Lotus 33 F1 Race Car

Constructor:	Lotus
Class	F1 Race Car
Designer:	Colin Chapman
Chassis:	Aluminium / steel monocoque
Engine:	V8 Coventry Climax BRM
Length:	140 in
Width:	68 in
Height:	31 in
Wheelbase:	92 in
Weight:	450 kilos
Wheels:	cast magnesium

The Lotus-Climax 25 was a Formula 1 racing car, which was developed by Lotus, built and used from 1964 to 1967 by the British Formula One team.

History

The Lotus 33 was an evolution of the Lotus 25. which appeared in 1964 and differed in detail only. It was used by Jim Clark to win his second World Championship in 1965 and was on certain occasions fitted with the 32-valve V-8 Coventry-Climax engine. Until the appearance of the 49, the car was raced by Team Lotus during 1966-67, with the 2-litre version of the Climax engine and, sometimes, with the 2-litre BRM V-8 unit. The chassis and front and rear suspension have been redesigned to accommodate the new, wider Dunlop tires. From the middle of the season replaced the Lotus 33 25 and 1965 was the dominant vehicle of the Formula 1 World Cup.

For the first season of the new 3-liter formula, the car got the 2-liter V8 engine from Climax as drive. Also, a BRM V8 engine was installed in some 33. Jim Clark was world champion with six wins in 1965 and Lotus secured the constructors' trophy. In 1966, however, the 33 was clearly inferior to Brabham's competition. Although Jim Clark still won the Tasman series, but also the Privateers could celebrate with the 33 only a few successes.

Colin Chapman put his Lotus Engineering company in the forefront of advanced motor racing during the fifties with a series of very lightweight and aerodynamically efficient sports-racing cars. He was expert in building multi-tubular spaceframe chassis of which every single frame component was put to work in either tension or compression. It was this expertise that won him the Vanwall consultancy contract during 1955, and in 1956 he introduced his own prototype single-seater Lotus, a front-engine device aimed at Formula 2 and using a Coventry Climax F PF four-cylinder engine. In 1960 he took to the mid-engined configuration with the Lotus Type 18, and its performance set the standards of the day, shaking even Cooper's grasp on Formula 1 in non-Championship events, if not in World Championship rounds.

Stirling Moss won the Monaco Grand Prix that season in Rob Walker's private Lotus-Climax 18, and won the Monaco and German Grands Prix in a similar Walker car in 1961. At the end of that year Innes Ireland gave Team Lotus their first Grande Epreuve victory with the much-improved and very sleek Lotus 21 spaceframe chassis car; for 1962 fast-developing Jimmy Clark became the Lotus number one driver, and Chapman devised a new car for him.There had been constant problems with tubular chassis chafing and puncturing the aluminium fuel tanks strapped to them, and the Lotus design team was at this time developing a backbone girder chassis for a new road car—which eventually emerged as the Elan.

Tests showed this slender backbone to be immensely rigid, and Colin visualized widening it until there was room for a driver to sit between its side sections, and boxing in those side sections to create fuel tank space. Thus, the epochal Lotus 25 was evolved, but it was a new idea and to hedge his bets Chapman also laid down a spaceframe alternative to pick up the latest all-independent suspension system developed for the Lotus 25.
The Lotus 25 chassis was formed in aluminium sheet, fitted over internal sheet bulkheads with not a tube in sight. It looked like an open bathtub in which the driver sat with fuel on each side of him.

The new Coventry Climax FWMV V8 engine was behind his shoulders. The 63 mm x 60mm engine had a displacement of 1498 cc, and produced about 190 bhp at 8500 rpm. Climax engines, incidentally, were now used by most British chassis-constructors, including Brabham, Cooper and Lola; only BRM, Porsche and Ferrari still made not only their own racing car chassis, but also the engines and transmissions.
The Lotus 25 made its debut in the 1962 Dutch Grand Prix and Clark led until suffering transmission troubles. He first won a Grande Epreuve in the car at Spa in Belgium, then won the British and United States Grands Prix. He led most of the way during the South African Grand Prix, but lost the World Championship when his engine lost its oil.
The Type 25 grew up into the wide-typed 200-horsepower Lotus 33 as driven to victory here at Silverstone in 1965 by Jim Clark.
jimmy Clark was virtually unbeatable during 1963 with the Lotus 25, the world's first successful monocoque-chassis Grand Prix car. During an incredible 1963 season, however, the Lotus 25 theme was developed and Jimmy
Clark won a record seven of the year's ten Championship rounds to claim his and Lotus's first world titles. In non-Championship races, Clark and the 25 won five more events. The Lotus 25 was the tap-root of modern racing car design and its immediate derivatives included the Indianapolis Lotus-Ford
29 and 38. These cars turned the Indy establishment away from the Offenhauser roadsters, reminiscent of 1939 Maserati’s, towards the pure performance potential of road-racing-derived modern chassis.
In 1964 the much-improved, big-wheeled Type 33 was introduced by Lotus and with updated 25s saw Clark challenging hard for the Championship yet again, only losing it on the last lap of the last race—in Mexico City. In 1965 Clark took the Championship convincingly in his Lotus-Climax 33s, winning
six races—five consecutively. He also won the Indy 500 in a Lotus-Ford 38 with 4.2-litre V8 engine.

As the Lotus 33s with two-litre engines continued racing in the first two seasons of the new three-litre Grand Prix Formula in 1966—67, so all constructors save Brabham followed the Lotus monocoque lead. Colin Chapman's innovation had succeeded in 1962 where Gabriel Voisin's had failed in 1923.

Major Successes

1964: 1st (Clark), British GP•, 1st (Clark), Solitude GP•, 2nd (Clark), Mediterranean GP
1965 ; 1st (Clark), South African GP ;1st (Spence), Race of Champions, Brands Hatch; 1st (Clark), Syracuse GP ; 1st (Clark), International Trophy, Goodwood ; 3rd (Spence), Daily Express Trophy, Silverstone ; 1st (Clark), Belgian GP ; 1st (Clark), French GP ;1st (Clark), British GP; 1st (Clark), Dutch GP ; 1st (Clark), German GP ; 2nd (Clark), Mediterranean GP ; 3rd
1966: 1st (Spence), South African GP; 3rd (Clark), Dutch GP•, 3rd (Clark), Gold cup Race, Oulton Park
1967: 2nd (G. Hill), Monaco GP in 1967, after the Grand Prix of Monaco , the 33 was replaced by the Lotus 49 .