Part Two
Chapter 12
During the early years of the automobile industry, the immediate goal of the engineers and inventors was simply reliability—to get a car to go somewhere and come back under its own power. Many bright automotive ideas ended with a horse, a towline, and laughter. Although progress was expensive, American motorists cheerfully paid the bills for it. In their enthusiasm for individual transportation, they bought the cars, reliable or unreliable, and thus provided the source of a substantial portion of the risk capital for experiment and production. Not many industries have been so well favored by their customers. In twenty years the reliability of the motorcar in relation to the street and road conditions of the time was pretty well established. Individual mechanized transportation, one of the great achievements in the progress of mankind, was a commonplace fact of life, and everyone could enjoy it.
Great as have been the engineering advances since 1920, we have today basically the same kind of machine that was created in the first twenty years of the industry. We still deal with a vehicle moved by a gasoline engine. The heart of the engine is still a piston in a cylinder, moved by the burning of a mixture of gasoline and air, which is fired at regular intervals by an electrical spark from a spark plug. The resultant power of the thrust of the piston turns a crankshaft, which, by way of a transmission mechanism, turns the rear wheels. Springs and rubber tires cushion the driver and passengers from the effects of bumps, and brakes stop the car by applying retarding force at the wheels.
But since 1920 enormous improvements have been made at every point: Engines are far more efficient, delivering more power more smoothly from the same amount of fuel—and the fuel has also been enormously improved. The transmission has undergone a complex evolution until it is now fully automatic. The suspension system has gone through an equivalent evolution, as have the tires, and together they provide a ride that was unimaginable forty years ago. The driver can call upon extra power sources for braking and steering and to operate windows, seats, and radio antennas. The body shines in a variety of hues, is usually entirely made of steel, and has safety glass. With the development of the automobile, its importance in everyday use has enormously increased and also the demand for better roads and highways has come. It is hard to imagine what effect roads such as those of today might have had on the development of the automobile of the early 1920s.
Today's driver, of course, would find the typical car of 1920 completely unsatisfactory. It had a four-cylinder engine whose crankshaft and associated connecting rods and pistons were inherently unbalanced. Ordinarily this car had two-wheel brakes with braking confined to the rear wheels; it had no independent springing of the front wheels; it had a sliding-gear transmission, and an engine of low power. It vibrated and often shimmied; it veered and sometimes skidded when the brakes were applied; it rode hard and rough; the clutch grabbed; the gears often clashed in the shifting, and, owing to the low power available, they always had to be shifted on hills of substantial gradient. But the car usually got somewhere and back; fortunately it was unable to go fast or far enough for many of its deficiencies to become serious drawbacks. It was roughly adapted to its environment—and its major parts were reasonably adapted to each other, at however low a level of integration and efficiency.
The problem of development of the automobile was to raise its level of efficiency, and this often meant raising the level of its integration. The automobile today, instead of the loose assemblage of parts and mechanisms of fifty-odd years ago, is a very complex and closely integrated piece of machinery. It is only in recent years that the mechanical arts have made possible the combined effect of high performance, operating convenience, and comfort that characterizes the modern motorcar.
General Motors' research laboratories and the engineering staffs have played a major role in the development of the automobile during the past fifty years, and continue to be in the forefront of engineering development. It would be impossible to describe everything of importance General Motors and the industry have done: that would require another book. Only a few important and interrelated advances in this development are discussed here.
Ethyl Gasoline and High-Compression Engines
The central problem in automotive engineering has been to develop a more satisfactory relationship between the fuel and the engine. The efficiency of a piston engine— its ability to make an effective use of fuel, and thus to get the greatest power from a given quantity of fuel—depends on its compression. The concept of compression is a simple one, but the general reader will need a few words about it. The piston has one position in which it is as far down in the engine's cylinder as it can go, and another in which it is as far up in the cylinder as it can go. When it is at the bottom of its stroke, the cylinder is filled with fuel—a mixture of atomized gasoline and air. When it is at the top of its stroke, the fuel charge is compressed. The fuel begins to burn as a result of the spark, and the hot gases produced will expand and push the piston down. The down movement then turns the crankshaft, which transmits power to the wheels. The compression ratio is the ratio between the volume of the cylinder when the piston is as far down as it can go and the volume that remains when it is as far up as it can go. This ratio merely compares the volume of the fuel charge in its uncompressed state with that in its compressed state. In the early twenties, the average compression ratio was about four to one.
