X-51 Development: A Chief Engineer s Perspective

Transcription

1 X-51 Development: A Chief Engineer s Perspective 17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 13 April 2011 Mr. Richard Mutzman CE AFRL/RZ Mr. Scott Murphy, CE X-51 Cleared for for Public Release Case Number: 88ABW Air Force Research Laboratory 1

2 Outline Program Overview Vehicle Overview Development Program Flight Test Program Post-Flight Investigation Summary Summary 2

3 Outline Program Overview Vehicle Overview Development Program Flight Test Program Post-Flight Investigation Summary Summary 3

4 1980 ~ LRC LRC LRC Scramjet Technology Development Approach Stair-step approach builds upon prior successes Operationally Responsive Spacelift (Robust, Responsive) Large Hypersonic Missiles Small Launch Systems Large Scramjets and CCEs Hypersonic Missiles/ Small Launch Systems Medium Scramjets Hypersonic Missiles (Time-Critical Targets) Small Scramjets TRL= X-51 Program Ramjets TRL=

5 X-51A Program Objective Flight test the USAF Hypersonic Technology (HyTech) scramjet engine, using endothermic hydrocarbon fuel, by accelerating a vehicle from boost (~M=4.5) to Mach 6+ Acquire engine data for ground to flight comparison (rules & tools development) Demonstrate an endothermically fueled scramjet in flight Prove viability of a free-flying, scramjet powered vehicle X-51A First Flight May 26 th, 2010 X-51A first flight was the product of a national team 5

6 Why Do an X-51A Flight Test? 6

7 X-51A Objectives Flight test the USAF Hypersonic Technology (HyTech) scramjet engine, using endothermic hydrocarbon fuel, by accelerating a vehicle from boost: ~M=4.5 to Max Mach = ~6+ Specific Objectives: Demonstrate clean air performance Correlate flight test data with ground test data and simulation/analyses Investigate acceleration/operation through Mach transients (compare to analysis) Investigate boost/free-flight transition & starting (compare to analytical predictions) There are two parallel processes taking place that must be balanced: Hypersonic Propulsion Flight Experiment Air Vehicle Development Effort Acquire Ground Test Data B-52 Integration Acquire In-Flight Test Data Airframe/Propulsion Integration Correlate Ground/Flight Data/Analyses Software Development Additional Areas of Hypersonic Research ATACMs Booster Integration Anchor Hypersonic Vehicle Design Tools Avionics Qualification Etc. 7

8 X-51A Baseline Schedule FY03 FY04 FY05 FY06 FY07 FY08 FY09 FY10 FY11 On Contract Dec 03 X-51 SRR Aug 04 X-51 PDR Dec 04 SJX61-1 Test X-51 CDR SJX61-2 Test FRR Jul 05 Nov 06 Jan 07 May 07 Sep 07 Apr 08 X-51 Flight 1 Sep 08 Jun 09 Flights 2-4 Dec 08 May 10 Mar, Jun,??? Completed Milestone Planned Activity Slipped Activity 8

9 Outline Program Overview Vehicle Overview Development Program Flight Test Program Post-Flight Investigation Summary Summary 9

10 X-51 Vehicle Overview X-51A Mass Properties Cruiser Operating Weight = 1225 lb JP-7 Fuel (Useable) = 265 lb Cruiser Launch Weight = 1504 lb Booster = 2277 lb Interstage = 160 lb Stack Gross Weight (Captive Carry) = 3942 lb Cruiser Modified ATACMS Booster Scramjet Engine AVD Stack length: 301 inches Cruiser length: 168 inches Max body width: 23 inches Engine flow-path width: 9 inches Flow-Through Inter-stage 10

