Chrysler started experimenting with aerodynamics in the 1920s, but not until 1969 did they release the most aerodynamic car of its time — one whose drag coefficient was not matched for many years, yet was built on an existing model with relatively few changes. This was the Dodge Charger Daytona, to be joined in 1970 by the Plymouth Superbird.

The 1969 Dodge Daytona had a drag coefficient (cd) of just 0.28, better than most cars made in the 1990s. It would have produced even less drag, if it weren’t for the tall spoiler (added to keep the rear wheels on the ground at high speeds). But, despite its 200 mph speed record (set by Buddy Baker on March 24, 1970, at 200.447 mph around Talladega), the car didn’t sell well, even for its limited production, largely — according to sages of the time — because people thought the aero look was ugly. The price was around $4,000, the engine was a 440 or Hemi, and the top speed was practically unbeatable in a production car.

1970 plymouth cars

The first-generation Viper, with its aerodynamic shape, had a cd of over .5; the 1994 Plymouth Duster had a cd of .42. ; the mid-1990s Eagle Talon had a cd of .36. Even the sleek Eagle Vision had a drag of .31, considerably higher than the 0.28 of the 1969 Charger Daytona. That car set a speed record that held for 13 years, to be broken by about 1 mph in 1983.

The Daytona’s rear wheels tended to lose their traction, until that massive spoiler was put on, because it carried a standard 440 cubic inch, 375-hp engine, and air would flow under the car and lift it. The optional powerplant was the fabled 426 Hemi, a 425-hp (plus) monster designed for racing.

wing spoiler
Aerodynamic development leading to the Dodge Charger Daytona and Plymouth Superbird

Bob Stuemke wrote,

    As a engineering student at the Chrysler Institute 1958-61, I was permitted to study reports in old files (while on a three-month student assignment to an Engineering Improvements Committee). In an experiment from about 1934, a slightly modified Airflow Crown Imperial sedan was equipped with the huge nine-main-bearing inline eight and high compression (about 6:1) Red Head, with 380 cubic inches of displacement. It had overdrive and slight modifications of the body to reduce air drag (smoothed out the headlamp eyebrows, etc.). This was clocked at well above 114 mph! It now sounds rather improbable, but I remember reading this report with absolute clarity after almost a half century.

Even Virgil Exner understood aerodynamic principles, though production cars did not show many of the existing knowledge. Still, some used the information that was out there. road runnerThomas Osiecki noted that Bob Osiecki’s Chrysler-powered “Mad Dog IV” set a world speed record of 181.561 MPH at Daytona International Speedway in 1961, largely through aerodynamic improvements.

Russ Shreve wrote:

    In 1964, I was involved in the design of a very advanced race car concept for JC Penney, which wanted to get into International Sports Car racing. One of the key features of their car would be better aerodynamics.

    In early 1965, I rented the University of Michigan wind tunnel for extensive tests. I hired University of Michigan-associated aerodynamicist Jim Amick to manage the tests and compile data into a report. Ron Martin built the wind tunnel models, and worked with Amick between runs making changes.

    Amick’s final report had a unique solution…The Wing.

    Amick’s March 1965 report included the following: “The divergence speed for a given combination of spring rates can be increased indefinitely by the installation of a horizontal airfoil at the rear of the vehicle. A convenient place for such a stabilizer might be above the rear deck. An airfoil of 15-inch chord mounted 20 inches about the rear deck and spanning the full width of the car would probably provide complete aerodynamic stability.

    Penney did not continue their interest in a race car, and following a breakup with my partner, he took a copy of Amick’s Wind Tunnel Report to Texas car builder and driver Jim Hall, in exchange for a job.

    wind tunnelIn 1972 Larry Chinoda stopped by my house; he was directly involved in the GM association with Jim Hall, and I showed Larry the original Amick report. Larry confirmed my partner had given the wind tunnel report to Hall, and that Hall was skeptical. Per Larry, he himself had been thinking of similar ideas, and when he read Amick’s report realized they had been proven in a wind tunnel. It was Chinoda that convinced Hall it was worth a try.

    There is little doubt Hall and Chaparral took race car aerodynamics well beyond Amick. However, I think it is time the world recognized the idea did not originate with Hall. The credit should go to Jim Amick.

Superbirds at Chryslers at Carlisle

Even before the Daytona, the Charger had been tuned for aerodynamics with the special Charger 500 model. As Burton Bouwkamp wrote in his history of the Dodge Charger:

    During the 1969 model, we added two aerodynamic models to reduce aerodynamic drag and improve the performance of the Charger on the longer NASCAR race tracks. At the beginning of the year we added the Charger 500 model. We changed the tunnel roof backlite to a flush fast roof line and we pulled the grille forward so that it was not recessed. Actually, this input came from our race teams. … From February 1 until September 14, Dodge won 15 races against Ford’s 22 wins. Not a winner but we were at the ballgame. With the debut of the second aerodynamic model in September 1969 – the Charger Daytona – at Talladega, Alabama, it was a new ballgame. From September 14th through the next year we won 45 out of and the next 59 races.

