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Technical Paper

ways of improving TAKE-OFF AND LANDING

1960-01-01
600026
SOME POSSIBILITIES for shortening the field length requirements of present-day jet aircraft are: Install leading-edge, high-lift devices which are retrofitable to present-day aircraft. Retrofit — or purchase new — aircraft powered by turbofan engines. These have an inherently higher take-off thrust to cruise thrust ratio than the jets, which vastly improves the take-off acceleration. Use boundary-layer control actuated by turbine discharge gas for immediate consideration in new aircraft engines. Use direct-lift jet engines. These will improve the block speed characteristics of the aircraft and also give vertical take-off and landing capabilities. This paper discusses the advantages of each of these possibilities. The author also describes the problem of airport location within a city, and its effect of total travel time.*
Technical Paper

the first year of the JET AGE . . . .reflections

1960-01-01
600059
THE FIRST YEAR of jet airline operation has brought many problems — and satisfactions — to the industry. Here the author discusses some of the more serious problems: 1. Scheduling. American Airlines used the “Monte Carlo” method to calculate payloads and flight times. 2. Baggage handling. Almost nothing annoys a passenger more than long waits for baggage at the end of a flight. One approach to the problem is the baggage expediter system. 3. Mechanical shutdowns. 4. Runway length. 5. Noise. Noise suppressors have not been effective enough, from the standpoint of communities surroundings airports. Development of the turbofan engine offers some hope in this area.*
Technical Paper

selection of Optimum Modes of Control for aircraft engines

1959-01-01
590047
THE optimum mode of control for an aircraft engine is dependent on both the configuration of the engine and its application. Each engine application requires several detail modes of control, one for each definable regime of operation of the engine. Discussions of control requirements can be simplified by classifying these regimes by objectives: physical limiting, thrust, and transient control. The turbojet engine is the basis for the discussion in this paper. Acceptable modes of control can often be selected by inspection of the engine and its application. Selection of an “optimum” control mode requires investigation of the operation of the engine and weapons system at every stage of its use. The selection of a “mode” of control requires a compromise between performance and other design factors. The need for simplicity and accuracy must be balanced against the stability requirements. The availability and flexibility of control components may limit the modes of control considered.
Technical Paper

a study of Self-Contained Starting Systems for Turbojet and Turboprop Engines

1960-01-01
600011
SUBSTANTIAL POWER is necessary to start the modern jet engine. Thus, starting equipment has become a major concern of air transport operators. This paper discusses the equipment used with self-contained starting systems. The authors discuss and evaluate a variety of self-contained systems: combustor, fuel-air combustion, cartridge, liquid propellant, hydraulic supported by auxiliary power units, and electric supported by APU. Possible future systems are: self-breathing systems, oxygen combustors, and liquid-oxygen-water-fuel combustors. It is emphasized that the choice of a starting system for a particular aircraft will depend on aircraft characteristics and the aircraft's intended use.*
Standard

Wrenches; Flare Nut, Crowfoot, 12 Point Non-Distorting

2018-07-20
WIP
AS4167D
This SAE Aerospace Standard (AS) covers 12 point flare nut crowfoot, flare nut wrenches, double end flare nut wrenches, combination box and flare nut wrenches, and ratcheting flare nut wrenches that are designed with the following requirements: (a) Non-distorting usage; (b) Possessing the strength, clearances, and internal wrenching design to be used on hydraulic tube fittings that conform to the requirements of SAE J514; (c) Transmitting torque to tube fittings without bearing on the apex of fitting wrenching points. Inclusion of dimensional data in this document is not intended to imply that all of the products described herein are stock production sizes. Consumers are requested to consult with manufacturers concerning lists of stock production sizes.
Standard

Wrenches, Ratcheting, High Strength

2012-01-19
WIP
AS6405
This specification covers high strength ratcheting wrenches used for attachment and detachment of high strength and high temperature aircraft fasteners.
Standard

