McLaren M20
Encyclopedia
The McLaren M20 was a sports prototype
developed by McLaren for the 1972 season
of the Canadian-American Challenge Cup. It served as a replacement for the team's M8Fs, but it later became the final Can-Am design created by McLaren before the team left the series after failing to secure the 1972 championship title. M20s continued to be entered by private teams
until the Can-Am championship was canceled at the conclusion of the 1974 season
. McLaren driver Denny Hulme
won two races during the 1972 season while Scooter Patrick won a single event in 1974 with a privately entered M20.
and Peter Revson
, more comfort during races. The M8F, as with previous McLaren sports cars, featured a large radiator
mounted in the nose of the car, through which air was drawn from openings in the nose, and exited upwards over the open cockpit. McLaren designers Gordon Coppuck and Tyler Alexander devised a solution to this heat problem by using two radiators, one each mounted on either side of the cockpit, and drawing air from the side of the bodywork. This meant that hot air exiting the radiator no longer passed over the cockpit, and decreased fatigue on the drivers.
With a radiator no longer housed in the nose of the car, McLaren designs were free to redesign the nose for better aerodynamic efficiency
. This resulted in the addition of an adjustable airfoil
between the front wheel fenders which increased the downforce
on the front end of the car, leading to increased grip while cornering. The new radiator design also required a redesign of the fuel tank
s within the car. The new tanks for the M20 were compacted around the cockpit and designed to flow from the outward tanks into the central tank so that as fuel was burned off during the race, it would not affect the weight distribution
of the car.
The engine of the M20 was once again a Chevrolet
V8 engine
, increased in displacement
to 509 cubic inch and producing approximately 750 horsepower
. Attached to the engine was a Hewland
Mk II gearbox, mounted behind the engine rather than between the engine and cockpit as competitors Porsche
and Alfa Romeo
used. The fiberglass
bodywork attached to the aluminium
chassis was similar to the M8F, maintaining the "Coke bottle" design, but with the addition of ducting on the side to feed the radiators. Brake
s were developed in conjunction with Lockheed
. Improving on the recently developed cross-drilled brakes from the previous season, grooves were machined into the discs to prevent outgassing. Goodyear remained as the team's official tire supplier.
In total, three M20s were built by McLaren in 1972. Unlike previous McLarens, no customer variants were developed for private teams
prior to McLaren leaving the Can-Am series, although all three cars were eventually sold to other teams.
was able to achieve victory after some tire difficulties, beating Porsche
's brand new turbocharged
917/10
. Further problems appeared at Road Atlanta
, where aerodynamics led to Hulme's car becoming airborne and flipping while following closely behind one of the Porsches. Although Hulme's car was destroyed and had to be replaced by the third M20, Denny was quickly able to recover and earned his second victory of the season at Watkins Glen International
, followed immediately by Revson in the other McLaren. Porsche earned their second victory in the next round, aided by rain on race day.
After maintaining a close battle with Porsche in the first four races, McLaren saw the rest of the 1972 championship hopes slip away as numerous mechanical problems, mostly related to their Chevrolet
motors, left them unable to finish several events. Although Hulme earned two second place finishes at Edmonton
and Riverside
, it was no match for Penske
-Porsche
driver George Follmer
. Hulme was able to maintain second place over the trouble season, but earned only half the points total that Follmer amassed; Revson meanwhile was classified sixth in the standings. After failing to secure the Can-Am Championship for the first time since 1966, team owner Teddy Mayer
decided to concentrate the company on Formula One
and USAC IndyCar
s, leaving the Can-Am series behind.
After McLaren no longer had use for the M20s, all three (including Hulme's rebuilt car) were sold to separate teams. Roy Woods Racing purchased one car for driver David Hobbs to continue campaigning in Can-Am, while Fred Corbett (under the guise of Commander Motor Homes) purchased a car initially for Mario Andretti
, who was later replaced by John Cannon. Corbett's M20 was modified to add a turbocharger in an attempt to better match Porsche's further improved car, the 917/30
. The third M20 was sold to the German Felder Racing Team for driver Helmut Kelleners
, who used it in the European Interserie
championship.
