Monday 6th July 1891
Born on this day, Earl Steele MacPherson, American automotive engineer, most famous for developing the MacPherson strut in the 1940s.
For most of World War I, MacPherson was in Europe working on aircraft engines for the U.S. Army. His experience there left an indelible impression on MacPherson, and his exposure to the advanced, sophisticated engineering informed everything he would do in the next half-century.
His entire pre-war career revolved around the automotive industry. From 1919 to 1922, he worked for auto manufacturer Liberty, before moving on to Hupmobile until 1934, when he joined General Motors’ central engineering office. In just one year, MacPherson would become Chevrolet’s chief design engineer. His task: direct the creation of a small car for Chevrolet.
That car never came to fruition. And it is a second small Chevrolet that never materialized for which MacPherson is generally remembered. The charge was to produce a Chevrolet that was to sell for $1,000 or less. The least expensive Fords and Chevrolets were priced at $1,050.
GM’s chairman, Alfred P. Sloan, was opposed to building small, cheap cars, believing (rightly it turned out) that the United States would be treated to unprecedented prosperity, and that conventional automobiles would win the day. As a compromise, Chevrolet embarked on the Chevrolet Light Car Project in 1945, and MacPherson was installed as chief engineer.
MacPherson assembled an incredible team of engineers for the project. Earl W. Rohrbacher, chief designer for mechanical components on the Light Car, noted in an article written by Karl Ludvigsen that “MacPherson didn’t like to rush a design,” adding “He liked to think it out very thoroughly before any experimental parts were built up. He said you saved money in the long run that way.” Parts did begin to be constructed, though, and when they did, they were world-class. Elements of the Light Car were described as “an engineer’s dream.”
The car featured a front engine and rear drive, since MacPherson decided that this was the best configuration for a four-door passenger car with a target weight of 2,200 pounds. The car was small: It was designed for just four passengers, and had a wheelbase of just 108 inches, eight inches shorter than a traditional Chevy.
It was the Light Car’s suspension system, though, that was truly revolutionary. MacPherson had combined the tubular shock absorbers and coil springs into tall towers that also guided the vertical travel of the wheels. Each of the car’s four wheels were suspended independent from each other. Tubular radius rods controlled the movement of the lower end of each tower. The Light Car–by now known as the Cadet–became the first car with a true MacPherson strut suspension.
The innovative suspension system was also employed at the rear, which is something you don’t generally see on modern cars. It had to be in this case, because MacPherson wanted more seat and trunk room, and to reduce unsprung weight and provide an exceptional ride.
In testing at the GM Proving Grounds in Milford, Michigan, the cars showed outstanding characteristics. The Delco Division worked to improve durability of the struts, while eliminating any squeaks with nylon bushings. The struts allowed for long wheel travel, while still providing light and pleasant handling, described as “snappy” by testers. Handling characteristics were better than that year’s Chevrolet’s, and even better than contemporary Cadillacs’.
Unfortunately, the project was proving to be expensive. At the $1,000-a-unit threshold, Chevrolet’s salesmen would have had to sell 300,000 Cadets a year to make a profit, something they felt was impossible. After tangling with GM engineering vice president James M. Crawford, who felt that the Cadet was “too much of a jewel of a car,” and pressed for more simplicity in its design and engineering, MacPherson had seen just about enough at General Motors.
MacPherson soon received an offer from Harold Youngren at Ford Motor Company, and he packed up and took his talents to Dearborn. In the intervening years, MacPherson’s genius was employed in the Ford overhead-valve six-cylinder, and most notably, in the use of his innovative suspension system in the front of the French Ford Vedette, and later, the English Ford Consul and Zephyr, and later on Volkswagen Type IVs and Super Beetles.
The combined advantages of low unsprung mass and space-saving design made the MacPherson strut suspension system the tool of choice for cars built in the 1980s. Ironically, it wasn’t until 1980, when the X-body Citation debuted, that Chevrolet would finally employ the system MacPherson designed.
