McLaren F1 Design

This information was taken from the McLaren F1 owners book and is copyright to McLaren Cars Ltd.

Aerodynamic Concept

Only such sophisticated wind tunnels can mimic the complex interaction
between a moving car and the road surface upon which it runs.

early model in the moving-ground wind tunnel

The McLaren F1's dramatic aerodynamic features are derived from McLaren International's long experience of trend-setting research for Formula One. The McLaren F1 is thus the first production car to benefit from first-hand design by a fully experienced team of Formula One trained aerodynamicists utilising the latest in moving-ground wind tunnels.

While most existing production cars are tested in fixed-floor tunnels in which the test-car's wheels are stationary, every Formula One acing car designer knows that modern moving-ground wind tunnels provide the only accurate representation of actual car aerodynamic behaviour. The McLaren F1 project has been developed, analysed and fine-tuned in the same moving-ground wind tunnel facility at Teddington, England, in which McLaren International's World Championship winning Formula One cars have been perfected. Only such sophisticated wind tunnels can mimic the complex aerodynamic inter-action between a moving car and the road surface upon which it runs.

working with the wind tunnel

Painstakingly-faithful 30 per cent full-size models of projected McLaren F1 forms have been investigated within an airstream velocity of 44 metres per second. Balance forces generated within the model have been computer assessed in terms of pitch, drag and downforce, while model surface pressure plots have also been recorded and analysed from 70-point Scanivalve sensing. Ultra-violet paint streamlining and flow visualisation have been employed in one of the most comprehensive wind tunnel analyses ever applied to a production road car design programme.

Ground Effect

By directing airflow beneath the working underfloor, airstream is
harnessed to generate powerful, stabilising downforce.

sketches of the fan-assisted aerodynamics

The McLaren F1 is the world's first production car to feature full ground-effect aerodynamics with fan assistance. By careful management of airflow between the McLaren F1's underfloor and the moving road surface beneath, powerful aerodynamic forces can be harnessed- as in Formula One - for the driver's benefit.

Management of this airflow regime has come to be known as a 'ground-effect' aerodynamic system. Airflow beneath the car is compressed against the underlying roadway and then released through an expanding-section exit channel; at the car's tail - the curving underfloor surface of which is known as the 'diffuser'. As airflow velocity has been accelerated through this underfloor 'venture' system, so the pressure within it falls, and this low pressure are may then be harnessed as downforce to suck the moving car bodily down against the roadway.

In 1978 Gordon Murray stunned the Formula One racing world by creating the Swedish Grans Prix winning Brabham BT46B 'Fan Car' driven by Niki Lauda, which generated massive aerodynamic downforce in part by fan assistance. It worked so well that Formula On rules were quickly altered to dismiss such devices! Now with the McLaren F1 project governed by only comparatively liberal International road-car regulations, that 'Fan Car' theme is to some extent being re-introduced.

A complex three-part rear diffuser beneath the F1's tail incorporates a central single surface and two reflex shapes each side generate sufficient downforce to overcome the car's natural aerodynamic lift.

Simultaneously, two powerful electric fans remove boundary layer air from the rolled S-wave or 'reflex' diffuser sections, helping to control movement of the Centre of Pressure - the truly significant aerodynamic factor affecting vehicle stability and handling.

Centre of Pressure Control

The only surface-braking aerodynamic device is the neat brake and balance
aerofoil to maintain the centre of pressure in the required location.

BB 'foil in action (slow motion)

At high speed, aerodynamic lift can compromise any car’s stability. Many high-performance sports cars carry wings to cancel this lift, but Formula One experience proves them inefficient and drag inducing. Major manufacturers often claim minimal drag coefficients - Cd - for new car shapes. Yet alone such figures are irrelevant. One crucial factor is aerodynamic centre of Pressure - CoP - through which lift and downforce react upon the moving car, It location is vital to car behaviour yet amongst production sports and supercar designs, few address CoP control.

Under maximum braking, weight transfer causes nose-down dive. Aerodynamically this attitude rushes effective CoP far forward, maximising front wheel load, minimising rear. The braking vehicles rear end is inevitably destabilised.