11 X-51A Material Composition Stack Structural Materials Tungsten (nosecap) Inconel (engine, cruiser fins) Titanium (interstage flowthrough, booster boattail) Aluminum (cruiser & interstage skin, booster fins) Steel (attachment lugs, booster skin & nozzle) Composite hot structure (cruiser fin LE) Cruiser TPS Materials BLA-S: Boeing Light-weight Ablator (sprayed-on) BLA-HD: Boeing Light-weight Ablator (honeycomb reinforced) BRI-16 Tile: Boeing Reusable Insulation FRSI: Flexible Reusable Surface Insulation SIP: Strain Isolation Pad (under tiles) 11

12 X-51A Subsystems Packaging Engine Subsystems (Packaged Wet in JP-7) Engine Fuel Pump Ethylene (Engine Start) Nitrogen (Fuel Pressurization) Detailed Line Routing Subsystems Bay GCU/IMU/GPS FADEC Flight Test Instrumentation (FTI) Detailed Line Routing FTS, FTI and Control Systems Antennas Sensors Control Actuators Detailed Line Routing JP-7 Fuel Integral Tanks 265 lb (usable) Sealing Concept Defined Fuel System Fuel Pump Detailed Line Routing Batteries Engine Systems Actuators (Li-ion Pack) Avionics and FTI Flight Termination System (Separate) 12

13 Fuel Cooled Scramjet JP-7 Fuel Tank Integral inlet & forebody Airframe Mounted Nozzle SJX61-2 at LaRC 8 ft HTT (U) 13

14 Modified Army TACMS Booster New FWD Skirt Hole Pattern: Match Drill FWD Skirt with Interstage Replace Existing Nozzle Exit Cone with Extended Exit Cone Material Changes for Performance Enhancements: Ti Boat tail Housing Al Control Fins Fixed Fins for Stability after release from B-52 Fin Locks added for B-52 carriage Booster Prime Contractor/ATACMS Integrator: Lockheed Martin Missiles & Fire Control Dallas, TX 14

15 Outline Program Overview Vehicle Overview Development Program Flight Test Program Post-Flight Investigation Summary Summary 15

16 X-51 Aerodynamic Development (> 3200 Runs) Cruiser NTS 157 September 1999 (ARRMD program) PSWT 720 October 1999 (ARRMD program) PSWT 724 March 2000 (ARRMD program) PSWT 802 August 2005 AEDC VKF Tunnel B January 2006 PSWT 817 April 2006 NASA LaRC UPWT August 2006 NASA LaRC 16-Foot Transonic Wind Tunnel Boeing PSWT 14% Stack SLA model Installed in Boeing NAART 14% Stack Model PSWT % Cruiser Model Inlet Test PSWT % Cruiser Model AVD X-51 Installed at NASA LaRC UPWT PSWT 724 April 2000 (ARRMD program) NAART 119 January 2004 AEDC VKF Tunnel B NAART 123 April 2004 & July 2004 NASA LaRC 16T Test 589 August 2004 NASA LaRC 16T Test 590 September 2004 PSWT 794 February 2005 & March 2005 PSWT 807 October & November

17 X-51 CFD Program Significant amount of CFD conducted for X-51 program 3,000 Euler cases 500 Navier-Stokes cases ~ 1,200,000 CPU hours expended on NASA Columbia computer ~ 300,000 CPU hours expended on Boeing computers OVERFLOW Grid System Three major CFD codes utilized OVERFLOW (NASA), Navier-Stokes: Utilized for detailed force and moment prediction BCFD (Boeing), Navier-Stokes: Utilized for rapid high fidelity solutions of complex configurations Cart3d (NASA), Euler: Utilized for rapid generation of large databases BCFD Grid System & Solution 17

18 Pressure Coefficient CL Cm Wind Tunnel to CFD Correlations Lift verses Alpha PSWT 802, Run 450 CART3D OVERFLOW (no sting) Alpha Pitching Moment verses Alpha AEDC 470, Run 32 AEDC 470, Run 83 CART3D (no sting) OVERFLOW (no sting) OVERFLOW (sting) Alpha Pressure Comparison at Mach 3.0 Euler CFD (CART3D) PSWT Test X 18

