Aero Imperative

Volkswagen XL1 Prototype (Source: Volkswagen)

Meeting the new CAFE standard of 54.5 mpg by 2025 will demand herculean efforts by designers and engineers to reduce all fuel-wasting sources of resistance to a car's motion. Reducing the mass of a car by replacing steel with lighter materials—like aluminum and carbon fiber reinforced plastics used in the Volkswagen's breakthrough XL1 prototype—is an obvious way to decrease its consumption of fuel or electricity in the case of an electric vehicle or hybrid. So "light-weighting" has become today's automotive buzzword.

The XL1 will only be available in limited numbers in Germany and Austria. Meanwhile, in America, aluminum has replaced much of the steel normally used for the body of the newest variant of the perennial sales leader, Ford's 2015 F-150 pickup. It consequently weighs some 450 pounds less than the previous model. Some of the additional cost of aluminum can be offset by a "weight-compounding effect." A lighter vehicle requires smaller, lighter and less expensive brakes, for example, and other suspension and driveline components. A smaller, lighter breed of three- and four-cylinder engines displacing as little as one liter, are coming onstream in place of larger engines without sacrificing performance.

Reducing air resistance, known simply as streamlining, delivers more bang for the buck than any other way of increasing fuel efficiency because it depends primarily on the car's shape. Although VW's designers and engineers might have spent more hours than usual in the wind tunnel tweaking the XL1's design, its shape wouldn't have made it inherently more expensive than any other.

Aerodynamic drag is especially pernicious at highway speeds. Rolling resistance, due largely to weight that continually flexes tires as they roll, essentially doubles when a car's speed increases from 30 to 60 mph. But aero drag multiplies as the square of the increase; it quadruples between 30 and 60. Even more astounding, the fuel consumed due to air drag increases as the cube of the increase; air drag consumes eight times the fuel at 60 mph as at 30. It turns out that most of the fuel burned by a typical car going faster than about 45 mph is spent overcoming aero drag. As engineers succeed in making cars ever lighter the crossover speed will continually drop below 45 mph. As engineers shave more weight, reducing air drag will increasingly become the most imperative way to increase efficiency.

So why wait? Since a car shaped for aerodynamic efficiency cost no more than one that struggles through the air, why not pull the stops and go all out for maximum aerodynamic efficiency right away? Because super slippery cars would differ so much from well-established norms that they would shock and alienate consumers who would regard them as strange, weird or downright ugly. We expect next year's models to be new. Otherwise, cars might still resemble Ford's Model T. But most of us have no taste for revolutionary design. So aesthetics will present as many obstacles as physics in the industry's quest for 54.5 mpg because, at best, we tolerate only evolutionary departures from designs we are already familiar with. If you were to introduce today's most beautiful car in 1930 it would have been a spectacular flop. Consider some recent and not so recent examples where consumer tastes have stymied aerodynamic progress: 

1934 Chrysler Airflow and Union Pacific Streamliner (Source: Chrysler)

Chrysler's infamous 1934 Airflow still sends chills down the spines of designers who would dare to pen radical aero designs. It was created during the so-called Streamlined Decade of the 1930s when cars, trains and busses weren't the only products displaying the so-called "streamlined" look inspired by a new class of sleek, all-metal airplanes like the Douglas DC-3. Vacuum cleaners, refrigerators and virtually every other class of product bore the streamlined look.

A car's coefficient of drag (CD) is the standard measure of a car's aerodynamic drag. It is derived from a comparison of the car's air drag to that of a disk of the same area as the car's frontal area—its profile as seen from head on, including all visible protrusions such as tires, door handles and mirrors. If its drag equalled that of the disk it would have a CD of 1.00—the worst possible case. The Chrysler Airflow's CD was reportedly around 0.50, corresponding to 50 percent of the draf of a disk with the same fontal area. Assuming the Airflow had a frontal area of 30 square feet, a wind tunnel test would have registered the same air drag as a 15 square-foot disk (0.50 X 30 sq. ft.).  That represented an improvement of better than 28 percent over the typical car of the period, which reputedly had a much worse CD of around 0.70. But that superior performance wasn't enough to counter the strangeness of its design.

Aero Citation Concept with 1980 Chevrolet Citation

When the oil crises of the 1970s led to escalating gasoline prices and long lines at gas stations the typical American car had a CD of between 0.55 and 0.6. Along with downsizing, automakers got more serious about improving aerodynamic efficiency. The 1980 Chevrolet Citation, for example, had a commendable CD of just 0.42.