As I have said, to design a more efficient and powerful engine of a given size means to increase the compression ratio. But here a serious problem stood in the way—engine knock. The gasoline-and air mixture should burn relatively slowly in order to push the piston down. If it detonated—burned too fast—the piston could not move rapidly enough to take advantage of the force generated. Indeed, not only was energy lost in engine knock, but the sudden force introduced severe strains on the engine parts, winch could, and did, damage the engine.
The key to higher compression was to find some way of reducing engine knock. But what was the cause of engine knock? In the early days of motorcar use, it was discovered that one could reduce engine knock by adjusting the time of the spark jump. Most cars, for many years, had a hand-operated spark-adjustment lever convenient to the driver for choosing the best spark setting for different driving conditions. People learned to retard the spark setting by hand when driving uphill, to prevent engine knock as the engine labored under the strain.
The man who began General Motors' important studies in engine knock and who was largely responsible for our breakthrough to a solution of the problem was Charles F. Kettering, who had long been interested in the whole question of ignition, fuels, and the like. No automobile runs and no airplane with a reciprocating engine flies today without benefit of the antiknock fuel developments pioneered by Mr. Kettering. He brought his early knowledge of this problem to General Motors, and he was research chief of General Motors when the solution was found. The solution, in the main, was Ethyl gasoline, made with the additive tetraethyl lead.
Up to the time of World War I, knock was thought to be caused by too early ignition when the spark was too far advanced. Soon after World War I it was discovered that there was another kind of knock which was called "fuel knock," for by changing only the fuel and fuel setting without adjusting the spark, this knock could be lessened or eliminated. One of the people working on this problem was the late Thomas Midgley, Jr. He had come up through the Dayton Engineering Laboratories, where he was an assistant to Mr. Kettering, to become in the early 1920s the chief of the fuel section of the General Motors Research Corporation. In the words of Dr. Robert E. Wilson, formerly chairman of Standard Oil of Indiana, and a close friend of Mr. Midgley:
. . . [Mr. Midgley] had definitely proven that, contrary to general belief, knocking and preignition were different things, and that knocking was a chemical characteristic of the fuel. He pointed out that benzol and cyclohexane, which latter he had succeeded in making in his Dayton laboratory, knocked much less than gasoline, and gasoline much less than kerosene.
Almost every time I saw Tom he had some new theory regarding the mechanism of detonation or of antiknock action, on which I was the professional skeptic. While successive theories were usually discredited by further experimental work, they were always stimulating and frequently led to discoveries of importance. The most striking example of this was in his early work when he was trying to theorize as to why kerosene knocked worse than gasoline. He seized upon the obvious difference in volatility, and postulated that possibly most of the kerosene remained in droplets until after combustion started and then vaporized very suddenly with a resultant too-rapid explosion. If this explanation were correct, he reasoned that by dyeing the kerosene it might be possible to make the droplets absorb radiant heat from the combustion chamber and hence vaporize sooner.
Had Tom been a good physicist he could have doubtless found by calculation that this theory was untenable, but being a mechanical engineer he fortunately decided that it was much easier to try it out than to do the calculations. He accordingly went to the stockroom in search of some oil-soluble dye, and as usual the stockroom was just out of the desired product. However, Fred Chase suggested that iodine was oil soluble and would color the kerosene, so Tom promptly dissolved a substantial quantity of iodine in the kerosene, tested it in a moderately high-compression engine, and found to his delight that the knocking was eliminated.
Tom immediately sent out to scour Dayton for all available samples of oil-soluble dyes and that afternoon tested out several different ones in rapid succession without getting the slightest result from any of them. To clinch the matter, he added a colorless iodine compound to the gasoline and found that this stopped the knock. Thus, the first theory of detonation went to start the graveyard, which is now fairly well filled, but along with its demise came the real birth of Tom as a chemist, and for the next few years he was an insatiable student of every branch of chemistry to aid him in endeavoring to explain his observations and to make new compounds for trial as antiknock agents . . .
Tom was then particularly enthusiastic about the possibilities of aniline though, as always seemed to be the case when he discovered a new antiknock agent, he had to go to work to improve the methods of manufacture and lower the cost before the agent would be economically feasible. He also had some hopes then for his first ethyl compound, ethyl iodide, if he could just locate a plentiful source of iodine . . .