19 Pitching Moment Coefficient, Cm X-51 Stack Has Mixed Static Stability (M = 0.8) Longitudinally unstable at launch Symmetric Fin Deflection Angle (degrees) Fin=-25 Fin=-20 Fin=-15 Fin=-10 Fin=-5 Fin=0 Fin=5 Fin=10 Fin=15 Laterally unstable for angles-ofattack less than 2 degrees Fin=20 Fin=25 Directionally unstable for angles-ofattack less than 6 degrees Lift Coefficient, CL Cn b Stability Cl b Stability Stability Stability Angle-of-Attack (Deg) Angle-of-Attack (Deg) 19

20 Pitching Moment Coefficient, Cm X-51 Cruiser Has Mixed Static Stability (High Mach) Longitudinally unstable Laterally unstable for angles-ofattack less than 9 degrees Directionally stable Symmetric Fin Deflection (deg) Fins=-20 Fins=-15 Fins=-10 Fins=-5 Fins=0 Fins=5 Fins=10 Fins=15 Fins= Lift Coefficient, CL Stability Cn b Stability Cl b Stability Stability Angle-of-Attack (Deg) Angle-of-Attack (Deg) 20

21 Specialized Databases Stage separation data Defines the aerodynamic interaction between the cruiser and the booster during stage separation Based on Navier-Stokes CFD M =0.8, a=0.65º Captive carry and launch data Defines the influence of B-52 on the aerodynamics of the stack during captive carry and launch Based on Euler CFD (Cart3d) Loads data Defines aerodynamic pressure and distributed forces for structural sizing Based on Euler CFD (Cart3d) M =0.8, a=6º 21

22 Delta Cp Specialized Databases Flush air data system Shows relationship between measured differential pressure and sideslip angle Mach 3.0 to 7 Defined by Wind Tunnel Data Flush Air Calibration Data Beta = -4 Beta = -3 Beta = -2 Beta = -1 Beta = 0 Beta = 1 Beta = 2 Beta = 3 Beta = 4 P11 P1 P2 P12 P101, P102, P103 on lower surface, right side at model stations 10.0, 12.0, 14.0 P3 P13 P104 P14 Beta vane calibration database Shows relationship between true and indicated beta Mach 0.6 to 2.5 P4 P23 P31 match P13 P21 on right side. P15 P16 P17 P97 Defined by Euler CFD P5 P18 P6 P19 P20 P98 P21 P7 P92 (cavity) P91 (cavity) P8 P99 P88, P89, P90 on lower chine surface, right side at model stations 20.0, 26.0, 32.0 Location for Flush Air Pressure taps P100 P9 P22 P10 P58 P59 P57 P60 P56 P55 P Angle-of-Attack (Deg) 22

23 Subsystems Development Full subsystem component development & qualification testing conducted Verification of combined vehicle and engine control system via Hardwarein-the-Loop testing Assembly and Checkout, and On-Aircraft testing conducted Actuator Qualification Ethylene System Dev Test GCU Qualification Hardware-in-the-Loop Assembly and Checkout Test Battery Qualification 23

24 X-51 Static Test Program Characterize flight vehicle load paths for Cruiser & Interstage primary hardware Correlate/validate FEM vehicle load distribution. Tested to 1.15 times the maximum flight limit load envelope No yielding or ultimate failure (FoS 2.0) 24

25 X-51A Propulsion Heritage (Crawl-Walk-Run) X-51A propulsion system has strong foundation in past component & system tests HyTech Flowpath Development Performance Test Engine (Jan 01) Copper heat sink construction Partial width flowpath Ground Demo Engine 1 (June 03) Flight weight Fuel cooled, but open loop fuel system X-51A Flight Test X-51A FCE SJX61-2 (Oct 08) Flight Clearance Engine Flight fuel pump & instr. Ground Demo Engine 2 (Mar 06) Center engine for X-43C Fuel cooled, closed loop fuel system X-51A Dev. Engine, SJX61-1 (Jul 07) Full X-51A forebody and nozzle Fuel cooled, closed loop fuel system 25

