The Lotus Mk.VI: Six of the Best

The Multi-tube chassis: Chapman’s Frame of Mind


In this article we examine the Lotus Mk.VI with special reference to the chassis.


Editor’s photograph of Lotus MK.VI taken whilst at Caterham Cars showroom.

This article performs four significant roles:-

  • It is a component of our forensic study of the Lotus taking one specific model and examining the minutiae of design and construction
  • A study of model development and speed of technological evolution. The MkVI very much acted as springboard into more advanced aerodynamic sports racing car design
  • An introduction to the space frame chassis which Chapman used up until the advent of the monocoque
  • It lends itself to learning opportunities and these are set out below

In a serious study of Chapman there is a considerable risk that the student can easily be subsumed in sophisticated science based design calculations .This can block a wider appreciation that Chapman was a considerable conceptual engineer [and Industrial Designer] and that much of the success of his design was adherence to first principles even when production economies would suggest cheaper alternatives although he was totally pragamtic around this and there are many instances where cost/performance were weighed towards  cost saving.

Therefore the editors believe it essential to grasp these first principles. Many textbooks assume level of knowledge and this can compromise a holistic appreciation. “The Automobile” by Singh Reyat the editors have found extremely useful and covers the mechanical subjects applicable to Chapman design methodology. We paraphrase much of his outline of these fundamental principles.

To date the editors have discussed Chapman’s transition from trials to track in dedicated articles covering the trials cars [Austin Seven Special, Mk’sII, IV and last Trials] and the 750 Formula sports car, the Mk.III. The Mk.VI holds an important role between these and the advanced aerodynamic sports racing cars to follow. There are important technological, commercial and competition dimensions to understand relating to the Chapman’s designs and products. We hope to draw out these and relate them to his products and estimate their significance in the marques development.

Subscribers will find the following A&R articles relevant and integrated with this piece:-

  • Lotus Mk.VI :Aesthetics
  • If so Inclined :Chapmans laid back approach [ with useable templates]
  • Chapman /Lotus chassis development
  • The 1172 Formula
  • The Trials of Chapman :Series of all the Trials cars
  • POP 444 [Owners appreciation Mk.VI]
  • The Lotus Mk.III and 750 Formula
  • Lotus Power plants

The diagrams provided are illustrative and intended to provide guidance. It’s appreciated that not all subscribers/ students can access illustrative material and it’s hoped these diagrams will assist in conceptualizing the subject.

Definition of the automobile

“An automobile is a self-propelled vehicle which is used for the transportation of passengers and cargo over the ground”

Fundamental requirements of the automobile are:-

  1. There should be a means for the development of power
  2. The rate of power development must be controlled
  3. An arrangement must exist to transmit the developed power to the driving wheels
  4. There should be a means to continue and discontinue power flow to the driving wheels
  5. There must be an arrangement to vary the torque
  6. The driving trust should be successfully carried in the vehicle
  7. The vehicle must have directional control
  8. There must be a means to stop the vehicle while it is running

The fundamental parts of the automobile are:-

  1. Chassis or frame
  2. Springs , shock absorbers, axles and wheels
  3. Power unit or engine
  4. Clutch, gearbox and transmission etc.
  5. Steering , brakes accelerator etc. [ the main controls by which vehicle is steered , stopped and sped controlled
  6. Fuel tank or reservoir
  7. Silencer, exhaust manifold
  8. Battery and electrical system
  9. Lamps gauges, switches , controls , information
  10. Sundries like spare wheel, hood, storage etc.

Power to weight ratio

“The performance of an automobile much depends on its ratio of power to weight. By keeping the weight down  to a minimum and installing engines of higher bhp , the best performance can be achieved ……….better its climbing abilities, the higher its maximum  speed  and better its acceleration………. A well designed streamlined car having a high power to weight ratio registers a low fuel consumption at a given speed”

Chassis Theory

Taken from the net:

The main functions of a frame in motor vehicles are: [1]

  1. To support the vehicle’s mechanical components and body
  2. To deal with static and dynamic loads, without undue deflection or distortion.

