While we were taking in the scenery of vintage Can-Am racers at the Long Beach Grand Prix, we overheard more than a few confused conversations over what exactly people were seeing. Were they old Formula 1 cars? Classic Indy racers? If you’re not familiar with the history of Can-Am, that’s an easy mistake to make. After all, Can-Am drivers sit with their heads out in the breeze, just like F1 and Indy cars did. However, Can-Am evolved from a separate lineage from F1–sports cars.
All open-top race cars have a tendency to look alien since they only bear the most superficial resemblance to the passenger cars we see every day. They have four wheels, (usually) an internal combustion engine, a driver, and…well, the comparisons tend to end there. So how do you know what you’re looking at from a given photo or in person or wherever? We’ve got you covered on a few basics to distinguish between sports cars and open-wheel cars from F1 and Indy .
The Big Differences
As the name suggests, open-wheel race cars do not have fenders but rather race with wheels uncovered. Ride-along mechanics largely disappeared in the mid-1920s from non-rally racing; unlike sports cars that still retained a second unused seat, grand-prix cars switched over to a monoposto setup. That’s Italian for “seating for one, please.” The removal of a second seat brought sleeker, narrower designs that reduced weight and drag. You can see these features on this Alfa Romeo 8C 2300 Monza, a single-seat grand prix car. Colloquially, you’ll probably hear the phrases “single seat,” “open wheel,” and “formula” used interchangeably when describing these kinds of cars. Open-wheel racers tended to compete in Formula 1 (and and its pre-war predecessors) and at Indianapolis, primarily.
From 1950 to 1960, the Indianapolis 500 was a round in the Formula 1 championship, though it seldom drew entries from the regular F1 teams and drivers of that era, save for a Ferarri entry in 1952 and Juan Manuel Fangio’s failed attempt to qualify in 1958. However, the 1960s saw renewed vigor with British F1 drivers Jim Clark and Graham Hill (above) winning at Indy in 1965 and 1966. McLaren won three times in the 1970s, which is particularly relevant with the recent news that McLaren-Honda F1 driver Fernando Alonso will sit out the Monaco Grand Prix next month to make his debut at the Indianapolis 500 with Andretti Autosport in a Dallara-Honda.
Sports cars, like the Can-Am cars and other open-top prototypes, can be distinguished in that they have covered wheels, usually with fenders of varying effectiveness. If you want to nail things down a little more, sports car prototypes have always been required to have a second seat or at least room (theoretically) for a second seat. Above is an Alfa Romeo 8C 2300 touring car, which carried the same running gear as the single-seater above. However, as you can see from this photo snapped at the famous Mille Miglia rally in the 1930s, the touring version had a second seat and sculpted fenders that, while probably not effective at keeping wheels from touching in wheel-to-wheel contests, still differentiated from the grand prix car.
Just as F1 drivers drove at Indianapolis, so too did open-wheel drivers race sports cars. Mario Andretti racked up a Formula 1 championship and an Indy 500 win in his career, but he also drove a Ford GT40 at the 24 Hours of Le Mans in 1966 and 1967 (Pro tip: If a car has a roof like the GT40, it’s a sports car). The GT40s had the pace, but Mario’s Ford didn’t hold up either year. Andretti just came up short for a Le Mans win by a single lap in 1995 while co-driving an open-top, Porsche-powered Courage (Pronouned “Coo-rahj”) prototype like the one above. A.J. Foyt, however, holds the distinction of winning Le Mans in a GT40 and a taking the victory at the Indy 500 (four times). Just for giggles, Foyt and Andretti also each won the Daytona 500.
1950s: Smooth Moves
1950s Open-wheel: Maserati 250F
The years following World War II found little time or economic viability for racing in Europe, but the founding of an official world-class championship called Formula 1 spurred automakers back to competition in the 1950s. Race car design here focused on smooth, drag-reducing bodies over basic tubular ladder frames. That gave rise to aesthetically pleasing, curvy race cars. The Maserati 250F typified this era and drivers like Sterling Moss and Juan Manuel Fangio (above) racked up several wins for Maserati, first with the inline-six version and later with a 3.0-liter V12. You’ll notice the obvious lack of fenders and an airplane-style cockpit that wraps mostly around Fangio in the photo.
1950s Open-Wheel: Kurtis-Kraft Offenhausers
The cars that raced at Indianapolis, generally called “Indy Roadsters,” looked similar to contemporary F1 cars with a long, curved hood and a contoured gas tank inside the rear bodywork. Kurtis-Kraft borrowed much of their design, debuted in 1948, from pre-war European racers. What they added, however, was the 270 cubic-inch Offenhauser, a four-cylinder engine used at Indy in various guises for more than 40 years. With the block and head all machined from one piece of iron, the Offy made horsepower from high compression and could run happily for hours every day and twice on Sundays. Like the Maserati, the wheels are uncovered, though the single-seat “cabin” has a very low beltline compared to the Maserati above.
1950s Sports Car: Jaguar D-Type
After finding commercial success with their XK120 roadster, Jaguar pushed their open-top designs to their pinnacle, the XKD. Better known as the D-Type, this might be the high point of ‘50s aerodynamic styling: the D-Type is all smooth lines with a rudimentary rollhoop and fighter plane-style fairing behind the driver. Among the innovations was a clean underbody design to reduce drag on the long Mulsanne straight at Le Mans. D-Type won three consecutive times at Le Mans from 1955 to 1957. The D-Type carries unmistakably bulging fenders and the second seat sits apart from the driver’s side with a separate windscreen for each side.