But it could have been better. Using a method for predicting a design's CD developed by England's Motor Industry Research Association (MIRA) (which I used while working in Ford's Advanced Vehicle Concepts Dept. during the 1960s) I altered its design for a 1980 magazine article. I retained the aerodynamically desirable fastback form, smoothed and rounded the nose, gave the windshield more curvature and skirted the rear wheels.  The method yielded a design with a predicted CD of just 0.27. This would have amounted to a 37 percent decrease in the Citation's air drag that might have yielded a 10 percent improvement in fuel economy. Despite quite humdrum looks by today's standards, it looked odd the time. When the magazine's editor saw my illustration of it he called it "the ugliest car I have ever seen."

1986 Mercury Sable (Source: Ford)

Six years after my Citation redesign exercise appeared in the magazine the similarly rounded and smoothed 1986 Mercury Sable achieved a CD of 0.29. (Skirts might have brought it nearer 0.27, but might have made the Sable even harder to accept.) The unusual, nearly grille-less designs of it and its Ford Taurus sibling met with initial consumer resistance. But they went on to become award winning sales champs and design icons that forced competition back to the drawing boards

2010 Toyota Prius with 2004 Prius (background) (Source: Toyota) 

Toyota's 2004 Prius broke new ground with a CD of 0.26. But, to this day, many people have not warmed to its unusual design. Designers tried to fix the design by incorporating crisper, more fashionable creases and squared-off edges for the 2010 model. Toyota claims a slightly better CD of 0.25 for the revised design. But I think they must have burned a lot of midnight oil in the wind tunnel eking out that extra one percent because the previous model looks inherently sleeker to me.

Volkswagen's XL1 prototype has a CD of 0.19. It is a plug-in hybrid with an 800 cc engine delivering 261 miles per gallon of diesel fuel. I think it's beautiful and wish I could have one. But what do you think?


Studebaker Dreams


When I became a designer at Studebaker-Packard in February of 1957 it was the fourth largest U. S. automaker, trailing only Detroit's Big Three. Technically, it was the oldest company in the auto business. It was founded 1852 by 26-year-old Henry Studebaker and his 21-year-old brother Clement when they set up shop as blacksmiths in South Bend, Indiana. Their 19-year-old brother John joined them after amassing a fortune in the California gold fields—not as a miner but a maker of wheelbarrows, which every miner, whether lucky or hapless, needed.

The brothers didn't make cars right away, of course, but horse-drawn wagons and carriages. They got their big start from a contract for 100 wagons the Army needed to put down an anticipated attempt by the Mormons to take over the Utah Territory. Studebaker eventually became the largest manufacturer of horse-drawn vehicles in the world with plants in Europe and Asia in addition to South Bend. Their sales facility in San Francisco had six stories.

So Studebaker was enormously prosperous in comparison with the likes of Henry Ford when, in 1902, its management decided to make horseless carriages. They chose electric power over gasoline or steam in deference to women, who wouldn't have to crank their cars in order to drive, and concern about environmental pollution. Yes, there were serious environmentalists even then.

Having merged with Packard in 1954, Studebaker-Packard was in dire straights when I joined the company. Designing a new car was always a matter of facelifting an old one. We pulled existing grille, taillight and bumper pieces from a storeroom of bits and pieces made from tooling already paid for. The front bumper of the Packard Hawk, for example, featured the large chrome "bombs" from recent Packard sedans but the horizontal piece between them came from the '49 Studebaker.

The company also forged a mutual assistance alliance with Mercedes-Benz aimed at reducing engineering and development costs. S-P had access to M-B's technology and parts bin. M-B had access to S-P's national sales and service network. S-P took little or no advantage from the arrangement that I knew of. Ironically, it was M-B who benefitted most. When S-P ceased production of cars in 1966, its dealers were left with only Mercedes products to sell, which turned out to be a boon. And Mercedes-Benz ended up, overnight, with the nationwide U.S. dealer network it sought—at virtually no cost.

With rising sales of Volkswagens and other European imports American automakers were compelled to think seriously about offering smaller, more efficient cars of their own, especially after the Rambler enable American Motors to overtake Studebaker. But Studebaker had nothing in the parts bin for making a small car. So management approached Glas, the German maker of Goggomobil minicars based in the Bavarian town ofDingolfing. They contemplated using Goggomobil's rear-mounted engines, transmission and suspension components under one or more bodies designed by Studebaker.

I was fortunate enough to be the only designer assigned to create a variety of vehicle concepts, including sedans, coupes, minivans and the roadster depicted above in a rendering I did on August 19, 1957. I concentrated on keeping costs as low as possible. The doors on the roadster would have been identical, for example. And the body would have been made of fiberglass, which by then the Corvette had shown to be feasible over four years of successful production.