It was at the annual meeting of the Society of Automotive Engineers in New York in January 1922 that Tom, with an air of great excitement and secrecy, showed me a little tetraethyl lead in a test tube and told me that that was really the answer to the whole problem. Its efficiency, he said, was very much higher than that of any previously discovered compound, and it appeared to be free from every one of the difficulties which had plagued earlier attempts to solve the problem. Of course, he did not yet appreciate either the toxicity or the deposit problems.
So, after all the years of experiments by Mr. Kettering, Mr. Midgley, and General Motors Research Corporation, we had the invention. But having an invention is one thing and getting to market with it is another. To make a long story short, in August of 1924 a corporation was formed called the Ethyl Gasoline Corporation, for the purpose of marketing tetraethyl lead as an antiknock compound. This company was a fifty-fifty partnership between General Motors and Standard Oil of New Jersey. Initially the Ethyl fluid was manufactured by du Pont under a contract and it was not until 1948 that Ethyl began producing all of its own requirements.
Tetraethyl lead was only one of the necessary steps in the development of high-compression engines. Despite its effects in improving the quality of the fuel, the fuel itself, in the early twenties, varied enormously in quality. Indeed, there was no known way of measuring one fuel against another to determine its relative value for use in a gasoline engine.
General Motors made a study of that situation and developed a method for measuring the antiknock qualities of fuels, or the ability of the engine to accept a given fuel in terms of the higher compression of the engine. This measurement scaled fuels according to their "octane number." Octane is a fuel with almost no knock; in the engineering of that day a rating of 100 in octane therefore was considered, practically speaking, a perfect fuel. Dr. Graham Edgar of Ethyl conceived the octane scale in 1926 and Mr. Kettering and the research engineers developed the first single-cylinder, variable-compression test engine by which fuel quality could be measured in terms of these octane numbers. A test engine utilizing the variable-compression principle was later adopted as standard by the automotive and petroleum industries.
Of course, one way to increase octane ratings was to add tetraethyl lead, but another was through better processes for refining crude oil. Tremendous progress has been made in cracking and in "re-forming" the hydrocarbons found in crude oil both to increase the yield of gasoline from a barrel of crude and to improve its octane rating before the addition of tetraethyl lead. This is another dramatic research story in itself and one in which Mr. Kettering and his associates played a very important part in pioneering. The octane rating of commercial gasolines available at filling stations was increased from 50 to 55 in the early twenties, to 95 to somewhat over 100 at the present time. (In aviation gasolines, octane ratings are even higher.) This has had a dramatic effect on fuel economy as measured in car miles per gallon for a given standard of performance and consequently on the efficiency with which we are today using our petroleum resources. (Note 12-1.)
Another factor in the reduction of knock was the design of the engine itself. We know today that in the engine combustion chamber a very complex shock-wave condition is produced by the explosion of the fuel. These shock waves can increase the temperature of the fuel very rapidly and contribute to detonation and knock. The study of various combustion-head shapes and contours has suggested special shapes for the least knock effect with the highest compression ratio.
Parenthetically, I will mention here one problem of engine design, quite independent of the fuel, which had a serious limiting effect on the development of more powerful engines. General Motors engineers made an important contribution to its solution. Vibration, which was always unpleasant, became a more critical engineering problem as speed and power started to go up. Then the unbalanced rotating and reciprocating parts in the engine became the source of destructive vibration and a limiting factor on the whole progress of the automobile.
One of the principal sources of vibration is the crankshaft, the "backbone of the engine," where any imbalance is felt throughout the engine and the car. General Motors Research Corporation began working in the early twenties on the problem of balancing engines, and a crankshaft-balancing machine was developed and first used in the production of the 1924 Cadillac engines. This machine, hundreds of which are now in use throughout the world, was exclusively a General Motors development and gave us a long lead in engine balancing in the industry. As in the case of many of our advances, we arranged to sell this equipment to other engine producers. Better balancing was a very important step in the reduction of wear and tear on the whole automobile structure and in permitting faster progress toward the satisfactory utilization of greater power and speed in practically all the engines we build.
