x-51 development: a chief engineer's perspective - aiaa · pdf file1 cleared for public...

1

Cleared for Public Release Case Number: 88ABW-2011-0846

X-51 Development: A Chief Engineer’s Perspective

Mr. Richard Mutzman CE AFRL/RZ

Mr. Scott Murphy, CE X-51

Air Force Research Laboratory

17th AIAA International Space Planes and

Hypersonic Systems and Technologies Conference

13 April 2011


2


Outline

• Program Overview

• Vehicle Overview

• Development Program

• Flight Test Program

• Post-Flight Investigation Summary

• Summary

3


Outline






• Summary

4


Scramjet Technology Development Approach

Hypersonic Missiles/

Small Launch Systems

Stair-step approach builds

upon prior successes

Large Hypersonic Missiles

Small Launch Systems

Operationally Responsive Spacelift

(Robust, Responsive)

Small Scramjets

Medium Scramjets

Large Scramjets and CCEs

LRC

LRC

LRC

Ramjets

Hypersonic Missiles

(Time-Critical Targets)

1980 ~

2010

2015

2020

2030

TRL=6 2010

TRL=6 1980

X-51 Program

5


• 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 26th, 2010

X-51A first flight was the

product of a national team

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+

X-51A Program Objective

6


Why Do an X-51A Flight Test?

7


X-51A Objectives

There are two parallel processes taking place that must be balanced:

• Acquire Ground Test Data

• Acquire In-Flight Test Data

• Correlate Ground/Flight Data/Analyses

• Additional Areas of Hypersonic Research

• Anchor Hypersonic Vehicle Design Tools

• B-52 Integration

• Airframe/Propulsion Integration

• Software Development

• ATACMs Booster Integration

• Avionics Qualification

• Etc.

Hypersonic Propulsion Flight Experiment Air Vehicle Development Effort

• 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)

Specific 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+”

8


X-51A Baseline Schedule

Planned ActivityCompleted Milestone Slipped Activity

FY03 FY04 FY05 FY06 FY07 FY08 FY09 FY10 FY11

On Contract

X-51 SRR

X-51 PDR

SJX61-1 Test

X-51 CDR

SJX61-2 Test

FRR

X-51 Flight 1

Flights 2-4

Dec 03

Aug 04

Dec 04

Sep 07

Sep 08

Dec 08

Nov 06

Apr 08

Jul 05

Jun 09

May 10

May 07

Mar, Jun, ???

Jan 07

9


Outline






• Summary

10


Scramjet Engine

Cruiser

Flow-Through

Inter-stage

Modified ATACMS

Booster

AVD Stack length: 301 inches

Cruiser length: 168 inches

Max body width: 23 inches

Engine flow-path width: 9 inches

X-51A Mass Properties

Cruiser Operating Weight = 1225 lb Booster = 2277 lb

JP-7 Fuel (Useable) = 265 lb Interstage = 160 lb

Cruiser Launch Weight = 1504 lb Stack Gross Weight (Captive Carry) = 3942 lb

X-51 Vehicle Overview

11


X-51A Material Composition

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)

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)

Stack Structural Materials

Cruiser TPS Materials

12


X-51A Subsystems Packaging

FTS, FTI and

Control Systems• Antennas

• Sensors

• Control Actuators

• Detailed Line

Routing

JP-7 Fuel • Integral Tanks

• 265 lb (usable)

• Sealing Concept

Defined

Subsystems Bay • GCU/IMU/GPS

• FADEC

• Flight Test Instrumentation (FTI)

• Detailed Line Routing

Engine Subsystems

(Packaged Wet in JP-7)

• Engine Fuel Pump

• Ethylene (Engine Start)

• Nitrogen (Fuel Pressurization)


Fuel System• Fuel Pump


Batteries• Engine Systems

• Actuators

• Avionics and FTI

• Flight Termination System

(Separate)

(Li-ion Pack)

13


SJX61-2 at LaRC 8 ft HTT (U)

JP-7 Fuel Tank

Airframe Mounted

Nozzle Integral inlet &

forebody

Fuel Cooled Scramjet

14


Modified Army TACMS Booster

New FWD Skirt Hole Pattern:

