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The method of flame ionization was used for measuring total hydrocarbons in both single-cylinder and multicylinder 4-cycle, direct injection diesel engine exhaust. Use of the emission parameters of hydrocarbon concentration, per cent unburned fuel, specific hydrocarbon rate, mass of hydrocarbons per million cycles, mass of hydrocarbons per mile, and mass of hydrocarbons per ton-mile are discussed. The basic approach used in the flame ionization detector is shown. The hydrocarbon sample was transferred from the exhaust system through a heated sample line and oven operating at 375 F. The sample line was aspirated to reduce the sample residence time to 2 sec. The effect various sampling locations have on hydrocarbon measurements from a single-cylinder engine is shown and discussed. The effects of load, speed, and injection timing on hydrocarbon emission data are shown for a single-cylinder engine.

Diesel engine exhaust emission characteristics vary considerably with the overall design of the combustion and fuel injection systems. Emission measurements were made on total hydrocarbons, nitrogen oxides, carbon monoxide, carbon dioxide, and smoke. The hydrocarbon measurements of the precombustion chamber engine are considerably lower than the direct injection engine. Less than five pounds of total hydrocarbons per 1000 gal of fuel are produced at rated conditions by all precombustion chamber engines studied. Precombustion chamber engines produce smaller quantities of the oxides of nitrogen when compared to direct injection engines. All diesels produced low carbon monoxide emissions. A novel technique for qualitative and quantitative evaluation of diesel exhaust odors is introduced. Exhaust odor intensity from the precombustion chamber engine is much less than that from the direct injection engine.

Methods used in diesel emissions measurement at the Bartlesville Petroleum Research Center are described; limitations, adequacy, and needs for further development of each are discussed. Smoke measurements are reported from work with the Hartridge meter, as well as newly developed instruments that are used to view smoke plumes directly, and which seem to offer advantage over smokemeters previously used. Experience in odor assessment by a human panel using reference odor materials is reported as encouraging. Odor intensity is judged with much greater reliability than odor quality; capability to assess the latter remains wholly inadequate. Results in application of the methods for measuring diesel emissions are intended to illustrate the use of experimental techniques to reveal engine and fuel factors as they influence the character, amount, and air-polluting effect of diesel emissions.

Automotive brake linings are complex composites of organic resin binders, asbestos fiber reinforcement, and property modifiers. Brake lining fade is believed to be due in part to gas evolution from pyrolysis of these components at the lining-drum interface. Differential thermal analysis, thermogravimetric analysis, and X -ray diffraction have been applied to the study of pyrolysis of these typical ingredients and the composites (linings) made from them. The relation between thermal decomposition of the lining components, the linings themselves, and fade in drag dynamometry is discussed. The final performance evaluation of friction materials with respect to fade characteristics can only be obtained from extensive qualification tests carried out on vehicles, one reason being that the true temperatures of the linings at their sliding interfaces with the drum are not known.

A study was made of the responses of pyrolytic gas chromatography (PGC) and the friction assessment screening test (FAST) to variations in curing conditions for a liquid, oil-modified, phenolic resin system. Both PGC, which characterizes the organic resin, and FAST, which characterizes the friction and wear properties, show systematic variations with changes in cure time and temperature. A linear relationship exists between the area of one PGC peak (phenol) and the wear as determined by the FAST procedure. A chemical kinetic model is postulated which relates the concentration of phenol produced on pyrolysis to a function of cure time and temperature. An index of cure is introduced which defines the curing conditions in terms of a single parameter. The PGC phenol peak area, FAST friction, and FAST wear correlate well with this index of cure.