Although none of the M20s were successful in 1973, the cars would once again be victorious during 1974. Roy Woods' M20 was sold to Herb Caplan's U.S. Racing for the 1974 Can-Am season
, with driver Scooter Patrick. Patrick successfully won the final race of the season at Road America
after the dominating Shadows
suffered mechanical problems. The Can-Am series would be cancelled shortly thereafter. Meanwhile, Kelleners's M20 was able to win in an Interserie event at the Nürburgring
en route to finishing second in the drivers championship.
Sports prototype
A sports prototype, also referred to as simply a prototype, is a form of racing car that is used as a top category in sports car racing. These purpose-built racing cars differ from street-legal and production-based racing cars that also compete in sports car racing.Prototype racing cars have...
developed by McLaren for the 1972 season
1972 Can-Am season
The 1972 Canadian-American Challenge Cup season was the seventh season of the Can-Am auto racing series. It consisted of FIA Group 7 racing cars running two-hour sprint events...
of the Canadian-American Challenge Cup. It served as a replacement for the team's M8Fs, but it later became the final Can-Am design created by McLaren before the team left the series after failing to secure the 1972 championship title. M20s continued to be entered by private teams
Privateer (motorsport)
In motor sport, a privateer is usually an entrant into a racing event that is not directly supported by an automobile manufacturer. Privateers teams are often found competing in rally and circuit racing events, and often include competitors who build and maintain their own vehicles...
until the Can-Am championship was canceled at the conclusion of the 1974 season
1974 Can-Am season
The 1974 Canadian-American Challenge Cup season was the ninth and final season of the original Can-Am auto racing series. It consisted of FIA Group 7 racing cars running half hour Sprint races followed by hour long Cup races...
. McLaren driver Denny Hulme
Denny Hulme
Denis Clive "Denny" Hulme, OBE was a New Zealand racing driver, the 1967 Formula One World Champion for the Brabham team....
won two races during the 1972 season while Scooter Patrick won a single event in 1974 with a privately entered M20.
Development
When McLaren designed their replacement for 1971's M8Fs, one of the team's primary goals was to improve the cooling structure of the cars in order to allow their racing drivers, Denny HulmeDenny Hulme
Denis Clive "Denny" Hulme, OBE was a New Zealand racing driver, the 1967 Formula One World Champion for the Brabham team....
and Peter Revson
Peter Revson
Peter Jeffrey Revson was an American race car driver who had successes in Formula One and the Indianapolis 500.-Background:Peter Revson was born in New York City, the son of Julie and Martin Revson....
, more comfort during races. The M8F, as with previous McLaren sports cars, featured a large radiator
Radiator
Radiators are heat exchangers used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in automobiles, buildings, and electronics...
mounted in the nose of the car, through which air was drawn from openings in the nose, and exited upwards over the open cockpit. McLaren designers Gordon Coppuck and Tyler Alexander devised a solution to this heat problem by using two radiators, one each mounted on either side of the cockpit, and drawing air from the side of the bodywork. This meant that hot air exiting the radiator no longer passed over the cockpit, and decreased fatigue on the drivers.
With a radiator no longer housed in the nose of the car, McLaren designs were free to redesign the nose for better aerodynamic efficiency
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
. This resulted in the addition of an adjustable airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
between the front wheel fenders which increased the downforce
Downforce
Downforce is a downwards thrust created by the aerodynamic characteristics of a car. The purpose of downforce is to allow a car to travel faster through a corner by increasing the vertical force on the tires, thus creating more grip....
on the front end of the car, leading to increased grip while cornering. The new radiator design also required a redesign of the fuel tank
Fuel tank
A fuel tank is safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled or released into an engine...
s within the car. The new tanks for the M20 were compacted around the cockpit and designed to flow from the outward tanks into the central tank so that as fuel was burned off during the race, it would not affect the weight distribution
Weight distribution
Weight distribution is the apportioning of weight within a vehicle, especially cars, airplanes, and trains.In a vehicle which relies on gravity in some way, weight distribution directly affects a variety of vehicle characteristics, including handling, acceleration, traction, and component life...
of the car.
The engine of the M20 was once again a Chevrolet
Chevrolet
Chevrolet , also known as Chevy , is a brand of vehicle produced by General Motors Company . Founded by Louis Chevrolet and ousted GM founder William C. Durant on November 3, 1911, General Motors acquired Chevrolet in 1918...
V8 engine
V8 engine
A V8 engine is a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft....
