The weird and wonderful cars of the ‘500,’ part 7

Published On May 12, 2016 » 9299 Views» By Marshall Pruett » Blogs, IMS, IMS History, Indy 500

We’re chronicling 100 days of Indy 500 history on #SpeedRead leading up to the historic 100th Running. With 17 days to go, racing journalist Marshall Pruett continues his look back at milestone cars and technology.

More Pruett: Weird and wonderful cars: Part 1Part 2, Part 3, Part 4, Part 5, Part 6The mighty “Offy” | Penske’s ’94 dominator | The “Fantastic” Turbine | Murphy’s Miller straight-8 | Yunick’s winged Watson More 100 days

We have fallen in love with the Indianapolis 500’s most accomplished designs since the Marmon Wasp won the first race in 1911. Since then, countless favorites have graced Victory Circle—Millers, Kurtis Krafts, Eagles, Penskes—and dozens of other race-winning cars or inspiring machines have enriched the great race.

And then, as history has recorded, we have the cars that reached too far or, in some cases, not far enough in pursuit of glory at the Indy 500. They stand as the weird and the wonderful, and some represent interesting footnotes—or origins—in chassis and engine design.

In Part 1Part 2, Part 3, Part 4, Part 5 and Part 6 of this series, we’ve enjoyed looking back at cars that aren’t household names, yet have become beloved entries in Indy’s technological march to May’s 100th 500. And we’re still going! We hope you enjoy Part 7.

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Has any Indy car gone from an ugly duckling to a swan and back to ugly like 1955’s Sumar Special? Built on a Kurtis roadster chassis with a venerable four-cylinder Meyer-Drake Offy up front in Terre Haute, Indiana, the stripped-down Kurtis was carried over from 1954, received a glorious full-width body and canopy for 1955, yet after practice, it had its sports car-style wheel enclosures and canopy removed prior to qualifying.

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Jimmy Daywalt qualified the unclothed Kurtis—which looked like the fenders had fallen off—a solid 17th and finished ninth. Without the fenders, the Kurtis—and the engine attached to the impossibly long exhaust pipe—received some cooling updates. The novel use of forward-facing louvers to draw air into the engine bay atop the nose, and complementary use of flush, rearward-facing louvers to extract that heated air from the engine bay was smart. Granted, some of that exiting air hit the bluff fuel tank strapped to the side and created turbulence, but aero progress was being made in stages and rounding the front of the fuel tank to reduce drag was not a consideration with the Sumar.

Removing the swoopy body and canopy appeared to help the Sumar Special’s performance, but given more development time, it would have been interesting to see how far the car could have progressed.


2. 1983 ARGO JM15

Argo’s success in Europe’s equivalent of the Mazda Road To Indy training series in the 1970s and early 1980s also drew interest in the United States. In Europe, future IndyCar stars Arie Luyendyk and Roberto Guerrero were among the young chargers to star in Argo’s junior formula cars, and with an inquiry from Indy 500 journeyman Bill Alsup for the 1983 race, designer Jo Marquart accepted the challenge to bring the brand to open-wheel racing’s biggest stage.

The Argo JM15 that followed was built specifically for Alsup, and in the hands of a bigger team, it’s possible the car could have been a success. With Alsup’s modest operation, the Cosworth DFX-powered JM15 never had a chance and failed to qualify.


Although Argo’s one and only Indy car chassis was quickly forgotten at IMS, it was part of an impressive class in 1983 that featured eight different chassis manufacturers trying to make the field of 33. Marchs, Eagles, Lolas, Penskes, Wildcats, Rattlesnakes and a Primus made the show. The JM15 missed the race, but still serves as a reminder of a time when drivers went and found constructors to build one-off specials for the 500 and accepted the risks that came with trying something different than their rivals.

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Alsup was able to make a handful of races outside of Indy with the Argo (shown above at Pocono in 1983) before he retired.

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Mike Mosley’s barely recognizable Eagle is a perfect visual representation of ideas added on top of ideas. Compared to most cars in 1971, the AJ Watson-modified Eagle was a series of small “aha!” moments bolted together from nose to tail. Take the addition of small front wings. Those aluminum creations were attached to the nose, and weren’t flush with the side of the nose or evenly spaced. And with another idea—this time, to add some sort of airflow diverter in front of the tires—more aluminum pieces were fashioned and bolted to the outside of the front wings.
(Despite the crude fabrication seen here in 1971, the same front-tire-air-diverter concept is used today with the Dallara DW12.)

And if the narrow front suspension and busy control arm/shock/anti-roll bar arrangement wasn’t enough of a drag-producing hindrance behind the front wings, the need for a small radiator became another ‘aha!’ moment. It was duly jammed into the limited space between the left-front wing and the suspension…

The sides of the Watson Eagle also sport ideas upon ideas.

