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NEITHER stylist nor engineer can be called the designer of a new automobile. Rather, as this paper shows, it is the team of stylist and engineer working together which creates a pleasing and practicable design. This paper is divided into four parts. Mr. Coppock, in the introduction, sets forth the problems involved in car design. How the stylist conceives his ideas for the new body is described by Mr. McRae under the heading “Styling the Car.” Under “Engineering Problems,” Mr. Coppock describes the body engineer's part in making the stylist's ideas practicable. Finally, Mr. McRae summarizes the changes made and compares the new model with the current model on which the new design was based.

FOR about five years, an exploratory project to study the application of gas turbines in automotive equipment has been conducted at the GM Research Laboratories. This paper summarizes the work thus far accomplished. Included here are descriptions of the two models of the Whirlfire gas-turbine engine developed and some operating experience obtained with these engines installed in the Firebird turbo-powered car and the Turbo-Cruiser transit bus. The Whirlfire installations have demonstrated that smooth, reliable operation, with very desirable power and torque characteristics, can be attained. They also indicate that future developments must be directed toward improved fuel economy, reduced acceleration time, and a suitable dynamic braking system.

USEFUL test procedures and instrumentation for evaluating the effects of combustion chamber deposits are described here. A multi-cylinder deposit-ignition counter has been developed which detects and records the deposit ignition occurring in the individual cylinders of a multicylinder engine. This new instrument measures basic deposit effects over a wide range of engine operating conditions and can be used either in the laboratory or on the road. The instrument is useful for studying the effects of fuels, lubricants, and additives in multi-cylinder engines. Since variation among individual cylinders can be detected, the instrument is also useful for studying engine design changes as well as operating conditions. Road and dynamometer test procedures for evaluating deposit-induced autoignition by the conventional audible method of detection are described along with the effects of several fuel-lubricant-additive combinations.

HOW electric-actuated trailer brakes synchronized with the air, hydraulic, or vacuum are braking system as used on tractors is described here. Brake balance between the electric and other systems used involves balance of brake buildup rime. This is done by having the two types of brakes build up simultaneously for their respective axle loads and tire sizes. A load control consisting of a variable rheostat does this job for the electric brakes. It is also used for balancing the electric brakes with the tractor brake system. The speed and versatility of electricity as used for trailer brakes make possible synchronized braking of combination vehicles without sacrifice of tractor brake speed — all brakes work simultaneously, resulting in shorter stops and less danger of jaakknifing. Other important safety features of the electric brake include: (1) They furnish an independent braking system for the trailer. (2) They are operated by a constant source of power.

THIS paper explains how the design problems were solved for the Firebird, a high-power, high-speed, light-weight, turbopowered car. Broad latitude was allowed the chassis engineer in designing the frame, suspension system, brakes, and steering. The result is the application of many unique features on the Firebird, some of which are used on an automobile for the first time.

IN order to study the practicability of reliable cross-country commercial jet transport operation, a series of simulated jet flights are in progress. Flights for these hypothetical airplanes are handled by regular United Air Lines dispatchers and are subject to the same delays, traffic restrictions, and holding as other real aircraft in the area. This paper presents results of the first year of this study and answers questions about such items as: variations in cruising altitude to avoid unfavorable winds, special routing because of jet streams, fuel reserve policy, reliability of schedules, and adequacy of present-day weather reporting.

BEGINNING with descriptions of some past and present transmission designs, this paper goes on to describe the twin turbine Dynaflow transmission used in the 1953 Buick models. This design uses the torque multiplying characteristics of a planetary gear set and a hydro-kinetic torque converter while retaining the smooth, uninterrupted power flow typical of a fluid torque converter. A unique feature of this Dynaflow torque converter is that all the power transferred is through the gear set and first turbine at low speeds and gradually and smoothly diminishes as the power transferred through the second turbine increases until it does all the work at higher speeds. Several vector diagrams analyzing the driving and reaction torques and forces aid in explaining the operation of the twin turbine Dynaflow.

METHODS of manufacture and materials used for turbine blades, buckets, and vanes are described in this paper. Precision forging of these turbine parts is the preferred method. Other manufacturing techniques discussed here include the lost-wax, frozen-mercury, and lost-plastic processes and sintered powder metallurgy, casting, and fabrication. Use of specially designed equipment has resulted in vast improvements in some operations. The paper discusses such new material developments as reinforced plastics, cermets, and titanium in addition to listing the standard alloys used for turbine buckets, blades, and vanes. A description of current British practices is also included.

A BETTER knowledge of the nature and causes of preignition and of its frequency during normal engine operation has been obtained by instrumenting a 9/1-compression-ratio engine on a test stand and an engine in an automobile with rate of change of pressure pickups. Photographic records of the oscilloscope traces produced by this instrumentation have enabled the determination of: 1. The relative tendency for preignition or postignition to occur and the relation of these phenomena to engine or car operating conditions. 2. The physical causes of the noises accompanying the several types of preignition. 3. The effect of retarded spark timing on deposit-induced preignition. 4. The significance of the “key-off” method of fuel rating.

KNOWLEDGE of loads on major structural parts of an airplane while in flight is needed for complete utilization of the airplane's strength and capabilities. Some in-flight measuring techniques and equipment for reducing the data thus obtained are discussed in this paper. Instrumentation and calibration of strain gages for measuring in-flight air loads are described in detail. Wing bending-moment measurements obtained on a Navy PV-2 airplane are used to illustrate data reduction procedure.

