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“Shaped Sonic Boom Demo Program

VIEWS: 21 PAGES: 32

									      Fixing the Sound Barrier
 The DARPA/NASA/Northrop-Grumman
Shaped Sonic Boom Flight Demonstration

          Peter G. Coen, NASA
                    &
      Roy Martin, Northrop Grumman

            EAA AirVenture
          Oshkosh, Wisconsin
              July 2004
             Shaped Sonic Boom Demonstration
                          SSBD
   First ever FLIGHT demonstration of sonic boom
    Shaping
   Design, fabrication and test using a surrogate
    aircraft
       Nose modification of an F-5E Fighter
   Primarily funded by DARPA, Northrop and NASA
   Extremely successful government/industry
    collaboration
     5 U.S. Government agencies
     8 U.S. aerospace companies
                        Sonic Boom Basics

                                                        Multiple Shock
                                                       Waves of Differing
                                                          Strengths




                                          Shocks
                                          begin to
                                           merge
Overpressure Dp

         Impulse

                   Duration                  All Shocks merged into “N-wave”
                              Rise Time
                          Sonic Boom Calculation Approaches
Whitham-Walkden Theoretical                       Computational
   Equivalent Area AE




                        Equivalent Length AE
   Theory of                                                          Minimum Initial Shock




                         Equivalent Area
  Sonic Boom                                   Lift

  Minimization                             Volume
                                                                     Minimum Overpressure

    Through                                 Length

Aircraft Shaping                                    George and Seebass, 1969

             Multiple Shocks                                      Shock Strength
              of Differing                                         and Position
               Strengths                                            Controlled

                                                                          Coalescence
                                                                           Prevented

   Shocks
  begin to
  Coalesce




     Shocks Coalesce into “N-wave”                         Shaped Boom at the Ground
              SSBD Background: Key Elements of
             Theory Validated in Previous Programs

                                                                A
                                                                                   A = 1.3. psf
                                                                B

                                               8

                                               7                       Rise Time
                                               6
                                                                                           0.25
                                               5                                           0.5
                                        Mean
                                                                                           0.75
                                      Loudness 4                                           1
                                       Rating
                                               3                                         B/A
                                               2

                                               1

                                               0
                                                     1           2          3
                                                           Rise Time, ms

                                       Noise Acceptability Benefit Verified: Sullivan 1990



Vehicle Design Approach Verified: Darden and Mack, 1979
  SSBD Provides a Missing Piece of the Puzzle
                     Design




                                 … Through Ground
                                 Measurement of
                                 Booms from
                                 Modified and
                                 Unmodified F-5Es
Demonstrate
                                                                  Design Mach 1.4
Shaped Boom                                                      Shock Thickening Adjusted
                                                             Ground Boom Signature Comparisons
Propagation in                                    1.4
                                                  1.2
                                                  1.0
                                                                                            M = 1.40
                                                                                            h = 32 kft.
                                                                                                               Tanh 1/P Modification



Real
                                                  0.8
                                                  0.6
                                                  0.4




Atmosphere…
                                                  0.2




                                       DP - psf
                                                  0.0
                                                  -0.2
                                                  -0.4
                                                  -0.6
                                                                          F-5SSBD
                                                                  SBD-24b @ 12,700 lbs.

                                                  -0.8                    F-5E
                                                                  F-5E @ 11,200 lbs.

                                                  -1.0
                                                  -1.2
                                                  -1.4
                                                         0   10     20       30        40       50        60   70     80      90       100
                                                                                            Time - msec
           Noise Acceptability
                          Key to SSBD Success: F-5E
   Aircraft Configuration Is Very Amenable to the Type of Forebody Modifications
    Required to Produce a Shaped Boom Signature
        Long Nose, Blended Canopy, and
         Inlets Relatively Far Back
                                                             F-5E
        Very High Overall Fineness Ratio
        Lightweight
                                                            RF-5E
   Modification Is Relatively Low Risk
    Due to Similarity with F-5 Family
        Extensive Database of Modified                      F-5F
         Forebodies with Comprehensive
         Wind Tunnel and Flight Testing
                                                           F-5 Aircraft Forebodies
   Cost-Effective Test Approach
        Limited Wind Tunnel Testing and CFD
         Analysis Required for F-5 Mod                         Initial Design
        Low Aircraft Operating Cost

