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A NEW arctic engine oil, designed to permit cold-weather operation of Army equipment, has been tested to determine required cranking effort. Data obtained are to be used to design new cranking equipment and to estimate the temperature limits of existing cranking equipment. Tests were conducted on six gasoline engines and five diesel engines using the new oil conforming to MIL-O-10295. Cranking the engines through a torquemeter permitted direct measurement of cranking torque. The results of the investigation are presented in this paper.

FATIGUE life of fighters, as discussed in this paper, is dependent on those variables which are a function of airplane mission characteristics and those which are a function of the operational environment. The first type of variable includes airplane design limit load factor, design range, combat and cruise altitude, and the basic kind of mission flown. The second class of variable includes gust loads, maneuver loads, landing-taxi loads, and the ground-air-ground cycle. This paper describes the fatigue damage caused by these factors in the flight histories of two hypothetical fighter aircraft.

PONTIAC'S new V-8 engine, the authors say, fulfills well design objectives of durability, simplicity of manufacture and servicing, and ready adaptability to future fuels and displacement increases. Important new features include: 1. Simplified casting of cylinder block and cylinder heads. 2. Valve train components designed for long valve gear life, quiet operation, and low cost. 3. A new gusher type of cooling system. 4. An engine ventilation system that scavenges harmful, corrosive diluents from all engine compartments. 5. A more-than-ample 12-v electrical system. 6. A wedge-shaped combustion chamber.

STUDIES of 20-mm-bore tool-steel ball bearings operated at 2500 rpm and lubricated with graphite, or molybdenum disulfide-air mist, or one of several liquids (both petroleum and synthetic types) are reported in this paper. Effective lubrication at 1000 F with graphite, at 850 F with molybdenum disulfide, and at 700 F with a synthetic diester was obtained. A second investigation of the effectiveness of molybdenum disulfide-air mist as a lubricant for high-speed roller bearings is also reported here. Successful operation of a 75-mm-bore cageless roller bearing at a DN of 0.975 × 106 (13,000 rpm) with no external heat added was obtained.

STUDIES of air contamination in the Los Angeles area show that even if all the hydrocarbons coming from sources other than automobile exhausts were removed from the atmosphere, there would still be sufficient concentration of hydrocarbons in certain areas to cause eye irritation and crop damage. Thus, it is clear that hydrocarbons must be removed from the exhaust gases of automobiles -and with an extremely high efficiency. The Air Pollution Control District recommends that engineers strive for a 90% removal under conditions of operation experienced in heavy traffic. This paper is the first in a Symposium on Air Pollution. Discussion of this and the other papers in the Symposium is at the end of the last paper, and starts on p. 618.

OZONE has been found to be a substantial part of the oxidant characteristic of Los Angeles' smog. Since automobile exhaust gases are capable of forming ozone in the air, they are considered a definite cause of smog. In studies reported here, ozone was produced in the laboratory and measured by rubber cracking and chemical tests. Exhaust gases from cruising and accelerating phases of automobile operation were irradiated to form ozone. Exhaust gas from idling and deceleration produced ozone photochemically after addition of NO2. Discussion of this paper starts on p. 618.

TESTS reported here, in which exhaust samples from city-driven test cars were analyzed by mass spectrometer, showed a loss of hydrocarbons out of the exhaust ranging from 5% of the weight of fuel entering the carburetor under steady driving to 19% during deceleration. It would take about 60% curtailment of exhaust content of hydrocarbons, the authors estimate, to return to the relatively smog-free conditions that existed before 1945. Discussion of this paper starts on p. 618.

A commercial kerosene, low freezing point kerosene (JP-1), and JP-4 are discussed as possible commercial transport jet fuels. Relative performance of these fuels is given. Estimated demand for a commercial jet fuel is small, and it is concluded that adequate quantities of any of the three fuels could be supplied by the petroleum industry. Relative fuel prices on the West and Gulf Coasts are discussed. It is predicted that kerosene and JP-4 will have about equal prices to the airlines. It is concluded that JP-1 type fuel would be the most expensive of the three fuels.

RESULTS of the 1953 CRC survey of octane-number requirements are presented in this paper. This 1953 survey initiated the use of a new technique, which included both full- and part-throttle procedures. Nine new-design models, represented by 235 cars, were tested using primary reference fuels, severity reference fuels, and a series of full-boiling-range gasolines. It differed from the previously used technique in that accelerations were made at a series of constant intake manifold vacuums from 10 in. of Hg to wide-open throttle.

MEASURING piston-ring wear by use of irradiated piston rings and modern detection equipment, as was done in tests reported here, is accurate, fast and overcomes any need of disassembling engines. Tests made with a variety of abrasives showed that size and properties of abrasives influence not only the amount of wear but also its duration. The same technique would work equally well, the authors say, in studying wear of any irradiated internal engine part in any type of piston engine.

EXPERIENCE with new plastics for truck bodies reported by these five authors yields a complexity of pros and cons. Among advantages claimed are: 1. High strength-weight ratio. 2. High impact strength and ability to absorb punishment and return to original condition without permanent damage. 3. Ease of maintenance, repair, and cleaning. 4. Good thermal insulation. 5. Resistance to chemical or electrolytic attack or deterioration. 6. Ease of bonding. 7. Adaptability to mass production techniques. Disappointments reported by various users include: 1. High cost of raw materials. 2. Low modulus of elasticity. 3. Low endurance limit. 4. Fractures from internal abrading of reinforcement. 5. Weakening and failure of structures because of poor adhesion between plastic and its reinforcement. 6. Inadequate and faulty engineering knowledge of the subject.Agreement is general, however, that plastics for trucks have a bright future, once the many problems have been ironed out.

HOW to go about improving scavenging efficiency in 2-stroke-cycle diesel engines through use of a static method of analysis is discussed here. Briefly, the steps are: 1. Determine airflow pattern in the existing cylinder design by means of instrumentation, and find the synthetic scavenging efficiency by plotting axial and tangential velocity components. 2. Decide what should be improved and the method of accomplishing this improvement, such as using a different port shape and angle. 3. Test the new design on the flow bench and compare with the original design for scavenging efficiency, tangential velocity distribution, and pressure drop. 4. Test the improved design in the engine.

TIRE thump has gained prominence as passenger cars have become quieter and roads smoother. Studies at the CM Proving Ground dating back to 1940 have shown thump to be a very complex example of the simple phenomenon that combining two closely spaced frequency components will produce a certain beat. Here the authors detail what has been learned about the physical characteristics of car and tire which go into producing thump of various frequencies and loudnesses. They also describe a newly developed portable instrument which measures the depth of modulation of the beat between two frequencies, thus serving as a uniform standard of tire thump severity.