As we learned more and more about knock, progress toward higher-compression engines became possible. From the four to one compression ratios of the early twenties, we have now come to ten to one and higher compression ratios. The development of fuels and engines proceeds in leap-frog fashion: an engine with higher compression demands a better fuel, and the availability of a better fuel encourages the production of more efficient engines. Under the urging of the automobile engineers, the petroleum industry has developed fuels of higher and higher octane ratings for general use. General Motors has supplied many high-compression test engines to the oil industry to help it develop higher octane fuels.
In this way the developments of tetraethyl lead and high-octane fuels have made possible the long-range improvement of the internal-combustion engine.
Transmission Development
I suppose almost everybody knows that the purpose of the transmission is to transfer power from the engine to the wheels of a car, and that this involves a change in the speed relationship between the automobile engine and wheels. The power developed by an engine depends on several things, but is closely related primarily to the rotational speed of the engine's crankshaft. With the old lower powered cars, everyone became aware of this upon climbing a hill. This usually required a vigorous speeding up of the engine and a shift to a lower gear to get the power needed. Back in the 1920s shifting gears by hand through the normal three speeds usually resulted in considerable clashing unless the driver had a high degree of skill.
From the time the General Motors Research Corporation was set up in 1920, transmissions were an important subject of study and discussion. At first we concentrated on electrical transmissions of various types, for a large percentage of the original staff of engineers were of electrical background. An electrical drive was developed, and one of this type was used for a time on General Motors buses. The electrical transmission, which was tried out very early in the history of the automobile (in the Columbia and Owen-Magnetic passenger cars) , eventually received its major commercial use in the large-vehicle field. This special form of transmission is used today in our diesel locomotives.
From 1923 on, the interest of our research organization in electrical transmissions for passenger cars declined. We began to study a wide variety of automatic transmissions, including the "infinitely variable" type—in which a large number of speeds were available in uninterrupted sequence, rather than a lesser number in fixed steps, as in the standard transmission—and the step-ratio type in which a fixed number of speeds could be selected automatically. And as early as the middle twenties a hydraulic type of transmission having bladed turbine wheels was investigated. Most of the general principles that went into the making of the fully-automatic transmissions were thus known to us, and were being carefully investigated, at least fifteen years before automatic transmissions became available in production cars.
In the late twenties General Motors developed the synchromesh gearshift, with which almost any driver could shift from one speed to another without clashing the gears.
This significant development was put into production by Cadillac in 1928. The principle was taken up by other General Motors car-division engineers and was further developed for large-volume production by our old Muncie Products Division. By 1932 we were able to extend synchromesh all the way down through the whole General Motors line to the Chevrolet passenger car.
By 1928 the Research Laboratories had reached a consensus on an automatic-transmission form that might be satisfactory. This was an infinitely-variable type using a steel-on-steel friction drive employing a mechanical principle like that of a ball bearing. The Buick Division was assigned the job of developing this transmission since we had no general engineering staff at that time. Many units were built and tests conducted, and it was finally determined to produce this type of transmission in 1932. However, despite our best efforts, we never managed to solve all the problems involved, and this transmission was never put in any General Motors car sold to the public, although many experimental units were tried out in our test cars. A good deal, of course, had been learned about the problems of infinitely-variable transmissions, but it turned out that this specific steel-on-steel type was not the answer to the problem. I was convinced that it would always cost too much and I turned it down for our cars.
Our research and engineering staffs continued to work on the various types of automatic transmissions. By 1934 a group of engineers in the Cadillac Division were finally on the road that was to lead to the first mass-production automatic transmission for passenger cars, the Hydra-Matic, a modern form of automatic transmission. This special design group was transferred to the corporation's Engineering Staff at the end of 1934 to become the Transmission Development Group. The transmission they were working on was of a step-ratio type rather than the infinitely-variable type; however, it shifted automatically under torque, as do all of today's automatic drives. (Torque is the turning effect transmitted by the engine to the drive shaft.) This group also prepared production plans for different sizes of such units to meet a range of different power and load demands for the different General Motors cars.
A set of pilot models was built, tested, and turned over to the Oldsmobile engineers. During 1935 and 1936 thousands of test miles were run on different experimental units from one end of the United States to the other. In 1937 both Oldsmobile and Buick (1938 models) came out with these semiautomatic transmissions. (A semiautomatic transmission is one which provides a range of step-ratio shifts with one or more being hand selected, and one or more automatically selected.) These were manufactured by the Buick Division and still required the use of a main clutch pedal for starting and stopping. Our engineers now discovered that the main clutch and its pedal could be eliminated by the use of a fluid coupling built within the transmission assembly. This feature, together with the development of full-range automatic controls, resulted in the Hydra-Matic transmission, produced by the newly organized Detroit Transmission Division. It was announced in October 1939 and first appeared on the 1940 Oldsmobile. The Cadillac Division was the next to accept the new transmission, for its 1941 model.