26 X-51 Engine Development Program Summary SJX61-1 at LaRC 8 ft HTT Development Program Addressed Key Risks: Engine ignition on ethylene & transition to JP-7 Engine performance to meet mission needs Subsystem component development & qual. Verification of combined fuel system & flowpath to manage thermal limits Over 16 mins/40 cycles during ground test program Subsystem Qualification Combustor Tests SJX61-2 at LaRC 8 ft HTT 26

27 Outline Program Overview Vehicle Overview Development Program Flight Test Program Post-Flight Investigation Summary Summary 27

28 X-51A Notional Mission 28

29 B-52H Flight Ground Track Vandenberg AFB Edwards AFB Pt Mugu Racetrack Launch Point San Nicholas Island 29

30 Preparing for Flight Test B-52 Systems Integration Laboratory Testing conducted to verify electronic interfaces GCU RTSIM MIL-STD 1760/1553 SMO SW (SIL) SMO OFP X-51 B-52 AVD on the ground (notional fixture) Conducted actual X-51 to B-52 on Aircraft System Integration testing Umbilical Extension (Minimize Length) UP GCU OFP (with TLI Mode) & ICS OFP (Power Distribution) FWD 11 April 2011 B-52 Hardware Modifications made to the Heavy Stores Adapter Beam and MAU-12 Launcher Heavy Stores Adaptor Beam (HSAB) ( Shear Pins (8 places) FWD Pi-fitting MAU-12 Ejector Side Tension Fitting (4 places) AFT Pi-fitting 30

31 Preparing for Flight Test Requirements for Successful Separation No re-contact between X- 51A and B-52 at any time after launch Nose and tail must not deviate more than 68 degrees laterally from the point of launch. 6-DOF Safe Separation analysis was conducted 11 April

32 Mission Control Center Ridely Control Center Used by X-37, and Spaceship One Unique requirement for X-51 data collection and display Fully trained and manned control room Boeing, PWR, HCTF, AFRL Multiple scenario simulations conducted Pt. Mugu Control Center Used by X-43A, HyFly Data displays, Hardware and Software adequate for X-51A program Multiple Range Assets Range Clearance Aircraft, Telemetry/FTS Relay Aircraft Radar Tracking & TM Sites Laguna Peak (TM only) Pt Mugu San Nicholas Island 11 April 2011 Vandenberg (TM only) Ridley Center Control Room Pt Mugu Control Room 32

33 Getting the Data is Key VAFB LOS SNI LOS Mugu LOS NP-3-D LOS T=582, Splash Down T= ~30, Separation T=295, Engine Shutdown T= ~32, Engine Start 33

34 Flight Test Instrumentation Challenging Instrumentation Selection Process Limited system bandwidth and vehicle power Leverage engine testing Performance & operability Environment determination & structural analysis Thermal management 341 Total Analog Sensors Cruiser Engine 171 Interstage/Booster Serial (GCU/FADEC) Port Antenna Master DAU Starboard Antenna S-Band Transmitters T/C Reference Junctions Aft Antenna Engine DAU Pressure Scanner GNC Pressure Transducer Avionics Pallet 34

35 Flight Test Safety Splashdown Dispersion established by Monte Carlo simulation Range termination trajectory limits established Hazard Boundary IIP Terminate Limit Line Redundant Flight Termination System On-board Hybrid Coupler Control box Lanyard Cutters (2) Safe and Arm (2) 11 April 2011 Down Range Surveillance Area Receivers (2) Manifold (2) Disconnects (2) 35

36 Risk Mitigation Challenged Flight Test Execution Near Ceiling of B-52 and Chase Above B-52 engine restart max altitude B-52 vulnerable to compressor stalls Near the JP-8 temp limit Multiple Airborne Assets Multiple Agencies Tight Timeline Limited B-52 fuel load Multiple Challenges Were Overcome for Successful Launch 36