Match Drill FWD Skirt with Interstage

Material Changes for

Performance Enhancements:

• Ti Boat tail Housing

• Al Control Fins

Booster Prime Contractor/ATACMS Integrator:

Lockheed Martin Missiles & Fire Control

Dallas, TX

Replace Existing Nozzle Exit Cone with

Extended Exit Cone

Fixed Fins for Stability

after release from B-52

Fin Locks added for

B-52 carriage

15


Outline






• Summary

16


X-51 Aerodynamic Development(> 3200 Runs)

• AVD

– PSWT 724 – April 2000 (ARRMD program)

– NAART 119 – January 2004

– 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 2005

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

Boeing PSWTNASA LaRC 16-Foot

Transonic Wind Tunnel

20% Cruiser Model Inlet Test

– PSWT 817

14% Stack Model – PSWT 794

AEDC VKF Tunnel B

14% Stack SLA model

Installed in Boeing NAART

X-51 Installed at

NASA LaRC UPWT

20% Cruiser Model

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

• 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

OVERFLOW Grid System

BCFD Grid System & Solution

18


Lift verses Alpha

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

-15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 20.0

Alpha

CL

PSWT 802, Run 450

CART3D

OVERFLOW (no sting)

Wind Tunnel to CFD CorrelationsPitching Moment verses Alpha

-0.015

-0.010

-0.005

0.000

0.005

0.010

-15.0 -10.0 -5.0 0.0 5.0 10.0 15.0 20.0

Alpha

Cm

AEDC 470, Run 32

AEDC 470, Run 83

CART3D (no sting)

OVERFLOW (no sting)

OVERFLOW (sting)

Pressure Comparison at Mach 3.0

-0.20

-0.10

0.00

0.10

0.20

0.30

0.0 50.0 100.0 150.0 200.0X

Pre

ss

ure

Co

eff

icie

nt

Euler CFD (CART3D)

PSWT Test 802

19


X-51 Stack Has Mixed Static Stability(M = 0.8)

• Longitudinally unstable at launch

• Laterally unstable for angles-of-

attack less than 2 degrees

• Directionally unstable for angles-of-

attack less than 6 degrees-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

-0.4 -0.2 0.0 0.2 0.4 0.6 0.8

Lift Coefficient, CL

Pit

ch

ing

Mo

men

t C

oeff

icie

nt,

Cm

Fin=-25 Fin=-20 Fin=-15

Fin=-10 Fin=-5 Fin=0

Fin=5 Fin=10 Fin=15

Fin=20 Fin=25

Symmetric Fin Deflection Angle (degrees)

-0.006

-0.004

-0.002

0.000

0.002

0.004

0.006

0.008

0.010

-15 -10 -5 0 5 10 15 20 25

Angle-of-Attack (Deg)

Cnb + Stability

- Stability

-0.003

-0.002

-0.001

0.000

0.001

0.002

0.003

-15 -10 -5 0 5 10 15 20 25


Clb

+ Stability

- Stability

20


X-51 Cruiser Has Mixed Static Stability(High Mach)

-0.030

-0.025

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

0.015

-0.25 -0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20 0.25

Lift Coefficient, CL

Pit

ch

ing

Mo

me

nt

Co

eff

icie

nt,

Cm

Fins=-20 Fins=-15 Fins=-10

Fins=-5 Fins=0 Fins=5

Fins=10 Fins=15 Fins=20

Symmetric Fin Deflection (deg)