Meanwhile a different kind of automatic transmission was under development by the GMC Truck & Coach engineering staff. This was known as a torque converter of the closed-circuit, fluid-turbine type. Such devices contain a set of bladed wheels, the blades being set at angles so that one bladed wheel, driven directly by the spinning of the engine, can pump the body of contained fluid into a second bladed wheel connected to the drive shaft, and so cause turning force on that shaft. There may be additional bladed wheels for changing the fluid-flow characteristics and in this way affecting the difference in speeds between the engine and the drive shaft—in other words, their speed ratio. This ratio, in a fluid torque converter, changes imperceptibly and gradually, rather than by a series of steps. The net drive effect is therefore very smooth.
The fluid torque-converter design with which General Motors engineers first worked had been developed in Europe. They eventually designed one which conformed better to American bus operating standards. We first used such a transmission in 1937 in our own buses and it was soon widely accepted. On the eve of the war, in October 1941, our Engineering Staff Transmission Development Group was at work on the problem of adapting the fluid torque converter to passenger cars.
With America's entry into the war, our advanced work on automatic transmissions for passenger cars was suspended, but an enormous new field for automatic transmissions opened. For the passenger-car driver, the automatic transmission is of value because of its convenience and simplicity in operation—there is one less thing about driving a car he has to think about. When it comes to buses, trucks, tanks, tractors, and the huge vehicles of modem warfare, automatic transmissions are needed for smooth functioning. As early as 1938 we had been urged by the military engineers to think about the problem of designing transmissions for large vehicles such as the M-3 and M-4 tanks. At this time these were steered by levers, and in some cases the operator had to let go of one of the steering levers in order to shift gears. In doing this he temporarily abandoned steering control. Furthermore, the speed of the vehicle during the gear-change interval would fall off rapidly and perhaps cause a stall, thus presenting a stationary target.
The Engineering Staff Transmission Development Group designed heavy-duty HydraMatics for these tanks. But there were heavier tanks being planned to carry bigger guns and more armor, and for these we explored the possibility of applying the fluid torque converter. Shortly after our entry into the war, the Engineering Staff built a pilot model of a fluid torque converter which solved the problem of maintaining vehicle motion while the ratio between the speed of the engine and the speed of the vehicle was being changed. Large numbers of these transmissions were built during World War II by General Motors' divisions.
Our Transmission Development Group also designed a specialized tank transmission and steering system known as the cross drive. This made it possible for a driver to control accurately, with a relatively small effort, the steering, braking, and automatic drive of big vehicles of more than fifty tons. These cross drives went into gun carriers, amphibious and regular cargo carriers, and other vehicles of tremendous weight, and our development work in this field continued after the war.
With the war's end the Engineering Staff began an intensive research program designed to adapt the fluid torque converter to passenger cars. This program was successful, and led to the Buick Dynaflow of 1948 and the Chevrolet Powerglide of the 1950 fine. The Dynaflow was the first fluid torque converter produced in volume for passenger cars.
Thus, by 1948, after many years of research and engineering development, General Motors offered to the public two different fully-automatic transmissions—Hydra-Matic and the fluid torque converter—which could be produced economically and efficiently even for low-priced cars. From the beginning, the car-buying public showed its approval of automatic transmissions—available on all of our cars—by its willingness to pay extra for them. Other automobile manufacturers used them in their cars as soon as they could—and in some cases the automatic transmissions used in their cars were built for them by General Motors. In the model year 1962 about 74 per cent of all the passenger cars sold in the United States—including General Motors' cars—were equipped with automatic transmissions. Among General Motors' passenger cars, 67 per cent of the Che violets, 91 per cent of the Pontiacs, 95 per cent of the Buicks, 97 per cent of the Oldsmobiles, and 100 per cent of the Cadillacs had automatic transmissions. During the 1962 model year about five million automatic transmissions were marketed by the industry, of which about 2.7 million were on General Motors cars. Thus this optional device has become an established feature of the American automobile.
