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This is an initial release of an Aerospace Information Report to provide methods for Engine Suppliers to follow to execute their in house performance models to generate datasets that are provided to airframe customers early in the conceptual design phase of an aircraft program. This AIR provides some general guidance for execution order and input settings to be used to execute the model.

This is an initial release of a recommended practice for exchange of tabular data between supplier and customer for performance prediction and model execution. It will recommend data presentation as well as any implied interpolation.

This SAE Aerospace Recommended Practice (ARP) provides guidance for the presentation of gas turbine engine transient performance models with the capacity to be implemented as digital computer programs operating in real time and is intended to complement ARP1257 and AS681. Such models will be used in those applications where a transient program must interface with physical systems. These applications are characterized by the requirement for real time transient response. These models require attention to unique characteristics that are beyond the scope of ARP1257. This document is intended to facilitate the development of mathematical models and the coordination of their requirements with the user. It will not unduly restrict the modeling methodology used by the supplier. The objective of this document is to define a recommended practice for the delivery of mathematical models intended for real time use.

This SAE Aerospace Recommended Practice (ARP) provides guidance for the presentation of gas turbine engine transient performance models with the capacity to be implemented as computer programs operating in real time and is intended to complement AS681. Such models will be used in those applications where a transient program must interface with physical systems. These applications are characterized by the requirement for real time transient response. These models require attention to unique characteristics that are beyond the scope of AS681. This document is intended to facilitate the development of mathematical models and the coordination of their requirements with the user. It will not unduly restrict the modeling methodology used by the supplier. The objective of this document is to define a recommended practice for the delivery of mathematical models intended for real time use. Models used in this application may also be contained in deliverable computer programs covered by AS681.

This document provides recommendations for several aspects of air-breathing gas turbine engine performance modeling using object-oriented programming systems. Nomenclature, application program interface, and user interface are addressed with the emphasis on nomenclature. The Numerical Propulsion System Simulation (NPSS) modeling environment is frequently used in this document as an archetype. Many of the recommendations for standards are derived from NPSS standards. NPSS was chosen because it is an available product. The practices recommended herein may be applied to other object-oriented systems. While this document applies broadly to any gas turbine engine, the great majority of engine performance computer programs have historically been written for aircraft propulsion systems. Aircraft and propulsion terminology and examples appear throughout.

Engine test data reduction programs may range from programs which are limited to calculation of external performance, e.g. thrust, fuel flow, and airflow, to those which include an analysis of component performance for consistency checks.

This Aerospace Recommended Practice (ARP) describes a class of digital computer programs for use by organizations other than the engine supplier for reduction of engine test data relating to the interface of the engine in the airframe or test facility. This ARP also is intended as a guide for the preparation of such computer programs.

This SAE Aerospace Recommended Practice (ARP) describes a class of digital computer programs for use by organizations other than the engine supplier for reduction of engine test data relating to the interface of the engine in the airframe or test facility. This ARP also is intended as a guide for the preparation of such computer programs.

This SAE Aerospace Recommended Practice (ARP) describes a class of digital computer programs for use by organizations other than the engine supplier for reduction of engine test data relating to the interface of the engine in the airframe or test facility. This ARP also is intended as a guide for the preparation of such computer programs.

This SAE Aerospace Information Report (AIR) provides a review of real-time modeling methodologies for gas turbine engine performance. The application of real-time models and modeling methodologies are discussed. The modeling methodologies addressed in this AIR concentrate on the aerothermal portion of the gas turbine propulsion system. Characteristics of the models, the various algorithms used in them, and system integration issues are also reviewed. In addition, example cases of digital models in source code are provided for several methodologies.

This is an initial release of a recommended practice for an interface to supplier simulations that utilize traditional inter-process communication (IPC) methods of shared memory and semaphore communications. These IPC methods are standard practice in the computer science world and allow for communication by separate processes running on a computer without any common runtime requirements. This allows things like 32-bit applications to talk with 64-bit applications, as well as any other compiler version or runtime library dependencies being required by the calling program to interface with the called model. This also allows the calling program and the called program to be run on separate CPUs to allow parallel execution of the called program as well as multiple instances of the called program to execute all on separate processors.