BB foil (as seen in the BBC Top Gear TV Special)

On the McLaren F1, the only surface-breaking aerodynamic device is its neat Brake and Balance 'Foil hinged into the tail deck. Activated automatically by electronic control sensing heavy braking, this BB 'Foil deploys at 30-degrees, slightly raising Cd, but crucially enhancing base-suction at the rear of the car to generate greater downforce from the underbody with its Centre of Pressure in the correct location. Thus braking stability is greatly enhanced by moving the CoP rearwards when conventional design would allow it to rush far forwards...

Deploying this BB 'Foil exposes rear brake cooling intakes to control the extra heat being generated by the brake application. BB 'Foil operation is an entirely different principle to anti-lock braking which maintains tyre adhesion by releasing the application on imminent lock. The McLaren F1's new system instead evenly increases tyre load during braking to postpone the onset of wheel locking.

The F1 driver may also partially deploy its BB 'Foil in a 'High downforce' mode. Unlike a traction-limiting control device this actually increases grip and traction - another of the McLaren F1's valuable safety options.

Engine

The F1's engine produces one of the highest specific outputs for
a large capacity naturally aspirated unit in production sports car history.

engine with cam cover removed

From the inception of the McLaren F1, it was decided to utilise both a purpose-designed transmission and a high performance 12-cylinder naturally aspirated engine of great efficiency, all integrated from the beginning into the overall F1 package. While offering great power, the engine also had to meet world-wide emission and green requirements since the McLaren F1's concept combines ultra-modern technology with the most noble Grand Touring car values.

The resultant naturally-aspirated V12 engine for the McLaren F1 has been purpose built by BMW Motorsport in Munich, Germany, to meet all these demands. Commissioned by McLaren Cars, BMW Motorsport's design and development team has been led by their universally acclaimed senior engineer Dipl. Ing. Paul Rosche. The McLaren F1's 6.1 litre 60-degree V12 engine is an entirely new four-cam, 48-valve unit extraordinarily compact design, sharing nothing with BMW’s unrelated smaller-capacity production-line V12.

The BMW Motorsport S70/2 V12 engine is individually hand-assembled and dyno-tested for each owner to produce one of the highest specific outputs for a large capacity naturally aspirated engine in production sports car history.

engine complete with manifold

Seeking performance with clean emission, the engine possess extremely efficient heads, continuous variable inlet valve timing and an emission-control system incorporating secondary air supply and four catalytic converters with Lambda exhaust gas analysis control.

This 4-cam, 48-valve, 60-degree V12 engine's 86mm bore and 87mm stroke displace 6,064cc. Compression ratio is 10.5:1 and with its chain driven DOHC valvegear and TAG Electronic Systems fuel injection and engine management, power output is over 550bhp at 7,500rpm., coupled to a peak torque in excess of 600Nm between 4,000 and 7,000rpm, with no less than 350Nm at only 1,500rpm!

The load bearing lightweight cylinder block is cast in aluminium-alloy with Nikasil coating. BMW Motorsport's renowned engine weight and size reducing technology has led to the 6.1 litre V12 being little larger than current 3.5 litre Formula One racing engines.

CAD drawing of exhaust manifold

Lightweight magnesium alloy castings provide the sump, oil-pump and variable valve-timing housings, cam-carriers and cam-covers. The airbox is made of carbon composite, while the voluminous exhaust catalysor system is cased in super-thin, ultra-high temperature resistant Inconel sheet just 0.8mm thick and doubling as the F1's rear crash structure. Dry sump lubrication ensures adequate flow under high cornering loads and minimises centre of gravity height. Cooling is handled by individual water pumps to each cylinder bank. All evidence of a total dedication to excellence.

Transmission

Gear ratios offer an ultra close 5-speed cluster for 0-160 mph,
plus a 6th speed 200 mph-plus capability..

Wheelbase length in most mid-engined sports car designs is increased by conventional clutch and final-drive arrangements forcing the drive-output centre rearwards. Until now, all attempts to minimise wheelbase length - such as siting gearbox and final-drive beneath the engine - have compromised handling, weight or efficiency.

