Designing with Elan

The commercialisation of Lotus’s in-house suspension analysis software means that we can all tap into the iconic car maker’s design know-how. Charles Clarke savours the ride.

If you’ve ever had the opportunity to drive a Lotus you’ll understand what world-class ride and handling are all about in a car.

Many of the models have had their foibles over the years. Remember the Elan with the pop-up lights, as driven by Emma Peel in The Avengers? The best at the time it might have been in the dry, but in the wet it was a nightmare.

But Lotus Engineering has just kept on honing its chassis and suspension skills, aided and abetted by improving dynamics knowledge and software. So much so that the current breed of Lotuses, the Elise 111R and the new Exige, defy description. There aren’t enough superlatives in any dictionary.

The Exige (the racier of the two) is shod in standard trim by special Yokohama tyres that look like motorbike tyres – slick with minimal grooves to keep them legal. The effect is nothing short of stunning – a true racecar for the road. There is substantial aerodynamic downforce, which, when coupled with the sticky tyres and significant mechanical grip from a highly tuned chassis and suspension system, make the Exige feel as if it’s on rails.

The highly tuned chassis and suspension come from superior software tools and good old-fashioned Lotus know-how. And the good news is that these are now available on the open market in the form of Lotus Suspension Analysis (LSA). This is the commercial version of the Lotus Engineering in-house software which has been under development for some 15 years. The quality of this development has gone hand in hand with the quality of the cars themselves, which is there for all the world to see in the Elise 111R and Exige. And just as you can buy the state of the art in a physical sense you can now buy it in a virtual sense too.

This is not just about dynamics – LSA is the encapsulation of Lotus Engineering suspension know-how in software. There are templates galore and even with no suspension design knowledge you can be looking at something halfway decent in about 10 minutes.

The great thing about this software is that it has the capacity to save you so much basic ‘grunt’ work. Most suspension configurations are pre-programmed – all you have to do is supply your dimensions and loads and you are ready for your analysis.

LSA was originally developed at Lotus for its ride and handling engineers. These engineers have been responsible for the vehicle dynamics of many of the world’s class-leading passenger cars, and they continue to use the package for in-house and client development projects. The PC-based software has been continually updated and refined to keep abreast of the latest trends in suspension configurations, design techniques and analysis requirements.

LSA’s interface with its unique 3D-viewing and editing environment and its rapid computational speed make it ideal for use by either designers or analysts at the concept design stage.

Common suspension layouts are pre-programmed into the software while the user-definable template feature enables unique suspension configurations to be constructed. It is interactive – once you have your configuration you can make ‘what if’ adjustments until you get the performance you’re looking for.

An optional module permits the addition of compliant bushes, the rate, position and orientation of which can easily be modified to allow effects such as lateral force steer due to compliance to be included in the analysis.

All significant suspension parameters are included in the output, including camber and castor angles, toe, kingpin angle, spring and damper ratios, and brake steer. Results can be displayed graphically or numerically over specified bump, rebound, roll and steer articulations.

External forces can be applied to the suspension as well as suspension spring loads, anti-roll bar forces and the influence of steering rack coupling and compliance. Calculations are updated instantaneously after each design change together with graphical result displays.

Lotus is targeting LSA at suspension designers and analysts across a wide range of organisations from OEMs to small performance engineering firms. Many top-flight professional and private motorsport teams are already said to be interested in the software, but for competitive reasons they are too shy to talk about it.

Several renowned academic institutions – including Cranfield’s Motorsport Department, London’s Kingston University, London, University LeMans, France and Kookmin University in Korea – also have the software.

LSA is available through a range of flexible licensing options from <link>Lotus Engineering Software=http://www.lesoft.co.uk</link>, starting from as little as £350 per month up to a perpetual licence price of £8,000. Small beer indeed when you consider the wealth of development incorporated in this code.

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