These include:

  • Weight of the body, passengers, and cargo loads.
  • Vertical and torsional twisting transmitted by going over uneven surfaces.
  • Transverse lateral forces caused by road conditions, side wind, and steering the vehicle.
  • Torque from the engine and transmission.
  • Longitudinal tensile forces from starting and acceleration, as well as compression from braking.
  • Sudden impacts from collisions

Suspension Theory and Practice

This article concentrates on the chassis. In follow up we will examine the suspension arrangements of the Mk.VI in greater detail.

However in relation to suspension and handling it’s important to note that Chapman saw the performance and handling of his designs holistically and primarily as a function of the chassis.

Production cars often adopted the single plane chassis for simplicity, cost etc. Often the overall performance did not warrant a sophisticated design. In such cars the chassis often flexed in use and this in turn impacted negatively on the handling .In an extreme the chassis twisted and in the process strove to steer the vechicle.This obviously has implications for handling, performance, predictability and safety.

Chapman understood this requirement and the Lotus Mk.VI chassis was designed not to flex or bend and thus improve performance.

Design Precedents and Influences

We know that Chapman read and researched widely. This directly supported his experience and feedback .In this section we examine some of proven designs that Chapman might have drawn upon. These do not diminish Chapman. From our Design Heroes series we note the constant creative mutation of technologies and materials and in fact how they are effectively reinvented to perform additional purposes. The very act of conceptual design is recognizing the potential within.

The multi tube chassis as we will note was neither new nor totally originated by Chapman. However what he significantly did was cast it into an affordable, democratic available structure that permitted low cost racing on scientific design principles.

Aviation Precedents

By the time that the Mk.VI was conceived Colin Chapman was a pilot. He had flown both at university and briefly at the RAF.

From interviews and records we are aware he read widely and absorbed colossal amounts of scientific and engineering material. What’s possibly more important is that he sought to make this knowledge malleable and put it in the service of his designs.

The main structural requirements of aircraft are that they should be lightweight but be able to withstand flight loads, landing loads and a wide range of vibration. In the aircraft structural members are designed to carry load or resist stress. In most cases the structural members are designed to carry end loads rather than side loads i.e. to be subject to tension or compression rather than bending .Ever part of the aircraft must be planned to carry the load imposed upon it.The determination of such loads is called stress analysis.

Within aeronautical engineering and commercial operation lightness is of considerable benefit. Aeronautical engineering therefore produced design philosophy directed towards maximum lightness, the most suitable materials and construction techniques available.

One of the great aircraft designers [Ed Heinmann] is attributed of saying:-

“Simplicate and add lightness”

Many of the principles of aeronautical engineering like structural are based on Newton’s laws.

When Chapman was conceiving his cars the Second World War was recently ended. Britain had won the war because of many factors not least the science focused disciplines and particularly the quality of the military aircraft.

Chapman would have been aware of this and the examples we believe he might have most appreciated are highlighted here.

Vickers Wellington

This British aircraft made a significant contribution during the Second World War. It’s believed it was designed by Rex Pierson and Barnes Wallis.

From the dedicated Barnes Wallis web site:

“Around this time, Wallis hit upon a revolutionary structural idea – rather than building an aircraft structure on the principle of a beam, which supports an external aerodynamic skin, he developed a new type of structure which had the structural members formed within the aerodynamic shape itself. This required the structural members to follow the curved outer shape of the fuselage and wings. These members followed geodesic curves in the surface, the shortest distance between two points in the curved surface – this gave the new structure its name, geodetics. By having the curves form two helices at right angles to one another, the geodetic members became mutually supporting, and the overall framework became immensely strong. In addition to being comparatively light and strong, the fact that the geodetic structure was all in the outer part of the airframe meant that the centre was a large empty space, ready to take payload or fuel.

The fuselage was constructed of a geodesic metal lattice which proved extremely strong and light.”

