LIMITATIONS of the two general methods available for determining hardenability in steel, the authors point out, are that the test piece may not have a sufficient cross-section in which to develop the desired series of cooling rates, and that a special test piece (known as the L-type) must be machined for steels of low hardenability. The method using the Wuerfel bomb described in their paper, they explain, is directed primarily toward removal of these two limitations. Stated in terms of the critical diameter, they report that the results of the method are reproducible within ⅛ in.
THE design and development of the new valve-in-head V-8 Chrysler engine of 7.5 compression ratio are described here. Among the features discussed by the authors are: the hemispherical combustion chamber, V-8 cylinder arrangement, double-breaker distributor, “thermal flywheel” on automatic choke, and exhaust-heated and water-jacketed throttle bodies. The hemispherical combustion chamber was adopted after it had displayed excellent volumetric and indicated thermal efficiencies, and an ability to maintain these high efficiencies in service. The high volumetric efficiency, for example, is considered to be due to such design features as valves not crowded together, nor surrounded closely by the combustion-chamber walls. They are thereby fully effective in the flow of the fuel-air mixture and the exhaust gases. The authors also present performance data for this engine, which, at full throttle, develops 180 hp at 4000 rpm and 312 ft-lb of torque at 2000 rpm.
THIS paper discusses the progress of research on the automotive gas turbine and predicts its future potentialities. Comparison of gas turbines and presently used engines shows the possibilities of the gas-turbine applications. Design, construction, and testing of gas turbines are discussed, especially in the light of economy and performance.
AS a basis for the analyses of this symposium, a hypothetical car has been used to evaluate the engine power distribution in performance. Effects of fuel,-engine accessories, and certain car accessories are evaluated. The role of the transmission in making engine power useful at normal car speeds is also discussed. Variables encountered in wind and rolling resistance determinations are reevaluated by improved test techniques. Net horsepower of the car in terms of acceleration, passing ability and grade capability are also summarized.
A SIMPLE method of predicting truck performance in terms of grade ability at a given road speed, taking into consideration rolling resistance, air resistance, and chassis friction is presented here. A brief review of fundamental considerations is given first, then the method recommended for predicting vehicle ability at a selected speed, and finally a few words on the prediction of maximum possible road speed and selection of gear ratios. The basis of the solution is the determination and expression of vehicle resistances in terms of horsepower - that is, in terms of forces acting at a velocity. A convenient method of solving the grade problem at a given speed is by means of a tabular computation sheet, which is given, together with tables and charts. These assist in making the computation an easy one as well as giving the necessary data on vehicle resistances.
THE Junkers 211B engine follows the usual German practice of very large displacements and conservative mean effective pressures and rotative speeds. However, the relative light weight per unit of displacement results in a net weight per horsepower that is not far above its competitors. Fully automatic devices which control propeller speed, manifold pressure, mixture ratio, spark advance, and supercharger gear ratio follow the German policy of removing all possible distractions from the pilot. This is one of three large liquid-cooled engines known to be produced in quantity in Germany; it powers an impressive percentage of the Luftwaffe. While of external appearance and displacement that resemble the Daimler-Benz DB-601 engine, the fundamental construction, detail design practice, and metallurgy of the Junkers 211B are surprisingly different.
INDUCTION heating is a process or method by which metal parts are heated by simply placing them in an alternating magnetic field. The action is that of the transformer, whereby electrical energy is transferred or passed over to another isolated electric or secondary circuit by means of the magnetic field; thus, no physical attachments or electrical contacts are necessary to have electrical currents, which are dissipated as heat, flow in the parts to be processed. The strength and frequency of the alternating magnetic field can be selected to produce any desired rate of heating and ultimate temperature. A circuit can be set up to dry lacquer at 160 deg. fahr. on thin sheet-metal parts or to melt in record time immense steel ingots. Induction heating is now commercially applied in automotive production to many processes, and these are specified.
PLYMOUTH'S new V-8 engine has a specific output of 0.65 bhp/cu in. and 145-psi bmep — obtained through a combination of high thermal, volumetric, and mechanical efficiencies. Good design, the author points out, has achieved this high output despite the dual-venturi carburetor and the 7.6/1 compression ratio, selected for satisfactory operation on regular-grade fuels. The engine has a bore and stroke of 3.563 × 3¼, weighs 568 lb without flywheel, is 29⅜ in. long, and is designed for optimum response to future compression ratio increases. (A report of oral discussion following presentation of this paper appears on p. 220, following “The New Packard V-8 Engine,” by W. E. Schwieder.)
WORK done in a development program relative to camshafts and tappets in the design of the Chrysler overhead-valve V-8 engine is described. The types of failure encountered are categorized as wear, scuffing, and fatigue. An accelerated test procedure was designed to promote early cam-tappet failures, and the development work was predicated upon the results obtained therefrom. Among the variables affecting the failure conditions, major emphasis was placed on material development. Specifically, the greater amount of time was spent in determining the optimum tappet material, while some time was devoted to the camshaft material. A combination of adjusted chemical composition and heat-treatment of hardenable cast iron for camshaft and tappets provided the best solution to the failure problems.
A good manager knows how to administer, direct, and allocate the resources of his organization to the best advantage. The main resources available to him are money; facilities, equipment, and material; people; time; information; and company reputation or image. These resources all interact to create conflicting demands. It is the job of the management scientist to resolve these conflicts satisfactorily through the application of quantitative techniques, some of which are described.
The heater air flow rate is a function not only of the heater itself but also of the size and location of the heater system air inlets, the car body air outlets, and the body surface pressure at these inlets and outlets. Favorable pressure conditions generally exist at the typical top cowl heater air inlet; however, the aerodynamics of each particular vehicle should be studied to confirm the existence of these conditions. Little consideration has been given to body air outlet pressure conditions since body leakage paths have generally served as adequate air outlets; but, as body leakage is reduced, specific air outlets must be considered and a knowledge of aerodynamics is essential to the achieving of appropriately sized and appropriately located air outlets.
IN 1951 Chrysler Corp. began working on a new torsion suspension. In this paper the authors describe details of the development and design of the suspension, now available on 1957 cars. The authors claim the Torsion-Aire suspension has the following advantages: reduced highspeed float, boulevard harshness, impact harshness, road noise, body roll, nose dive, and acceleration squat; better directional stability and cornering ability; fewer lubrication points; and a better balanced ride. The main feature of the front suspension is the use of torsion bars. One of the principal advantages of torsion bars is their weight: 10 lb as compared to 15.8 lb for a 1956 production coil spring.
THIS paper outlines tests made to verify the SAE recommended practice for estimating truck ability performance described in TR-82. The author has collected data on four vehicles and compares it with the results computed in TR-82 and with a Method X. The data includes information on air and rolling resistance, effect of wind velocity, chassis friction power, grade ability, and the like. The author concludes that the SAE method of TR-82 is at the present time the most reliable method for computing truck ability.
THIS paper explains a few of the basic principles of the character of sound and the mechanism of human hearing. The author describes some simple experiments which demonstrate the relationship between intensity and loudness and the nature of harmony. He also points out the difficulties of accurately analyzing sound electronically, and the resulting importance of combining the finest electronic equipment with sharp, attentive human faculties. Five basic ways to reduce noise and the mechanics of each are described. The effect of these methods on the work of the sound engineer is indicated.