, increased in displacement
Engine displacement
Engine displacement is the volume swept by all the pistons inside the cylinders of an internal combustion engine in a single movement from top dead centre to bottom dead centre . It is commonly specified in cubic centimeters , litres , or cubic inches...
to 509 cubic inch and producing approximately 750 horsepower
Horsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
. Attached to the engine was a Hewland
Hewland
Founded by Mike Hewland in 1957, Hewland is a British engineering company specialising in racing-car gearboxes. Hewland was the first company to manufacture a bespoke racing-car gearbox....
Mk II gearbox, mounted behind the engine rather than between the engine and cockpit as competitors Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
and Alfa Romeo
Alfa Romeo
Alfa Romeo Automobiles S.p.A. is an Italian manufacturer of cars. Founded as A.L.F.A. on June 24, 1910, in Milan, the company has been involved in car racing since 1911, and has a reputation for building expensive sports cars...
used. The fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
bodywork attached to the aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
chassis was similar to the M8F, maintaining the "Coke bottle" design, but with the addition of ducting on the side to feed the radiators. Brake
Brake
A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes....
s were developed in conjunction with Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
. Improving on the recently developed cross-drilled brakes from the previous season, grooves were machined into the discs to prevent outgassing. Goodyear remained as the team's official tire supplier.
In total, three M20s were built by McLaren in 1972. Unlike previous McLarens, no customer variants were developed for private teams
Privateer (motorsport)
In motor sport, a privateer is usually an entrant into a racing event that is not directly supported by an automobile manufacturer. Privateers teams are often found competing in rally and circuit racing events, and often include competitors who build and maintain their own vehicles...
prior to McLaren leaving the Can-Am series, although all three cars were eventually sold to other teams.
Racing history
Two new McLaren M20s made their debut at Mosport Park, the inaugural round of the 1972 season. The #5 entry of Denny HulmeDenny Hulme
Denis Clive "Denny" Hulme, OBE was a New Zealand racing driver, the 1967 Formula One World Champion for the Brabham team....
was able to achieve victory after some tire difficulties, beating Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
's brand new turbocharged
Turbocharger
A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...
917/10
Porsche 917
The Porsche 917 is a racecar that gave Porsche its first overall wins at the 24 Hours of Le Mans in 1970 and 1971. Powered by the Type 912 flat-12 engine of 4.5, 4.9, or 5 litres, the 917/30 variant was capable of a 0- time of 2.3 seconds, 0– in 5.3 seconds, and a top speed of over .There are 6...
. Further problems appeared at Road Atlanta
Road Atlanta
Road Atlanta is a 2.54-mile road course located just north of Braselton, Georgia, USA. The facility is utilized for a wide variety of events, including professional and amateur sports car and motorcycle races, racing and driving schools, corporate programs and testing for motorsports teams...
, where aerodynamics led to Hulme's car becoming airborne and flipping while following closely behind one of the Porsches. Although Hulme's car was destroyed and had to be replaced by the third M20, Denny was quickly able to recover and earned his second victory of the season at Watkins Glen International
Watkins Glen International
Watkins Glen International is an auto race track located near Watkins Glen, New York, at the southern tip of Seneca Lake. The facility is owned by International Speedway Corporation...
, followed immediately by Revson in the other McLaren. Porsche earned their second victory in the next round, aided by rain on race day.
After maintaining a close battle with Porsche in the first four races, McLaren saw the rest of the 1972 championship hopes slip away as numerous mechanical problems, mostly related to their Chevrolet
Chevrolet
Chevrolet , also known as Chevy , is a brand of vehicle produced by General Motors Company . Founded by Louis Chevrolet and ousted GM founder William C. Durant on November 3, 1911, General Motors acquired Chevrolet in 1918...
motors, left them unable to finish several events. Although Hulme earned two second place finishes at Edmonton
Edmonton International Speedway
Edmonton International Speedway, also known as Speedway Park, was a multi-track auto racing facility located in the present Cumberland and Hudson neighborhoods of Edmonton, Alberta, Canada. The facility featured a ¼ mile drag strip, a 14-turn road course, and a ¼ mile short oval...
and Riverside
Riverside International Raceway
Riverside International Raceway was a race track or road course in Riverside, California. The track was in operation from September 22, 1957, to July 2, 1989...
, it was no match for Penske
Penske Racing
Penske Racing is a racing team that competes in the IndyCar Series and NASCAR. They also previously competed in road racing, and Formula One. Penske Racing is a division of Penske Corporation, and is owned and chaired by Roger Penske...