-0.0004

-0.0002

0.0000

0.0002

0.0004

0.0006

0.0008

0.0010

-10 -5 0 5 10 15


Cnb

+ Stability

- Stability

-0.0005

-0.0004

-0.0003

-0.0002

-0.0001

0.0000

0.0001

0.0002

0.0003

0.0004

0.0005

-10 -5 0 5 10 15


Clb

+ Stability

- Stability

• Longitudinally unstable

• Laterally unstable for angles-of-

attack less than 9 degrees

• Directionally stable

21


Specialized Databases

• Stage separation data

– Defines the aerodynamic

interaction between the cruiser

and the booster during stage

separation

– Based on Navier-Stokes CFD

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

M∞=0.8, a=0.65º

22


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

• Beta vane calibration database

• Shows relationship between true and

indicated beta

• Mach 0.6 to 2.5

• Defined by Euler CFD

P1

P2P3

P4P5

P6

P7

P8P9

P10

P11

P13

P14

P15

P17P19

P18P16

P20

P12

P21

P22

P54

P59

P57

P58

P56

P55

P92

(cavity)

P91

(cavity)

P98

P97

P99P100

P104

P60

P23 – P31 match

P13 – P21

on right side.

P101, P102, P103 on lower

surface, right side at model

stations 10.0, 12.0, 14.0


chine surface, right side at

model stations 20.0, 26.0, 32.0

P1

P2P3

P4P5

P6

P7

P8P9

P10

P11

P13

P14

P15

P17P19

P18P16

P20

P12

P21

P22

P54

P59

P57

P58

P56

P55

P92

(cavity)

P91

(cavity)

P98

P97

P99P100

P104

P60

P23 – P31 match

P13 – P21

on right side.


surface, right side at model

stations 10.0, 12.0, 14.0


chine surface, right side at

model stations 20.0, 26.0, 32.0

Location for Flush Air Pressure taps

Flush Air Calibration Data

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

-15 -10 -5 0 5 10 15 20


De

lta

Cp

Beta = -4 Beta = -3 Beta = -2 Beta = -1 Beta = 0

Beta = 1 Beta = 2 Beta = 3 Beta = 4

23


Subsystems Development

• Full subsystem component development & qualification testing conducted

• Verification of combined vehicle and engine control system via Hardware-

in-the-Loop testing

• Assembly and Checkout, and On-Aircraft testing conducted

Actuator Qualification GCU QualificationEthylene System Dev Test

Battery QualificationAssembly and Checkout Test

Hardware-in-the-Loop

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)

25


X-51A Propulsion Heritage(Crawl-Walk-Run)

Ground Demo Engine 1 (June ’03)

•Flight weight

•Fuel cooled, but open loop fuel system

Performance Test Engine (Jan ’01)

•Copper heat sink construction

•Partial width flowpath

Ground Demo Engine 2 (Mar ’06)

•Center engine for X-43C

•Fuel cooled, closed loop fuel system

HyTech Flowpath

Development

X-51A Dev. Engine, SJX61-1 (Jul ’07)

•Full X-51A forebody and nozzle

•Fuel cooled, closed loop fuel system

X-51A FCE SJX61-2 (Oct 08)

•Flight Clearance Engine

•Flight fuel pump & instr.

X-51A propulsion system has strong

foundation in past component & system tests

X-51A Flight Test

Video - Hypersonics Anthology_rev 03-03-09.wmv

../../Publicly Releasable Information/Videos/Video - Engine Test - 2008-08-28 - SJX61-2 Test Run 25, High Def (Cleared for Public Release - 88ABW-2008-0242).wmv

26


X-51 Engine Development Program Summary

SJX61-2 at LaRC 8 ft HTT

SJX61-1 at LaRC 8 ft HTT

Subsystem Qualification

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

Combustor Tests

27


Outline






• Summary

28


X-51A Notional Mission

29


B-52H Flight Ground Track

Edwards

AFB

San

Nicholas

Island

Vandenberg

AFB

Pt Mugu

“Racetrack”

Launch Point

30


Preparing for Flight Test

11 April 2011

Umbilical Extension (Minimize Length)

AVD on the ground

(notional fixture)

SMO OFP

GCU OFP

(with TLI Mode)

&

ICS OFP

(Power Distribution)

FWD

UP

FWD Pi-fitting

AFT Pi-fitting

Shear Pins

(8 places)

Heavy Stores

Adaptor Beam

(HSAB)

(

Side Tension

Fitting (4 places)