   Supersonic Performance Capability
    with Margin
                                                               Final Design
                                                                                                                   FOR PUBLIC RELEASE

                                                                                                       Build-Up Approach To
                                                                                                      Development & Validation
                                                          Extensive CFD                                         Inlet Shock Flight Test              Boom Tunnel Tests
                                                                                                                NASA Dryden                         NASA Glenn
                                                                                                                  Feb 02                            Mar & May 02




                                                Mod Shape Defined Jan 02


                                            Correlations Completed
                                             SSBD WTM-2 Near-Field Pressures                                       S&C Tunnel Test                     Force Tunnel Test
                                                    M = 1.367, CN = 0.132, h/L = 1.5,  = 0
                                                                                                  o

                               0.04

                               0.03

                               0.02

                               0.01
DPlocal / P local freestream




                               0.00

                               -0.01

                               -0.02

                               -0.03
                                              Euler - 24b WTM-2 @ MFR = 0.76
                               -0.04

                               -0.05
                                              24b4 WT Data @ MFR = 0.76 - 0.80 - Rdg. 143 (P3)

                                              24b4 WT Data @ MFR = 0.76 - 0.80 - Rdg. 157 (P4)
                                                                                                                                 NGC LSWT                             AEDC 4T
                               -0.06
                                                                                                                                  Aug 02                               Oct 02
                                       35      40         45         50          55         60   65   70   75
                                                                 Along Track (Model) - inches



                                                    IDRs - 12/01 & 2/02                                         PDR - 3/02              CDR - 7/02             Pre-FRR - 1/03


                                                                                                                               FOR PUBLIC RELEASE
              SSBD F-5E Handling Qualities
                Engineering Predictions
   Longitudinal Stability Comparable F-5F, Minor Reduction Dynamic
    Stability Damping
   Directional Stability of F-5SSBD is Comparable to F-5F with 275
    Gallon Centerline Tank
   Directional Stability is Positive for AOA of Planned Flight
    Envelope
   Subsonic and Supersonic Handling Qualities Satisfactory and
    Comparable to other F-5 Configurations (with Stability
    Augmentaion Engaged)
   Use Aft CG Limit of F-5F (More Forward than F-5E)




                                                  25% MAC
                                       L.E. MAC




                                                  Design C.G.


                                     FOR PUBLIC RELEASE
                    Test Aircraft Selection
   Arranged Loan of Navy F-5E
    - Destined for “Boneyard” - Extended 50 Flight Hrs
   Navy Assumed Safety of Flight Risk
    - Navy Flight Clearance Review
    - Navy Test Pilot Participation ( CDR “Spike” Long)




                                   FOR PUBLIC RELEASE
                                  FOR PUBLIC RELEASE


                     Fabrication & Flight Operations
   USN F-5E Arrives NGSA         Mod Nose Attached                  Fairings Attached




 Jan 03                       Mar 03                            Apr 03

          Pre-Flight Prep                First Taxi                         First Flight




May 03                        9 Jun 03                          24 Jul O3

   Envelope Expansion               Back-to-Back &                   21 Flawless Flights
     & Ferry Flights                 Probe Flights                     Over 1 Month!