Wrenches, Hand, Twelve Point, High Strength, Thin Wall

2015-08-05
WIP
AS954H
This SAE Aerospace Standard (AS) covers high strength thin wall (commercial) sockets, universal sockets, box wrenches and torque adaptors which possess the strength, clearances, and internal wrenching design so configured that, when mated with 12-point fasteners conforming to the requirement of AS870, they shall transmit torque to the fastener without bearing on the outer 5% of the fastener's wrenching points. Inclusion of dimensional data in this document is not intended to imply that all of the products described herein are stock production sizes. Consumers are requested to consult with manufacturers concerning lists of stock production sizes. The dimensional limits of box and combination wrench lengths have been established to provide configuration control for tool storage applications.
Technical Paper

Wind Tunnel Measurements of Simulated Glaciated Cloud Conditions to Evaluate Newly Developed 2D Imaging Probes

2019-06-10
2019-01-1981
Instrumentation that has been used for characterization of mixed-phase and glaciated conditions in the past, like the OAP probes, are subject to errors caused by variations in diffraction on the images away from the object plane and by the discrete nature of their particle detection and sizing. Correction methods are necessary to consider their measurements adequate for high ice water content (IWC) environments judged to represent a significant safety hazard to propellers and turbofan engine operability and performance. For this reason, within the frame of EU FP7 HAIC project, instrumentation characterization and validation is considered a major element need for successful execution of flight tests campaigns. Clearly, instrumentation must be sufficiently reliable to assess the reproducibility of artificial clouds with high ice water content generated in icing tunnels.
Standard

Weather

2016-11-12
HISTORICAL
AS6286/4
This document shall be used in conjunction with: - AS6286, Training and Qualification Program for Deicing/Anti-icing of Aircraft on the Ground - AS6286/1, Processes including Methods - AS6286/2, Equipment - AS6286/3, Fluids - AS6286/5, Health, Safety and First Aid - AS6286/6, Aircraft Deicing/Anti-icing Diagrams, No-Spray-Zones
Technical Paper

Water Vapor Pollution of the Upper Atmosphere by Aircraft

1971-02-01
710323
The two combustion products which future technology will be unable to eliminate from present day jet engines are carbon dioxide and water vapor. The potential climatic change effects of carbon dioxide are considered to be a small part of a larger CO2 problem. Water vapor added to the troposphere forms contrails. The paper will assess the non-conclusive evidence of increased cirrus cloudiness at certain locations. Finally the potential climatic effects of added water vapor in the stratosphere on the radiation budget, the small decrease in ozone, and polar night cloudiness is evaluated in the light of future commercial aviation injections of water vapor.
Technical Paper

Variable Cycle Optimization for Supersonic Commercial Applications

2005-10-03
2005-01-3400
Variable cycle engines (VCEs) hold promise as an enabling technology for supersonic business jet (SBJ) applications. Fuel consumption can potentially be minimized by modulating the engine cycle between the subsonic and supersonic phases of flight. The additional flexibility may also contribute toward meeting takeoff and landing noise and emissions requirements. Several different concepts have been and are currently being investigated to achieve variable cycle operation. The core-driven fan stage (CDFS) variable cycle engine is perhaps the most mature concept since an engine of this type flew in the USAF Advanced Tactical Fighter prototype program in the 1990s. Therefore, this type of VCE is of particular interest for potential commercial application. To investigate the potential benefits of a CDFS variable cycle engine, a parametric model is developed using the NASA Numerical Propulsion System Simulation (NPSS).
Technical Paper

Variable Cycle Engines for Advanced Supersonic Transports

1975-02-01
751086
Variable Cycle Engines being studied for advanced commercial supersonic transports show potential for significant environmental and economic improvements relative to 1st generation SST engines. The two most promising concepts are: a Variable Stream Control Engine and a Variable Cycle Engine with a rear flow-control valve. Each concept utilizes variable components and separate burners to provide independent temperature and velocity control for two coannular flow streams. Unique fuel control techniques are combined with cycle characteristics that provide low fuel consumption, similar to a turbojet engine, for supersonic operation. This is accomplished while retaining the good subsonic performance features of a turbofan engine. A two-stream coannular nozzle shows potential to reduce jet noise to below FAR Part 36 without suppressors. Advanced burner concepts have the potential for significant reductions in exhaust emissions.
Technical Paper