The SAE Aerospace Standard document AS681 is the parent document of this SAE Aerospace Recommended Practice (ARP). AS681 applies to Engine programs written to conform to this document. This ARP specifies a set of functions and their expected behaviors that constitute a function based Application Program Interface (API) for gas turbine engine customer programs. The functions specified in this API are delivered by the Supplier as part of the Engine model.

This document defines generic language independent functions and specific appendices for implementations in C and Fortran.

The function based API specified in this ARP represents an alternative to the Fortran COMMON block structure, as specified in AS4191, historically used to communicate with an engine program. The customer may request emulation of the AS4191 interface if desired.

The SAE Aerospace Standard document AS681 is the parent document of this SAE Aerospace Recommended Practice (ARP). AS681 applies to Engine programs written to conform to this document. This ARP specifies a set of functions and their expected behaviors that constitute a function based Application Program Interface (API) for gas turbine engine customer programs. The functions specified in this API are delivered by the Supplier as part of the Engine model. This document defines generic language independent functions and specific appendices for implementations in C and Fortran. The function based API specified in this ARP represents an alternative to the Fortran COMMON block structure, as specified in AS4191, historically used to communicate with an engine program. The customer may request emulation of the AS4191 interface if desired.

This SAE Aerospace Recommended Practice (ARP) specifies a set of functions and their expected behavior that constitute an Application Programming Interface (API) for gas turbine engine customer programs. The main body of this document contains a description of each of the API function calls and of the data that passes through these functions. Implementations of this API in specific programming languages are contained in separate appendices. These appendices include language specific details and the definitions for each function as required for the given language. AS681 is the parent document of ARP4868. All of AS681 applies to customer engine programs written to conform to this document.

This document provides recommendations for several aspects of air-breathing gas turbine engine performance modeling using object-oriented programming systems. Nomenclature, application program interface, and user interface are addressed with the emphasis on nomenclature. The Numerical Propulsion System Simulation (NPSS) modeling environment is frequently used in this document as an archetype. Many of the recommendations for standards are derived from NPSS standards. NPSS was chosen because it is an available product. The practices recommended herein may be applied to other object-oriented systems. While this document applies broadly to any gas turbine engine, the great majority of engine performance computer programs have historically been written for aircraft propulsion systems. Aircraft and propulsion terminology and examples appear throughout.

Steady state engine performance programs discussed in this Standard will be confined to two basic performance categories: preliminary design or specification. Preliminary design programs may vary in scope, but will be representative of the defined engine performance until the engine is defined by a specification. A specification program will accurately represent the engine described by the specification and will identify the appropriate model specification. Normally, the computer program will be the primary source of performance data. Two additional categories of program are status and data reduction interface programs, which are covered by ARP 1211 and 1210 respectively.

Steady state engine performance programs discussed in this Standard will be confined to two basic performance categories: preliminary design or specification. Preliminary design programs may vary in scope, but will be representative of the defined engine performance until the engine is defined by a specification. A specification program will accurately represent the engine described by the specification and will identify the appropriate model specification. Normally, the computer program will be the primary source of performance data. Two additional categories of program are status and data reduction interface programs, which are covered by ARP 1211 and 1210 respectively.

This SAE Aerospace Standard (AS) provides a performance station designation system for aircraft propulsion systems and their derivatives. The station numbering conventions presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. The contents of this document were previously a subset of AS755E. Due to the growing complexity of station numbering schemes and an industry desire to expand nomenclature descriptions, a decision was made to separate the “station numbering” and “nomenclature” contents of AS755 into two separate documents. AS755 will continue to maintain standards for station numbering. SAE Aerospace Standard AS6502 will maintain standards for classical nomenclature moving forward.