MAU-12 Ejector

• Conducted actual X-51 to B-52

on Aircraft System Integration

testing

• B-52 Systems Integration

Laboratory Testing conducted

to verify electronic interfaces

• B-52 Hardware Modifications made to

the Heavy Stores Adapter Beam and

MAU-12 Launcher

GCURTSIM

SMO SW

(SIL)

MIL-STD

1760/1553

X-51 B-52

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 2011

32


Mission Control Center

11 April 2011

• 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

• 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

• Vandenberg (TM only)

Ridley Center Control Room

Pt Mugu Control Room

Ridely Control Center

Pt. Mugu Control Center

33


Getting the Data is Key

VAFB LOS

NP-3-D LOS

SNI LOS

Mugu LOS

T=582, Splash Down

T=295, Engine Shutdown

T= ~32, Engine Start

T= ~30, Separation

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 - 134

– Engine – 171

– Interstage/Booster - 36

• 1382 Serial (GCU/FADEC)

Avionics Pallet

S-Band

Transmitters

Pressure

Scanner

T/C Reference

Junctions

GNC Pressure

Transducer

Starboard

Antenna

Engine

DAU

Aft

Antenna

Port

Antenna

Master

DAU

35


Flight Test Safety

11 April 2011Disconnects

(2)

Hybrid

Coupler

Receivers

(2)

Control

box Lanyard

Cutters (2)

Manifold (2)

Safe and

Arm (2)

• Splashdown Dispersion established

by Monte Carlo simulation

• Range termination trajectory

limits established

• Redundant Flight Termination

System On-board

Down Range

Surveillance

Area

IIP

Terminate

Limit LineHazard Boundary

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

37


X-51 First Flight Overview

First Flight Events:• Clean release from B-52

• Booster ignition at 4 sec

• Cruiser separation at ~ 30 sec

• 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

Notional Mission

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 143 sec

Total mission time 210 sec

Peak acceleration during mission ~0.18 g

Total distance travelled 150 NM

Cleared for Public Release: 88ABW-2010-6072

39


Outline






• Summary

40


ATACMS Booster

Aft cover to

protect igniter

(air-launch)

Increased nozzle

expansion ratio

Fixed fins for

stability after B-

52 release

Fin locks to

prevent flutter in

captive carry

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

41


50 60 70 80 90 100 110 120 130 140 150-6

-5

-4

-3

-2

-1

0

1

2

Time Since Launch (sec)

Fin

An

gle

(d

eg

)

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)

Engine JP-7 Fuel

System

Vehicle & Engine Subsystems

Electrical Power Systems

Vehicle Fuel System

Cruiser

Fins (U)

0 20 40 60 80 100 120 140 1600

2000

4000

6000

8000

10000


Pu

mp

Sp

ee

d (

RP

M)

Pump Speed

Pump Speed Request

42


Scramjet Engine Operation

Heat Exchanger Thermal Loads

Flight Performance vs. PredictedPerformance, 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

43


On JP-7

Anomaly Occurs

Inlet Unstarts

Engine & Vehicle Recover

Ethylene Ignition

Cruiser Tare

Cruiser Axial Acceleration

44


UNCLASSIFIED

0 20 40 60 80 100 120 140 160 180 200 2204

4.2

4.4

4.6

4.8

5M

ach

Nu

mb

er

0 20 40 60 80 100 120 140 160 180 200 220-0.5

0

0.5

Mach Number

Axial Acceleration

UNCLASSIFIED

0 20 40 60 80 100 120 140 160 180 200 2200

2

4

6

8

Pre

ssu

re (

psia

)

Cruiser Bay Pressure

Atmospheric Pressure from BET

0 20 40 60 80 100 120 140 160 180 200 2200

500

1000

1500

2000

Tem

pera

ture

(F

)

