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Objectives of the Saturn Program have necessitated a more accurate knowledge of the vehicle mass and lift-off weight. Since propellants constitute the major portion of the vehicle mass, a method of accurately determining and regulating the quantity of propellants on board the vehicle is a primary requirement. Several elements are involved in providing accurate on-board quantities of vehicle propellants. Of most significance are the vehicle propellants sensors, storage and transfer facilities, and a system to monitor the sensors and control the transfer facilities. The purpose of this paper is to describe the functions and operation of the Propellant Tanking Computer System (PTCS) which performs this propellant monitor and control function for Saturn IB and Saturn V vehicles. The PTCS was developed for NASA KSC by G.E., KSCSO.

During the F-1 rocket engine program, turbine exhaust gases have been successfully used to film cool large thrust chamber nozzle extensions. This design concept provides the engine with a detachable nozzle of low weight, simple construction, and a service life equivalent to that of the basic engine. Several nozzle extension concepts are reviewed, and a comparison is made in terms of operational advantages and engine application as defined by required nozzle geometry, heat flux, and available coolant. The particular application for which the gas-cooled concept is the most desirable engineering choice is discussed in detail. Experimental data obtained during development are presented, with particular emphasis given to thermal analysis considerations. The correlation observed between predicted and measured temperatures is also discussed.

The Douglas Aircraft Co. has developed a concept known as the Fixed Service Tower (FST) to increase the efficiency of medium space vehicle buildup and servicing operations. Advantages of the concept are presented in this paper by first discussing present flight preparation procedures for the National Aeronautics and Space Administration Improved Delta vehicle and then discussing how these procedures would be improved by utilizing the FST techniques. Aspects of the FST, which are covered in detail, include location, configuration, flexibility, growth potential, launch environment, cost, and implementation status.

In the past testing of airborne electronics equipment has for the most part fallen into the category of either completely manual or fully automatic. While manual test equipment is relatively simple and inexpensive, it is too slow for testing many of today's multiple-output electronic packages. To reduce checkout time, more sophisticated automatic test systems have been built. However, the automated equipment requires elaborate programming and storage facilities, and the overall cost of this equipment tends to be astronomical. This paper presents an examination of current maintenance problems in the Tactical Air Command and investigates problems associated with some of the automatic test systems in use today. The merits of semiautomatic test equipment are discussed as a possible optimum solution to many of these problems. As an illustration, a design problem is presented along with a practical approach and solution.

Some insights into problems associated with the design and use of ground vehicles for tactical missile and electronic systems are presented. The problems of shock and vibration, operating deflections, and range of payloads are treated briefly. Some guidelines are provided in selection and design of ground vehicles, and descriptions are provided of some vehicles currently in use.

On-board test systems are reviewed from the initial establishment of a need through the technical and economic trades of implementation. The varying needs of different users are considered along with the assistance that can be effected in operations and maintenance activities. Systems within the state-of-the-art are discussed along with idealized future possibilities.

In order to efficiently maintain an operational aircraft in its intended environment, adequate and timely aerospace ground equipment (AGE) must be made available for the first flight test phase of the aircraft development program. This demands that a systematic approach to defining AGE be instigated early in the conceptual design phase and that a program considering the following disciplines be established: intended aircraft mission and utilization, maintenance goals, and reliability of the aircraft in terms of individual subsystems and their interface functions. These primary variables are combined to establish the basic requirements for AGE. The detailed requirements for AGE must be obtained through aircraft subsystem analysis designating to what extent each subsystem requires support and then how this support is to be implemented.

Spark plug thermal characteristcs were investigated for both propane and butane at various altitudes. These tests show that under ordinary conditions, if the correct spark plug heat range is installed at sea level, the selection does not need to be changed for higher altitude operation. Operating spark plug temperatures were lower with butane as compared with propane and may warrant, in some instances, a hotter heat range. Knock-limited spark advance increased with altitude, but decreased with increasing compression ratios. There is no significant spark plug voltage requirement change under running conditions, as altitude is increased from roughly sea level to 8000 ft.

Accident statistics indicate that postcrash fire is one of the most serious threats to human life in aircraft crashes. It is also a serious threat in automotive crashes. Several methods are available to reduce this hazard. The simplest and most effective method is through control of the fuel spillage. Aircraft crash testing has shown that fuel systems incorporating tough, flexible fuel tanks that are smooth in contour, free from rigid attachments, and mated with flexible fluid lines are capable of preventing fuel spillage during crashes involving decelerative loading above the human survival range.

A working system of peak to valley surface roughness control has been developed and is in use on selected aerospace production hardware. The system, while similar to the Swedish H system, has additional flexibility for the design engineer. A test in which seven companies participated proved the compatibility of roughness values obtained.

This paper defines system effectiveness and identifies the framework within which such a program operates. The objectives of a system effectiveness program are covered, along with the tasks in the program. An example of the use of the model during system life is given. The role of the modeler is outlined, especially his responsibility for good communications with the system effectiveness team. No detailed mathematical terminology is used.

