Static Max Thrust (lbs)43750 Supercruise (M=2) BCA (lbs)5051

Inlet and Duct Design Variable Inlet Design Inlet Location Duct Location and Inlet Location

Inlet Inlet in front of the Leading edge

Nozzle   Ejector design cools the afterburner and nozzle   The converging-diverging design allows easier transitions between subsonic and supersonic   Nozzle Length ~ 2.5 feet   Afterburner & Nozzle ~ 6.3 feet

Nozzle Design Alternative   A component of the F119   Vectoring flaps are the most common vectoring-nozzle type   Need to do Trade Studies of cost and surface sizing to see if beneficial 2D Thrust Vectoring

Propulsion – Capture Area

TSFC VS. M and Altitude for Military Thrust for F119

Trade Studies

~57000 feet for BCA

Trade Studies

Stability and Control   The Basics   4 control surfaces   Elevons, Ailerons, Rudder Ailerons – 2 configurations   Subsonic & Supersonic   Elevons – Only on subsonic configuration   Designed for increased stability at loiter speed   Rudder – Vertical twin tails   rudders sized to allow for stability at M=2+   Leading edge flaps   Used to alter camber and decrease lift during morphing phase

Stability and Control Subsonic Supersonic

Stability and Control  Advanced controls  Fluidic thrust vectoring  Increased maneuverability and performance at high supersonic  Advantages  Disadvantages  Fly by wire controls  Automatic cg maintenance  Using sensors and fuel pumps

Stability and Control   Maintenance of center of gravity  Phases:  1. subsonic cg  2. supersonic cg  3. subsonic post-payload drop  4. supersonic cg post-payload drop

Stability and Control

Detailed Weight analysis   Wing weight: lbs   Subsonic wing: lbs Supersonic wing: lbs   Fuselage weight: lbs   Installed engine weight: lbs   Vertical tail weight:   Fuel system weight (empty):   Payload: 2000 lbs   Avionics weight: lbs   Final component build up weight (empty): lbs   With fuel: lbs

Landing Gear   Main Landing Gear   Max static load: lbs   Extended length: 60 in.   Nose Landing Gear   Min static load: lbs   Max static load: 10, lbs   Dynamic breaking load:   Extended length: 72 in.   Kinetic Energy absorbed by breaking: 6.85x10^6 ft-lbs   Vertical Kinetic Energy absorbed by deflecting shock and tire: 223,995.6 ft-lbs

Materials and Structures   Aircraft Skin  Mach 0.55, 55,000 ft  ~10 ° F  Mach 2.2, 55,000 ft  ~250 ° F   Titanium Alloy or other specialized material   Airframe   Brazed steel honeycomb?   Titanium / Magnesium (risky)   Aluminum structure with heat-protective tiles   Wing and wing spars   Titanium / Advanced Composites   The Tooth – Tucked Wing Stabilizer   Al   Other   Stainless steel heat shield over the engine   Steel Engine Mounts Key Materials for the Straight Jacket Aerodynamic Heating Drivers

Materials and Structures   Belly Skin   New Age material   “Smart” Materials   Micro Piezoelectric actuators   Must change and sustain aerodynamic drag load   Elevons and Ailerons   Seamless “smart” material Key Materials for the Straight Jacket Aerodynamic Heating Drivers

Materials and Structures   Airframe   Wing Spars   Spar caps   Wing Attachment Fittings   Use steel to provide high strength and fatigue resistance   Belly Skin   Circular Wing Rotation Shaft   Titanium   Other   Engine mounts   Morphing mechanisms  steel, titanium, Al where applicable Stress, Stiffness and Strength Drivers

Materials and Structures Limit Loads  Limit Loads +4 to -2  UAV Factor of Safety  Sources  Takeoff  Acceleration to Mach 2  Wing loading in Subsonic “Strike Patrol”  Other  Airloads  Inertia Loads  Landing  Takeoff  Powerplant Typical Vn Diagram

