Building on a sporting legend
Original article date: June 2000
Keeping the weight down has long been a recipe for success for Lotus. On two new models the company is taking advantage of bonded aluminium space frames
Lotus, the legendary sports car manufacturer, is building on the successful Elise model. Three new models incorporating a bonded aluminium space frame chassis are headed for road and track.
This summer, Lotus is to begin building a new sports car for GM subsidiaries Vauxhall and Opel called the VX 220 and the Speedster. Both take advantage of space frames made by Hydro Automotive Structures that weigh in at just 68kg.
In fact, the VX 220/Speedster tips the scales at only 850kg, paired up with a 2.2 litre mid-mounted engine. The bonded aluminium chassis offers not only light weight, but also high torsional rigidity, absolutely necessary for precise control at high speeds.
The bonded frame allows an even lighter chassis than with other methods. Adhesive bonding allows thinner extrusions because the aluminium is not subjected to the strength-sapping welding process, according to Lotus.
In all, there are more than 60 parts in the Elise space frame. The individual extrusions come from Hydro Aluminium Extrusion in Tonder, Denmark. Machining is performed at Hydro Automotive Structures in Bromyard, England, anodising at Hydro Aluminium Extrusion in Bedwas, Wales and assembly is at Hydro Automotive Structures’ plant in Worcester, close to Lotus.
The bonding adhesive is precisely applied by robotic equipment. The assembled chassis is placed in an oven and heated to 185degC to cure the adhesive.
Lotus and Hydro developed the space frame for the Elise – a first for a production road car. The high strength-to-weight ratio and the light components meant that Lotus could use a smaller engine – a 1.8 litre in the original Elise – saving money and even more weight. The Elise weighs just 699kg and even the beefed-up 143hp Elise 111S tips the scales at just 714kg.
Also in production now with space frames from Hydro is the 340R, an exclusive sports car based on the Elise. The stripped-down 340R will be limited to a production of just 340, the company says. The concept car was originally designed with no doors, no side windows, no roof and minimal bodywork.
Next in line is the M250 coupe. Light weight, combined with a powerful V6 mid-placed engine, mean that the M250 will perform well on acceleration. It is expected to go into production in 2002.
- Hydro Aluminium Structures
- Hydro Aluminium Extrusions
June 2000