Utilization of a Dual Spool Compressor Test Facility to Aid Development of Turbofan Engines

1974-02-01
740823
The development of compression systems for advanced twin-spool turbofan engines became increasingly more difficult as stability, performance, weight, and cost reduction goals were increased. Experience indicated that single-spool compressor component tests did not completely duplicate stability limits determined by flight engine tests. A requirement existed for a component test technique to develop the entire twin-spool compression system in a simulated engine environment, with sufficient operating flexibility to reproduce critical operating points that might be incurred during actual engine operation. The Pratt & Whitney Aircraft dual-spool compressor facility was designed and built to meet this requirement. The dual-spool facility has been employed in the development of several advanced models of the JT9D engine, in the JT10D demonstration engine development program, and in a U.S.
Standard

Using a System Reliability Model to Optimize Maintenance Costs A Best Practices Guide

2019-05-07
CURRENT
JA6097_201905
SAE JA6097 (“Using a System Reliability Model to Optimize Maintenance”) shows how to determine which maintenance to perform on a system when that system requires corrective maintenance to achieve the lowest long-term operating cost. While this document may focus on applications to Jet Engines and Aircraft, this methodology could be applied to nearly any type of system. However, it would be most effective for systems that are tightly integrated, where a failure in any part of the system causes the entire system to go off-line, and the process of accessing a failed component can require additional maintenance on other unrelated components.
Standard

Using a System Reliability Model to Optimize Maintenance Costs A Best Practices Guide

2013-05-16
HISTORICAL
JA6097_201305
SAE JA6097 (“Using a System Reliability Model to Optimize Maintenance”) shows how to determine which maintenance to perform on a system when that system requires corrective maintenance to achieve the lowest long-term operating cost. While this document may focus on applications to Jet Engines and Aircraft, this methodology could be applied to nearly any type of system. However, it would be most effective for systems that are tightly integrated, where a failure in any part of the system causes the entire system to go off-line, and the process of accessing a failed component can require additional maintenance on other unrelated components.
Journal Article

Using Numerical Simulation to Obtain Length of Constant Area Section in Scramjet Combustor

2020-03-16
Abstract Constant area section length downstream to the fuel injection point is a crucial dimension of scramjet duct geometry. It has a major contribution in creating the maximum effective pressure inside the combustor that is required for propulsion. The length is limited by the thermal choking phenomenon, which occurs when heat is added in a flow through constant area duct. As per theory, to avoid thermal choking the constant area section length depends upon the inlet conditions and the rate of heat addition. The complexity related to mixing and combustion process inside the supersonic stream makes it difficult to predict the rate of heat addition and in turn the length. Recent efforts of simulating the reacting flow inside scramjet combustors are encouraging and can be useful in this regard. The presented work attempts to use simulation results of scramjet combustion for predicting the constant area section length for a typical scramjet combustor.
Standard

Using Engine Test Data to Model Engine Performance

2019-11-05
CURRENT
AIR5509A
This document defines the process steps involved in collecting and processing engine test data for use in understanding engine behavior. It describes the use of an aero-thermal cycle model for reduction and analysis of those data. The analysis process may include the calculation of modifiers to match the model to measured data and prediction of engine performance based on that analysis.
Standard

Using Engine Test Data to Model Engine Performance

2012-11-01
HISTORICAL
AIR5509
This document defines the process steps involved in collecting and processing engine test data for use in understanding engine behavior. It describes the use of an aero-thermal cycle model for reduction and analysis of those data. The analysis process may include the calculation of modifiers to match the model to measured data, and prediction of engine performance based on that analysis
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