Lotus 79:”May the Force be with you”

Lotus 79:”May the Force be with you”


For this piece we are highly indebted to Colin Campbell and his work “Automobile Suspensions”.

We quote from his work extensively.

This item is promoted because it is: –

  • Complementary and an evolution extension of existing pieces.
  • It has a strong mathematical and mechanics content and hence to learning opportunities
  • It offers scope in interpreting the forensic success of the type 79

Subscribers might like to see the directly relevant and integrated A&R pieces that complement and help structure this article: –

  • Lotus 78 &79 including “Black Beauty”
  • Lotus 80,81and 86

Campbell on 1970’s racing cars: –

“Modern racing cars carry such a high percentage of the weight and the footprint area at the rear that they can be said to be steered in a bend by the throttle foot.

A typical weight distribution would be 33/67 and typical tyres widths 20″ at rear and 10″ at front. Rear end loads are usually increased in all but the most acute bends by the down thrust of a rear wing, a large inverted aero foil. A smaller front wing is provided to increase the effective load on the front wheels

During 1978-79 the overall down thrust was increased beyond the actual weight of the car. This was achieved by the application of a Venturi-effect underneath the car and the development of sliding skirts on the body sides to “seal in “the depression below the car. The penalty of these aerodynamic tricks has been the loss in maximum speed, but the cornering speed has been increased dramatically. Measurements reported by Motor [3rd march 1979] made on a lotus 79 gave the cornering acceleration of 2.05g .fig 6.2 shows how the downforce are distributed on the Lotus 79………………….

all F1 and many F2 cars in 1979 were what are popularly called “ground effect2 cars ………..designed to create Venturi effect underneath the ca body to produce surprising down force, thus increasing the available cornering forces in high speed corner by as much as 40% it is essential in such a system to maintain a good air seal between the sides of the body and the road surface. Sliding skirts have been developed for this purpose m but two critical factors threaten their viability. The first is the condition of the track surface, the second is the extent of body roll. Modern billiard -table surfaces on the F1 circuits have made it possible for relatively short skirts to be used, moving up and down in the slides under bump and rebound and roll. Obviously, any tendency to roll on corners as much as typical racing cars of the early 1970’s did calls for the provision of vey cumbersome deep slide mechanisms………..

figures 10.8 and 10.9 are based on measurements reported by Motor [March 3rd, 1979] in a 150mph [67m/s] corner and show the Lotus 79 rolling at a value very close to this limit ……………….

The disposition of the maim masses, the engine, transmission, radiators, fuel tanks and driver on a GP car are as close to the ground as the designer can put them ………..since the roll centre is very close to the ground level the roll moment in a corner taken near the limit is very high ,extremely stiff springs are required to resist this moment .even though progressive rate springs are used , the ride is so hard young men in excellent physical condition fell battered at the end of a race .

Fig 10.8 and 10.9 show that the inner tyres of a F1 only contribute about 305 of the total cornering force in a 150mph corner. if then we could design racing cars with “no-roll” suspension in which load transfer did not take place we could make more efficient use of the inner tyres and corner at even higher speeds .what is of equal importance [until the ban ground effect car!] is that a “no-roll” suspension would assist the designer in the design of a ground effect body”

Figure 1.diagram from Campbell.

Figure 2.diagram from Campbell.

Learning Opportunities

Our learning /educational opportunities are intended to be challenging thought provoking and requiring additional research and/or analysis.

These opportunities are particularly designed for a museum/education centre location where visitors would be able to enjoy access to all the structured resources available in conjunction with any concurrent exhibition.

In this instance we suggest the following might be appropriate: –

  • What forces are applied to a car?
  • How are they measured/calculated?
  • What units are involved- use example in illustrations Campbell’s fig.6.2
  • How do these, measurements feed into component design?
  • What is the weight of the type 79?
  • Compare the respective downforces in the 79 design, what contribution do they make?
  • What are the respective units in current F1 cars?
  • What were Chapman’s and Lotus proposed design solutions to the negative issues highlighted by Campbell?

Exhibitions, Education and Economics

In the museum context the editors believe that commercial considerations are both necessary and complementary with its educational objectives.

For these reasons our suggested outline Business Plan includes provision for promoting products and services which share Chapman’s ideals of mechanical efficiency and sustainability. In addition we propose merchandising that explain and interprets the social and cultural context of Chapman’s designs in period. It’s suggested there will be catalogue for on line purchasing.