The design proved an excellent load range to power –ratio.

An example can be seen at the Brooklands Museum, London.

Hurricane, c 1935

It’s believed that the Hawker Hurricane was designed by Sidney Camm.

The primary structural design principle was based on the Warren truss box girder which formed the primary fuselage. See details of Warren Truss used in civil engineering below.

A truss is a rigid framework made up of members such as beams, struts and bars to resist deformation by applied loads. The truss frame fuselage is generally covered in fabric. The truss frame itself is usually constructed of steel tubing welded together in such a manner that members of the truss can carry both tension and compression loads, this type of fuselage normally also has triangular  cross  bracing .It is based on geometrical form.

See details below.

Automobile Precedent’s

The editors provide very brief details permitting subscribers to conduct their own detailed research and comparisons.

Cistalia and Cistalia GP

Two Cistalia are believed to have adopted a space frame chassis: the front engine racing car and the much more advanced and sophisticated Cistalia-Porsche GP 360 designed by Ferry Porsche c 1947-49.This was mid-engine single seat racing car.

Mercedes Benz 300 SLR

“The Mercedes-Benz 300 SL was one of the first road going cars to be fitted with a high performance chassis .The aim behind its design was to produce an extremely fast touring car  with luxurious appointments , and for structural reasons it was decided to use a space frame chassis”

Buckminster Fuller’s Dymaxion cars

Subscribers are directed direct to our dedicated article on Buckminster Fuller in our Design Heroes series. Buckminster Fuller drew up plans for the “4D” Auto [airplane c 1928] and later Dymaxion cars. These were based on aircraft practice and included triangulated space frame chassis and his sketches clearly indicate the tubular frame in three dimensional form proposed.

Jaguar C-Type

From the net

The Jaguar C type used for racing adopted a space frame chassis as opposed to the conventional ladder chassis used on the production road cars. From the net:


The road-going XK120’s 3.4-litre twin-cam, straight-6 engine produced between 160 and 180 bhp (134 kW). The version in the C-Type was originally tuned to around 205 bhp (153 kW). Later C-Types were more powerful, using triple twin-choke Weber carburettors and high-lift camshafts. They were also lighter, and from 1952 braking performance was improved by disc brakes on all four wheels. The lightweight, multi-tubular, triangulated frame was designed by Bob Knight.[1] The aerodynamic body was designed by Malcolm Sayer. Made of aluminium in the barchetta style, it was devoid of road-going items such as carpets, weather equipment and exterior door handles.

The editors deliberately mention the Jaguar as it was British. It would have received considerable publicity and was raced shortly before the Lotus Mk.VI.Its important to study he chassis in some detail and appreciate the car was being raced with an engine almost 3 times the size of the Lotus Mk.VI.

Civil /Structural Engineering precedents

We must note that Colin Chapman qualified in engineering. He might not have been the most dedicated of students and possibly did not wish a career in structural or civil engineering. However he would have completed the syllabus and absorbed all the principles and fundamentals. [One of the most important applications was the Warren Truss – see below] Significantly he would understand the vocabulary of the discipline and been able to converse with other engineers.

Structural and civil engineers although primarily concerned with utility, function, performance and economy often appreciate that these qualities are the basis of aesthetics.

Colin Chapman had finely attuned aesthetic sensitivities applied to engineering problems.

Structural theory

Taken from the net:

Structural engineering depends upon a detailed knowledge of loads, physics and materials to understand and predict how structures support and resist self-weight and imposed loads. To apply the knowledge successfully structural engineers will need a detailed knowledge of mathematics and of relevant empirical and theoretical design codes. They will also need to know about the corrosion resistance of the materials and structures, especially when those structures are exposed to the external environment.

The criteria which govern the design of a structure are either serviceability (criteria which define whether the structure is able to adequately fulfill its function) or strength (criteria which define whether a structure is able to safely support and resist its design loads). A structural engineer designs a structure to have sufficient strength and stiffness to meet these criteria.