TESPAFT

T1034

T1035

T1036

T1046

T1087

Aft Seal Temps Engine Bay

Temp Rise

Aft Bay Temp Rise

Unstart

TM Loss

JP-7 Only

Pressure Rising


45


X-51 Anomaly InvestigationMethodology

Scramjet Engine Demonstrator Flight 1 Timeline

Flo

wpath

and E

ngin

e S

enso

rsA

ft B

ay

Senso

rsE

xtern

al S

enso

rsE

ngin

e B

ay

Senso

rsF

wd A

vionic

s B

ay

Senso

rs

Unexp

ect

ed e

ngin

e

opera

tion

Exp

ect

ed E

vents

–

Engin

eE

xpect

ed E

vents

– V

ehic

leU

nexp

ect

ed V

ehic

le D

ynam

ics

Tim

e

Imode 1 = Boostfrom 4.0752 to 28.0856 sec

Imode

3

Imode 4

Time (sec) 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225

Launch: T = 0 sec

UTC: 17:11:20.616946

1425 seconds after DC1 ON

T=14.890

T1027

FTS environment aft T begins to rise

T=17 to 23

Normal engine prestart

sequence

T=23 to 28

Normal engine

start sequence

T=33

FADEC declares engine lit

T=36

Transition declared

T=32.010

BPV loop isolator

fault TRUE

T=35

T1034, T1035, T1036

Engine to aft A/F seal T1034 starts to rise

T=39.410

T1027

FTS environment plateau, then rise

T=42

Run declared

T=57 +

T1043, T1044

2 port-side long seal T’s start increasing

T=57

T1078

TESPFWD Scanner temps start

increasing

T=64.3

T1034, T1035,T1036

Engine to aft A/F seal T’s rise sharply

T=69.24

PSLOC

0.1 PSIA step in nacelle pressure

followed by rate change

T=79.67

T1029, T1030

Fwd eng mount RS, aft eng

mount RS begin to rise

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=94

PXXX

Lost pneumatic

meas

T=108.763

PXXX

Lost pneumatic

meas

T=120.503

PXXX

Lost pneumatic

meas

T=132.098

PXXX

Lost pneumatic

meas

T=94.090

T1034

Engine to aft A/F

seal reaches 566

dF, signal lost

T=105.2

T1027

FTS env aft T reaches max T then

slight decrease

T=120.418

T1079

TESPAFT Scanner temps exceed

636R max op limit

T=140

T1046

Engine to fwd A/F seal T begins to rise

T=141.669

T1078

TESPFWD Scanner temps exceed

636R max op limit

T=154.537

P0001-0064

Many scanner 1

meas drop out

T=159.980

Inlet unstart

T=159.924

PSLOC

Rapid step change

T=160

FADEC/VMS event and fault

detections

Imode 5 = Runfrom 42.9893 to 176.0001 sec

T=161 – 175.3

Engine and vehicle performance

nominal

T=160

HEX exit TCs show heat load

distribution change

T=160-178

TMCH1, TE*, TM*

All HEX metal T’s begin increase

T=169.56

T1027 and A1026

FTS environment aft T and accel lost;

short to ground

T=160.2

TF1, TF2, TF3

Temps begin to rise

T=160

T1030

Eng to A/F struc perf I/F

kink in curve

T=161

P0001-0064

All scanner 1 meas

drop out

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

T=172.7

T1029

Eng to A/F struc perf I/F steeper rise

T=175.305

GCU detects loss of

FADEC communication

T=178.5 – 187.8

T1084

FTS receiver T sharply

increases

T=189.947

P0064-P0128

Scanner 2 meas start to drop out

T=198

T1084

FTS receiver T peaks at 1502

dF, signal lost

T=201

T1030

signal lost

T=203.132

T1078

TESPFWD Max

scale of 736R

T=210.5

T1029

signal lost

T=208.433

T1081 TRJC3

Read 608R max

(highest of 3) 645R

max op lim

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 72-79 dF,

signal lost

T=211

T1078

signal lost

UNCLASSIFIED

Export Controlled

UNCLASSIFIED

Export Controlled

T=211

T1084

signal lost

T=57

T1079

TESPAFT Scanner temps start

increasing

T=211

T1080,T1081

signal lost

T=16 – 18.83

Roll anomaly

Deg: 0 > -41.2 > 8.8

T=54.6

Bank command

Vehicle suddenly rolls left

T=159.75

Roll anomaly

Vehicle suddenly starts

rolling right

T=43.78

IMU Beta

Goes from – to +

T=62.33

IMU Beta

Suddenly jumps from

0.115 to 0.548 deg

T=72.87

IMU Beta

Suddenly drops from

0.7172 to 0.0721 deg

T=121.763

IMU Beta

Builds to greatest value

T=164.971

IMU Beta

Goes from – to +

T>160

Forebody ramp (57") and cowl

(64") pressure elevation

T=122.26 – 157.18

Nozzle pressure gradient

Reversing and oscillating

T=175???


