Lotus 25

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The Lotus 25 was a Formula 1 racing car of the British manufacturer Lotus. He was the first Formula 1 car that had a monocoque, and is considered a milestone in racing history, who revolutionized the formula 1. The 25 was initially reserved for the Lotus factory team. 1963 won the factory driver Jim Clark with his driver and Lotus both the Constructors' World Championship.

Construction

A special feature of the Lotus 25 was its monocoque structure. Similar concepts had other manufacturers repeatedly been realized since 1950, including the Jaguar D-Type 1954 and Marcos with the GT 1959. In Formula 1, there was such a design, however, until the early 1960s not. Lotus founder Colin Chapman took the concept of the monocoque generally considered by Marcos; Observers see a significant structural similarity of Marcos and the Lotus monocoque.

The Lotus 25 was like the Marcos GT a chassis in shell construction, which, however - was not made ​​of plywood, but is made of aluminum - unlike Marcos. The chassis was a net weight of 30 kg very easily. The body was made ​​of plastic. The monocoque construction caused despite low weight, very high strength of the chassis, on the one hand, increased security and on the other hand improved the handling in bends. The engine was enclosed in a mesh ear - steel frame. This led to an almost lying seating position of the driver, nicknamed the "bathtub " brought the car and Jim Clark initially met with little enthusiasm. The chassis was similar to that of the Lotus 24 at the front axle upper control arm were implemented as a rocker, which operated the internal spring and shock absorber unit and installed delta wishbones. The rear axle was down from a double wishbone and trailing arms with outboard springs and dampers. These rack & pinion steering and disc brakes were front and rear. Wheels size: 15 × 5.5 -inch front, 15 × 8 inch rear.

The 25 has been used over the years with different engine-transmission combinations. The Lotus factory team used 1962-1965 Coventry - Climax - FWMV engines (90 °) with eight cylinders. Displacement was ³ at 1497 cm. From this, the engine developed 190 hp at 10,000 rpm. Used for power transmission along a Lotus lying five-speed transmission from ZF (type 5DS10 ), which was positioned on the rear axle, and a two- disc sintered metal clutch. The top speed of this version was about 250 km / h

In addition to the work team and the private Reg Parnell Racing team continued intermittently type a Lotus 25. The team took an eight-cylinder engine from BRM (Type P56 ) and a five-speed gearbox from Hewland.

Race Results in Formula 1

Lotus retained the first 25 of his own works team. Not until 1964 that came with Reg Parnell Racing a private team into the possession of two Lotus 25 Parnell put the car almost continuously from one to the spring of 1967. For other private teams the Lotus 25 appeared only sporadically.

Works team

1962

The Lotus 25 debuted at the first World Cup race 1962 in the Netherlands. Initially, only Jim Clark drove the new car, while his teammate Trevor Taylor began an older Lotus 24. For the French Grand Prix, a second 25 was ready: Clark received the new chassis (R2 ), while Taylor took over the previously driven by Clark car ( R1).

When Renne debut of the Lotus 25 at Zandvoort Clark fell after a long battle with Graham Hill in second position due to a coupling defect from. The race for the Grand Prix of Belgium won before Graham Clark and Phil Hill. The second victory in a Lotus 25 Clark won the Grand Prix of Great Britain. His third victory came at the U.S. Grand Prix at Watkins Glen. At the end of the season was Clark with 30 points behind Graham Hill Vice World Champion and behind Lotus BRM also second in the Constructors' World Championship.

1963

1963 won the combination Clark / Lotus 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 was a revised front suspension and 13- inch wheels. In the summer of the same year the model was replaced by the successor Lotus 33. Until then, Clark won two of his three wins this year on a Lotus 25

Reg Parnell Racing

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

1964, Chris Amon and Mike Hailwood regular driver of the team, in a race came Hailwood Peter Revson at the point where. Amon was fifth at the Grand Prix of the Netherlands, Hailwood sixth in the opening race in Monaco. Apart from that, there were only five other target arrivals, of which Hailwood eighth place in Austria was the best. In the other race, the team suffered from the unreliability of the BRM engine, five times led to a technical failure.

1965, Reg Parnell Racing is the only team that still started a Lotus 25. The work team was already switched to the Lotus 33, which in turn was initially not the customer teams. In this year were with Richard Attwood and Innes Ireland, two former Lotus factory driver the regular drivers for Reg Parnell. Next to them denied Chris Amon and Mike Hailwood and two Tony Maggs one race apiece. It was in this year ten stage finishes for the team, but not in the points.

1966 was the first year of the so-called three - liter formula: For the first time were aspirated engines with a displacement up to 3.0 liters approved. Parnell was none of the new engines available, so the team retained the combination of Lotus 25 and BRM engine throughout the season. However BRM pierced the small eight-cylinder in the course of the year to 2.0 liters. Parnell got this engine in the spring of 1966. During this season only Mike Spence drove for Reg Parnell. He also was a former Lotus factory driver. He fell in nine races out of seven times, twice - in the Netherlands and in Italy - he came in fifth place finish.

For the 1967 season Parnell earned two previous chassis of BRM. The company's five -year-old Lotus 25 was only used twice this year: At the opening race in South Africa Piers Courage went with him at the start, but did not finish. In the Netherlands, Chris Irwin drove the car, finishing in seventh place. That was the last Formula 1 race a Lotus 25

Rob Walker Racing

The British private Rob Walker Racing Team placed at the South African Rand Grand Prix in December 1965 a Lotus 25 with 1.5 liter large Climax engine for Jo Bonnier one. Bonnier fell in the 19th round due to a defective radiator prematurely.

Formula 2

The seventh and final frame 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.

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