-Porsche
Porsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
driver George Follmer
George Follmer
George Follmer is a retired American race car driver, and one of the most successful road racers of the 1970s. He was born in Phoenix, Arizona....
. Hulme was able to maintain second place over the trouble season, but earned only half the points total that Follmer amassed; Revson meanwhile was classified sixth in the standings. After failing to secure the Can-Am Championship for the first time since 1966, team owner Teddy Mayer
Teddy Mayer
Edward Everett "Teddy" Mayer was an American motor racing entrepreneur who was successful in several categories of racing, including Formula One and IndyCars....
decided to concentrate the company on Formula One
Formula One
Formula One, also known as Formula 1 or F1 and referred to officially as the FIA Formula One World Championship, is the highest class of single seater auto racing sanctioned by the Fédération Internationale de l'Automobile . The "formula" designation in the name refers to a set of rules with which...
and USAC IndyCar
American Championship Car Racing
Since 1916 there has been a recognized United States national automobile racing National Championship for drivers of professional-level, single-seat open wheel race cars. The championship has been under the auspices of several different sanctioning bodies since 1909. Since 1911, the Indianapolis...
s, leaving the Can-Am series behind.
After McLaren no longer had use for the M20s, all three (including Hulme's rebuilt car) were sold to separate teams. Roy Woods Racing purchased one car for driver David Hobbs to continue campaigning in Can-Am, while Fred Corbett (under the guise of Commander Motor Homes) purchased a car initially for Mario Andretti
Mario Andretti
Mario Gabriele Andretti is a retired Italian American world champion racing driver, one of the most successful Americans in the history of the sport. He is one of only two drivers to win races in Formula One, IndyCar, World Sportscar Championship and NASCAR...
, who was later replaced by John Cannon. Corbett's M20 was modified to add a turbocharger in an attempt to better match Porsche's further improved car, the 917/30
Porsche 917
The Porsche 917 is a racecar that gave Porsche its first overall wins at the 24 Hours of Le Mans in 1970 and 1971. Powered by the Type 912 flat-12 engine of 4.5, 4.9, or 5 litres, the 917/30 variant was capable of a 0- time of 2.3 seconds, 0– in 5.3 seconds, and a top speed of over .There are 6...
. The third M20 was sold to the German Felder Racing Team for driver Helmut Kelleners
Helmut Kelleners
Helmut Kelleners is a former race driver from Germany, winning the Spa 24 Hours and the 24 Hours Nürburgring.His son Ralf Kelleners is also a race car driver.- Career:* Spa 24 Hours* Joest Racing* 1000 km Nürburgring* 24 Hours Nürburgring...
, who used it in the European Interserie
Interserie
Interserie is the name of a European-based motorsport series started in 1970 that allows for a wide variety of racing cars from various eras and series to compete with less limited rules than in other series....
championship.
Although none of the M20s were successful in 1973, the cars would once again be victorious during 1974. Roy Woods' M20 was sold to Herb Caplan's U.S. Racing for the 1974 Can-Am season
1974 Can-Am season
The 1974 Canadian-American Challenge Cup season was the ninth and final season of the original Can-Am auto racing series. It consisted of FIA Group 7 racing cars running half hour Sprint races followed by hour long Cup races...
, with driver Scooter Patrick. Patrick successfully won the final race of the season at Road America
Road America
Road America is a road course located near Elkhart Lake, Wisconsin on Wisconsin Highway 67. It has hosted races since the 1950s and currently hosts races in the NASCAR Nationwide Series , American Le Mans , SCCA Speed World Challenge Series, ASRA, and AMA Superbike series.- Current track and...
after the dominating Shadows
Shadow Racing Cars
Shadow Racing Cars was a Formula One and sports car racing team, founded and initially based in the United States although later Formula One operations were run from Britain.-1971-1972: Early years in CanAm series:...
suffered mechanical problems. The Can-Am series would be cancelled shortly thereafter. Meanwhile, Kelleners's M20 was able to win in an Interserie event at the Nürburgring
Nürburgring
The Nürburgring is a motorsport complex around the village of Nürburg, Germany. It features a modern Grand Prix race track built in 1984, and a much longer old North loop track which was built in the 1920s around the village and medieval castle of Nürburg in the Eifel mountains. It is located about...
en route to finishing second in the drivers championship.