Advent of the Downforce-Inducing Aerodynamic Appendage

by James Kraus

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Ferrari 250 GTO

While aerodynamic efficiency was occasionally a consideration in the design of road cars as early as the 1920s, it was only from a perspective of achieving reduced air resistance. Interest in generating aerodynamic downforce did not manifest itself until the 1960s. Not surprisingly, experimentation and development first occurred in the competition arena. 

246 SP

Ferrari 246 SP

The initial appearance of aerodynamic addenda to create downforce came not in Formula One, but in sports car racing. The earliest application was the lip or ducktail spoiler developed for the Ferrari 246 SP Dino in 1961 by legendry Ferrari engineer Vittorio Jano.

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Ferrari 250 GTO with early-style separate rear spoiler

Soon thereafter, Ferrari installed one on the 250 GTO, at first separately affixed, then integrated into the aluminium bodywork on later cars. Thus the early 250 GTO became the first road car with a bolt-on (or in this case, riveted) aerodynamic aid.

Rear ducktail-style lip spoilers quickly spread among the racing fraternity.

Chaparral 2A

Chaparral 2A

A few years later, during the 1965 season, the Chaparral 2A and McLaren M1B sprouted lower front spoilers (air dams) designed to reduce front-end lift.

M1B

McLaren M1B

By the end of 1965, the first separately attached lower front spoiler was added not to an exotic road car, but as standard fitment on the 1966 Chevrolet Corvair.

1966 Chevrolet Corvair Corsa

1966 Chevrolet Corvair Corsa

The black molded-plastic Corvair air dam made perfect sense; prior to the mid-1960s, it was thought that rear-engine cars were overly sensitive to crosswinds at speed because they lacked the stabilizing mass of a front-mounted powertrain. The fact however, was that the vast majority of cars of the era suffered from severe frontal aerodynamic lift at speed, often in the range of 130kg (300 lb) or more.

The presence of a heavy front engine and gearbox was merely a band-aid that camouflaged the source problem. With it’s new front air dam fitted, the Corvair’s high-speed stability became a non-issue. Although largely unheralded upon its introduction, this front spoiler was the progenitor for all those that followed in the 70s, 80s and 90s.

The functionality of the separate front air dam is generally incorporated in contemporary automotive designs from careful shaping of the front facia, although in many instances, a flexible black-plastic dam is still utilized, often recessed back far enough as to be unnoticable.

906 PIC Sebring 1966

Porsche 906 at Sebring, 1966

On the race circuit, front air dams or downforce-inducing front corner winglets began to appear with increasing frequency; spreading quickly to the Ferrari 330 P3, Lola T-70, Porsche 906 and others during the 1966 World Sportscar Championship.

1966 also saw the first application of a rear-deck lip spoiler on a mass-production road car; the newly-introduced Dodge Charger. As with the Ferrari GTO, this spoiler was born on the racetrack.

Chrysler engineers had high hopes for their new fastback Dodge on the high speed NASCAR superspeedways, and the new car indeed displayed superb high-speed capability during testing, but drivers found it woefully unstable. The cure was a small aluminium rear spoiler.

1966 Charger

1966 Dodge Charger

The spoiler would not be legal on the track unless it was offered to the public (in the 1960s American “stock” car racing was still actually based on stock production cars.) Thus the spoiler became available in mid-1966 over the counter or as a dealer-installed option for $29.95. They also came in a box as standard equipment with 426 Hemi-engine models, to be installed by the dealer or owner.

 Cotton Owens Garage 1966 NASCAR Championship Charger with 14 first place trophies. The tiny spoiler helped bring home the bacon.

Cotton Owens Garage 1966 NASCAR Championship winning Dodge Charger

Unfortunately, very few of these spoilers were ever purchased or installed. At the time, only diehard race fans had any clue as to what a “spoiler” was and the average buyer was probably aghast at the idea of having holes drilled through the sheet metal of his shiny new Charger.

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1967 Chevrolet Camaro

Following in the Charger’s footsteps, in 1967 Chevrolet dealers began offering a rigid plastic rear deck spoiler through their parts departments for the new Camaro in order to homologate it for use in SCCA Trans-Am racing. It first appeared at the press launch of the Camaro Z-28 at California’s Riverside Raceway in November of 1966.

Camaro

1967 Penske-Sunoco Trans-Am Camaro

This spoiler became available as a standard factory production option (paired with a front air dam) on 1968 Z-28 models.

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1968 Chevrolet Corvette

The all-new 1968 Chevrolet Corvette C3 debuted in the fall of 1967 with a standard black ABS plastic front spoiler, similar in design to the earlier Corvair unit.