37 X-51 First Flight Overview First Flight Events: Clean release from B-52 Booster ignition at 4 sec Cruiser separation at ~ 30 sec Notional Mission Scramjet started on ethylene & transitioned to JP-7 Initial acceleration as expected Engine performance nominal Engine fuel system control & cooling as expected Anomaly occurred ~65 sec into flight; observed elevated cruiser / engine bay temps Total scramjet time ~ 143 sec Loss of telemetry at 210 sec 37

38 Mission Highlights Boosted Mach 4.85 End-of-Boost altitude 58,200 ft Altitude at scramjet start 61,300 ft Altitude at End-of-Mission 62,300 ft Mach number at JP-7 Takeover 4.74 Max Mach number 4.87 Time on scramjet Total mission time Peak acceleration during mission Total distance travelled 143 sec 210 sec ~0.18 g 150 NM Cleared Cleared for Public for Release Public Release: Case Number: 88ABW ABW

39 Outline Program Overview Vehicle Overview Development Program Flight Test Program Post-Flight Investigation Summary Summary 39

40 ATACMS Booster Increased nozzle expansion ratio Material changes: Ti boat-tail housing Ti/Al fins ATACMS Modifications Proven in Flight One: Good match to expected trajectory, scramjet engine start point very close to predicted condition Implies accurate prediction of combined booster performance / X-51A stack aero Fin locks to prevent flutter in captive carry Aft cover to protect igniter (air-launch) Fixed fins for stability after B- 52 release 40

41 Pump Speed (RPM) Fin Angle (deg) Vehicle & Engine Subsystems Cruiser Fins (U) Upper Left Fin (Pos) Upper Left Fin (Com) Lower Left Fin (Pos) Lower Left Fin (Com) Upper Right Fin (Pos) Upper Right Fin (Com) Lower Right Fin (Pos) Lower Right Fin (Com) Electrical Power Systems Time Since Launch (sec) Vehicle Fuel System Engine JP-7 Fuel System Pump Speed Pump Speed Request Time Since Launch (sec) 41

42 Scramjet Engine Operation Performance, Operability & Thermal Loads Cooled HW perf. on JP-7 consistent with pre-flight predictions Operability consistent with pre-flight predictions; slightly less margin because of elevated pressure Heat exchanger thermal loads consistent with predictions Flight Performance vs. Predicted Heat Exchanger Thermal Loads 42

43 Cruiser Axial Acceleration Anomaly Occurs Engine & Vehicle Recover On JP-7 Ethylene Ignition Inlet Unstarts Cruiser Tare 43

44 Pressure (psia) Mach Number 5 JP-7 Only UNCLASSIFIED Mach Number Axial Acceleration Unstart Cruiser Bay Pressure 6 Atmospheric Pressure from BET 4 2 Pressure Rising TM Loss Temperature (F) TESPAFT T1034 T1035 T1036 T1046 T1087 Aft Seal Temps Engine Bay Temp Rise UNCLASSIFIED Aft Bay Temp Rise