Loads imposed on structures are supported by means of forces transmitted through structural elements. These forces can manifest themselves as tension (axial force), compression (axial force), shear, and bending, or flexure (a bending moment is a force multiplied by a distance, or lever arm, hence producing a turning effect or torque).

Warren Truss

From the net:

The Warren truss was patented in 1848 by its designers James Warren and Willoughby Theobald Monzani, and consists of longitudinal members joined only by angled cross-members, forming alternately inverted equilateral triangle-shaped spaces along its length, ensuring that no individual strut, beam, or tie is subject to bending or torsional straining forces, but only to tension or compression. Loads on the diagonals alternate between compression and tension (approaching the center), with no vertical elements, while elements near the center must support both tension and compression in response to live loads. This configuration combines strength with economy of materials and can therefore be relatively light. The girders being of equal length, it is ideal for use in prefabricated modular bridges. It is an improvement over the Neville truss which uses a spacing configuration of isosceles triangles.


A preserved original Ansaldo SVA aircraft, showing the Warren truss-pattern interplane wing strut layout

Warren truss construction has also been used in airframe construction for aircraft since the 1920s, mostly for smaller aircraft fuselages, using chrome molybdenum alloy steel tubing, with popular aircraft such as the Piper J-3 Cub. One of the earliest uses for the Warren truss in aircraft design was for the interplane wing strut layout, as seen in a nose-on view, on the Italian World War I Ansaldo SVA series of fast reconnaissance biplanes, which were among the fastest aircraft of the First World War era. Warren truss construction is still used today for some homebuilt aircraft fuselage designs that essentially use the same 1920s-era design philosophies in the 21st century.



The integral members of a truss bridge

The nature of a truss allows the analysis of the structure using a few assumptions and the application of Newton’s laws of motion according to the branch of physics known as statics. For purposes of analysis, trusses are assumed to be pin jointed where the straight components meet. This assumption means that members of the truss (chords, verticals and diagonals) will act only in tension or compression. A more complex analysis is required where rigid joints impose significant bending loads upon the elements, as in a Vierendeel truss.

In the bridge illustrated in the infobox at the top, vertical members are in tension, lower horizontal members in tension, shear, and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension. The central vertical member stabilizes the upper compression member, preventing it from buckling. If the top member is sufficiently stiff then this vertical element may be eliminated. If the lower chord (a horizontal member of a truss) is sufficiently resistant to bending and shear, the outer vertical elements may be eliminated, but with additional strength added to other members in compensation. The ability to distribute the forces in various ways has led to a large variety of truss bridge types. Some types may be more advantageous when wood is employed for compression elements while other types may be easier to erect in particular site conditions, or when the balance between labor, machinery and material costs have certain favorable proportions.

The inclusion of the elements shown is largely an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection, the availability of machinery and the cost of labor. In other cases the appearance of the structure may take on greater importance and so influence the design decisions beyond mere matters of economics. Modern materials such as prestressed concrete and fabrication methods, such as automated welding, and the changing price of steel relative to that of labor have significantly influenced the design of modern bridges.

Note that Isambard Kingdom Brunel adopted this method in his Royal Albert Bridge [see A&R article] and the Forth Bridge.

The 1172 Formula

Students will not be able to grasp the fullest appreciation of the Lotus Mk.VI without first understanding the 1172 Formula .We therefore direct subscribers to our dedicated article.

Chapman was an active member of the 750Motor Club that sponsored and generated this formula. It was intended and structured to generate close affordable racing that invited innovation .Chapman had raced the Lotus Mk.III in the 750 Formula and had possibly gone beyond the spirit. In the Lotus Mk.VI he applies considerable care to ensure compliance and the editors believe it was an enormous competition and commercial success as a result.

The 1172 Formula was based on using the Ford side valve components from their utilitarian models dating from the 1930’s.