In this instance we suggest the following might be appropriate: –

  • “We can work it out”
  • Force Majure
  • Air Force
  • Chapman forced into……….
  • Chapman& The Force of Imagination
  • Chapman: A determined force
  • Lotus Forces for Courses
  • Lotus: Combined Forces
  • Lotus: Force Fed
  • Lotus 79:application of Natural force
  • Forces & Sources
  • Lotus: Force Fields
  • Lotus Design: Forces not beyond Control
  • Lotus 79: Forced Induction
  • Lotus 79: Innovation –Forced upon them
  • Lotus 79: The Magnitude of Force
  • Chapman and Lotus: Applied Forces
  • Chapman and Lotus 79: Weight on the Mind
  • Chapman and the Lotus 79: Cornering Force


The success of the Type 79 is directly related to the application of physics, mechanics and an understand of forces. .These principles are worked through with mathematics and provide data which the engineers can comprehend and use.

Engineering designers need to appreciate first principles and formula involved and be able to perform the necessary calculations. Indeed Chapman and his colleagues fully appreciated those forces involved and noted by Campbell. It’s interesting to note how they responded.

The proposed CCM&EC has a declared objective of advancing education by using exhibits and archive as source of reference, inspiration and example. Most curriculum subjects can be included but obviously those related to engineering, science and mathematics are particularly important.

The fundamental subjects of mechanical engineering usually include [from the net]:-

Mechanical engineers are also expected to understand and be able to apply basic concepts from chemistry, physics, chemical engineering, civil engineering, and electrical engineering. All mechanical engineering programs include multiple semesters of mathematical classes including calculus, and advanced mathematical concepts including differential equations, partial differential equations, linear algebra, abstract algebra, and differential geometry, among others.

In addition to the core mechanical engineering curriculum, many mechanical engineering programs offer more specialized programs and classes, such as control systems, robotics, transport and logistics, cryogenics, fuel technology, automotive engineering, biomechanics, vibration, optics and others, if a separate department does not exist for these subjects.[17]

Most mechanical engineering programs also require varying amounts of research or community projects to gain practical problem-solving experience. In the United States it is common for mechanical engineering students to complete one or more internships while studying, though this is not typically mandated by the university. Cooperative education is another option. Future work skills [18] research puts demand on study components that feed student’s creativity and innovation. [19

Mohr’s circle, a common tool to study stresses in a mechanical element

Main article: Mechanics

Mechanics is, in the most general sense, the study of forces and their effect upon matter. Typically, engineering mechanics is used to analyze and predict the acceleration and deformation (both elastic and plastic) of objects under known forces (also called loads) or stresses. Sub disciplines of mechanics include

  • Statics, the study of non-moving bodies under known loads, how forces affect static bodies
  • Dynamics the study of how forces affect moving bodies. Dynamics includes kinematics (about movement, velocity, and acceleration) and kinetics (about forces and resulting accelerations).
  • Mechanics of materials, the study of how different materials deform under various types of stress
  • Fluid mechanics, the study of how fluids react to forces[28]
  • Kinematics, the study of the motion of bodies (objects) and systems (groups of objects), while ignoring the forces that cause the motion. Kinematics is often used in the design and analysis of mechanisms.
  • Continuum mechanics, a method of applying mechanics that assumes that objects are continuous (rather than discrete)

Mechanical engineers typically use mechanics in the design or analysis phases of engineering. If the engineering project were the design of a vehicle, statics might be employed to design the frame of the vehicle, in order to evaluate where the stresses will be most intense. Dynamics might be used when designing the car’s engine, to evaluate the forces in the pistons and cams as the engine cycles. Mechanics of materials might be used to choose appropriate materials for the frame and engine. Fluid mechanics might be used to design a ventilation system for the vehicle (see HVAC), or to design the intake system for the engine.

We believe the museum setting can advance STEM skills in a meaningful way.

Often science can seem abstract, detached, and theoretical and without application but when seen in the context of a highly successful racing car may be able to invite interest and participation.


Automobile Suspension.Campbell.Chapman&Hall.1981.

ISBN: 412164205

Please note the editors of the A&R attempt to give the broadest spectrum of references but not all are available for consultation in an article. However by noting their existence it may assist students in their research.

*Items in italics non A&R library books.