B. S. Cunningham Company

Cunningham C-1

The first product of the new company was the Cunningham C-1 roadster. On the design team were Cunningham, Walters, G. Briggs Weaver and Blake.[11] Only one C-1 was built, with serial number 5101.[8] The car was completed in late 1950, and is generally listed as from the 1951 model year.[12]

The chassis was made of 3 in (76 mm) steel tubing with a central X-brace.[9] The rear suspension was a custom-made De Dion tube. The tires were mounted on knock-off wire wheels. Wheelbase was 105 in (2,667 mm), and the track front and rear was 58 in (1,473 mm). The engine was a 331 cu in (5,424 cc) Cadillac V8.

The C-1 was used in practice at Le Mans, but did not race.[8] In 1951 it appeared at the Mount Equinox hillclimb, where it finished fourth driven by John Fitch.[13]

Cunningham C-2R

The C-1 was followed by the C-2, of which three were built, all to racing specifications and so called C-2R. The C-2R's front suspension used Ford parts, while the rear suspension had Oldsmobile springs and the brake system used Cadillac components. Unable to secure a supply of the Cadillac engine, Cunningham substituted a version of the Chrysler FirePower V8 in the C-2R.

The C-2R debuted at Le Mans in 1951.[14][15] All three cars were entered, driven by teams John Fitch and Phil Walters, George Rand and Fred Wacker Jr., and Briggs Cunningham and George Huntoon. The best finish was eighteenth, for the Fitch/Walters car.

1953 Cunningham C-3 Cabriolet

To have his namesake cars homologated as a manufacturer for Le Mans, Cunningham undertook to build 25 examples of the C-3 road car.[16][10]

The C-3 also used the 331 cu in (5,424 cc) Chrysler FirePower V8, but with a new intake manifold with four Zenith 1-bbl carburetors, and a dual exhaust system. Power was raised to 220 hp (164.1 kW) from the factory version's 180 hp (134.2 kW).

Two different transmissions were offered; a three-speed manual from Cadillac, or Chrysler's Presto-Matic semi-automatic fluid-coupled two-speed with electric overdrive, for an effective selection of four forward ratios.

The C-3's large-diameter tube chassis was similar to that of the earlier C-2, but the C-2's De Dion tube gave way to a coil-spring live axle located by upper and lower trailing arms on each side.[17]

Two pre-production cars similar in appearance to the C-2Rs were completed in West Palm Beach; a roadster with chassis number 5205, and a coupe with chassis number 5206X. A third chassis, number 5206, was sent to the workshops of carrozzeria Vignale in Turin, Italy, where it received a new coupe body styled by designer Giovanni Michelotti, then working at Vignale.[11][18][19][20] The factory considered chassis 5206 the official prototype, and subsequent cars received the Michelotti body style.

Twenty-seven C3s were built. One reference reports eighteen coupes and nine convertibles.[16] Others report twenty coupes and five convertibles with bodies by Vignale, plus the two cars bodied at the West Palm Beach factory.[21][11] Initially priced at US$9,000 ($101,469 in 2022 dollars [22]), the cost of a C-3 rose to US$15,000 ($169,115 in 2022 dollars [22]) by 1951.[11]

The New York Museum of Modern Art named the C-3 Continental Coupé one of the "10 Best Contemporary Automobiles".[23][16][24]

Cunningham C-4R

By the time development of the C-4R started, Bill Frick had left the company. The new car was designed by Weaver.[25] During the car's development the team was also joined by mechanic and bodyman Herbert "Bud" Unger, who did the bodywork for the C-4R and C-5R.[26] The C-4R was 16 in (406 mm) shorter, 4 in (102 mm) narrower, and 900 lb (408.2 kg) lighter than the C-2R. The De Dion tube rear suspension was also gone. Although a new independent rear suspension of Cunningham's own design was touted early in the car's development, it seems that later a live axle on coil springs was substituted.[27][28] Also new was a Cunningham-designed 5-speed manual transmission. Brakes were Chrysler Al-Fin units twenty percent larger than those on the C-2Rs, and the earlier car's wire wheels had been replaced with knock-off Halibrand magnesium wheels.[28]

To provide Cunningham's cars with more power from their FirePower engine, Chrysler engineers John Platner and Don Moore began an engine development project called A311.[29][30] In its ultimate form the A311 engine used a gear-driven, high-lift long-duration camshaft, special pistons, roller tappets, dual valve springs, special pushrods, Hilborn fuel injection with tuned intake stacks, and a compression ratio of 12:1. Output was estimated to have been 300 hp (223.7 kW), high enough to flex the block and require a stiffening plate between the bottom of the block and the sump. Cunningham used a carbureted version of the engine, and had to reduce the compression ratio to 7.5:1 to accommodate the fuel available to the teams at Le Mans.

Two C-4R roadsters were built, as well as a single coupe with truncated bodywork designed in collaboration with German aerodynamicist Wunibald Kamm that was designated the C-4RK.[2]

During practice at the 1952 24 Hours of Le Mans the new transmissions caused problems, and were replaced with 3-speeds. In the end the C-4R of Briggs Cunningham and Bill Spear finished fourth overall.[31] At the 1953 24 Hours of Le Mans a C-4R roadster finished seventh, and the C-4RK coupe tenth. The C-4Rs returned to La Sarthe in 1954 to take third and fifth.

A C-4R won the 1953 12 Hours of Sebring.

In 1954, a C-4R driven by Briggs Cunningham and Sherwood Johnston finished sixth in the 12 Hours of Reims.[32]

Cunningham C-5R

A single all-new C-5R was prepared for the 1953 24 Hours of Le Mans. The front suspension comprised a solid beam axle sprung by torsion bars.[28] This reduced weight by 30 lb (13.6 kg) and allowed the use of 17 in (432 mm) diameter Al-Fin drum brakes mounted inboard of the 16 in (406 mm) wheels.[33][28] At the rear was a live axle on coil springs as on the later C-4Rs.

The engine remained the Chrysler V8, but power had been increased by 10 hp (7.5 kW).[33] A 4-speed transmission from a Fiat truck replaced the earlier 3-speed units.[28]

When the car arrived at Le Mans for the race the French observers named it "Le Requin Souriant" — the smiling shark.[34]

At the end of the 24 Hours Walters and Fitch finished first in class and third overall.

Cunningham C-6R

Primary responsibility for the chassis and body design of the C-6R fell to Unger. Engines considered for the car included a two-stroke inverted V-12 designed by Mercury Marine's Carl Kiekhaefer, and the Ferrari V-12 from the Italian marque's 375 MM.[28]

The engine finally chosen was the 179.5 cu in (2,942 cc) four-cylinder Offenhauser from Meyer & Drake.[35] After consulting with Leo Goossen, the engine's designer, Cunningham's team managed to get power output up to 270 hp (201.3 kW).

The transmission in the C-6R was a four-speed manual by ZF.[36][28]

At the 1955 Le Mans the C-6R retired on lap 202. Second and third gears had failed, and the engine burned a piston, ending the car's run.[35][37]

The car raced at Elkhart Lake a few months later, where the engine failed again. The Offy was then replaced by a Jaguar inline-six engine.