Understanding Chapman and the Lotus Mk.VI: First Principles

Colin Chapman trained and qualified with BSc in engineering. The discipline teaches students to adopt fundamental design criteria /methodology that includes:-

  • Consideration of manufacturing tolerance
  • Design form
  • Ease of maintenance and accessibility
  • Ergonomics
  • Strength /size requirements
  • Fulfillment of function
  • Reliability
  • Cost / life expectancy
  • Ease of manufacture
  • Efficiency of operation [ effectiveness]
  • Simplicity of layout

Colin Chapman therefore approached the problem with considerable holistic conceptual appreciation .Foremost in his mind would be:-

  • All the fundamentals of the automobile outlined above
  • Knowledge of best practice and performance in aviation
  • His own theoretical academic knowledge
  • His proven driving skill and feedback loop
  • His knowledge of the Ford components as used in trials cars
  • His membership of the 750 Motor club , its regulations , its members are their product requirements and commercial opportunities resulting and possibly beyond this viable costs
  • The 1172 regulations themselves setting the parameters
  • Access to specialist to translate the design into reality particularly the Allen brothers
  • The personal drive, confidence , ambition and hunger to deliver
  • Possibly not known as SWAT analysis then but an acute awareness of limitations and creativity to overcome and turn to advantage

Form and Function of the Lotus Mk.VI

In the editors mind the Lotus Mk.VI chassis is a beautiful object in its own right. It possesses a classical architectural order, hierarchy and evident, logical self-articulation.

Throughout there is a logical of multi-use of components.[note other schools of design thought sought to give each function and dedicated perfect separate component]

The editors suggest subscribers might like to look at period photographs of the chassis body-unit .Sources include:-

“The Lotus”                            Autosport                   2/10/1953

“The Lotus Chassis             Road & Track            June, 1953

Lotus                                      Sunburst                   1995

In addition cutaway drawings are also extremely useful. The most obvious being featured in “The Lotus Project” [see details above]

Other drawings are available on the net.


This image is of model the editor constructed using an artist’s mannequin to illustrate form and function. It’s recommended this is seen in context of text and other diagrams provided.

chassis 2

This illustrative diagram is not drawn to scale but is hoped indicates the 3 D nature of the multi-tube chassis.

Chassis: Weights & Measures

The Lotus Mk.VI is extremely objective and lends itself to vigorous analysis. Not only is it beautiful; it is extremely elementary and capable of very accurate formal structural analysis.

We have noted that in fact the multi-tube arrangement forms when clad with the stressed aluminium panels a chassis-body unit [CBU]

“The Lotus Project” article September 25th, 1953 observed:-

“The frame structure is of the multi tubular construction braced and strengthened by flat alloy panels riveted to the main lower tubes 1.7/8th inch x 18 SWG while the upper ones are 1 inch round and square of the same thickness is employed”

The weight of this in period has been quoted as:-

Autocar          25/9/1953      63 lbs.

Autosport*     2/10/1953      55lbs              90lbs [with all brackets & stressed panels

120 lbs. with standardized bonnet etc.

*”The Lotus Project” written by John Bolster.

This article also features a significant photograph of Bolster holding the claimed 90 lb. CBU.

Another photograph that underscores this fact appears in “Lotus Seven and Caterham” by Morland which features a photograph with the caption:-

“Lotus 6 chassis held by ace Lotus 6/7 restorer Mike Brotherwood.This demonstrates how light the chassis construction is”

In his text he refers to the chassis as weighing 55 lbs. with main tubes of 17/8th dia. and 18 g. [90 lbs. with stressed panels]

More recently Kelsey in a magazine article [Thoroughbred and Classic Cars, 1994] quoted that:-

“I experimented with making the chassis lighter by using 20 gauge tube instead of 18 gauge , and 16 gauge sheet instead of 10 for various brackets and components and eventually got down to 36 lbs. for a complete chassis”

The Mk.VI is extremely amenable to forensic analysis.

Many technical publications including Costin & Phipps provide statistics on typical tube weight comparisons.

Examples are:-

Dia or section sq. / [in] Profile Sq. /round Wall thickness /SWG gauge Weight lb. per ft.