Balloon Tires and Front-Wheel Suspension
From the beginning the problem of supplying a smoother and softer ride has been one of the most complex in automotive engineering. Since a car went much faster than a horse-drawn vehicle, it communicated the irregularities in the road surface to the passengers with greater intensity. The internal-combustion engine added its own source of discomfort in the form of vibration. Consequently, improvements in the cushioning of the driver and passengers were necessary, and this need increased as cars became speedier.
One basic approach to this problem was through the tires. Early motorcars had used solid-rubber or vented solid-rubber tires. These were soon replaced by inflated tires, but in this early stage neither the rubber nor the construction was good enough, and interminable tire-changing was a sad necessity on any extended trip.
By the early twenties the rubber companies had learned a good deal about construction methods, chemistry, rubber curing, and selection of materials. Tires were much better, and engineers began to consider the possibility of low-pressure tires, which would create a softer and more resilient air cushion under the wheels. Many problems had to be met, particularly in connection with steering and ride. The engineers had to deal with front-end instability, scuffing of the treads, squeals on turns, driving under fast braking conditions, and a peculiar condition known as wheel tramp, caused by a slight imbalance of the rotating mass of tire and wheel. These phenomena did not show up as major problems until car owners began to take long road trips at high speeds.
During this development of modern, low-pressure tires, General Motors engineers made important contributions because of our many miles of test road work under varying conditions. The General Technical Committee from the first maintained close contact with the tire industry, co-operating in standardization of sizes, and in the establishment of the best types, treads, and sections. Our recommendations, based on our research, have been incorporated year after year in better and safer tires.
The second basic approach to the improvement of the ride, and one of greater engineering complexity, was by way of the suspension—the attachment of the wheels to the chassis.
In one of my early trips abroad, my attention was called to an engineering development used in the production of European cars —the independent springing of the front wheels. Up to that time, independent springing had not been used in production cars in the United States. The use of this principle, of course, would add considerably to the comfort of the ride.
In France I came in contact with an engineer named Andre Dubonnet, who had given considerable study to the matter and had taken out a patent on one form of independent springing. I brought him back to this country and put him in contact with our engineers.
Quite independently, Lawrence P. Fisher, then general manager of our Cadillac Division, had engaged a former Rolls-Royce engineer, Maurice Olley, who also was interested in working on the problem of ride. Mr. Olley recorded his recollections of the development of independent suspension in a letter he has written for me. I will continue the story in his words:
You have asked for my recollections of independent suspension on General Motors cars . . . You'll have to excuse the very personal atmosphere of the following notes, which may give the impression that independent suspension was a one man show. It was very far from that, and owes a great deal to Henry Crane, Ernest Seaholm [chief engineer of Cadillac], Charles Kettering and a number of Cadillac and Buick engineers. Also to the tolerance and constant support of L. P. Fisher, who accused the writer at that time of being the first man in GM to spend a quarter of a million dollars in building two experimental cars!
You will recall that I came from Rolls Royce to Cadillac in November of 1930. Frankly I was surprised to find Rolls Royce so popular. A Rolls Royce car had just completed a phenomenal test at the new GM Proving Grounds, and had been torn down for inspection . . .
At Rolls Royce, for the past several years, we had been engaged in a concentrated drive on riding quality. The British factory had become intrigued by this work because of the fact that cars which were considered acceptable on British roads, were far from acceptable when exported, even to the improved roads of the United States. And we were beginning to realize that this was not because . . . American roads were worse, but because the waves in them were a different shape.
A great deal of work had been done at Rolls Royce along the lines of swinging cars from overhead pivots to measure their moments of inertia . . . measuring the stiffness of chassis frames and coachwork . . . and measuring the suspension rates of the springs as installed on the actual car. The British factory had also developed one of the first practical ride meters, which consisted simply in measuring how much water was lost from an open-topped container in a measured mile at various speeds.
Some of this practice had been carried over to Cadillac in 1930, and soon we also were swinging cars, measuring installed spring rates, etc. We also built ourselves a "bump rig", along the Rolls Royce lines (the first in Detroit) and used it to produce a synthetic ride on a stationary car.