1960s Less Is Far, Far More
1960s F1/IndyCar car: Lotus 25
Two things stand out from this decade of F1 and the Lotus 25 and its Lotus 29 cousin define both of them. The Cooper Climax F1 car justified an engine placed between the axles for high-performance cars with the 1959 Formula 1 championship. Not only do the wheels stick out, they’re also moved farther from the minimalist bodywork with exposed suspension. The pedals on this car are basically at the front axle, just inches from the small radiator in the nose. British race car builder Colin Chapman’s Lotus 25 was an incredibly tiny race car that housed the 1.5-liter V8 that fit F1 regulations of the time. Lotus later modified their F1 design to accept an 255 cubic-inch aluminum Ford V8 based on the Fairlane Thunderbolt’s 260 to run at Indianapolis, coming out with a win in 1965 for Lotus racing legend Jim Clark. Clark was later killed in a similarly designed Lotus Formula Two car at Hockenhrimring in Germany in 1968. Racing has always taken a toll.
1960s Sports Car: Lola T70
In the mid-1960s, the Sports Car Club of America introduced a new race series, the Canadian-American Challenge Cup. Can-Am basically was an open formula and were probably the closest thing to modern prototype racing. Unlike Le Mans, manufacturers didn’t have to build street-car “homologation” versions, so the builders went nuts. Chassis from sports-racer specialists like Lola—whose Eric Broadley built the precursor for the Ford GT40, as well—carried over the minimalist ideas of Colin Chapman and others, then crammed the biggest V8s they could behind the driver of the open-top T70. Like the D-Type above, you can’t miss the flared fenders with the rear fenders featuring air intakes. Around this time, the second seat became a vestigial item; you could theoretically fit a second very-small human next to the driver if comfort and/or safety weren’t a priority.
1970s Downforce At Last!
1970s F1/IndyCar car: McLaren-Ford M23 and Ferrari 312
Experiments with downforce had started sporadically going back to the late 1950s with sprint cars, but things ramped up in the 1970s. The general idea was that teams started to figure out more aerodynamics that were more complex than making cars look like an airplane wing in profile. In fact, that aerofoil design had nasty tendency to lift the rear wheels at high speeds. However, a wedge-shaped car would use the wind at high speed to push the car down into the ground. The F1 film Rush features two of these wedge-designed cars with some large rudimentary wings, the McLaren M23 and Ferrari 312T. Both were F1 cars, but Indy design had similar aero and a wedge profile.
1970s sports car: Matra-Simca MS670
Can-Am came to an end by the 1970s, by which time the cars like the McLaren M8F and Porsche 917/K were basically entire wedges that enclosed the massive tires. The aerodynamic designs in Europe still favored low drag because Le Mans—a track that rewarded higher top speeds—was still the ultimate prize. However, cars like the howling V12 French Matra-Simca still were generally wedge-shaped. Large rear wings tacked kept the Matra’s the rear wheels on the ground. The boxy fenders looks a bit strange today—to say nothing of the “alarmed fish” nose of the Matra—but they house the wheels just the same. Again, there’s room for a seat next to the driver, but you couldn’t get more than a gallon of milk if you needed some 500-horsepower grocery-gettin’.
1990s And Beyond: Begin Modernity
1990s F1/IndyCar car: Penske PC-23/Mercedes
By the 1990s, open-wheel race cars had begun developing aerodynamics from big front and rear wings along with “ground effects,” also known as the Venturi effect. Basically, the underbody design could “suck” the car to the ground ground to create additional downforce that also minimized drag. The 1994 Penske chassis was perhaps not the best-designed in the field, but it might be one of the most famous of the last 50 years at Indianapolis thanks to The Engine, an Ilmor-built and Mercedes-branded beast that steamrolled the field. The front wings on these Indy aeros were (and still are) small to minimize drag while creating just enough front grip to bite in the corners. Formula 1 design of the era, like the McLaren MP4/8 made famous by Ayrton Senna, had similar design principles but used bigger wings to generate higher levels of downforce.
2000s sports car: Audi R10
Sports car prototypes largely moved away from open-top cars for several years, but the introduction of the Le Mans Prototype (LMP) class in the late 1990s found Audi with a fresh approach. The R8 featured an open cockpit, a 3.6-liter twin-turbo V8, and many modular parts that let the Audi crews replace just about anything—famously including the entire gear stack in the transmission—on the car in a handful of minutes. That R8 design managed five wins at Le Mans, the most ever for a single model of car. Audi followed that up with the R10 TDI (above) with a monstrous 5.5-liter twin-turbo diesel V12 and F1-inspired aerodynamics (though still with closed wheels). Audi dominated Le Mans with the diesel R10, R15, and R18 LMP cars, picking up the first-ever diesel win at Le Mans in 2006 and then adding another seven oil-burner victories. Audi left sports car racing at the end of 2016, taking with them an astounding record over 18 appearances at Le Mans with 13 overall victories and podiums in every single Le Mans in which they competed.
You made it to the end! Here’s a bonus photo that Larry Chen shot at the Long Beach Grand Prix of a Can-Am car undergoing some work. You can see the two-seat configuration pretty clearly when it’s naked. They’re surprisingly small underneath the bodywork…almost like an F1 car with fenders. If you want to learn more, I highly recommend Cyril Posthumus’ books Classic Racing Cars and Classic Sports Cars; they’re very informative with great cutaways of most cars.