1”                                             Round                        18                                            0.488

1”                                             Square           18                                            0.643

1 3/4”                                      Round                        18/16                                      0.90/1.15

2”                                             Round                        18/16                                      1.00/1.32

Comparable material weights are given in lbs. /cu ft.

Aluminium                            161

Steel                                       490

Magnesium                           114

Carbon fibre moulding        95

Kevlar moulding                   90

Metal comparison in sheet form [lb. /wt. per sq. ft.]

SWG               Magnesium               Aluminium                Steel

16                    0.73                            1.02                            3.13

18                    0.54                            0.76                            2.23

20                    0.41                            0.57                            1.75

Using this data and the known measurements of the chassis is relatively easy to calculate chassis weights. The chassis is symmetrical in the main and this aids the speed of the exercise.

chassis 3

Figure 1.These photographs are intended to reinforce the text and call attention to the light weight of the multi tube chassis. Note chassis is not an original Lotus Mk.VI but is generally illustrative.

The Overall Technical Specification of the Lotus Mk.VI

The editors have quoted the statistics given by Taylor in their article on the last Lotus trials car and to avoid repetition subscribers are directed to this.

The Lotus MK.VI: Power to weight ratio

We noted above in our theoretical requirements that power to weight ration is important.

A great service of Taylors work is that this ptw ratio can be both calculated and contrasted with other models.

The editors average the Mk.VI as possibly weighing 8.5cwt.The car was fitted with a variety of engines. With the most modest; the Ford 1172 cc side valve the common accepted bhp figure are between   35and 45 bhp

This equates with the Mk.VI delivering a ptw ratio of 82.35 bhp per ton with the lower powered engine.

Note that if the overall weight were to increase to 9 cwt the ptw ratio drops to 77.7 bhp per ton again with the lower powered engine.

This is a yardstick of performance and also indicative why Chapman was so obsessional about weight.

Competition and Commercial aspects of the Lotus Mk.VI.”Faster thank you Think”

“Faster than you think! Was strap line to Chapman’s advertisement for the MkVI and built on a journalist observation that the car was “preposterously fast”

The Lotus Mk.VI was a phenomenal success .It was developed through 1952 with the prototype and “production” of serious customer deliveries started in 1953.

During its production life to c 1955/56. It sold about 100 units. There was at the time no effective competition perhaps other than Dellow as a marque and little opposition in track competition .Almost inevitably the Mk.VI would achieve dominance in results which of course accelerated a beneficial spiral generating more sales and more results.

Some of the successes quoted by Chapman in period advertisements included:-

“Competition success 1953: First Production Year.

In one season only the first four  Mk.VI gained forty –seven awards in competitive events , circuit racing , sprints and hill climbs- including 19 firsts………….Colin Chapmans car – chassis No.9 ……..has raced in many events at 11 meetings and has never been beaten in class. Since then the cars have been even more successful and in the hands of private owners more than 120 awards were won during 1954 by over 40 different drivers .It can be seen from this that success in competition is not confined to a few “works “ cars and drivers but is available toall LOTUS owners”

Additionally at the end of the 1954 season a ESSO advertisement in Motor Racing celebrated the success of Peter Gammon in Lotus Mk.VI [ UPE 9] that he had achieved 17 firsts out of 29 races entered and specifically in the 1500 cc scratch races :-

14 [1st], 2[2nd] and 1 [3rd].

Series students might like to go further and consult the 1172 Formula annual awards along with the 750 Motor club records. Essentially the Mk.VI was dominant at this level of racing until replaced by the Nine, Seven and Eleven, although it continued to compete against these much more advanced cars.

The Mk.VI was not cheap. Lotus advertisements, May 1953 [see A&R article] quoted:-

  • CBU at £110
  • Full road legal body work set :£75
  • There was a menu for adaptions and other accessories [ details in subsequent articles]

These figures allow us to look at the important profit margin as this multiplied over the units sold made the company viable and provided some capital to invest in the next generation of cars. It also contributed to a skilled workforce employed at Hornsey.

