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Standard

A Primer of Aircraft Multiplexing

1972-01-01
CURRENT
AIR1207
Today's sophisticated aircraft are required to effectively perform a variety of missions. With the advent of micro-miniaturization in electronics and advanced digital computers, a new generation of avionics equipment and systems can be utilized to increase the capabilities of the aircraft. As the quantity and variety of equipment and functions increases, the problems of inter-connecting these equipments with wires presents a constraint on size, weight, signal conditioning, reliability, maintainability and electromagnetic control. Conventional wiring has resulted in large bundles of wires and many connectors which adds excessive weight and reduces the space available for the pilot and other vital elements. This limitation can be relieved significantly by the application of well proven multiplexing techniques.
Standard

Performance of Low Pressure Ratio Ejectors for Engine Nacelle Cooling

1999-03-01
CURRENT
AIR1191A
A general method for the preliminary design of a single, straight-sided, low subsonic ejector is presented. The method is based on the information presented in References 1, 2, 3, and 4, and utilizes analytical and empirical data for the sizing of the ejector mixing duct diameter and flow length. The low subsonic restriction applies because compressibility effects were not included in the development of the basic design equations. The equations are restricted to applications where Mach numbers within the ejector primary or secondary flow paths are equal to or less than 0.3.
Standard

Electromagnetic Compatibility (EMC) System Design Checklist

1971-10-01
CURRENT
AIR1221
This checklist is to be used by project personnel to assure that factors required for adequate system electromagnetic compatibility are considered and incorporated into a program. It provides a ready reference of EMC management and documentation requirements for a particular program from preproposal thru acquisition. When considered with individual equipments comprising the system and the electromagnetic operational environment in which the system will operate, the checklist will aid in the preparation of an EMC analysis. The analysis will facilitate the development of system-dependent EMC criteria and detailed system, subsystem, and equipment design requirements ensuring electromagnetic compatibility.
Standard

COMPARISON OF GROUND-RUNUP AND FLYOVER NOISE LEVELS

2002-12-16
CURRENT
AIR1216
Because of the special circumstances under which these tests were conducted, it is necessary to carefully define the limitations on the validity of the results. The measurements and the comparisons reported here apply only to the specific locations of the noise sources and microphones and only for the specific weather and ground-surface conditions existing at the time of the tests. It cannot be assumed that these conditions are representative of most field measurements of aircraft exterior noise.
Standard

SELECTING SLIPPER SEALS FOR HYDRAULIC-PNEUMATIC FLUID POWER APPLICATIONS

1973-06-01
HISTORICAL
AIR1244
The SLIPPER SEAL is defined and the basic types in current use are described. Guide lines for selecting the type of Slipper Seal for a given design requirement are covered in terms of friction, leakage, service life, installation characteristics and interchangeability.
Standard

Thermodynamics of Incompressible and Compressible Fluid Flow

2017-12-27
WIP
AIR1168/1A
The fluid flow treated in this section is isothermal, subsonic, and incompressible. The effects of heat addition, work on the fluid, variation in sonic velocity, and changes in elevation are neglected. An incompressible fluid is one in which a change in pressure causes no resulting change in fluid density. The assumption that liquids are incompressible introduces no appreciable error in calculations, but the assumption that a gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the loss coefficient of the particular duct section or price of equipment. Fit 1A-1 shows the error in pressure drop resulting from assuming that air is incompressible. With reasonably small loss coefficients and the accuracy that is usually required in most calculations, compressible fluids may be treated as incompressible for velocities less than Mach 0.2.
Standard

Aerothermodynamic Systems Engineering and Design

1989-09-01
CURRENT
AIR1168/3
This section presents methods and examples of computing the steady-state heating and cooling loads of aircraft compartments. In a steady-state process the flows of heat throughout the system are stabilized and thus do not change with time. In an aircraft compartment, several elements compose the steady-state air conditioning load. Transfer of heat occurs between these sources and sinks by the combined processes of convection, radiation, and conduction in the following manner: Convection between the boundary layer and the outer airplane skin. Radiation between the external skin and the external environment. Solar radiation through transparent areas directly on flight personnel and equipment and on the cabin interior surfaces. Conduction through the cabin walls and structural members. Convection between the interior cabin surface and the cabin air. Convection between cabin air and flight personnel or equipment.
Standard

Heat and Mass Transfer and Air-Water Mixtures

2011-07-25
CURRENT
AIR1168/2A
Heat transfer is the transport of thermal energy from one point to another. Heat is transferred only under the influence of a temperature gradient or temperature difference. The direction of heat transfer is always from the point at the higher temperature to the point at the lower temperature, in accordance with the second law of thermodynamics. The fundamental modes of heat transfer are conduction, convection, and radiation. Conduction is the net transfer of energy within a fluid or solid occurring by the collisions of molecules, atoms, or electrons. Convection is the transfer of energy resulting from fluid motion. Convection involves the processes of conduction, fluid motion, and mass transfer. Radiation is the transfer of energy from one point to another in the absence of a transporting medium. In practical applications several modes of heat transfer occur simultaneously.
Standard

Heat and Mass Transfer and Air-Water Mixtures

2001-08-01
HISTORICAL
AIR1168/2
Heat transfer is the transport of thermal energy from one point to another. Heat is transferred only under the influence of a temperature gradient or temperature difference. The direction of heat transfer is always from the point at the higher temperature to the point at the lower temperature, in accordance with the second law of thermodynamics. The fundamental modes of heat transfer are conduction, convection, and radiation. Conduction is the net transfer of energy within a fluid or solid occurring by the collisions of molecules, atoms, or electrons. Convection is the transfer of energy resulting from fluid motion. Convection involves the processes of conduction, fluid motion, and mass transfer. Radiation is the transfer of energy from one point to another in the absence of a transporting medium. In practical applications several modes of heat transfer occur simultaneously.
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