Lotus 25 Race Car

Constructor:	Lotus
Class	Race Car
Designer:	Colin Chapman
Chassis:	Aluminium / steel monocoque
Length:	3556 mm
Width:	1549 mm
Height:	787 mm
Wheelbase:	2311 mm
Mass:	450 kg
Tire:	Dunlop L Racing

The Lotus 25 was a Formula 1 racing car, which was developed by Lotus in 1962 and used by various private teams until 1964

History

The Lotus 25 was a Formula 1 racing car of the British manufacturer Lotus. Pioneering yet another form of ultra-lightweight construction for competition cars, Colin Chapman introduced his "monocoque" Lotus 25 at the Grand Prix d'Europe at Zandvoort. The stressed light-alloymain structure is extremely rigid yet provides more driver and fuel space than the previous multi-tube chassis frame. This was the first Formula 1 car with a monocoque and is considered a milestone in racing history, who revolutionized F1. The 25 was initially the Lotus factory team reserved. In 1963, works driver Jim Clark won the drivers' and lotus drivers' championship with him at the same time as the Constructors' World Championship. 

The Lotus 25 monocoque chassis pioneered a fashioning racing car design. It is light and made an immediate impact when Jim Clark won the Belgian, British and
American GPs. These victories gave Lotus second place in the Manufacturers' Championship for the third year running. This was the pioneer of the monocoque Grand Prix cars and was powered by the Coventry-Climax V-8 engine. It was consistently raced by Team Lotus from its debut at the 1962 Dutch Grand Prix until superseded by the similar, but improved 33 in 1964.The model was used by Jim Clark to win his first World Championship in 1963.

A special feature of the Lotus 25 was its monocoque construction. The Lotus 25 lightweight and rigid construction.Main structure is composed of two D-shaped, rivetted sections which accommodate driver, form the body floor and permit the use of flexible fuel bags within the longerons. Total fuel capacity was increased to 32 gallons (Imp.) by this method of construction, yet driver space was greater. Coventry-Climax V8 engine, transmission, and suspension are attached to a steel sub-frame. Suspension of the Lotus 24 and 25
is virtually identical. Comparable concepts had been implemented repeatedly by other manufacturers since 1950, including Jaguar with the D-Type from 1954 and Marcos with the GT from 1959. In Formula 1, however, such a construction did not exist until the early 1960s. Lotus founder Colin Chapman adopted the concept of the monocoque in the general view of Marcos; Observers see a clear constructive similarity of the Marcos and the Lotus monocoques. 

The Lotus 25 had like the Marcos GT a chassis in shell construction, which, however - unlike the Marcos - was not made of plywood, but made of aluminium. The chassis was very light with a dead weight of 30 kg. The body was made of plastic.  The monocoque construction caused despite its low weight, a very high strength of the chassis, on the one hand, increased safety and on the other hand the driving behaviour of improved cornering. The engine was enclosed in a grid ear steel frame. front suspension by unequal length wishbones and coil spring/damper units mounted within body panelling rear suspension by reversed lower wishbones, single top links, double radius arms, coil spring/damper unThis led to an almost lying seating position of the driver that earned the car the nickname "bath" and initially met with little enthusiasm at Jim Clark. The chassis was similar to that of the Lotus 24. On the front axle, the upper wishbones were designed as rocker arms, which actuated the internal spring and shock absorber unit, as well as a wishbone mounted below. The rear axle consisted below of a triangular wishbone and double trailing arms with external springs and dampers. In addition, there was a rack and pinion steering and disc brakes front and rear. Wheel size: 15 × 5.5 inches at the front, 15 × 8 inches at the rear.

The 25 was used over the years with different engine-gearbox combinations. The Lotus factory team used Coventry Climax FWMV engines (90 °) with eight cylinders from 1962 to 1965. The capacity was 1497 cc. From this, the engine developed 190 hp at 10,000 / min. For power transmission Lotus used a longitudinal five-speed gearbox from ZF (type 5DS10), which was positioned at the rear axle, and a two-disc sintered metal clutch. The maximum speed of this version was about 250 km / h.

In addition to the factory team, the private racing team Reg Parnell Racing used a Lotus 25 at times. The team drove an eight-cylinder engine from BRM (type P56) and a five-speed gearbox from Hewland.