45 X-51 Anomaly Investigation Methodology Scramjet Engine Demonstrator Flight 1 Timeline Time (sec) T<0 B-52/X-51 Mach miscompute T=0 Flowpath hardware cold soaked to T=-70 deg F during captive flight Launch: T = 0 sec UTC: 17:11: seconds after DC1 ON T<0 All systems on as expected T=4.050 Booster motor case pressure sensor jumps off scale (ignition) T= Post-launch booster roll anomaly (commanded actuator to stop -25 deg for.4 s and.6 sec) T=2 Post-launch roll transient T=3 Beta-vane voted out T=0 Lost RADAR contact Imode 1 = Boost from to sec T= Roll anomaly Deg: 0 > > 8.8 T=10-25 FADEC local pressure (PSLOC) starts to rise from 1.71 psia T=17 to 23 Normal engine prestart sequence T=23 to 28 T= T1027 Normal engine start sequence FTS environment aft T begins to rise T=23.93 Vehicle starts rolling right T=22.56 Inlet starts T=20 Pump starts T=20 DPPT voted out T=20-30 A0003 Engine accel A1 rings T=17 PIV open flag set to TRUE T=26 Roll angle reaches 153 deg T=28.03 Vehicle starts rolling left T=30 Roll angle reaches Imode 3 deg, start rolling right T=33 T=~28 Missed IMODE=2 Roll angle reaches deg, start rolling left T=?? Contrail observed on vehicle T=33 FADEC declares engine lit immediately after separation from booster T= BPV loop isolator fault TRUE T=36 Transition declared Imode 4 T = 32 Ethylene performance low T=28-32 Ethylene remained hotter and more pressurized during flight than ground tests T = PSLOC increases by ~1 psi during engine start, then drops back down T=35 T1034, T1035, T1036 T=42 Run declared Engine to aft A/F seal T1034 starts to rise T=35 Starboard plunger temperature begins rising T=45 Intended roll maneuver T= T1027 ends T=43.78 IMU Beta Goes from to + T=~43 TFCAVE out of family T=40 Nozzle pressure rises rapidly above predicted levels T=43-53 Nozzle forward pressure degradation FTS environment plateau, then rise T=54.6 Bank command Vehicle suddenly rolls left T=57 T1078 TESPFWD Scanner temps start increasing T=57 T1079 T=62.33 IMU Beta T=65 Ny disturbance Suddenly jumps from to deg TESPAFT Scanner temps start increasing T=57 + T1043, T port-side long seal T s start increasing T=64.3 T1034, T1035,T1036 T=69.24 PSLOC 0.1 PSIA step in nacelle pressure followed by rate change Engine to aft A/F seal T s rise sharply T=65-70 Nozzle pressure discontinuities (fwd and aft) T=75 Ny disturbance T=72.87 IMU Beta Suddenly drops from to deg T= Positive side acceleration T=79.67 T1029, T1030 Fwd eng mount RS, aft eng mount RS begin to rise T = Slow decrease in acceleration in flight direction T=86 T1035,T1036 Engine to aft A/F seal T s reach 465 df and 376 df, signal lost T=86 PXXX Lost pneumatic meas T=87 T1030 Structural performance interface thermocouple shows temperature rising T= T1034 Engine to aft A/F seal reaches 566 df, signal lost T=94 PXXX Lost pneumatic meas T= Slow decay in combustor peak pressure up to inlet unstart T= Nozzle pressure degradation T= Temperature drift in A3 accel T= PXXX Lost pneumatic meas T=105.2 T1027 FTS env aft T reaches max T then slight decrease T= PXXX Lost pneumatic meas T= IMU Beta Builds to greatest value T= T1079 TESPAFT Scanner temps exceed 636R max op limit T= PXXX Lost pneumatic meas T=120 Decrease in engine throat centerline pressure and increase in PS2.2 T= Vehicle roll builds to 22 deg T= ??? Acceleration in flight direction decreases T= ??? Acceleration in lateral direction starts increasing T= Nozzle pressure gradient Reversing and oscillating T= T1078 TESPFWD Scanner temps exceed 636R max op limit T=140 T1046 Engine to fwd A/F seal T begins to rise T= Aileron command is decreased to zero