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1969 Pontiac GTO Judge. This wing was found to actually increase rather than decrease lift. It was revised for 1970 in order to produce the desired effect.

By 1969, Buick, Chevrolet, Dodge, Ford, Mercury, Oldsmobile and Pontiac were producing cars with bolt-on front air dams, rear spoiler lips, rear wings, or some combination thereof. Unfortunately, some of these were mere styling accoutrements, offering no actual improvement in downforce.

Instead of being mandated by engineering and designed by aerodynamicists, aero aids were all too often mandated by marketing and designed by stylists.  As an example, the street version of the 1969 Mercury Cyclone Spoiler II had a rear wing, but when it went racing, the engineers removed it and added a more efficient small ducktail.

In the realm of add-on attachments, drag minimization was not neglected in the quest for downforce. The 1969 Dodge Charger Daytona and 1970 Plymouth Road Runner Superbird featured an added aerodynamic modification designed to decrease drag rather than increase downforce; stainless steel trim at the sides of the windscreen were added to smooth airflow over the A-pillar rain channel.

Petty Enterprises Plymouth Road Runner Superbird

Petty Enterprises Plymouth Road Runner Superbird

A decade later, a similar version of this device (in black molded plastic) was used the VW Golf GTI.

BMW 2002 Turbo

BMW 2002 Turbo

In 1973, BMW launched the 2002 Turbo with a flexible black polyurethane rear spoiler lip of the sort that would soon become ubiquitous on road cars harbouring any sort of sporting pretensions. With the advent of flexible paints, most rear lip spoilers migrated back to body-colour, although some are now rendered in carbon fibre for that boy-racer allure currently coveted by automobile manufacturer’s marketing departments.

Most of the benefit of the traditional rear lip spoiler has been achieved in late-model automotive designs by simply raising the height of the rear deck.

Interestingly, BMW has recently taken to calling their rear deck spoilers Gurney Flaps, even though Dan Gurney himself did not utilize such devices until the 1970s, and then only atop wings. If one wants to give a rear deck lip spoiler a proper name, they should rightly be called Jano Flaps.

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2 thoughts on “Advent of the Downforce-Inducing Aerodynamic Appendage

  1. Another excellent article. Just for clarification though, is there documentation of the first production car to achieve real downforce and not a simply a reduction in lift? It’s helpful to think of a typical closed (fast back) sports car of the 60’s as behaving very similar to a wing and creating lift at the rear. Hence the use of rear spoilers first.

    I have read elsewhere that the seriously lightened Corvette Grand sports which were supposed to be Cobra killers enjoyed little success due to severe front end lift at speeds above 120 mph. If I recall correctly they only won one major race (Sebring?) when pitted against the Cobras.

    • Great question; I doubt any of the examples mentioned here actually achieved any net downforce for the vehicle as a whole. The added devices considerably reduced lift, but I believe they would not have been enough to completely eliminate it, or indeed generate overall downforce. By today’s performance car standards, these vehicles all had rather generous ground clearance, and with all that uncontrolled air (this being well before the undertray/diffuser era) rushing underneath, it is quite difficult to eradicate lift completely.

      I have no idea what production car would have been the first to achieve zero lift or actual downforce at both ends; I would hazard a guess that it may have been the Ferrari F355 of 1994.

      The C2 Corvette did have a lot of frontal lift, which is no surprise if you look at the frontal design in profile. The vee-shaped nose terminates in a sharp apex located extremely high off the ground, pushing lots of air downward and the car upward. It is pure conjecture on my part, but it is quite possible that the Grand Sport, running without front bumpers, actually suffered greater lift than the stock Sting Ray. The original bumpers likely would have deflected some of the down-rushing air and sent at least a small portion off to the sides.

      As to the success of the Grand Sports, they were doomed from the start. GM management (during the short-lived no-racing era) forced Chevrolet to cancel the program after only five cars were built. The small production run forced the cars to run as GT Prototypes in international races, and in Modified classes in domestic U.S. competition. Cobras ran as Production Cars. Thus, the Grand Sports had to compete with the likes of Ferrari 275 Ps and Porsche 904s.

      The first appearance of the Grand Sport was at Bahamas Speed Week in 1963. There they performed quite well, coming in third and fourth overall in the Governor’s Trophy race behind a Scarab Chevrolet and a Ferrari 250 P with the highest-finishing Cobras placing eleventh and twelfth. The only Overall Victory for the GS of which I am aware was the 1963 Glen Classic SCCA race at Watkins Glen, New York with well-known Corvette driver Dick “The Flying Dentist” Thompson behind the wheel.

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