Factors contributing to winter hot starting difficulties encountered in some modern automotive gasoline engines were investigated in a two-phase study. These factors were evaluated first in test cars and then in a test stand engine under more closely controlled laboratory conditions. The effect of oil viscosity on an engine's hot cranking torque requirements and the ability of batteries at various charge levels to supply sufficient power to satisfy these requirements were extensively investigated; whereas the effects of viscosity index improvers, precombustion reactions, engine hot soak time, and oil temperature were only briefly investigated. The present ASTM D 445 viscosity at 210 F was shown to be inadequate for predicting the hot cranking performance of multigrade oils and a method for determining an oil's hot cranking “engine viscosity” was developed.

This paper describes an evolutionary family concept of Saturn V derivative launch vehicle systems, discusses their performance capabilities, and outlines their ability to perform orbital and high-energy missions at minimum total program cost. The versatility and utility of the Saturn V launch vehicle system have been well publicized with respect to its ability to inject sizeable exploratory payloads throughout the Solar System and with respect to its earth orbital capability to exploit near earth by utilizing a manned space station derived from the third stage. The complete flexibility of the evolutionary Saturn V system is identified through derivative launch vehicle concepts which utilize a “common core” design. These vehicles demonstrate potential ability to span the earth orbital and planetary pay-load spectrum. The validity of this evolutionary concept is analyzed and derivative candidates are evaluated in terms of design commonality and traffic levels.

The characteristics of current space propulsion systems are reviewed, including performance, storability, restart, and throttling. Their limitations are discussed with emphasis in the area of long-term storage coupled with high performance. Potential methods for overcoming limitations also are reviewed.

A critical evaluation of spacecraft propulsion requirements for the 1970 decade is presented. The anticipated types of this time period are surveyed to identify future applications of present hardware and areas requiring new propulsive media. A prediction of the technological advancements to be anticipated during the latter part of the 1970's will be ventured.

This paper explores some of the many considerations which enter into the choice of a specific spacecraft propulsion system for a particular application. The environment and its influence on propulsion requirements are discussed in general terms, characteristics of several propellant combinations are presented and an example of a typical ambitious mission is used. A general conclusion is that the state of the art of spacecraft propulsion technology must advance on a broad front in the time period prior to project definition in order to provide the technological options which allow significant optimization of the complete project propulsion system.

Systems to determine gross weight and location of the center of gravity on transport airplanes have become commonplace and effective while operating in environments relatively known to the equipment designers. The system being proposed for the Boeing Supersonic Transport must operate at temperatures, accuracies, and functional capabilities exceeding that of equipment designed heretofore. Large aircraft of the Supersonic Transport configuration require precise determination of the longitudinal center of gravity prior to takeoff to assure economical and safe operation of the airplane. Requirements for the Boeing Supersonic airplane demand locating the center of gravity to within ±7.5 inches of the design center of gravity and gross weight to within ±0.5 percent of actual, including all mechanization errors. Sensors performing this task must operate in a temperature range of −55°F to +475°F.

A current status of development of aircraft integral weight and balance systems (IWBS) as applied to cargo aircraft is presented. This discussion describes testing, installation, and calibration procedures including related problems, errors, accuracy requirements, and system functions. Knowledge of these current system limitations and problems will provide a better appreciation of the design requirements and complexities of the IWBS.

STAN is the on-board weight and balance system presently used by Pan American on its cargo aircraft. Based on 1-1/2 years of operational experience as a secondary or check system to the weight and balance manifest, STAN has substantially justified itself through its accuracy and reliability. Its success suggests the feasability of developing a primary weight and balance system, which would be of significant value, especially on the forthcoming supersonic and jumbo jets.

The application of air breathing turbofan engines to a variable geometry, lifting, entry spacecraft provides a Cruise-spacecraft having increased operational flexibility. This spacecraft can accomplish a high performance, 3000 nautical mile lateral range mission, by combining the glide available from its medium hypersonic L/D (1. 7 to 2. 3) with subsonic cruise in the atmosphere. In this application, it excels low L/D spacecraft requiring orbit maneuvers to enhance lateral range. It is competitive with high L/D spacecraft while avoiding some of their advanced aerodynamic and thermal protection system technologies. For the reduced lateral range logistic mission, the spacecraft can utilize the “liquid L/D” principle to reduce cruise fuel and replace it with additional cargo. The Cruise-spacecraft is a medium L/D, slim, lifting body which uses an ablative lower surface and a radiative upper surface for protection during entry.