I don't know why management decided not to pursue the project. Decision makers probably concluded that, whichever concept they chose, it would have been too small and too anemic for American tastes. The largest Goggomobil engine had a displacement of only 484 cc, while the VW had a considerably more robust 1192 cc engine. 



Maintaining Excitement

Since nothing remains new forever, even for minutes, a new car's ability to fascinate and excite viewers begins to fade immediately. So to maintain the brand's ability to excite consumers automakers have a longstanding tradition of periodically introducing new or freshened designs (called facelifts) that differ enough from their predecessors. But this strategy has its limits. Like a movie actor who has one too many facelifts, designers have to periodically start from scratch with a brand new face—as actors sometimes wish they could. Typically, an "all new" design appears every four years or so. During the highly competitive Fabulous Fifties American automakers introduced all-new models as often as every other year or, in a few cases, annually. 

"All New" 1968 Pontiac GTO

The all-new design of the 1968 Pontiac GTO, arguably the most beautiful American car of its day, is credited to William Porter who headed the advanced studio where its theme originated. Bill Porter was one of Detroit's most highly regarded designers, a "designer's designer." When given a clean sheet of paper he strove to create "high concept" designs, to borrow Hollywood's terminology, for the same reason good screenwriters avoid wordiness. Typical of Porter's work, the '68 GTO was clean, simple and elegant.

1968 Pontiac GTO concept sketch by William Porter

Porter's sketch depicts curves and surfaces that flow smoothly rather than changing direction often or abruptly. The unifying, body-colored nose and subtle fender blisters are the outstanding visual features of the design. The blisters' cross-sections depart only gradually and slightly from the underlying body shape; that's why they seem so subtle. They lend the car's overall form a Coke-bottle shape that is barely discernible, if at all, especially in lighter colors. 

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Creating Excitement


2004 G2 Prius (background) and 2010 G3 Prius (foreground). (Source: Toyota)

Toyota’s global design chief, Akihiro “Dezi” Nagaya, who was responsible for design of the groundbreaking 2004 Prius, has promised that future Toyotas will look more emotional, dynamic, aggressive and, generally, more exciting. How will designers fulfill his pledge? In a word, with more information—the only thing capable of exciting the nervous system and arousing the emotional states that characterize aesthetic experience.  

That confusing word "information" means a lot of things ranging from "knowledge" and bad guys snitching on each other to the bits and bytes stored in a computer's memory. To understand what it means in the context of design we merely dig down to its Latin root; “to inform” simply means “to form or shape” something, which is what car designers do, of course.

Since shaping something always changes its form, information always involves variation of some sort. More variation equals more information equals more excitement. When a designer bends a flat sheet of metal into a curve it gains information. Bending it further—varying its shape abruptly enough to crease it—adds even more exciting information.

So the creased sides of the current G3 (third generation) Prius, introduced in 2010, embody more information than the smoothly curved sides of the 2004 G2 (second generation) Prius. Likewise, the zig-zagging outlines of the G3's headlights—which change direction more frequently and more abruptly than those of the G2's simpler lights—embody more information. These two features are enough to make most people conclude that the G3 Prius seems more complex and active than the G2, as though something more is happening throughout its form. That is to say, it seems generally more exciting.

And just about everyone agrees about which design is more exciting than another. Just ask anyone. But their judgments are based on nothing more tangible than feelings, after all, even if there is broad consensus. A designer would be better off knowing just how exciting a design is—and exactly how much information should be added or subtracted to make it just right. 

Semantic profiles of G2 Prius and G3 Prius

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2013 Toyota Avalon Design Analysis

The first thing I noticed about Toyota's new 2013 Avalon was the juxtaposition of contrasting themes in the design of its front end. The smaller upper grille has a traditional Toyota look reminiscent of the Camry, for instance, and the Prius. It and the lights flanking it sweep in a smooth arc across the nose in keeping with the dictates of good aerodynamic efficiency. It says in effect "I'm sleek and slippery." The bolder, more prominent grille below harkens back to the wide, low scoop of a vintage racecar. It seems to jut out boldly. It says, "I'm powerful and aggressive." Both messages are appropriate; we expect cars to seem both slippery and powerful.

1936 Cord 810 sedan.

Such dissonant themes have energized many great designs, like Gordon Beuhrig's curvaceous 1936-37 Cord with the boxy and dissonant "coffin-nosed" hood. The powerful look of the hood signified the powerful Lycoming V8 engine beneath it. The straight louvers that wrapped around it expressed the Art Deco look, which was popular at the time. In stark contrast, the rest of the car expressed the "Streamlined" look of the period—smooth, gently-curved surfaces, teardrop-shaped fenders—inspired by modern all-metal aircraft of the 1930s.


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