This paper briefly describes systems effectiveness work currently under way at the Army Missile Command. Two basic types of systems effectiveness analyses performed on Army missile systems are described together with their time phasing during the life cycle of the weapon. The Command conducts major operations research studies at the outset of each major development program and at points where significant changes in system characteristics occur. All system performance parameters are analyzed in the context of a “mix” of weapons in a dynamic battlefield environment. Factors such as mobility, survivability, kill probability, and firepower are considered. Normally, these studies are used to demonstrate the cost effectiveness of proposed systems and to conduct initial parametric design trade-off studies. The second type is that of mission reliability assessment.

Frequently, a choice between system concepts must be made on the basis of something other than a detailed evaluation of the design effectiveness of these systems. This paper develops a rudimentary analysis process for use in addressing this problem.

This paper discusses general and specific requirements of AFSCM 375-5 as applied to control and surveillance systems. The ingredients of the total design concept to achieve operational effectiveness includes specifications, analyses, engineering reviews, and tests. The concepts of utility, acquisition time, effectiveness, and cost are discussed. Model and trade-off considerations are presented. Applications of WSEIAC and AFSCM 375-5 principles and procedures to three complex electronic systems are illustrated.

The purpose of this paper is to identify and discuss some of the principle administrative aspects encountered in the management of systems effectiveness programs. The administrative aspects of the process which are discussed deal with the problem of achieving credibility in the results, from the manager's point of view, by varying the constraints imposed on the study to provide a sensitivity analysis of the effects of the constraints on the results, and with the need for the identification of the point of diminishing returns in each investigation. An example analysis is diagrammed and the administrative task is shown to be that of providing the control, the guidance, and the environment of understanding among all of the technical disciplines involved.

The nacelle design for high bypass ratio turbofan engines installed on high subsonic aircraft is treated in this paper. The high bypass ratio turbofan, with its greater airflow per pound of thrust, presents different problems from those of existing turbojets and low bypass ratio turbofans. For example, there is some bypass ratio, depending upon aircraft payload range and engine geometry, above which the “ short duct” has advantage. The determination of this bypass ratio for a typical case is presented. For a bypass ratio 8 turbofan, the short duct nacelle has 3–4% better airplane direct operating costs than the long duct. With the short duct established as the preferred geometry for high bypass ratio turbofans, the problems of the air inlet, inlet cowl, fan nozzle, fan afterbody, and gas generator afterbody are discussed. Also, the thrust reverser, which affects the nacelle geometry, has been considered.

Both DOD and NASA have established management practices to assure that for each system the mission success requirements are identified, communicated and achieved. Industry contractors who serve these customers must prove that they have the ability to predict and control costs, schedules, and technical performance to the degree required to achieve the potential cost effectiveness of the system. This paper deals with the technical segment of the cost assurance, schedule assurance, and technical assurance triad. It presents a logical system for identifying all activities that experience has shown are critical to achieving system effectiveness. It covers the major techniques for assuring that resources, in the form of documented technology, facilities, and qualified people, are available for each critical activity. Finally, it summarizes program management techniques for assuring that these resources are applied to each project in accordance with cost effectiveness principles.

The present emphasis is on product (system) effectiveness or overall performance and total costs of a product, including costs of development, ownership, and obsolescence. This concept of product value highlights the need to identify and clarify the interrelationships of the acquisition, use, and maintenance elements to achieve product or system requirements within cost limits. The problem is to recognize and assess all the significant elements for trade-offs and to establish the interrelationships with the necessary clarity and visibility for decision making. A product effectiveness program with cost constraints utilizes a basic approach: 1. Defining product purpose and use goals, and applying fixed constraints, such as costs, schedules, and skills. 2. Development and utilization of a checklist to help assure inclusion of all product effectiveness factors, using experience and analysis data. 3.

The use of high bypass ratio engines for future transports presents the opportunity to improve greatly the operational use of thrust reversers. By eliminating the gas generator reverser, or by merely spoiling the thrust of the hot gas stream, the need for reducing power due to hot exhaust ingestion can be alleviated. Engines of the 8:1 bypass ratio class can achieve today's level of reverse thrust effectiveness by reversing only the fan stream. Engines of the 3:1 bypass ratio class require fan stream reversal plus spoiling of the gas generator exhaust. An analysis is presented indicating the desired effectiveness level for the individual fan and gas generator reversers. Design features and model testing of a particularly promising type of fan thrust reverser are discussed in detail. Test results are presented which provide information for the designer and which relate some features of fan thrust reverser geometry to performance.

The progress with the use of deflected thrust in European V/STOL airplanes is reviewed. The difficulties which arise in adopting this concept are examined and commented upon in the light of the practical experience which has been accumulated. Several configurations are discussed: the single sided deflector, a more complex rotating cascade version, the tilting pod-engine configuration, and the vectoring nozzle.