Is in negative direction

T=200???


Is almost zero

T=122.26 – 157.18???

Acceleration in flight direction decreases

T=122.26 – 157.18???

Acceleration in lateral direction starts increasing

T=23.93

Vehicle starts rolling right

T=22.56

Inlet starts

T=26

Roll angle reaches 153 deg

T=28.03

Vehicle starts rolling left

T=45

Intended roll maneuver

ends

T=30

Roll angle reaches -174.58

deg, start rolling right

T=33

Roll angle reaches 145.2

deg, start rolling left

T=160.990

PSLOC

Additional spike

to 7.8 psia

T=181.24

PSLOC

>2X spike (false reading

due to FADEC reset)

T=197.1-197.2

A1-A4

All 4 engine accels

spike +- 100g

T=201-207

A4

Engine aft accel 5

spikes > 500g

T=??

Contrail observed on vehicle

immediately after separation from

booster

T=.430 - .535

Post-launch booster roll anomaly

(commanded actuator to stop -25

deg for .4 s and .6 sec)

T=0

Lost RADAR contact

T = 32

Ethylene performance low

T = 65-122

Slow decrease in acceleration in flight direction

T = 32-43

PSLOC increases by ~1 psi during

engine start, then drops back down

T=87

T1030

Structural performance interface

thermocouple shows temperature

rising

T=4.050

Booster motor case pressure

sensor jumps off scale (ignition)

T=10-25

FADEC local pressure (PSLOC)

starts to rise from 1.71 psia

T=17

PIV open flag set to TRUE

T<0

All systems on as expected

T=20

Pump starts

T=40-160

Positive side acceleration

T=35

Starboard plunger

temperature begins

rising

T=40

Nozzle pressure rises rapidly

above predicted levels

T=43-53

Nozzle forward pressure

degradation

T=65-70

Nozzle pressure discontinuities

(fwd and aft)