Dodge Charger Daytona and Plymouth Superbird car construction

The Daytona was built as though it was an option package, thanks to a low budget and last-minute modifications to win races – indeed, existing Chargers were converted to become Daytonas. Take a Dodge Charger (440 or Hemi), stick a wedge over its nose and a three foot metal spoiler on the rear, and you’ve pretty much got a Daytona (this is an exaggeration, as Petty Enterprises’ Kurt Romberg pointed out to me. There was also an under-nose spoiler, vertical stabilizers, and a backlight modification, which he notes “are integral parts of the package”).

The Daytona wouldn’t have been complete without at least one quirk, and it picked a good one. Driven too slowly, it could overheat. Increasing speed (or switching to the next-year’s Superbird) took care of the problem (“I was just trying to cool it down, officer!”). Unlike many muscle cars, even the Hemi Daytona was quiet at idle.

winged warrior

A year later, Plymouth took a Road Runner, and gave it the same treatment (with some changes so it wouldn’t overheat at “low” speeds, such as 55 mph). The Superbird was a little slower at top speed, but it had huge cartoon graphics that made 160 mph just a little more fun.

The Daytona and Superbird were considered ugly at the time, but 20 years later, they seem graceful, and maybe even commonplace (except for that spoiler – and their 18 foot length – and whoosh! Where’d it go?).

Superbird interior
NASCAR wing car development (by Curtis Redgap)

Excerpted from Curtis’ excellent article on Chrysler’s NASCAR efforts

Department heads from Plymouth and Dodge were called to get together for a meeting on ways to improve their NASCAR racing cars. Either they had to find 85 more horsepower out of the Hemi engine or they had to decrease drag by 15% to achieve enough speed to put the Fords in the back of the pack.

It was already well documented that the Hemi in NASCAR racing form was developed as much as it would ever be. So, the answer to more speed was to cut the drag. The answer to that was already sketched out by two different designers totally independent of one another. The amazing thing is that their respective designs had the nose of the proposed car nearly the same! The rear wing on one design was a two stage affair, while the other resembled the final result of the proposed Dodge Charger Daytona. …

window inserts

Plymouth made their commitment to build a winged car. Their own version. This was based on Richard Petty’s commitment to return to Plymouth to drive that creation. … Someone thought that doing the Plymouth version would be easy. Just send a Belvedere two door over to Creative Industries Inc., where the Dodge Daytona for the commercial street market had been built. There they could hang a sloped nose and rear wing on the Plymouth and go racing with it. Having to build 2,000 cars for commercial sale prior to January 1, 1970 didn’t leave Plymouth much time.

Dodge Charger Daytona – at Daytona Speedway

The aerodynamic engineers warned Plymouth that it wasn’t going to be anywhere near as easy to get a winged car with the Plymouth. Scoffing, Plymouth went ahead and had Creative Industries literally hang a nose on the front and put a wing on the rear of a stock Belvedere. It was awful! It looked terrible. In that form, it was some sort of monster.

Locked out of the styling of the Dodge Daytona, the styling department at Plymouth made sure that they were involved with the creation of the wing Plymouth all the way. When they saw what Creative Industries had done, they threw a fit. Faced with having to build 2,000 cars since NASCAR had upped the ante to get in, commercial acceptance was vital. Something had to be done and done quickly.

1970 superbird

A proposal to hang a Charger front clip on the Belvedere was quickly rejected. The two body styles were vastly different. Trying to tinker with the current Belvedere fenders just didn’t work out. Wind tunnel testing showed that by doing that, it actually increased drag!

They also had a problem with the rear window on the Belvedere, which was causing a large drag on the rear of the car. Engineers had the means to cure it, but the surgery to do it stuck out like a sore thumb on the roof. They had some money for development, but to cure the rear window drag would have meant changing the entire rear quarter panels, the rear deck lid, the roof sail panels where it sweep into the truck, and leading edge of the rear window where it went into the roof, the rear window itself, and the back valance where the trunk lid locked down. Essentially, a whole new car. No way, said the top management.

dodge daytonaInstead, they concentrated on the rear wing. In the end, the side stabilizer part of the wing were 40% larger than the Daytona. The wing was swept back further, and the stabilizers titled in towards the trunk more. The front “beak” of the Plymouth cut into the air at a slightly higher angle than the Daytona. The front air inlet was redesigned to stop any overheating problems. In the end, what had been achieved without redesigning the entire car was a 99.5% stability rate with a small increase in drag. It was not quite as clean as the Daytona. The numbers looked excellent.

… Coronet front fenders and a Coronet hood were grafted on the Belvedere body. The lines were the same, but the Dodge was more aerodynamic. Once that decision was achieved, it took only a week to clay in the entire car and get that model into the wind tunnel. With results coming in that looked decent, two weeks later a fully operational car was off and running at the Chrysler Proving Grounds at Chelsea. Having achieved that, then the prints and materials were sent over to Creative Industries where the street commercial Plymouths were built. Just prior to that, the model designation was changed from Belvedere to Road Runner SuperBird!