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Standard

The Advanced Environmental Control System (AECS) Computer Program for Steady State Analysis and Preliminary System Sizing

1997-10-01
HISTORICAL
AIR1706B
Many different computer programs have been developed to determine performance capabilities of aircraft environmental control systems, and to calculate size and weight tradeoffs during preliminary design. Many of these computer programs are limited in scope to a particular arrangement of components for a specific application. General techniques, providing flexibility to handle varied types of ECS configurations and different requirements (i.e., during conceptual or preliminary design, development, testing, production, and operation) are designated “company proprietary” and are not available for industry-wide use. This document describes capabilities, limitations, and potentials of a particular computer program which provides a general ECS analysis capability, and is available for use in industry. This program, names AECS1, was developed under the sponsorship of the U.S. Air Force Flight Dynamics Laboratory (References 1 and 2).
Standard

THE ADVANCED ENVIRONMENTAL CONTROL SYSTEM (AECS) COMPUTER PROGRAM FOR STEADY STATE ANALYSIS AND PRELIMINARY SYSTEM SIZING

1986-10-01
HISTORICAL
AIR1706A
Many different computer programs have been developed to determine performance capabilities of aircraft environmental control systems, and to calculate size and weight tradeoffs during preliminary design. Many of these computer programs are limited in scope to a particular arrangement of components for a specific application. General techniques, providing flexibility to handle varied types of ECS configurations and different requirements (i.e., during conceptual or preliminary design, development, testing, production, and operation) are designated "company proprietary" and are not available for industry-wide use. This document describes capabilities, limitations, and potentials of a particular computer program which provides a general ECS analysis capability, and is available for use in industry. This program, names AECS1, was developed under the sponsorship of the U.S. Air Force Flight Dynamics Laboratory (References 1 and 2).
Standard

Spacecraft Boost and Entry Heat Transfer

2008-02-19
HISTORICAL
AIR1168/11
The prediction of vehicle temperatures during ascent through the earth’s atmosphere requires an accurate knowledge of the aerodynamic heating rates occurring at the vehicle surface. Flight parameters required in heating calculations include the local airstream velocity, pressure, and temperature at the boundary layer edge for the vehicle location in question. In addition, thermodynamic and transport air properties are required at these conditions. Both laminar and turbulent boundary layers occur during the boost trajectory. Experience has shown that laminar and turbulent heating are of equivalent importance. Laminar heating predominates in importance in the stagnation areas, but the large afterbody surfaces are most strongly affected by turbulent heating. Once the local flow conditions and corresponding air properties have been obtained, the convective heating rate may be calculated for a particular wall temperature.
Standard

Spacecraft Boost and Entry Heat Transfer

2011-07-25
CURRENT
AIR1168/11A
The prediction of vehicle temperatures during ascent through the earth’s atmosphere requires an accurate knowledge of the aerodynamic heating rates occurring at the vehicle surface. Flight parameters required in heating calculations include the local airstream velocity, pressure, and temperature at the boundary layer edge for the vehicle location in question. In addition, thermodynamic and transport air properties are required at these conditions. Both laminar and turbulent boundary layers occur during the boost trajectory. Experience has shown that laminar and turbulent heating are of equivalent importance. Laminar heating predominates in importance in the stagnation areas, but the large afterbody surfaces are most strongly affected by turbulent heating. Once the local flow conditions and corresponding air properties have been obtained, the convective heating rate may be calculated for a particular wall temperature.
Standard

GUIDE FOR PREPARING AN ECS COMPUTER PROGRAM USER'S MANUAL

1980-06-01
HISTORICAL
ARP1623
These recommendations apply to the user's manual for any computer program pertaining to aircraft ECS. This includes computer programs for: a Cabin air conditioning and pressurization performance. b Avionics equipment cooling system performance. c Engine bleed air system performance. d Compartment and equipment thermal analysis. e Environmental protection system performance. These recommendations apply to user's manuals for generalized computer programs as well as those for a specific component or system.
Standard

Environmental Control Systems Life Cycle Cost

2017-02-07
CURRENT
AIR1812B
This report contains background information on life cycle cost elements and key ECS cost factors. Elements of life cycle costs are defined from initial design phases through operational use. Information on how ECS designs affect overall aircraft cost and information on primary factors affecting ECS costs are discussed. Key steps or efforts for comparing ECS designs on the basis of LCC are outlined. Brief descriptions of two computer programs for estimating LCC of total aircraft programs and their use to estimate ECS LCC, are included.
Standard

Environmental Control Systems Life Cycle Cost

1997-10-01
HISTORICAL
AIR1812A
This report contains background information on life cycle cost elements and key ECS cost factors. Elements of life cycle costs are defined from initial design phases through operational use. Information on how ECS designs affect overall aircraft cost and information on primary factors affecting ECS costs are discussed. Key steps or efforts for comparing ECS designs on the basis of LCC are outlined. Brief descriptions of two computer programs for estimating LCC of total aircraft programs and their use to estimate ECS LCC, are included.
Standard

Engineering Analysis System (EASY) Computer Program for Dynamic Analysis of Aircraft ECS

1996-05-01
HISTORICAL
AIR1823A
The Engineering Analysis SYstem (EASY) computer program is summarized in this report. It provides techniques for analysis of steady-state and dynamic (transient) environmental control system (ECS) performance, control system stability, and for synthesis of optimal ECS. General uses of a transient analysis computer program for ECS design and development, and general features of EASY relative to these uses, are presented. This report summarizes the nine analysis options of EASY, EASY program organization for analyzing ECS, data input to the program and resulting data output, and a discussion of EASY limitations. Appendices provide general definitions for dynamic analysis, and samples of input and output for EASY.
Standard

ENVIRONMENTAL CONTROL SYSTEMS LIFE CYCLE COST

1985-10-01
HISTORICAL
AIR1812
This report contains background information on life cycle cost elements and key ECS cost factors. Elements of life cycle costs are defined from initial design phases through operational use. Information on how ECS designs affect overall aircraft cost and information on primary factors affecting ECS costs are discussed. Key steps or efforts for comparing ECS designs on the basis of LCC are outlined. Brief descriptions of two computer programs for estimating LCC of total aircraft programs and their use to estimate ECS LCC, are included.
Standard

ENVIRONMENTAL CONTROL SYSTEM TRANSIENT ANALYSIS COMPUTER PROGRAM (EASY)

1994-09-01
HISTORICAL
AIR1823
The Environmental Control Analysis SYstem (EASY) computer program is summarized in this report. Development of this computer program initially was sponsored by the U.S. Air Force Flight Dynamics Laboratory. (See References 1, 2, 3, and 4.) It provides techniques for determination of steady state and dynamic (transient) ECS performance, and of control system stability; and for synthesis of optimal ECS control systems. The program is available from the U.S. Air Force, or as a proprietary commercial version. General uses of a transient analysis computer program for ECS design and development, and general features of EASY relative to these uses, are presented. This report summarizes the nine analysis options of EASY, EASY program organization for analyzing ECS, data input to the program and resulting data output, and a discussion of EASY limitations. Appendices provide general definitions for dynamic analysis, and samples of input and output for EASY.
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