THIS paper describes an investigation into the best design of seat suspension for tractors having pneumatic tires with a rigid rear axle. Test results show that some of the factors entering into a good tractor supension include: 1. A ratio between the natural frequency of the seat and the natural frequency of the tires of about 0.4 to 0.5. 2. A supplementary seat deflection 1½ times the static seat deflection to avoid bottoming. 3. Use of suspensions having nonlinear characteristics in order to hold seat deflection within practical limits. 4. Adjustable seat-spring action to compensate for the varying weights of drivers.

VARIOUS structural problems encountered in the design of high-speed turboprop propellers are discussed in this paper. Formulas for a number of design factors are also given here. These include: 1. Blade efficiency. 2. Power capacity. 3. Advance/diameter ratio. 4. Limiting tip speed. 5. Periodic lift. 6. Propeller normal force and moment. The paper also describes two types of vibration occurring with turboprop installations: 1. First-ordered aerodynamically excited vibration. 2. Subsonic stall flutter. The author shows how these vibrations may be accurately predicted and controlled by proper design of the propeller blades.

A COOPERATIVE study of carburetor icing is described in this paper. Tests were conducted using 13 fuels of varying volatility in one complete car and six 1953 passenger-car engines. The effects of engine design variables, fuel volatility, alcohol additions to the fuel, and weather conditions were determined. Ice formation occurred in all engines, but there was a considerable variation in its effect on different engines. As would be expected, fuel volatility significantly influenced carburetor icing, and it is apparent that certain portions of the fuel boiling range exert considerably more influence than other portions. The addition of alcohol to fuels reduced stalling due to carburetor icing. The concentration of alcohol required depended primarily on the volatility of the fuel to which it was added.

IMPORTANT gains in passenger-car engine power and efficiency have resulted from design improvements that take advantage of increasing gasoline antiknock quality. Experiments with 7/1, 9.5/1, and 12/1 compression ratio reported in this paper show how similar gains can be achieved in tractor engines by applying the same principles. Of particular importance to this and future development programs that are to use these principles effectively, the authors say, are: 1. Careful choice of compression ratio for best utilization of antiknock quality of current and possible future fuels. 2. Good combustion-chamber configuration. 3. Good volumetric efficiency. 4. Best possible compromise between friction reduction and reduced thermal efficiency. 5. Control of ignition timing. 6. Control of coolant flow to all parts of jacket.

RESULTS of tests performed on a modified type F-4 CFR engine show that precombustion reactions in both the fired and motored engine gave the same carbonyl products. The maximum specific yields of these carbonyls were similar for a given fuel compressed with comparable pressure-time-temperature histories in both motored- and fired-engine tests. As the motored engine seems to duplicate precombustion reactions occurring in a fired engine under normal operating conditions, the authors of this paper conclude that the motored engine, offering ease of control and sampling, is a convenient and valid tool for combustion research.

DATA from several fatigue-test programs are examined in this paper for corroboration of basic factors which have been proposed for predicting more accurately the fatigue strength of full-scale steel members. Important among these factors are hardness, service loading, range of stress, and sharpness of the stress gradient at the critical zone. Although the type of steel is often regarded as a primary factor, its hardness may be more basic, as it correlates better with endurance limit than other physical tests. Test results show that this hardness-strength relationship is useful in evaluating the effect of surface treatments on strength improvement in soft and medium-hardness steels.

OCTANE requirement increase and combustion-chamber deposit weights are lower with the new high V.I. oils than with conventional SAE 20–20W oil containing bright stock, according to the authors. Fuel economy at 30 mph constant speed is slightly better, they found, using the new high V.I. oils than it is when a 100 V.I. lubricant of equivalent Saybolt viscosity at 210 F is used. The high V.I. oils seem to have no advantage in normal suburban highway driving. Intake-valve deposits are heavier with the new high V.I. oils than with conventional lubricants. Whether these deposits are due to the V.I. improver or to failure of the volatile base stocks to wash the deposits from the valve backs is not known.

RESULTS of tests conducted on more than 5400 vehicles show that since 1942 there has been considerable improvement in the brake performance of all types of motor vehicles using our highways. A gap existing between the levels of performance of commercial vehicles and passenger cars has been reduced. However, through adequate brake maintenance, the performance of commercial vehicles still can be improved appreciably, and the gap between the performance of trucks and passenger cars can be narrowed still further. This paper shows the magnitude of past improvement, the current levels of brake performance, and how the brake performance of commercial vehicles can be further improved through maintenance.

THE efforts of one manufacturer to solve the problem of jet-engine noise suppression when test facilities are near residential communities are reported here. The authors describe the construction of several suppressors and give data on their effectiveness. Their experience covers a run-up suppressor and also a portable unit of the water-injector type-both developed for the B-52 airplane, and a water-spray muffler for ramjet engines. They emphasize the fact that, since World War II, airplane manufacturers have been required to spend more and more time, effort, and money in attempts to cut down the noise produced by airplane and guided missile powerplants. The efforts of their company, they point out, are similar to those of other airplane companies. It appears that the problem is growing. No simple solution is yet in sight.

ORIGINS of propeller noise and possible means for its reduction both within and external to turboprop aircraft are discussed here. Decreasing the tip speed and increasing the number of blades of turboprop propellers result in quieter performance within the aircraft but with a heavy weight penalty. Changes in certain aircraft design parameters, such as increasing clearance between fuselage wall and propeller tips, can also reduce internal noise and vibration. Improvements in external turboprop noise can be achieved by use of quiet-type propellers, increased rate and angle of climb, preferential runways, adequate airport zoning, and sound-dissipating foliage and ground covers.