                                               FOR PUBLIC RELEASE
           FOR PUBLIC RELEASE


SSBD F-5E Cockpit Modifications
                Preparation for First Flight
   Test Plan Approved by NAVAIR
   Civil Landing Permits from USAF, USN, US Army
   F-5E Spare Parts from Marines at YUMA MCAS
   Flight Readiness Reviews: NAVAIR, DARPA, Northrop
    Grumman, NASA Dryden, NASA Langley
   Aircraft Prep, EMC, Low and High Speed Taxi
   Real Time Telemetry for First Flight and Envelope
    Expansion Flight Tests
   Pre-position T-38 Chase from Seattle to St. Augustine
    - Extremely Useful for Test Pilot Proficiency
                                  FOR PUBLIC RELEASE
                                   FOR PUBLIC RELEASE


                       First Flight of SSBD F-5E

   Takeoff from St. Augustine (8000 Ft Rwy)
   Test Area Over the Atlantic (W-158)
   Boeing T-38 Chase (Mike Bryan)
   Landing at Cecil Field (12,500 Ft Rwy)
                     Envelope Expansion Flights


Maneuver Block:
 Pitch Doublet

 Yaw Doublet

 Steady Sideslips

 30 Bank to Bank

 Windup Turn

(Augs-On then Off)




                                    FOR PUBLIC RELEASE
        FOR PUBLIC RELEASE


Cross Country Ferry Flights
                                                  FOR PUBLIC RELEASE

                              Back-to-Back Data Flight
                                            27 August 2003
       (45 Second Separation Between Aircraft During Supersonic Run)

                                                                       NAS Fallon VFC-13 F-5E and
                                                                        F-5 SSBD at Palmdale, CA


                                                                            F-5 SSBD Takes Off
                                                                            at Dawn Enroute to
                                                                         EAFB Supersonic Corridor




F-5 Pilots
                       Roy Martin
 CDR Darryl “Spike” Long      LCDR Dwight “Tricky” Dick


                                                                 FOR PUBLIC RELEASE
     FOR PUBLIC RELEASE


SSBD Flight Path

   Edwards AFB
Supersonic Corridor




                             32




                   FOR PUBLIC RELEASE
         FOR PUBLIC RELEASE


Ground Recording Array Setup
                                                                                                        FOR PUBLIC RELEASE


                                                                          First-Ever Shaped Sonic Boom
                                                                             Recorded 27 August 2003
                      Signatures recorded
                       during SSBD back-
                      to-back data flights
                      in the Edwards AFB
                        supersonic flight
                          corridor early
                            morning

                       Flight conditions:
                            Mach 1.36+,
                         Altitude 32,000 ft
                         Design Mach 1.4
                           Shock Thickening Adjusted
                       Ground Boom Signature Comparisons
           1.4
           1.2
                                                       M = 1.40
           1.0                                                            Tanh 1/P Modification
                                                       h = 32 kft.
           0.8
           0.6
           0.4
           0.2
DP - psf




           0.0
           -0.2
           -0.4
           -0.6
                                     F-5SSBD
                             SBD-24b @ 12,700 lbs.

           -0.8                      F-5E
                             F-5E @ 11,200 lbs.

           -1.0
           -1.2
           -1.4
                  0     10     20       30        40       50        60   70     80      90       100
                                                       Time - msec




                                                                                                                      FOR PUBLIC RELEASE
           Lessons Learned from Initial Tests

   Florida in July has BIG Thunderstorms in PM!
   Navy Flight Clearances Are Difficult and
    Expensive, but Great Confidence Builders
   Don’t Depend on Using Ground References for
    Early Morning Flights into a Rising Sun!
   Program Will Cost Twice Your Initial Estimate
   Good Programs Attract Interest & Support
   Shaped Sonic Boom Theory is Valid

                               FOR PUBLIC RELEASE
                      FOR PUBLIC RELEASE


            Test Background/Objectives          Shaped Sonic Boom
                                                   Experiment



 Based on the Success of the DARPA SSBD Program,
NASA Created a Follow-On Program to Further Explore
 the Characteristics and Robustness of Shaped Sonic
       Booms Using the F-5 SSBD Test Aircraft

   Up to 21 Test Flights Planned
       Achieve M1.4, 32k ft. Design Condition
       Collect Data at Off-Design Conditions
       Collect Back-to-Back Data with Navy F-5E
       Collect Near-Field Probing Data with NASA F-15
       Collect Data Above Ground Turbulence Layer with
        USAF TPS Glider
       Attempt to Record Focused Boom


                      FOR PUBLIC RELEASE
                                   Shaped Sonic Boom Experiment