Most previous studies of entry maneuverability of high L/D vehicles from low altitude earth orbit have been concerned with defining the maximum crossrange performance without regard to the downrange distance. However, for certain “quick return” missions, entry within a limited downrange distance may also be desirable. Results of a study to define the effects of various entry techniques in minimizing the distance to the heel of the footprint, within reasonable heating limitations, are presented. Studies were made for a spacecraft having a maximum hypersonic L/D of 2.2. A computer program was utilized that simulated entry in four phases: 1. An entry pullout phase, 2. A modulated bank angle phase, to suppress skip, 3. A constant bank angle phase, held until a desired heading was achieved. 4. A terminal glide phase at maximum L/D. Any combination of bank angle and angle of attack could be selected for each phase, except Phase 2, where bank angle was modulated as necessary to prevent skip.

The Air Force has been studying the problem of orbital space flight emergencies to identify the more promising approaches for an emergency return capability. Based upon an initial study, reentry escape systems were selected for further investigation. A detailed analysis of potential orbital emergencies and their impact upon the characteristics desired in escape systems has been conducted. Also, the interface with the ground support net and the status of the technology areas required for subsystem development have been briefly examined.

Many agencies are currently investigating the utility of maneuverable spacecraft, especially lifting vehicles, for a number of potential applications. Much of this effort has been directed toward the critical technical questions of performance and design; however, addendum activity has been associated with developing the supporting logic for maneuvering systems. It is shown that the basic concepts involved in the technology of reusable spacecraft represent, to a large extent, augmentation of X-20, ASSET, and PRIME efforts. An appraisal of the vehicles and operational tasks considered is presented and a possible alternate design point is postulated. Particular emphasis is placed on developing a conclusive rationale for advanced vehicles. The relationship of the stage and one-half or “tip-tank/spacecraft” concept to improving the economics from the standpoint of booster amortization and reusability is suggested.

Experimental data on performance and cooling from sea level and altitude firing tests of fluorine/oxygen mixtures with light-hydrocarbon fuels are presented. The majority of the work has been oriented toward pressure-fed rocket applications, with testing at 5000-lb vacuum thrust and 100-psia chamber pressure. Work in progress is at chamber pressures of 250 and 500 psia, being oriented toward pump-fed rocket applications. High delivered specific impulse levels have been demonstrated. One problem, apparently unique to these propellants, is that performance at the optimum mixture ratio is extremely sensitive to incomplete mixing.

Through an examination of NASA functions and space program areas and their interrelationship, it is shown that the objectives of MSA earth orbital programs are: to develop space systems that will contribute to the solution of basic national problems by exploiting space for human welfare and knowledge, to exploit space for the advancement of science and technology, and to develop space capabilities precursor to planetary exploration. The role of a space station in the earth orbital program is that of a manned orbital research facility capable of exploiting the unique features of the space environment in combination with the capabilities of man as an onboard investigator to accomplish a broad spectrum of research and development in all areas of interest. Man's role in the orbiting research facility is similar to his role in a research laboratory on earth.

Unmanned satellites have now been used for almost a decade in useful earth-oriented applications; communication, navigation, geodetic survey, meteorology. In the coming 1970-1980 era, these applications are expected to increase in number and expand in scope; and to be augmented by additional applications having to do with the discovery and monitoring of the earth's natural resources, and of other phenomena of interest to man -- disasters, patterns of cultural development, oceanic traffic, and others. These latter tasks fall within the functional category of “observation” tasks wherein the principal role of a space system will be the collection of information, both by direct observation and by gathering data emitted from sensors deployed over the earth's surface. Eventually, these observation functions will be complemented by satellite-directed surface activity -- ships, aircraft, land vehicles.