In conjunction with Traction Products Inc., McLaren Cars have imaginatively solved such problems, with the McLaren F1's final-drive gear offset alongside its clutch, absolutely minimising engine/drive output centreline separation. This layout within a transverse-shaft gearbox - already inherently short front front-to-rear - provides an exceptionally compact assembly within an extremely rigid cast magnesium casing accepting major rear suspension loadings.

The F1 is also the first production car to adopt current Formula One practise by featuring a 200 mm diameter aluminium flywheel and carbon clutch assembly. Their extremely low mass and inertia greatly enhanced engine response and efficiency, and also save weight. The 6-speed gearbox has a full synchromesh gearchange with helical gears for optimum strength, quiet high-speed running and quick and efficient gear changing.

Further features include a sophisticated lubrication system, a remote clutch operating mechanism tailored to provide optimum pedal weight and action, and an integrated purpose-designed starter system. Gear ratios offer a close 5-speed cluster for 0-160 mph (267 km/h) plus a 6th-speed presenting a comfortable, peaceful and long-striding 33 mph (53 km/h) per 1,000 rpm cruising gear - plus top speed capability of well over 200 mph (321 km/h). The final-drive assembly also features a limited-slip differential, while purpose-made constant-velocity jointed high grade allow-steel drive shafts are used.

Electronics

Technology is employed which has been strictly confined until
now to the highest levels of Formula One and sports car racing.

Close collaboration between McLaren Cars and their sister company in the TAG-McLaren Group - TAG Electronic systems - has provided the F1's highly innovative and sophisticated engine and chassis control features.

The Engine Management system - EMS - combines the technology TAG has applied in Formula One and Group C management systems with the stringent extra demands of road-going emission control. Its computing power is approximately tens times that of a mass-market equivalent. It provides individual ignition timing and fuelling control for every pulse on each cylinder and also manages the engine's variable valve timing. Its software algorithms, which calculate ignition timing and fuel quantity, consider such diverse factors as the rate of throttle movement and ambient atmospheric conditions. Split-second calculations are repeated on every firing cycle to ensure the most instantaneous information is acted upon.

Further software algorithms monitor conditions within the inlet manifolds commanding precisely calculated mixture enrichment or leaning-out during rapid throttle variations to provide genuine Formula One-style engine response. The EMS employs feedback from four oxygen sensors to ensure the fuel/air ratio never exceeds the optimum working range of the exhaust-cleaning catalytic converters. Hence, even the world's most stringent emission requirements are complied with. An additional EMS function is to monitor engine use, logging temperature extremes, peak revolutions reached, high loads when not properly warmed through and myriad other details of the V12's operational life. This engine logging can then be accessed during normal servicing to identify cause and effect.

A second electronics unit, the Car Equipment controller - CEC - manages everything from the electrically-heated cockpit glass to the brake cooling-duct flaps. Glass de-icing load can soar as high as 1000 Watts, handled by a TAG-designed DC/DC converter. The CEC also monitors battery state and alternator charging and regulates glass heating load to suit. Brake-cooling flap control is derived from road speed and brake-line pressure sensors. The aerodynamic BB 'Foil is also CEC controlled, via cockpit command when high downforce mode is elected, although brake cooling demands automatic over-ride as required.

The CEC also supplies data to the instrument panel, manages the F1's anti-theft system, checks all lamps, controls the courtesy lights and decides when to switch on the engine-bay cooling fans. It monitors all electrical system functions and checks safety conditions, for example braking the window lifts should they become obstructed. it also prevents the windows from being opened above 130 mph (209 km/h).

Both CEC and EMS systems constantly monitor both themselves and all functioning of the F1's other electrical systems. If a fault should be detected, the CEC can signal the driver via the instrument panel display, indicating both the fault and its severity. In servicing, both EMS and CEC units can communicate with the standard BMW computerised service tester, but a second more unusual facility is also featured. A modem telephone link is fitted in the car, permitting direct downloading of information to McLaren Cars. Diagnostic circuits within the EMS and CEC then identify faulty components an transmit the information direct for assistance.

