Search Results

The problems encountered in casting grey iron parts with wall thicknesses of 0.125 in. or less are in the areas of controlling the metallurgical structure, the chemical analysis, and varying cooling rates. Special test molds have been designed to determine the structure of grey irons of varying wall thicknesses. Spectrographic chemistry determination techniques are available for fast and accurate determination of all metallic elements when they are in percentages above 0.1%. Equipment is available for determining the cooling curve of grey irons. Changes in structure and chemistry however must be evaluated by use of statistical techniques, using various charts. Dimensional control problems are handled by rules of design. Casting finish problems are controlled by engineering.

Justifying the use of electric control systems for such an important duty as control of lift engines (in, say, VTOL transport) and elimination of a mechanical linkage must devolve on past experience, as regards both technical capabilities and reliability. This paper describes an electrical engine control that has extensive service experience and discusses its reliability record. A more modern control is also described, to illustrate available techniques. In addition, the requirement peculiar to jet lift engines, and the engine failure case, are demonstrated by a typical system for multi-engine aircraft. Some suggestions for instrumentation and display are given.

A digital computer and special program were used, along with new thermodynamic data, to recalculate and extend the scope and range of the classic combustion gas charts of Hottel and co-workers. A series of hydrocarbon and nonhydrocarbon fuels was treated over a range of fuel-air ratios, with temperatures extended up to 7200 R and pressures up to 15,000 psia. This, the first paper of a series, incorporates the resulting charts for isooctane at four mixture ratios ranging from 20% lean to 40% rich. Auxiliary charts for inducted mixture properties determination and a set of sample calculations are also included.

This paper outlines and discusses several of the important problems which must he solved by the airframe propulsion designer to obtain a high thrust-to-weight ratio lift engine installation. Problems considered include starting, air induction, exhaust, fire protection, and VTO control. The thrust-to-weight ratio degradation from bare engine to final installation is shwon for a typical example. Some installation requirements, which must also be considered by the engine designer, are noted.

A comprehensive cycle analysis has been developed for four-stroke spark-ignited engines from which the indicated performance of a single cylinder engine was computed with a reasonable degree of accuracy. The step-wise cycle calculations were made using a digital computer. This analysis took into account mixture composition, dissociation, combustion chamber shape (including spark plug location), flame propagation, heat transfer, piston motion, engine speed, spark advance, manifold pressure and temperature, and exhaust pressure. A correlation between the calculated and experimental performance is reported for one engine at a particular operating point. The calculated pressure-time diagram was in good agreement with the experimental one in many respects. The calculated peak pressure was 10 per cent lower and the thermal efficiency 0.8 per cent higher than the measured values. Thus this calculational procedure represents a significant improvement over constant volume cycle approximations.

Unmanned lunar vehicles will explore the moon’s surface prior to manned landing. These vehicles will be controlled from earth and will gather data on elevation contours and surface roughness, soil conditions and classification, electromagnetic radiation and micrometeorite conditions, and the substrate makeup and seismic conditions. Considered are lunar environment, radiation hazard, payload design criteria, environmental control, control and guidance systems, communication systems, and scientific instrumentation.

This paper discusses the development of criteria necessary to establish reliable lunar exploration and construction vehicle concepts. To establish the basis for the development of these criteria, an exploration mission using the presently conceived Apollo launch vehicle system is described. The criteria resulting from the study of the contribution made by the hostile lunar environment and the life support system requirements within the framework of the selected mission are established. Soils testing in a hard vacuum is described, as are tests of models under simulated lunar terrain environment. Two lunar vehicle configurations are reviewed, including design parameters and subsystem development.

This paper tells of the changes made to the standard Aircraft J-57 turbojet engine in order to convert it to an industrial gas generator, problems encountered during the 8000 hr protoyype test, and changes made to solve these problems. The author concludes that the modified J-57 is a fully acceptable industrial gas generator, and the same expectations are held for Pratt & Whitney Aircraft's modified J-75 and JT-12 gas generators that have also been placed in industrial use.

Although the introduction of turbine engines in commercial aircraft brought many anticipated advantages in increased safety and reliability, many problems involving basic reliabilities arose to plague the operators. Underlying causes for various design limitations are preoccupation of the airlines, military inheritance, inadequate development, demonstrations in lieu of tests, knowledge interchange, and others.

A new engine indicator which adequately meets the increasingly stringent demands being made on internal combustion engines is discussed. This is the model MPRE-MV indicator. The new indicator is a simplified, water-cooled model. It gives better performance and permits wider application than other types of indicators and has improved dynamic performance due to careful selection of the damping characteristic and strain generating tube.

This paper outlines the operation of the Volvo-Matic transmission in its various phases and describes the functions of the automatic control system, its parts, and operating features. The Volvo-Matic is a fully automatic, geared torque converter transmission which has three main components -- torque converter, planetary gear, and automatic control system. Appreciable improvements have been noted in acceleration, maneuverability, smoothness, ease of handling, and in the anticreep and hill-holding device in the Volvo-Matic. Maintenance and servicing are simplified so that a trained mechanic can completely overhaul a Volvo-Matic in 3 hr using standard equipment.

Research and development studies leading to the design of an improved piston for a submarine diesel engine are described. The four phases of the studies are (1) radioactive piston ring wear investigations, which show that this wear increased sharply at the higher engine power outputs; (2) fusible alloy plug temperature measurements; (3) piston thermocouple tests, which led to the conclusion that only by modifying the internal construction of the piston could significant improvement in piston temperatures be made; and (4) redesign of piston. The new piston has raised the reliability of the engine from unsatisfactory to satisfactory, and will now be applied to the engines in the fleet.

Recent mathematical descriptions of the human operator in control systems are reviewed. Available models are shown to have certain shortcomings when applied to automobile driving. It is proposed that “self-pacing” and “programed-transient” behavior are requisite to satisfactory characterization of the driver.

The family car of a not-too-distant tomorrow will be “an automotive living room on wheels.” An air-conditioned vehicle equipped with television for back-seat riders, pull-out tables for games or dining, vanity-table and clothes-storage compartments, seats that convert into luxuriously upholstered davenports, or serve as sleeping couches when the car's recessed window blinds are pulled down. The power plant and driving line will be simplified to one of three procedures: a front engine front drive, a rear engine rear drive, or a turbine or fuel cell all-wheel drive. The entire design will be based on the largest possible “living room” mounted between the most reasonable wheelbase and without noticeable overhang.

The scope of this paper is cycloidal propulsion - practical land applications of the drive principles. New information includes advantages of the drive, control functions, twin rotor functions, auto-rotation, single rotor model, twin rotor model, load glide, tow tractor, warehouse operation, gantry crane, and additional possible applications. Limitations of the drive are also discussed.

The current mobility available to tactical units is discussed and the problems surrounding the specific requirements and the determination of vehicle performance are presented. Mobility is broken down into seven elements and the method for specifying each element is presented. A complete discussion of the soft soil performance is reviewed and future mobility requirements are offered in general terms.

Flying qualities of single and twin engine planes are reviewed here. To meet requirements of cross-country flying, modern light planes have excellent stability and desirable stall characteristics. Take-offs and landings are simple maneuvers because of inherent stability of tricycle gear, improved steering, and dependable braking. Nonprofessional pilots fly these planes confidently, since engine-out controllability and climb performance are good. Future development considers instrument flying and aerodynamic refinements to provide better spiral stability in approach configuration, reduced trim changes resulting from improved flaps, gear, and power. Possibly greater inertia characteristics will minimize rapid oscillations encountered in rough air.