Blooming by design

Lotus Engineering’s versatile vehicle architecture concept shows that the UK automotive industry can remain competitive in the niche market. Charles Clarke reports.


When UK manufacturing bemoans the loss of its automotive industry, people often seem to forget that we have one of the most vibrant automotive OEMs on our doorstep in the shape of Lotus Cars.

What distinguishes Lotus from Morgan, Bristol and other specialist limited production sports car makers is Lotus Engineering — a dedicated and independent automotive design and R&D facility with access to Lotus’ ride and handling test track.

Lotus Engineering is centred around its testing workshops and custom build facilities. The technologies used in these facilities are at the heart of the design work that Lotus Engineering undertakes, both for its external clients and for itself, with testing equipment, software and specialist expertise in metalworking, bonding and vehicle architecture combining to give its expertise in product design.

Like the rest of the UK auto industry, Lotus has had a chequered history but, since its takeover by Malaysian car maker Proton in 1996, it has not looked back. Despite its offshore ownership, it is a distinctively British enterprise in its outlook and the investment keeps on coming. The Lotus factory in Hethel, near Norwich, is state of the art — it boasts two design studios, one exclusively for Proton and the other for Lotus and the external clients of Lotus Engineering.

A typical external client scenario brings Lotus Engineering a test car whose performance is lagging behind its manufacturers’ expectations. The Lotus ride and handling engineers take the car out on the track, and then put the car onto a unique piece of equipment called a suspension kinematics and compliance measurement system (SKCMS).

For half a day, the rig pulls, pushes and measures to calibrate the performance of every nut, bolt and bearing. The data gathered during the calibration allows the engineers to evaluate whether the car is built ‘as designed’ and it identifies components that are not performing to specification.

The SKCMS rig can also be linked to Lotus’ inhouse developed suspension kinematics software (now available commercially) so that calculated values can be verified in practice.

The SKCMS rig was probably a major factor in Lotus’ recent British GT championship success in the first year of trying. A year that started as a ‘shake down’ exercise ended in triumph when Lotus secured outright GT3 Team Championship honours.

As talented as its drivers are, it is no coincidence that one of them, Gavan Kershaw, is a senior Lotus ride and handling engineer in his day job. This means he has access to the track, the kinematics software and the SKCMS rig. Kershaw knows what kind of suspension kinematics suit his driving style and the factory facilities help him tune his car exactly the way he likes it.

These facilities help make Lotus a fast operator in more ways than one. The GT3 was a late entrant because of last-minute rule changes that made a Lotus entry a viable proposition — they built the car in just two months. The car went on to trounce the Aston Martin DB9s and Porches.

This followed an exercise where the company built a custom Lotus GT racer for a Malaysian client in just six months liaising with Racing Technologies Norfolk (RTN) for the carbon bodywork and Swindon Racing Engines for the powertrain. Timescales were so tight that it was quicker to use traditional craft skills and clay models than to go via the hi-tech route.

Lotus’ speed on the track also translates to its commercial models. The original Elise, esteemed as a stripped-down, budget-priced performance car and one of the first production car chassis to be assembled using bonding rather than welding, went from concept to production prototype in just nine months — and this was more than 10 years ago.

The Elise chassis marked a world’s first in the use of aluminium extrusions and bonded construction. The current production Elise chassis is virtually unchanged from its original design, which speaks volumes for Lotus innovation and development skill. The chassis is so successful that the chassis of the Aston Martin Vanquish — the Warwickshire-based premium car maker’s supercar marque — was developed by Lotus Engineering and based on the Elise.

For its next generation of sports cars, Lotus has developed VVA (versatile vehicle architecture), a way of making limited design and production viable by producing more vehicle configurations based on the same platform. In this, it is following a trend set by volume car makers — for example, the Ford Mondeo shares a common basic platform with the Mazda 6 and the Jaguar X type.

The VVA concept is the solution to the niche vehicle conundrum — how do you produce 10,000 to 15,000 vehicles a year and control costs in such a way that the eventual price tag to the customer is affordable? Lotus discovered that economies of scale kick in at about 40,000 vehicles a year but this far outstrips the demand. So if the investment was amortised over three or four variants from common components, their combined sales would reach the magic volume. In this way demand would be satisfied and so would cost control.

To demonstrate this, Lotus has developed a number of conceptual variants based on VVA, including a two-seater mid-engined ‘supercar’, projected to sell 2,000 units a year; a four-seater front-engined GT coupe, targeted for 5,000 sales a year; and, in what would be a major departure for the company, a front-engined 4×4 seven-seater people carrier, whose projected sales would reach 30,000 units per year. All share the same floorplan unit, a low-cost structure in folded aluminium, married with high-pressure die cast (HPDC) and extruded components unique to each model. These would generally be bonded to the underbody using adhesive technologies, with the bonds secured by rivets.

This concept envisages saving costs by also using the same electrical components across all the variants, as well as using the same assembly lines for underbodies and the same trim and final assembly lines.

Lotus has built a concept model of the 4×4 seven seater, called the APX, to demonstrate the VVA concept, but in practice the ‘pure’ VVA has proved too expensive to take to full production.

Lotus now aims to use a low-investment version of the concept for own products. This takes elements of VVA but tries to avoid the costliest types of components, such as aluminium corner castings.

The architecture is based around a ‘tub’ underbody common to all the variants, but instead of the expensive HPDC components — which even the projected sales of the seven-seater model could not fund — it uses aluminium front subframes and front and rear bumper beams, with a steel rear subframe, generally formed from extrusions, laser-cut and folded sheet parts, whose configuration varies according to the car type. These technologies will be manifested in forthcoming new Lotus models due to be introduced in late 2007, including the replacement for the Esprit. Lotus also intends to offer the platform for client projects.

Lotus Engineering has been behind the design and construction of some of the most successful cars in history: it has won countless awards around the world. Through extensive investment in state-of-the-art technology and testing facilities, Lotus Engineering will continue to develop class-leading vehicles for both external customers and Lotus Cars.