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Lotus 25

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Lotus 25
CategoryFormula One
ConstructorTeam Lotus
Designer(s)Colin Chapman
PredecessorLotus 21 / Lotus 24
SuccessorLotus 33
Technical specifications
ChassisAluminium monocoque
Suspension (front)Double wishbone, with inboard coilover spring/damper units.
Suspension (rear)Lower wishbone, top link and radius rod suspension, with outboard coilover spring/damper units.
EngineCoventry Climax FWMV, 1496cc, 90° V8
Naturally aspirated, mid-mounted
BRM P56, 1498 cc, 90° V8
Naturally aspirated, mid-mounted
TransmissionZF 5DS10 5-speed manual
TyresDunlop
Competition history
Notable entrantsTeam Lotus
Reg Parnell Racing
Brabham Racing Organisation
Notable driversUnited Kingdom Jim Clark
United Kingdom Trevor Taylor
United Kingdom Mike Spence
New Zealand Chris Amon
United Kingdom Mike Hailwood
United Kingdom Richard Attwood
Debut1962 Dutch Grand Prix
RacesWinsPodiumsPolesF/Laps
4914181418
Constructors' Championships2 (1963, 1965)
Drivers' Championships2 (1963, 1965)
n.b. Unless otherwise stated, all data refer to
Formula One World Championship Grands Prix only.

The Lotus 25 was a racing car designed by Colin Chapman for the 1962 Formula One season.[1][2] It was a revolutionary design, the first fully stressed monocoque chassis to appear in Formula One. In the hands of Jim Clark it took 14 World Championship Grand Prix wins and propelled him to his 1963 World Championship title. Its last World Championship win was at the 1965 French Grand Prix.

It was the first Formula One car to use Esso fuel.[3]

History

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Jim Clark at the 1964 Dutch Grand Prix.
Gerhard Mitter at the 1965 German Grand Prix.
Richard Attwood in Reg Parnell Racing privately entered Lotus 25 at the 1965 German Grand Prix.

An early brainchild of Chapman's fertile mind, the original sketches for the car were made on napkins while Chapman discussed his idea while dining out with Frank Costin (designer of Vanwall, Lotus Mk.8, 9, 10, 11 and Lotus 16 bodies, later of Marcos fame). The unveiling of the 25 at Zandvoort in 1962 was a shock for the competition, and particularly for teams like Brabham and UDT/Laystall who had recently purchased 24s from Lotus, with the understanding that they would be "mechanically identical" to the works cars - Chapman reserved the right to alter the bodywork of the cars.[4]

The monocoque made the car more rigid and structurally stronger than typical F1 cars of the period. The 25 was three times stiffer than the interim 24, while the chassis weighed only half as much.[5] The car also was extremely low and narrow, with a frontal area of 8 sq ft (0.74 square metres) as compared to the normal 9.5 sq ft (0.88 square metres).[5] It was also envisaged to have a column gear lever, to keep the cockpit width to a minimum, although this was only experimental and discarded. To assist the low profile and low frontal area, the driver reclined sharply behind the wheel (an idea seen in the 18, and pioneered over a decade previously by Gustav Baumm at NSU[5]), leading to the nickname 'The Bathtub', while front coil/damper units were moved inboard (as in the 1948 Maserati).[a] The 25 was powered by the Mk.II 1496cc through to the Mk.5 1499cc versions of the Coventry Climax FWMV V8 in crossplane and flatplane formats. Later, Reg Parnell Racing in 1964 fitted BRM P56s of similar specification to their second-hand 25s.

Some privateers who had been buying Lotus chassis were disgruntled by the fact Chapman refused to provide them 25s. These teams, including Rob Walker Racing, were given Lotus 24s, while the works team had exclusive use of the 25 for Jim Clark and Trevor Taylor. When it first appeared at the Dutch Grand Prix, the futuristic 25 was inspected by John Cooper, who asked Chapman where he had put the frame tubes in the car.

Seven cars were built in total, numbered R1 to R7. Four cars - R1, R2, R3 and R5 - were written off (three of them by Trevor Taylor) in accidents between 1962 and 1966. The most successful was R4, which Clark drove to all seven of his World Championship wins in 1963. This car was later crashed by Richard Attwood then rebuilt as a Lotus 33 using a spare monocoque of that type and unofficially known as R13.[6]

Racing history

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The car gave Clark his first World Championship Grand Prix victory, at Spa in 1962. He took another win in Britain and again in the USA, which put him in contention for the title, but while leading the final race in South Africa a much publicised engine seizure cost him the title to Graham Hill.

Clark gained his revenge the following year, taking his first World Championship in the 25, by winning 7 races, Belgium, France, Holland, Britain, Italy, South Africa, and Mexico. Lotus also won its first constructors' championship. Following the United States GP, a 25 was taken to the Indianapolis Motor Speedway for evaluation, where they also trialled Lucas electronic ignition for Ford.[7] The results were encouraging enough for Colin Chapman to mount his ultimately successful challenge on the Indianapolis 500.

The 25 was again used during the 1964 season, winning a further three races in Clark's hands. At the final race in Mexico, just as in 1962, the Climax engine developed an oil leak and with literally a lap to run Clark coasted to a halt in sight of world championship victory, this time conceding to John Surtees. Despite the introduction of the Lotus 33 in 1964, the 25 was still used until well into the 1965 season, Clark taking the car's final win at the 1965 French Grand Prix.