Ergonomics

Probably more design effort had been invested in the
F1's ergonomics and controls than in any other area.

The F1 design team has worked unremittingly to site every primary and secondary control in precisely its proper place. One powerful tenet of F1 design has been to overcome many of the old-established layout problems usually affecting mid-engined road cars. These often result in offset primary controls which are forced towards cabin centreline by front wheel arch intrusion. There is an awkward compromise between turning circle - indicating front wheel steering lock - and driver pedal space.

McLaren F1 cabin

The F1's unique one-plus-two seating configuration avoids any such compromise. Its centreline driving position offers a spacious footbox with perfectly aligned pedals tailored to each individual owner'' preference. A lightweight carbon-composite seat finished in padded Connolly hide is moulded and tailored in Formula One style to each owner's form.

Much design time has been devoted to centre-drive support. Visibility is outstanding. Even the grip shape of the specially-made Nardi F1 steering wheel involved many hours of research, design and development. Steering is weighted for the driver. Nothing is allowed to mask steering 'feel'. A minimal, Formula One-style dash panel in carbon composite, presents clear specially-made analogue instrumentation, plus a liquid crystal computer read-out.

Hand controls include finger-tip flipper switches behind the steering wheel boss, and an intricately crafted right-hand manual gearchange. Passenger space and comfort have not been forgotten. The McLaren F1 can accommodate two 95 percentile adult passengers - an industry standard indicating that only 5% of the population will be taller - in secure, safe and air conditioned respose - providing yet another feature unmatched by any other supercar.

Interior

In an intentional return to 1930's prestige car practise,
each McLaren F1 will have been detail-finished to its new owners' requirements

hand-crafted, individually tailored interior

The F1's interior is hand-crafted in Connolly Soft Assisted Aniline leather employing the very finest selected hides available. The driver seat will have been hand-built and individually shaped and trimmed in the manner the McLaren International Formula One racing team applies for its Grand Prix drivers. Similarly the steering wheel position will have been set-up and the foot pedals specially built, shaped and tailored to assure the finest possible ergonomic match.

Full air conditioning is standard in the F1, with separate airflow ducting for driver and passengers. Side window drop-sections are electrically powered, while door locking is achieved by remote control. Secondary controls and switches have all been specially designed, each finely engraved for identification.

The instrument panel combines analogue dials with a high-technology read-out screen and information system. A defined ignition sequence is displayed on the dash panel instrument screen when the driver initiates the start procedure. On the switch panel beside the driver's right hand, a flick-up trigger shield exposes the neat red starter button beneath.

Glass and Finish

A carbon composite outer shell and a new standard in laminated glass

Glass specification for the McLaren F1 is demanding: laminated glass throughout, a large double curvature windscreen at 23-degrees to the horizontal. Hence the perennial problem of large area glass de-icing and de-misting has to be overcome. A conventional hot-air defrosting system, bulky and inefficient, was rejected in favour of electrically heated glass throughout. St Gobain of Aachen has particular expertise in automotive glass and a dedicated team was assigned to meet McLaren Car's needs.

Their imaginative approach yielded revolutionary new methods of glass assembly for improved optical quality, plus the exciting new concept of de-icing by resistive film within the glass. Plasma sprayed onto the inside of outer glass laminate provides both its tint and heating element to offer speedy windscreen and side-window defrost and demist. it also reduces transmission of heat by 20 per cent and of ultra violet light by 85 per cent, giving protection to the interior finish and furnishing. Under EC test conditions, the F1's glass is completely cleared of ice seven times faster than the regulations require.

To preserve the McLaren F1, its creators have collaborated with Sonneborn & Rieck Ltd to develop high-technology coatings and finishes for its advanced composites body. S & R perfected entirely new patented coatings combined with water-based paint technology in a major step towards the elimination of petro-chemical solvent use. Some of the coatings use 100 per cent 'solids' formulae which have no thinning agent to evaporate and affect the environment during application. these new processes offer better durability, high abrasion and scratch resistance and minimise colour degradation.

		Responsibility: Richard Rutter