In the period the full cost of constructing an MkVI was between £450-£600 .Our research into price relativity informs us this was expensive although extremely good vfm.An existing donor helping keep costs down. Although some years later the construction of a decent , reasonably performing  Ford 1172 or Austin Seven Special was approximately £250.The Mk.VI held its price well as second hand advertisements confirm. It was a practical robust rugged dual use sports car. With its high quality coachwork by Williams & Pritchard it was professional and attractive.

It was only later in the decade that a rival emerged. This was Ginetta and their MK.II [see dedicated marque article on Ginetta to follow] .Subscribers might like to see a quality article written by Malcolm McKay describng and contrasting the two models.*

Another source of contrast is Morland [see references below] All evidence suggests the total success of the Mk.VI.It very much helped establish the brand , proving the product , delivering favourable road tests reports etc. and laying financial foundations [ although as noted much support came from the Allen family]

The editors believe that the MK.VI became a victim of its own success. It would lock Chapman into an ever increasing spiral of technical sophistication in track competition. There would be no going back.

In our next set of articles we will explore how Chapman went forward from this base line into the generation of Costin body designed aerodynamic sports racing cars.

Learning Opportunities

The editors consider one of the better methods of comprehending the Chapman methodology is through self-discovery. For this reason we provide base line information and diagrams and invite students and subscribers to explore, conceptualize and deduct.

We suggest that our drawings, diagrams and verbal descriptions are absorbed. [See also A&R articles on aesthetics; particularly Lotus Mk.VI].When absorbed they are capabale of being integrated and structured permitting the student to conduct either elementary exercises or projections.

chassis 4

The editors suggest some of the more obvious:-

  • Sketch in body outline overlaying chassis diagram [ refer A&R article on aesthetics of Mk.VI if needed for assistance]
  • Sketch in chassis on working drawings extrapolating from chassis diagram
  • Consider how suspension would work with chassis
  • Evaluate practicality of overall package
  • Using diagram undertake estimation of chassis weight
  • Consider alternative design package
  • Consider and evaluate against the Ford 1172 side valve chassis of the period or Austin Seven
  • Contemplate how Chapman might have made a creative leap from the Lotus Mk.III chassis to that of Mk.VI [see A&R article for guidance]
  • Contemplate how the MK.VI might be simplified and cost reduced and generally consider the evolution into the Lotus Seven
  • Study and absorb details of Mk.VI chassis and explore ,compare and contrast with that of Mk.VIII, IX [see A&R articles to follow]
  • Consider the aesthetics of the Mk.VI and compare and contrast with peer sports/ racing cars of era and evaluate in terms of appearance and desirability /vfm
  • Students with engineering background may wish to explore the complexity of construction [ both chassis and body], the likely assembly time and proceed to address the price in period and hence profit margins.[ note A&R article on 1172 formulae assists and gives comparisons with home built alternatives]
  • Contemplate the advance nature of the Mk.VI and the competition , commercial time gap before rivals caught up; suggest explanations
  • Examine the deployment of Ford components and the means by which added value and performance were achieved cost effectively

Note our diagrams are provided so students / subscribers can print and annotate.

Transition to Aerodynamic Sports Racing Cars

The Mk.VI we note was conceived a dual use practical sports car and particularly for participation in 1172 Formula racing .At this type of event in period aerodynamics were not a major consideration although within practicality and with detracting from utility the Mk.VI had features to reduce drag. A detailed study of UPE 9 is revealing.

The Mk.VI was the precursor of the aerodynamic cars. They also used tube space frame chassis and in some cases a similar front suspension and mechanical components.

At least two Mk.VI were fitted with more streamlined bodies of the “organic” perhaps rather than the Costin “scientific” specification. Photographs are available on the net.

The editors will be extending our study of the Chapman aerodynamic sports racing cars with articles on the front engine cars: the Mk.VIII, IX, Eleven, Fifteen and Seventeen.