            SSBE Experiment Designed to Collect Quality Data from Many Sources


             Test Summary                                        Test Schematic

• 21 flights in 9 days
• 8 flights back to back with baseline F- 5E         F-5 SSBD operated by Northrop
• 4 flights with F-15 probe aircraft                  Grumman generates shaped
• 45 probe data sets                                     boom over sensor array
• 13 flights with glider
• 1300 boom recordings                                                                Unmodified F-5E from
• 2 focus booms recorded                                                              USN VFC-13 used to
                                                                                       generate baseline
                                                                                        boom signature
                      Microphone on USAF Test
                     Pilot School glider measures         DFRC F-15 probes
     30,000 ft       boom above turbulence layer         pressure field below
                                                              F-5 SSBD



                                                                                        Boom senor array
          8,000 ft                                                                    (42 sensors total), on
                                                                                       & off the flight track
                                                    North Edwards AFB Runway         NASA, Wyle Labs, NGC,
                                                                                        Gulfstream, Eagle
     FOR PUBLIC RELEASE


Revised Ground Track      Shaped Sonic Boom
                             Experiment




     FOR PUBLIC RELEASE
                                   FOR PUBLIC RELEASE


                         SSBE Test Summary                Shaped Sonic Boom
                                                             Experiment


   Met or Exceeded All Flight Test Goals
   21 Test Flights Conducted January 12–22, 2004
        1 Functional Check Flight
        8 F-5 SSBD Solo Flights
        8 F-5 SSBD / F-5E Back-to-Back Flights
        4 F-5 SSBD / F-15B Probing Flights
   Repeatable Data Collected Between M1.35 and M1.45
   Well Over 1300 Sonic Boom Signatures Recorded by Ground
    Sensor Array at EAFB North Base
   USAF TPS Glider Obtained Excellent Data Above Ground
    Turbulence Layer on 14 Flights
   45 Near-Field Probing Measurements Obtained with F-15
   Successfully Recorded Focused Boom on 2 Flights
   Excellent Weather for Meaningful Data Collection Experienced
    Throughout Test Phase
                                   FOR PUBLIC RELEASE
                       FOR PUBLIC RELEASE


              Initial SSBE Flight Test Results   Shaped Sonic Boom
                                                    Experiment



                     F-15B Probe Data




Glider Data




                        Ground Data


                       FOR PUBLIC RELEASE
                                FOR PUBLIC RELEASE


                   SSBD/SSBE Program Summary                     Shaped Sonic Boom
                                                                    Experiment



   Shaped Sonic Boom Persistence Theory was Proven in
    Actual Flight Conditions
       Sonic Boom Intensity Can Be Reduced Through Aircraft Shaping
       Shaped Ground Boom Signature for a Supersonic Aircraft Can Be
        Predicted
   DARPA and NASA Were Delighted with the Quantity and
    Quality of the Supersonic Data
       Mapped Shockwave Propagation Around the Near-Field of SSBD
        Aircraft, at the Mid-Field Using a Glider, and at the Ground Level in
        Various Atmospheric Conditions
       Recorded Boom Focus Data Using ¼ G Pushover
   Program Data Will be Invaluable to Future Supersonic
    Aircraft Designs – Allows Designers to Go Forward with
    Confidence in Ability to Predict Boom Signatures
                                FOR PUBLIC RELEASE
A Tribute To The SSBD Team
         SSBD/SSBE Test and Support Team

                                                  NAVY •
                                             • US        W
                                          SA              YL
                                      • NA                   E
                                RPA                              LA
                                                                   BS
                        N   • DA                                        •E
                   A
               UMM                                                        AG
           P GR                                                             LE
      TH RO                                           SSBD                       AE
  R                                                                                RO
NO
USA                                                                               AM
   F•
        US                  SHAPED SONIC                                      T RE
             AR                                                             FS
               MY
                    • BO       BOOM DEMO                                  UL
                        EIN                                             •G
                            G   • LO                           ON
                                    CK                     T HE
                                      HEE                AY
                                         DM
                                              ART I N • R
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