Major Successes
1962:1st (Clark), Belgian GP; 1st (Clark), British GP; 1st (Clark), United States GP ; 2nd (Clark), Mexican GP
1963: 2nd (Clark), Lombank Trophy, Snetterton ; 1st (Clark), Daily Express 1st (Clark),Trophy, Silverstone ;Belgian GP; 1st (Clark), Dutch GP.1st (Clark), French GP; 1st (Clark)',
British GP ; 2nd (Clark), German GP ;1st (Clark), 2nd (Taylor), Cannon Races, Karlskoga; 2nd (Arundell), Mediterranean GP; 1st (Clark), Italian GP; 1st (Clark), Gold cup Race,
Oulton Park; 3rd (Clark), United States GP ; 1st (Clark), Mexican GP ; 1st (Clark), South African GP
1964: 1st (Clark), News of the World Trophy, Goodwood; 3rd (Spence/Arundell), Syracuse GP ; 3rd (Arundell), Aintree ' 200 ' ; 3rd (Arundell), Daily Express Trophy, Silverstone ; 1st (Clark), Dutch GP 1st (Clark), Belgian GP

Formula 1 

Lotus kept the 25 first his own factory team. It was not until 1964, with Reg Parnell Racing, a private team in the possession of two Lotus 25th Parnell used the car almost throughout until the spring of 1967. In other private teams, the Lotus 25 appeared only occasionally.

Factory Team 

1962 

The Lotus 25 debuted at the first world championship round in 1962 in the Netherlands. At first, only Jim Clark drove the new car, while his teammate Trevor Taylor used an older Lotus 24. For the French Grand Prix, a second 25 was ready: Clark got the new chassis (R2) while Taylor took over the car (R1) previously driven by Clark.

In the race debut of the Lotus 25 at Zandvoort Clark fell after a long duel with Graham Hill lying second by a coupling defect. The race for the Belgian Grand Prix won Clark ahead of Graham and Phil Hill. The second victory on a Lotus 25 Clark took the Grand Prix of Great Britain. His third victory followed at the US Grand Prix in Watkins Glen. At the end of the season, Clark also finished second in the Constructors' Championship with 30 points behind Graham Hill and Lotus behind BRM.

1963 

In 1963, the combination Clark / Lotus won seven of the ten World Championship races and thus both the drivers and the Constructors' World Championship.

1964 

For the 1964 Formula 1 season, the Lotus 25 received a modified front suspension and 13-inch wheels. In the summer of the same year the model from the successor Lotus 33 replaced. Until then, Clark won two of his three wins this year on a Lotus 25.

Reg Parnell Racing

The British private team Reg Parnell Racing took over in early 1964 two Lotus 25 and put them until 1967 in Formula 1 World Championship races.

In 1964, Chris Amon and Mike Hailwood were regular drivers of the team, in a race on the site of Hailwood's Peter Revson. Amon finished fifth in the Dutch Grand Prix, Hailwood sixth in the inaugural race in Monaco. Apart from that, there were only five more finish line finishes, of which Hailwood's eighth place in Austria was the best. In the remaining races, the team suffered from the unreliability of the BRM engine, which led to a technical failure five times.

In 1965, Reg Parnell Racing was the only team to use a Lotus 25. The factory team had already switched to the Lotus 33, which in turn was not available to the customer teams at first. This year, two former Lotus factory riders, Richard Attwood and Innes Ireland, were the regular pilots for Reg Parnell. Next to them Chris Amon two and Mike Hailwood and Tony Maggs each ran one race. There were ten final finishes for the team this year, but not in the points.

1966 was the first year of the so-called three-litre formula: For the first time, naturally aspirated engines with a displacement up to 3.0 litres were approved. Parnell did not have any of the new engines available, so the team retained the Lotus 25 and BRM engine combination throughout the season. However, BRM drilled the small eight-cylinder in the course of the year to 2.0 litre capacity. Parnell received this engine in the spring of 1966. This season, only Mike Spence drove for Reg Parnell. He too was a former Lotus factory driver. He was eliminated seven times in nine races and twice in the Netherlands and Italy in fifth place.

For the 1967 season Parnell acquired two previous year's chassis from BRM. The company's five-year-old Lotus 25 was only used twice this year: At the opening race in South Africa went Piers Courage with him at the start, but did not get the finish. In the Netherlands, Chris Irwin drove the car and finished seventh. That was the last Formula One race of a Lotus 25.

Rob Walker Racing 

The British private Rob Walker Racing team put in the South African Rand Grand Prix in December 1965 a Lotus 25 with 1.5 litre Climax engine for Jo Bonnier. Bonnier dropped out early in the 19th round due to a broken radiator. 

Formula 2 

The seventh and last chassis of the Lotus 25 (R7) was rebuilt in 1967 according to the rules of Formula 2. It received a 1.5-liter four-cylinder engine from Cosworth. Mike Spence drove the car in some races for Reg Parnell Racing.