T= Surface disturbance T= A4 accel at back of engine begins to drift from temperature T= P Many scanner 1 meas drop out T= Engine and vehicle performance T= Roll anomaly T= Inlet unstart T=160 FADEC/VMS event and fault detections T= PSLOC Rapid step change T=160 T1030 nominal Vehicle suddenly starts rolling right Eng to A/F struc perf I/F kink in curve T=161 P T=161 T1043,T1044 Engine to long A/F seals T rises sharply T=161 T1039,T1040,T1041,T1042 Engine to long A/F seals T begins to rise slowly All scanner 1 meas drop out T=160 HEX exit TCs show heat load distribution change T= TMCH1, TE*, TM* All HEX metal T s begin increase T=160.2 TF1, TF2, TF3 T= IMU Beta Goes from to + T=160 Rapid increase in acceleration in flight direction T=160 Vehicle sideslip drops to nearly zero after unstart T=160 A1025 accel is excited Temps begin to rise T= PSLOC Additional spike to 7.8 psia T>160 PSLOC and cruiser aft ESP P1006 T>160 GCU IMU temp rise T= Forebody pressure increase T=160 Pressure distribution in inlet changes after unstart T=160 A1026 trends depart T=160 Nozzle pressures approach nominal after unstart Sensor not excited during unstart event T= T1012 Aft starboard temperature anomaly T=160 T1011 Temperature drops T = 175 Rapid loss in acceleration in flight T= GCU detects loss of FADEC communication T=172.7 T1029 Eng to A/F struc perf I/F steeper rise T>160 Forebody ramp (57") and cowl (64") pressure elevation T=175??? Nozzle pressure gradient Is in negative direction T= T1027 and A1026 direction T=176 Combustor restarts T=175 Ethylene leaks / is released T>160 PSLOC resets to higher pressure after unstart FTS environment aft T and accel lost; short to ground T= T1084 FTS receiver T sharply increases T=174 T1020 Aft most surface temperature rises rapidly T=175+ Multiple FADEC railkills T= PSLOC >2X spike (false reading due to FADEC reset) T=182 T1046 Signal lost T=180 Inlet ramp temperature starts decreasing T= P0064-P0128 T= A1-A4 All 4 engine accels spike g Scanner 2 meas start to drop out T=183 T1012, T1017, T1019, T1020 Aft starboard chine and upper transition chine temperature sensors rise rapidly T=198 T1084 T=201 T1030 signal lost T= T1078 TESPFWD Max scale of 736R T=200??? Nozzle pressure gradient Is almost zero FTS receiver T peaks at 1502 df, signal lost T= T1081 TRJC3 Read 608R max (highest of 3) 645R max op lim T= A4 Engine aft accel 5 spikes > 500g T=211 T1078 signal lost T=210.5 T1029 signal lost T=211 T1043, T1044 Engine to long A/F seals 519 df / 601 df, signal lost T=211 T1039,T1040,T1041,T1042 Engine to long A/F seals df, signal lost T=211 T1084 signal lost T=211 T1080,T1081 signal lost T>200 T1001=95 deg F T1015=130 deg F T>211 Data loss Data review summit held 1 month after flight SED-WR Consortium, AFRL, AFFTC, and NASA all participated Expected Events Vehicle UNCLASSIFIED Export Controlled Expected Events Engine Unexpected Vehicle Dynamics Time Imode 5 = Run from to sec Flight data reviewed by discipline; what did you see and how does it compare with expectations? Vehicle avionics, subsystems, and software all apparently operating as expected; review continues to ensure adequate margins Combined timeline of observations developed and grouped by vehicle areas Unexpected engine operation Fwd Avionics Bay Sensors External Sensors Aft Bay Sensors Flowpath and Engine Sensors Engine Bay Sensors UNCLASSIFIED Export Controlled Fault Tree developed through facilitation by a fault-tree specialist Unexpected Internal Vehicle Environments 76 nodes Unexpected Loss in Vehicle Acceleration 63 nodes Analysis actions assigned to assist node closure 45