Materials and Structures Subsonic Wing Air Loads on Lifting Surfaces Spanwise LoadingTotal Vertical Load  Also airloads due to control deflection  Need additional steel stringers at 20% span Root Shearing Force89,394 lb Bending Moment3.2*10^6 ft-lb (For maximum G Loading)

Materials and Structures Supersonic Wing Air Loads on Lifting Surfaces Spanwise LoadingTotal Vertical Load Root Shearing Force 122,720 lb Bending Moment1.5*10^6 ft-lb ( For maximum G Loading)

Materials and Structures Spanwise Distribution of Drag Loads Subsonic WingSupersonic Wing  Approximation  Constant 95% avg drag load from root 80% span  120% avg drag load from 80% to wingtip Subsonic Root Shear5,912 lbSupersonic Root Shear16,372 lb Bending Moment 2.2*10^5 ft-lb Bending Moment2.6*10^5 ft-lb Subsonic WingSupersonic Wing Subsonic WingSupersonic Wing

Materials and Structures   Torsional Load found from Wind Tunnel Tests   Use airfoil moment coefficient summed from root to tip   Consider also   Inertial Loads   Powerplant Loads   Landing Gear Loads

Materials and Structures   Use Shear Loads and Bending Moments   Calculate Mass moments of inertia   Use these to size I-Beam spar caps   Size spar caps to absorb majority of bending force   Size cross-sectional area of web to absorb shear Mass Moment of Inertia

Performance   Total Mission Duration   6 hours 56 minutes   Egress and Ingress at M=2   Strike Patrol - Subsonic Velocity for Maximum Endurance (55,000 ft)   Reserves - Subsonic Velocity for Maximum Endurance (Sea Level)   5,685 ft Takeoff distance   Ground roll, Transition, and Climb over a 50 ft barrier   Thrust capabilities and high L/D enable short TO distance   6,421 ft Landing distance   Approach (clearance of 50 ft barrier), Flare, and Ground Roll

 Desire Ps=0 contours to envelop those of an opponent Performance Sustained Load Factor (Ps = 0) Specific Excess Power at Max Thrust with n=1

 Want Ps Maximized at each energy height to minimize climb time Performance Lines of Constant Energy overlaid onto lines of constant Ps (n=1)

Performance Dog House Plots

Performance Performance Requirements and Review

Conclusions

Cost 100 aircraft total purchase  RTD&E: $9,469,990,078  Flyaway: $1,882,680,488  Other costs: $1,135,329,434  Total acquisition: $1.2488x10 10  Unit flyaway cost: $113,526,705.70

Future Work Needed   WING STABILTY IN MORPH!!   CG Maintenance system   Creation of “Belly” material   Wind tunnel testing   Thrust Vectoring   CFD Analysis   Area ruling and minimization of wave drag   Nozzle placement – Trade studies   FEM   Subsystems / Mechanizations

Lessons Learned   Interdependence and communication   Personal responsibility to get the work done   Work for a real life sponsored project   Break the rules of standardization

References and Acknowledgements

References Raymer, Daniel P. Aircraft Design: A Conceptual Approach American Institute of Aeronautics and Astronautics, Inc., 1999 Beer, Ferdinand P., DeWolf T. John, and E. Russell Johnston, Jr. Mechanics of Materials McGraw-Hill, US Military Aircraft. Federation of American Scientists. Thrust Specific Fuel Consumption, NASA Glenn Research Center F-22 Raptor F119-PW-100 Engine, Globalsecurity.org

First we’d like to thank the Academy… Dr. James Lang Project Advisor Charles Chase Lockheed Martin Sponsor John Meissner MAE 155 Teaching Assistant Dr. Vistasp M. Karbhari UCSD Professor of Structural Engineering Tom Chalfant UCSD MAE Machine Shop Manager And all of the pilots and jets that fly over UCSD … everyday. Thank You.