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Streamlining - aerodynamics in early vehicle design

The Trumpfler Dropfenwagen

The Trumpfler Dropfenwagen

Early car designers saw the teardrop as the most aerodynamically efficient shape. There were scattered attempts to incorporate this thinking before Austrian Paul Jaray used a wind tunnel he’d built to perfect designs for Zeppelin airships to test automobile designs, too. He founded his own firm in 1924 to promote streamlining automobiles.

Jaray’s work was applied to Tatras and Chrysler Airflows as manufacturers began to take aerodynamics seriously. This made sense as air resistance is the enemy of performance; at sixty miles per hour, a car expends most of its energy just pushing against the wind. 

Early streamline experiments include the bullet-shaped one-off 1914 Alfa Romeo Castagna Aerodinamica and the limited production 1921 Rumpler Tropfenwagen as seen in Fritz Lang’s Metropolis movie.

Aerodynamic designers studied fluid dynamics to determine the most efficient airflow over a car, but this didn’t always result in beautiful automobiles, as Chrysler learned when their groundbreaking streamlined 1934 Airflows {{Airflow Link}} bombed in the marketplace. 

Though many “streamlined” cars of the thirties and forties looked sleek, very few were actually wind tunnel tested. An experimental rear-engine sedan by John Tjaarda of Briggs, a body supplier to Ford, was later re-designed as a front engine car that sacrificed its true aerodynamics for a more pleasing “streamlined style.” Introduced in 1933, the Lincoln Zephyr’s beautiful fake streamlining brought it instant sales success. 

During the thirties and forties, interest in applying aerodynamics to increase auto efficiency grew. Norman Bel Geddes designed miniature streamline pod cars for General Motors’ spectacular Futurama Exhibit at the 1939 New York Worlds’ Fair.

Streamlining became such a fad in the 1930s that a style of architecture called Streamline Moderne was inspired by it. Still, very few cars were actually wind tunnel refined up to the late seventies when better fuel economy was mandated by the government. Nowadays, cars are streamlined to decrease fuel consumption, lessen wind noise, and increase performance.

Aerodynamic engineer Winibuld Kamm refined Jaray’s thinking in the mid-thirties when he discovered that a cropped-off, flat tail worked well as a replacement for the awkward, tapered tear drop shape drawn out to a point at the rear of the car. A truly aerodynamic tapered tail would be so long as to be impractical. 

Visionaries attempting streamlined “long tail” cars often found rear-engine layouts worked best. William Stout produced several streamlined, rear-engined proto-minivans he called Scarabs. Paul Jaray designed a streamlined, rear engine Tatra that stayed in production for decades.

Airship designer Sir Charles Burney built thirteen aerodynamic rear-engine sedans from 1930-34. Buckminster Fuller’s 1933 Dymaxion car took aircraft inspired bodywork to the limit. Far and away the most commercially successful of the original streamliners, Volkswagen’s Beetle was introduced as an everyman’s vehicle that eventually became the world’s biggest selling car. 

Chrysler’s doomed Airflows rank high on the list of truly aerodynamic pioneers. Chrysler had licensed Jaray’s patents in order to build beetle-shaped cars that were decades ahead of competing cars, but the Airflows flopped as they leapt too far past public tastes. The company saved itself from financial disaster by rushing new models called “Airstream” into production.

The Airstreams appeared streamlined but were designed with aesthetic considerations as first priority and well outsold the truly streamlined Airflows. The Airflow’s failure didn’t totally destroy designers’ enthusiasm for aerodynamic shapes. A chastened Chrysler retreated to conservative production designs, but nevertheless  commissioned a radical dream car by legendary designer Alex Tremulis.  

The 1941 Thunderbolt had a vaguely aerodynamic,“beetle” or “bathtub” look that many designers of the forties assumed would be the dominant post-war body shape. But for the most part, only small, independent manufacturers actually produced such designs for sale. Beetle-bodied Hudsons and wind tunnel refined “Airflyte” Nashes sold well enough in the post war sellers’ market but when Detroit’s major manufacturers introduced modern, “three-box” designs, the tubby shapes soon looked obsolete.

Aerodynamics became an arcane word to designers who were busy dazzling the public with fake rocket ship and jet plane references, gobs of chrome, two-tone paint,  and soaring tail fins. French firm Citroen kept the faith with its 1955 DS sedan that swam against the overstyled mid-century tide with an aerodynamic body that looked straight out of the future. 

Chrysler design Vice President Virgil Exner tested his breakthrough 1957 Forward Look cars in a wind tunnel to tune their tail fins for added high-speed stability, but with very few exceptions, the industry turned a blind eye to aero concerns until the seventies’ energy crises forced improvements in efficiency. Wind cheating body styles can easily add several miles per gallon to a car’s fuel economy while costing manufacturers significantly less than other engineering advances might.

Today, nearly all cars are streamlined for wind-cheating efficiency. This has inspired complaints that they all resemble one another. It’s true, most of the blame for today’s ubiquitous “jelly bean” shapes can be laid at the door of efficient, streamlined design. That means designers’ challenge for automobiles’ second century is to bring brand-specific drama to aerodynamically slick bodies that slip through the air with the greatest of ease, but still assert their individuality. So far, results are decidedly mixed, with retro-referencing designs showing the most distinction, but often suffering from short shelf lives. 

By Jim Cherry