Early in 1932 we built the "K 2 Rig" . . . consisting of a complete seven passenger limousine, on which it was possible, by moving weights, to produce any desired changes in relative deflection of front and rear springs and in the moment of inertia of the vehicle. No instrumentation was used on this to measure ride. With the assistance of Henry Crane, to check up on our efforts, we simply asked ourselves under which conditions we got the best ride.
This was the best method because we did not know then, and do not know today, what a good ride is, but we could make so many fundamental changes in ride on this vehicle in a single day's running, that our impressions remained fresh, and direct comparison was possible.
It was at this stage, early in 1932, that we began to feel the urge towards independent suspension. The K 2 Rig was telling us, in no uncertain terms, that a flat ride which was an entirely new experience, was possible if we used front springs which were softer than the rear. But you will recall that all attempts to use extremely soft front springs with the conventional front axle fell down badly, because of shimmy . . . and a general lack of stability in handling . . .
The next step after the K 2 Rig therefore consisted in building two experimental Cadillac cars . . . These had two different independent front suspensions . . . [One of these was that developed by Mr. Dubonnet; the other, the "wishbone" type, we had developed.] An independent rear suspension was also used, as we had in mind that, as soon as possible, we should also get rid of the conventional rear axle (a change which in my own opinion is now several years overdue).
On these cars which were ridden by many of the Corporation engineers, it was evident that we had something very special in the way of improved ride and handling. We also ran into our usual share of troubles. The chief of these was the steering, which, especially on the wishbone suspension, was not free from shimmy.
We had to redesign the steering mechanism several times . . .
Finally, by March of 1933, we were ready for a full-dress demonstration. Early in March the General Technical Committee met at the Cadillac Engineering Building to ride our two experimental cars, and a Buick car without independent front suspension, but with an I.V. [infinitely variable] transmission . . .
I recall that [you] and Mr. Grant were riding one of the [wishbone-type] cars, when Ernest Seaholm and I, in one of the accompanying cars, pulled up alongside [you] at the traffic light in River Rouge. We could see [you] smiling widely at Dick Grant [vice president of sales] in the rear seat, and moving the flat of [your] hand up and down [and] horizontally. Within two miles from the Cadillac plant the flat ride had sold itself!
After the run to Monroe and back on the three cars, the Committee sat at the Cadillac plant, and Seaholm and I, in the background, awaited the verdict, with the pious hope that Cadillac would be granted a clear year's run on the new suspension, ahead of the other divisions.
O. E. Hunt [vice president of engineering], I recall, led off by asking Mr. Grant what he thought of the new automatic transmission.
You will recall that in March of 1933 there was not a bank open in the United States, and anyone who owned a farm was thankful that at least he could eat. Under these circumstances Dick Grant's reaction was not surprising. He turned down the [automatic] transmission, and the hundred dollar cost that went with it, as something that a Buick buyer could very well do without. "But", said he, "if I could have a ride like you've shown us, for a matter of fifteen bucks, I'd find the money somehow."
Dutch Bower [chief engineer] at Buick had already put in his claim for the new front suspension, and the Oldsmobile and Pontiac engineers also seemed determined that they would show it in New York next November.
Then finally Bill Knudsen [the general manager of Chevrolet] declared in words of one syllable that Chevrolet [was] not going to be left out. O. E. Hunt tried to persuade him that there were not enough center-less grinding machines available in the United States to grind the wire for the coil springs for Chevrolet. But Knudsen was adamant, saying that the machine tool industry had been in a bad way for years, but they were going to be busy for the next year at least. And Chevrolet actually made the New York Show in November with their 1934 model on the Dubonnet suspension. Pontiac also inherited this suspension from Chevrolet, while the three other divisions adopted the wishbone suspension.
This meeting stays in my mind because it was such a tremendous demonstration of American enterprise in action. In the face of the conditions then existing, the millions of expenditure to which the Corporation was committing itself argued a type of courage which was new in my experience. I still remember Ket's statement, "It seems to me we can't afford not to do it."
We thus introduced simultaneously two different types of independent front-wheel suspension. However, after some further improvements on the wishbone type, it became apparent that it was cheaper and easier to manufacture and more trouble-free in operation, and soon all our lines of cars adopted it.
Duco
One of the striking scenes of America today viewed from the air in the daytime is the splash of jewel-like color presented by every parking lot. The colors are of an enormous variety, and the finishes are nearly indestructible.
