SAE AIR5020A

INTRODUCTION
FOREWORD
SAE E-33E SUBCOMMITTEE MEMBERSHIP
1 SCOPE
  1.1 Limitations
2 REFERENCES
  2.1 Applicable Documents
      2.1.1 Section 1
      2.1.2 Section 3
      2.1.3 Section 4
      2.1.4 Section 5
      2.1.5 Section 6
      2.1.6 Section 7
  2.2 Symbols
3 TIME-DEPENDENT THRUST CONSIDERATIONS
  3.1 Thrust/Drag Accounting
      3.1.1 Basic Equations
      3.1.2 Installed Net Propulsive Force
      3.1.3 Airframe System Drag Force
      3.1.4 Force Accounting Development and Application
  3.2 Propulsion System Net Thrust
      3.2.1 Inlet Streamtube Force
      3.2.2 Intrinsic Net Thrust
      3.2.3 Quasi-Steady Limits
  3.3 Quasi-Steady Limits for Aircraft Dynamic Maneuvers
      3.3.1 Aircraft Performance
      3.3.2 Installed Engine Net Thrust
  3.4 Quasi-Steady Engine Transient Limits for
      Throttle-Dependent Aerodynamic Forces
  3.5 Summary
4 IN-FLIGHT THRUST METHODS
  4.1 Gas Path Methods
      4.1.1 F/W square root of T and F/AP Methods
      4.1.2 Tailpipe Method
  4.2 Engine Transient Simulations
      4.2.1 Aerothermodynamic Model
      4.2.2 Simplified Linear Model
      4.2.3 Model Validation
      4.2.4 Application of Transient Models for In-Flight
            Thrust
  4.3 Engine-Independent In-Flight Thrust Methods
      4.3.1 Inlet/Exhaust Survey Method
      4.3.2 Trunnion Method
      4.3.3 Excess Thrust Method
  4.4 Summary
5 TEST FACILITIES
  5.1 Propulsion (Ground-Level and Altitude) Test
      Facilities
      5.1.1 Facility Configurations
      5.1.2 Facility Operating Concepts
      5.1.3 Engine Sweep Testing
      5.1.4 Aircraft Inlet Flow Simulators
      5.1.5 Power and Thrust Vector Transient Evaluation
  5.2 Aircraft Installed Facilities
  5.3 Aerodynamic Model Test (Wind Tunnel) Facilities
      5.3.1 Wind Tunnel Capabilities
      5.3.2 Wind Tunnel Operating Characteristics
  5.4 Flight Test Facilities
  5.5 Summary
6 TEST DATA ACQUISITION SYSTEMS
  6.1 In-Flight Thrust Measurement
      6.1.1 Gas Path Methods
      6.1.2 Transient Simulation Methods
      6.1.3 Excess Thrust Measurement Methods
  6.2 Ground and Flight Test Facility Measurements
      6.2.1 Engine Thrust/Force Measurement
      6.2.2 Engine Total Airflow Measurement
      6.2.3 Engine Local Airflow Measurement
      6.2.4 Engine Rotor Speeds and Variable Geometry
            Positions
      6.2.5 Engine Fuel Flow
      6.2.6 Pressure Measurements
      6.2.7 Temperature Measurements
      6.2.8 Aircraft Aerodynamic Forces
      6.2.9 Accelerometer Measurements
  6.3 Data Processing
      6.3.1 Propulsion Test Facility
      6.3.2 Wind Tunnel
      6.3.3 Flight Test Facility
  6.4 Measurement Uncertainties
      6.4.1 Propulsion Test Facility
      6.4.2 Wind Tunnel
      6.4.3 Flight Test Facility
  6.5 Summary
7 FLIGHT TESTING
  7.1 Aircraft Performance
  7.2 Aircraft Lift and Drag Force Balance Equations
  7.3 Excess Thrust Measurement Options
      7.3.1 Flight Path Accelerometer (FPA)
      7.3.2 Body Axes Accelerometers (BAA)
      7.3.3 Energy Method
  7.4 Flight Test Maneuvers
      7.4.1 Quasi-Steady-State Maneuvers
      7.4.2 Dynamic Maneuvers
  7.5 Data Consistency Checks
  7.6 Evaluation of the Quasi Steady-State Assumption
      7.6.1 Quasi Steady-State Maneuvers
      7.6.2 Dynamic Maneuvers - Fixed Throttle
      7.6.3 Dynamic Maneuvers - Variable Throttle
      7.6.4 Dynamic Maneuvers - Additional Considerations
  7.7 Validation of Transient Thrust Measurement
      7.7.1 Throttle Transients - Step Inputs
      7.7.2 Throttle Transients - Frequency Sweeps
  7.8 Summary
8 GUIDELINES FOR TIME-DEPENDENT THRUST DETERMINATIONS
  8.1 Aircraft and Engine Operating Conditions
  8.2 Force Accounting
  8.3 In-Flight Measurement Methodology
      8.3.1 Scope and Nature of Program
      8.3.2 Economics and Resources
      8.3.3 Accuracy Requirements
  8.4 Flight Test
APPENDIX A Three-Dimensional, Time-Dependent Equations for an
           Aircraft Propulsion System
APPENDIX B Program Listing of One-Dimensional, Time-Dependent
           Equations

Specifies to examine aircraft and engine operating conditions under which the quasi-steady thrust assumption is valid.

The purpose and intent of Subcommittee E-33E’s effort, the reporting objectives, and the limitations inherent in the reported findings and recommendations are reviewed since these factors are the basis of the information contained in this document.SAE E-33E Subcommittee was formed to assess the level of industry experience that exists in the area of thrust determination during aircraft time-variant operating conditions. A prime objective was to provide a center for gathering expertise and to be a forum for the exchange of ideas and viewpoints. The committee recognized that a practice for the rigorous treatment of time-dependent thrust did not exist and that several critical aspects of its accounting would need to be investigated.The specific objectives of this document are:aTo examine aircraft and engine operating conditions under which the quasi-steady thrust assumption is valid.bTo determine the extent to which time-dependent (nonstationary) force accounting for engine net thrust and propulsion system throttle-dependent terms is required, consistent with existing and developing thrust-minus-drag techniques.cTo report time-dependent thrust methodologies and measurement techniques used for flight and ground testing.dTo present the results of a data review of state-of-the-art methodology appropriate to the determination of aircraft-installed thrust during quasi-steady and dynamic maneuvers.eTo provide guidelines for validating and improving time-dependent thrust determination as appropriate to a specific program.