46 Unexpected Environments Fault tree reproduced for illustrative purposes only (no intent to brief details) Unexpected High Pressure Unexpected High Temp Unexpected Internal Vehicle Environments Unexpected Vibe & Shock Pressure & Temperature Focus Areas Communication with flowpath or external env. Engine to airframe seals Flowpath wall breach Internal sources to increase pressure or temp NOTE: Vibe & Shock determined to be as expected 46

47 Temperature (F) Elevated Engine Bay Temps Located at aft seal Seal temps Cruiser Nozzle Nozzle Engine / Airframe Aft Seal Temperature (T1034) Engine / Airframe Aft Seal Temperature (T1035) Engine / Airframe Aft Seal Temperature (T1036) Engine Bay Side Temperature (FWD) Engine Bay Side Temperature (AFT) Thermal Modeling of TCs (Gas Path Temperature) Thermal models connect measurements to one driving environment: Engine flow-path temperature (U) Engine Ignition Located in engine bay Time Since Launch (sec) 47

48 PF1 Aft Interface Investigated Key Interface Issues Post flight investigation found as-built engine / cruiser interfaces did not fully meet design intent Engine in short Gap filled with DC done blind (potential for holes) Thermal seal uncompressed in cold condition Thermal seal allowed to move relative to aft end of engine (potential for steps) Leading edge of thermal seal 3/8 cell honeycomb- BLA-HD FTV1 Interface Side View of Thermal Seal END of engine DC gap fill - yellow lines added to define fill area NOTE: Picture is FTV1, not first flight vehicle View 48

49 Unexpected Accel Loss Fault tree reproduced for illustrative purposes only (no intent to brief details) Unexpected Decrease in Thrust Observed Decrease in Accel During JP-7 Operation Unexpected Increase in Drag Thrust Focus Areas Inlet performance / mass capture Fuel delivery to engine Lower than expected performance Changes in flowpath geometry Faulty Accel Readings & Unexpected Increase in Mass Drag Focus Areas Incorrect drag predictions Increased drag from vehicle dynamics Unexpected change in OML geometry Unexpected fluid dynamic effects 49

50 Cruiser Drag Comparison 50

51 Unexpected Loss in Acceleration Integrated Force Analysis In-flight Flowpath force derived from flight data Abrupt change in flowpath force at the time of temperature anomaly (U) Integral PdA calculated from engine pressure Nominal nozzle force calculated from ground test data Key Finding Integrated flowpath force (inlet-engine-nozzle) is lower than expected based on measured flight performance of engine as compared to ground test data (i.e. Not all the expected thrust was going out the back of the engine! ) 51

52 Nozzle Leak Thrust Impact Less than 10% mass flow leak required to explain missing T-D UNCLASSIFIED 52

53 Investigation Summary Leakage at nozzle interface concluded to be most probable cause of elevated engine & vehicle bay pressures & temps. Leakage at nozzle interface & nozzle IML change concluded to be most probable cause of reduced acceleration prior to 160s. Post flight investigation found asbuilt engine / cruiser interfaces did not fully meet design intent. Remaining three engines removed, interfaces modified to remove all potential leak paths. Pre- and post engine installation leak checks added. 53

54 Loss of Vehicle 54

55 Temperature (F) Elevated Nozzle Bay Temps FTS Receiver Temp (Aft Bay) FTS Control Box Temp (Aft Bay) FADEC Temperature (FWD Bay) FWD Bay Aft Bay No increase in fwd bay temp Time Since Launch 55

56 Possible Nozzle Burn Through PF1 corner BLA-HD install exposed sides of BLA-HD matrix (U) Increased exposure of phenolic walls increases rate of ablation and may have caused loss of cells and insulation Side-Cut BLA-HD Cells Nozzle Top-Edge BLA-HD 56

57 Outline Program Overview Vehicle Overview Development Program Flight Test Program Initial Data Results Post-Flight Investigation Summary 57

58 Summary X-51A first flight results a major step towards validating state of the art design tools, models, and verification test methodologies for Mach 4-6 class hypersonic vehicles and validate the viability of SCRAMJET propulsion technology Key Areas Validated Hypersonic vehicle design, control and performance modeling Hydrocarbon scramjet engine design (2-D), control & ground test methodology What Remains for X-51-Size Systems Integrated performance of vehicle and vehicle maneuverability considerations (planned for subsequent flights) Next Flight Planned for Early

59 QUESTIONS? 59