T=70-160

Nozzle pressure degradation

T=28-32

Ethylene remained hotter and more

pressurized during flight than

ground tests

T=60-160

Slow decay in combustor peak pressure up to inlet unstart

T=~43

TFCAVE out of family

T=120

Decrease in engine throat centerline pressure and

increase in PS2.2

T=150-160

Aileron command is

decreased to zero

T=146-159

Surface disturbance

T=159.82

Forebody pressure increase

T>160

GCU IMU temp rise

T>160

PSLOC resets to

higher pressure after

unstart

T=160

Pressure distribution in inlet

changes after unstart

T = 175

Rapid loss in acceleration in flight

direction

T=160

Rapid increase in acceleration in

flight direction

T=160

T1011

Temperature drops

T=0

Flowpath hardware cold soaked to

T=-70 deg F during captive flight

T=20-30

A0003

Engine accel A1 rings

T=60 - 160

Temperature drift in A3 accel

T=160-180

T1012

Aft starboard temperature anomaly

T=180

Inlet ramp temperature starts

decreasing

T=174

T1020 Aft most surface

temperature rises rapidly

T=183

T1012, T1017, T1019, T1020

Aft starboard chine and upper

transition chine temperature

sensors rise rapidly

T=160

A1026

Sensor not excited

during unstart event

T>200

T1001=95 deg F

T1015=130 deg F

T=160

Nozzle pressures approach

nominal after unstart

T=160

Vehicle sideslip drops to nearly

zero after unstart

T=150-160

A4 accel at back of engine

begins to drift from

temperature

T<0

B-52/X-51 Mach

miscompute

T=3

Beta-vane voted out

T=2

Post-launch roll transient

T=20

DPPT voted out

T=~28

Missed IMODE=2

T=65

Ny disturbance

T=75

Ny disturbanceT=122-160

Vehicle roll builds to 22 deg

T=175+

Multiple FADEC railkills

T=176

Combustor restarts

T>211

Data loss

T=175

Ethylene leaks / is released

T=160

A1025 accel is excited

T>160

PSLOC and cruiser aft ESP P1006

trends depart

T=182

T1046

Signal lost

• Data review summit held 1 month after

flight

– SED-WR Consortium, AFRL, AFFTC, and

NASA all participated

– 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

• 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

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

NOTE: Vibe & Shock

determined to be as expected

Pressure & Temperature Focus Areas

• Communication with flowpath or external env.

– Engine to airframe seals

– Flowpath wall breach

• Internal sources to increase pressure or temp

47


20 40 60 80 100 120 140 1600

100

200

300

400

500

600


Tem

pera

ture

(F

)

Engine / Airframe Aft Seal Temperature (T1034)



Engine Bay Side Temperature (FWD)

Engine Bay Side Temperature (AFT)

Thermal Modeling of TCs (Gas Path Temperature)

Engine Ignition

Located in engine bay

Seal temps

Cruiser Nozzle

Located at aft seal

Thermal models connect measurements

to one driving environment:

Engine flow-path temperature (U)

Elevated Engine Bay Temps

Nozzle

48


END of engine

Leading

edge of

thermal seal

DC 93-104 gap

fill - yellow

lines added to

define fill area

3/8” cell

honeycomb-

BLA-HD

PF1 Aft Interface Investigated

• Post flight investigation

found as-built engine /

cruiser interfaces did not

fully meet design intent

• Engine 0.1 - 0.2 in short

• Gap filled with DC-93-

104… 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) NOTE: Picture is FTV1,

not first flight vehicle

FTV1 Interface

Side View of Thermal SealKey Interface Issues

View

49


Observed Decrease

in Accel During JP-7

Operation

Unexpected

Decrease in

Thrust

Unexpected

Increase in Drag

Faulty Accel

Readings &

Unexpected

Increase in

Mass

Fault tree reproduced for

illustrative purposes only

(no intent to brief details)

Unexpected Accel Loss

Thrust Focus Areas

• Inlet performance / mass capture

• Fuel delivery to engine

• Lower than expected performance

• Changes in flowpath geometry

Drag Focus Areas

• Incorrect drag predictions

• Increased drag from vehicle dynamics

• Unexpected change in OML geometry

• Unexpected fluid dynamic effects

50


Cruiser Drag Comparison

51


Abrupt change in flowpath

force at the time of

temperature anomaly (U)

Unexpected Loss in Acceleration

• In-flight Flowpath

force derived from

flight data

• Integral PdA

calculated from

engine pressure

• Nominal nozzle force

calculated from

ground test data

Key FindingIntegrated 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!”)

Integrated Force Analysis

52


Less than 10% mass flow leak required to explain missing T-D

Nozzle Leak – Thrust Impact

UNCLASSIFIED

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 as-

built 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.

54


Loss of Vehicle

55


0 20 40 60 80 100 120 140 160 180 200 2200

200

400

600

800

1000

1200

1400

1600

1800

2000

Time Since Launch

Tem

pera

ture

(F

)

FTS Receiver Temp (Aft Bay)

FTS Control Box Temp (Aft Bay)

FADEC Temperature (FWD Bay)

FWD Bay

Aft Bay

Elevated Nozzle Bay Temps

No increase

in fwd bay temp

56


Possible Nozzle Burn Through

PF1 corner BLA-HD install exposed sides of BLA-HD matrix (U)

Nozzle Top-Edge

BLA-HD

Side-Cut

BLA-HD

Cells

Increased exposure

of phenolic walls

increases rate of

ablation and may

have caused loss of

cells and insulation

57


Outline





• Initial Data Results

• Post-Flight Investigation

• Summary

58


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

Summary

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 2011

59


QUESTIONS ?

x-51 development: a chief engineer's perspective - aiaa · pdf file1 cleared for public...

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