It started by adding bodywork to the sides of the chassis parallel to the cockpit. Rather than add a rear wing to the car, the Eagle received a mid-mounted aero ramp that added some downforce, but with scoops affixed to both sides of the bodywork to cool small radiators alongside the turbocharged Ford V8, the air was filled with obstacles as it made its way to the back of the car and left over two small exit ramps.


Using mid-ship aero ramps—with fenced enclosures—was an interesting approach during the Indy 500’s big growth spurt with wing-based performance. Mosley started 19th and finished 13th in the 1971 race.

The 1971 Parnelli Jones PJ Colt chassis also ventured down the path of mid-chassis aerodynamics as Joe Leonard’s car made use of a similar (but more elegant and effective) wing-and-ramp system.


With the PJ Colt serving as a mere suggestion of what was coming, a truly wild car—the Colt’s successor—turned the concept to the skies.



The Indy 500 went from the Watson/Eagle and PJ Colt to the Vel’s Parnelli Jones 1 (VPJ-1) in just 12 months. Talk about a fantastic time for conceptual freedom.

The Parnelli VPJ-1 took the idea of making light downforce at the middle of the chassis from ramps to outright insanity with giant dihedral (upswept) wings next to its drivers. The late Maurice Phillippe, who designed the car for Indy 500 winner-turned-team owner Parnelli Jones and Vel Miletich, wrapped his arms around radical aerodynamics and an extreme chassis layout to make a bold statement with the VPJ-1.

The car’s original concept called for nothing other than its dihedral wings, but early track testing confirmed more downforce—and vastly improved chassis balance—would be required for the project to continue.

Of the most obvious visual cues, Phillippe responded by incorporating three sets of wings on the cars built for Mario Andretti, Al Unser and Joe Leonard. With the two front wings, two mid wings and rear wing combined, the VPJ-1 must own the record for the widest wingspan and greatest total surface area for any winged Indy car.

Phillippe also went about conditioning the air that would hit the dihedral wings with a sweet touch: The front suspension’s upper rocker arms were raised and shrouded with bodywork to curve the air and meet the leading edge of the mid wings with a cleaner flow.


The incredibly low nose meant cooling for the turbocharged Offy four-cylinder engine would need to be handled elsewhere on the chassis. And with the need to leave free and clear space beneath the mid wings to generate downforce, Phillippe struck upon another innovative solution by widening the bottom of the car next to the cockpit and placing the radiators within the chassis just aft of the fuel tanks. Fed by NACA ducts, the VPJ-1’s stacked packaging—curved fuel cells that made way for the radiators—was one of many indicators Phillippe was unafraid to try new things with the car. The mid wings even had engine ancillaries built into the design–openings for oil coolers can be seen in the photo below.

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Phillippe’s unchecked creativity was, unfortunately, brought down to earth by the 2.5-mile Indianapolis Motor Speedway. The dihedral wings created aerodynamic instability that could not be cured, and with persistent overheating problems leading to numerous engine explosions, the decision was made to strip the mid wings from the VPJ-1 and tack the oil radiators to the outside of the bodywork where the water radiators were held.

Minus the dihedral wings, the VPJ-1 became a contender.


Unser would rally from 19th on the grid to finish second, just ahead of Leonard in third. Andretti, who started fifth, ran in the same position late in the race but fell to eighth after running out of fuel.

Outside of Indy, Leonard would prove the VPJ-1’s effectiveness by winning USAC’s National Championship.


Our last topic is one that’s still relevant today: An abundance of wings located in unexpected places. In road course trim, a Dallara DW12 fitted with either a Chevy or Honda aero kit has more winglets than anyone could have imagined in the 1970s and 1980s, and just for the sake of fun, here’s a look at a series of Indy cars that took wing mounting to uncharted territories.

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1977 Wildcat DGS: upper deck upper element

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1971 Hawk II Offy: a short splitter and two odd winglets at the back

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1973 Parnelli VPJ-2 Offy: the first car with a swan-neck rear wing mount?


A modern swan-wing mount.

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1981 Eagle: it made use of a rear wing, giant underwing with giant Gurney flaps, and even added two smaller wings at the base of the underwing exit.

1983 March, Penske, and Wildcat: the same cars used at the Indy 500 went to road courses and received extra wings at the base of the rear Penske and Wildcat, a full-width wings positioned above the nose (white March), and a third wing above the nose and standard wings (red March).



About The Author

Marshall Pruett

Marshall Pruett transitioned from more than 20 years as an open-wheel and sports car mechanic, engineer and team manager into his current role as a writer and reporter in 2006. Follow him @MarshallPruett []