In 1964, Reg Parnell Racing began racing the 25, using the BRM P56 V8 engine, with limited success. Chris Irwin placed Reg Parnell Racing's 25/33 hybrid 7th in its final World Championship race at the 1967 Dutch Grand Prix, scene of the model's debut five years earlier.[8]

World Championship results

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(key) (results in bold indicate pole position; results in italics indicate fastest lap)

Year Entrant Engine Driver 1 2 3 4 5 6 7 8 9 10 11 Points1 WCC
1962 Team Lotus Climax FWMV 1.5 V8 NED MON BEL FRA GBR GER ITA USA RSA 36 (38) 2nd
Jim Clark 9 Ret 1 Ret 1 4 Ret 1 Ret
Trevor Taylor 8 Ret 12 Ret
1963 Team Lotus Climax FWMV 1.5 V8 MON BEL NED FRA GBR GER ITA USA MEX RSA 54 (74) 1st
Jim Clark 8 1 1 1 1 2 1 3 1 1
Trevor Taylor 6 Ret 10 13 Ret 8 Ret Ret 8
Peter Arundell DNS3
Mike Spence 13
Pedro Rodríguez Ret Ret
Brabham Racing Organisation2 Jack Brabham 9
1964 Team Lotus Climax FWMV 1.5 V8 MON NED BEL FRA GBR GER AUT ITA USA MEX 37 (40) 3rd
Jim Clark 4 1 1 Ret 1 Ret Ret4
Peter Arundell 3 3 9 4
Mike Spence 9 4
Gerhard Mitter 9
Reg Parnell Racing Chris Amon Ret
BRM P56 1.5 V8 DNQ 5 Ret 10 Ret 11 Ret Ret 3 8th
Mike Hailwood 6 12 8 Ret Ret 8 Ret 8 Ret
Peter Revson DNS5
1965 Team Lotus Climax FWMV 1.5 V8 RSA MON BEL FRA GBR NED GER ITA USA MEX 54 (58)6 1st
Jim Clark 1
Mike Spence 8
Gerhard Mitter Ret
Giacomo Russo Ret
Moises Solana 12 Ret
Reg Parnell Racing BRM P56 1.5 V8 Tony Maggs 11 2 8th
Richard Attwood Ret 14 13 12 Ret 6 10 6
Mike Hailwood Ret
Innes Ireland 13 Ret Ret 10
Chris Amon Ret Ret
1966 Phil Hill Climax FWMV 1.5 V8 MON BEL FRA GBR NED GER ITA USA MEX 87 6th
Phil Hill DNS
1967 Reg Parnell Racing BRM P60 2.1 V8 RSA MON NED BEL FRA GBR GER CAN ITA USA MEX 0 NC
Piers Courage Ret
Chris Irwin 7
Source:[9]
1 Points were awarded on a 9-6-4-3-2-1 basis to the first six finishers at each round, but only the best placed car for each make was eligible to score points. In 1962 and 1966 only the best five results from the season were retained, and only the best six results for 1963, 1964 and 1965. In 1967 the best five results from the first six rounds and the best four results from the last five rounds were retained.
2 Jack Brabham raced the spare works Lotus after engine failure forced him to retire his own car.
3 Plans for Arundell to race the spare car were abandoned.
4 Clark swapped cars with Spence's Lotus 33 during the race following mechanical problems.
5 Revson tried out Hailwood's car in practice while the latter was away qualifying for the TT.
6 Total points scored by all Lotus-Climax cars, including 45 points scored by drivers of Lotus 33 variants.
7 Total points scored by all Lotus-Climax cars, including 8 points scored by drivers of Lotus 33 variants.

References

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Notes

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  1. ^ "Chapman was not concerned to be original, merely to be thorough."[5]

Citations

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  1. ^ Automobile Year. No. 10. 1964–1965. pp. 198–199. {{cite magazine}}: Missing or empty |title= (help)
  2. ^ Radu, Vlad (9 August 2023). "Lotus 25: The Legendary Race Car That Changed Formula 1 Forever". AutoEvolution. Archived from the original on 30 August 2024. Retrieved 22 November 2024.
  3. ^ "1000 Formula One Races" (PDF). ExxonMobil. April 2019. p. 7. Archived (PDF) from the original on 22 November 2024. Retrieved 22 November 2024.
  4. ^ Blunsden, John (July 1962). "Lotus "Ramlösa" - Segervagnen i Spa" [Lotus' Frameless: the Victory Machine at Spa]. Illustrerad Motor Sport (in Swedish). No. 7–8. Lerum, Sweden. pp. 6–7.
  5. ^ a b c d Setright 1974, p. 1230.
  6. ^ Nye, Doug (August 2013). "A whole bunch of trouble". Motor Sport. p. 74. Archived from the original on 17 June 2018. Retrieved 22 November 2024.
  7. ^ Super Street Cars. September 1981. p. 34. {{cite magazine}}: Missing or empty |title= (help)
  8. ^ Jenkinson, Denis (July 1967). "1967 Dutch Grand Prix race report: Lotus back in business". Motor Sport. Archived from the original on 2 June 2024. Retrieved 22 November 2024.
  9. ^ "Lotus 25 car-by-car histories". OldRacingCars. 3 January 2018. Retrieved 23 January 2019.

Bibliography

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Media related to Lotus 25 at Wikimedia Commons

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