All this is in contrast to the appearance of automobiles in the early twenties, when Ford, Dodge, Overland, and General Motors were using only black enamel on high-volume jobs. The external finish was then a subject of general complaint. The practices of the carriage industry had been carried over into automobile manufacturing without much change; automobiles for the first twenty five years of their existence wore carriage paint and varnish. The customer could not understand why the finish of a carriage lasted for a long time, while when he bought a car the paint would sometimes soon peel off. The fact, of course, was that the carriage and the motorcar were very different mechanisms. The automobile was subject to much harder service; it was used in more kinds of weather, and the heat of the engine produced temperature changes in parts of the car—with a resultant disastrous effect on the finish.
We dreamed of what a wonderful thing it would be if a finish could be developed which would last even if the car stood out in all kinds of weather. We also began to realize that a good, fast-drying finish could revolutionize our time schedules and the consequent cost of production.
The finishing process at that time, using paint and varnish, was slow and cumbersome. Between the time a car was ready to be finished and the time the job was completed, something like two to four weeks went by, depending among other things on the temperature and humidity. It can readily be seen that this created a terrible inventory problem.
For a while many automobile manufacturers shifted from paint and varnish to oven-dried enamels, in an effort to deal with some of these problems. The Dodge Brothers' open car, for example, was wholly oven finished with no paint or varnish. This was a black Gilsonite enamel which was very durable. However, oven finishing was only a transition—there was a better and cheaper answer to the problem.
On July 4, 1920, more by accident, I think, than by intention, a chemical reaction was noted in one of the du Pont laboratories which led to the development of a nitrocellulose lacquer eventually called Duco. It was observed that a lacquer base could be created which would carry more color pigment in suspension, and produce more brilliant colors. Three years of experiment and development were required to get the bugs out of the new product. This was a co-operative project of the General Motors Research Corporation under the direction of Mr. Kettering and the du Pont laboratories. A Paint and Enamel Committee was organized in General Motors in 1921 (ironically both paint and enamel were soon to be superseded), and the first body finished in the new lacquer came off the production line in 1923. It was the "True Blue" Oakland of the 1924 line.
The new lacquer product, under the trade name Duco, was made available to the entire motorcar industry in 1925. There were still many problems to be solved, and research continued in the du Pont and General Motors research laboratories. A very important part of this work was the development of undercoats, for Duco as first developed was not very adhesive and sometimes stripped from the metal. Duco also required the use of natural resins, which were limited in quantity and of variable quality. In time, the invention of synthetics relieved us of dependence on these variable natural products.
Color had always been available in automobile finishes, both in the paint-and-varnish period and in the enamel period that followed it, but it was expensive and the range was limited. Duco, by reducing the cost of color finishes and increasing enormously the range of color that could be economically applied to cars, made possible the modern era of color and styling. Furthermore, its quick drying removed the most important remaining bottleneck in mass production, and made possible an enormously accelerated rate of production of car bodies. Today a car can be finished in an eight-hour shift, compared to the two-to-four-week period of the paint-and varnish age.
Consider the saving in space alone: a production of 1000 cars a day once required space for 18,000 cars in process, since three weeks on the average were needed for the finishing work—that is, twenty acres of covered indoor space. Think of what this would mean at today's production rates of 15,000 or more cars per day.
Since the introduction of nitrocellulose lacquers in the twenties, there has been continuous study to improve them and to reduce the cost of application. In 1958 General Motors introduced a new line of finishes based on the acrylic resins. These again were the product of over eight years of research in our laboratories in co-operation with resin manufacturers. The acrylics are even more durable than the nitrocellulose lacquers and are capable of producing even more pleasing colors.
There were many other important improvements in which General Motors played a key role. Crankcase ventilation in the 1920s eliminated one of the main causes of deterioration of the engine. "Internal" crankcase ventilation, which reduced air pollution, was pioneered by General Motors in 1959 and made available to the industry in 1962. The development of four-wheel and hydraulic brakes contributed greatly to the safer and more effective use of the motorcar. Four-wheel brakes were not an exclusive General Motors development, but we participated in improving them, helped develop volume production, and created a special division to manufacture them for our cars. The corporation also took a leading role in the development of power brakes, power steering, car air-conditioning, and innumerable other refinements of the automobile. These are only a few important selections from the results of the ingenious and untiring labor of many thousands of research workers, engineers, and others who have given their professional interest to the development of efficient and comfortable individual transportation.