Subsequent Multi tube chassis and legacy

The essential correctness of the Chapman multi –tube chassis is evidenced by its longevity and adaptability. From the Mk.VI onwards it was the chassis principle of the majority of the competition cars [excepting the Elite] until the introduction of the monocoque in single seat GP cars and the backbone chassis in the road cars. It was used for the Lotus sports /sports racing cars, GP and then mid-engine GP and sports racing models.

Not least it was the forerunner of the Seven and hence the present day Caterham. The Chapman inspired multi tube frame has therefore been in continuous development for 63 years.

During the 1960’s after Chapman had moved to the monocoque many GP marques retained the space frame in various forms.

Today many specialist firms still continue to use the Chapman inspired multi tube principle often with wishbone suspension.

This returns us to first principles and the Chapman design methodology. If the product could have been substantially improved or simplified it would have been over this time. The fact it has not is testimony to and reinforces our understanding of Chapman using first principles

Exhibitions, Education and Economics

The extremely high survival rate of the Mk.VI stands testimony to its utter correctness, its enduring appeal, fundamental sustainability and its living source of inspiration.

The Mk.VI lends itself to exhibition in a multi-faceted manner all containing essential learning opportunities. The editors suggest some of the following are possible:-

  1. Its link pin role in the development of the Lotus marque [time and place]
  2. As an example of fundamental correctness – first time
  3. Its role and performance and generator of the 1172 Formula [including the nursery role of British racing and drivers post war]
  4. The superb foundation for subsequent sophisticated aerodynamic cars
  5. A study in the pure architecture of the multi tube chassis
  6. The role of aesthetics and coachwork in appeal and sales
  7. The forerunner of the Seven and the component car industry
  8. A study in the flexibility and adaptability of its specification bog basic to highly sophisticated
  9. Chapman’s ability to work alchemy with Ford components and the basis of Industrial design and mutation of materials
  10. A study in price and value for money in era. How it was perceived/received and marketed

Nearly all these are sources of an educational programme and learning opportunity. Nearly all contain aspects of design, engineering, marketing not least elementary science and mathematics, with an overarching appreciation of the social, economic and cultural determinants of the era.

In its own limited way the MK.VI was a machine that helped Britain catapult itself out of austerity and onto the road of dominance in international motor sport.

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.


Our conclusions are brief and unmistakable:-

  1. The Mk.VI was outstanding: commercially and competitively. These are linked
  2. It was remarkable dual purpose car offering excellent vfm.It set the precedent for the Seven and many component cars to the present not least the Caterham
  3. It is case study in the best of Industrial Design; the Mk.VI is a product with fitness for purpose primarily through the intelligent incorporation of inexpensive components .It perfectly radiates added value and remains an example for today’s designers. It also possessed a unique blend of theory practice and exceptional artisan craft skill
  4. Its competition achievements and resultant publicity galvanized the brand and Chapman providing resources for growth and not insignificant customer base
  5. Simply it looked and was the business

In future articles we will build and refer to this foundation on which Chapman and the brand would build. Chapman’s frame of mind like his chassis was structured, logical and increasingly driven.

All Lotus Mk.VI were built at Hornsey.


The Automobile.H.Singh Reyat.Chad.2013.

ISBN: 8121902142

Colin Chapman’s: Lotus Engineering. Haskell.


Colin Chapman: Inside the Innovator.Ludvigsen


The Science Museum Library. The Barnes Wallis Archive.

Lotus Seven and Caterham.Morland .Osprey.1994.

ISBN: 1855324903


ISBN: 1857781473

Brunel’s Britain.Beckett.Biddles.1985.

ISBN: 0715379739[nb good for diagrams and appreciation of theory /practice of bridge /truss construction and works with A&R dedicated article]

*”Marque Makers” by Malcolm McKay, “Classic and Sports Car, Jan.2002. Comparison of Ginetta and Lotus Mk.VI.

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.