In-house designs : Aluminium Metro

A lesson in lightness

FOLLOWING the success of the BL Technology developed lightweight ECV3 project, it was decided to evaluate a system of manufacturing for building aluminium structured vehicles and then test the structural integrity and durability. This Metro is one of six vehicles built as replicas of steel production vehicles, and employs the system of bonding panels, which has become more widespread in the industry.

Although the MG Metro pictured above looks completely standard, it has been constructed using these principles, and although there aren’t many miles on the clock, it’s weathered the years remarkably well. The entire structure has been bonded with Permabond adhesive – a system developed by ALCAN in conjunction with BL Technology – and all its panels are fashioned from aluminium. Spen King oversaw its development, and was passionately in favour of lightweight construction – however, cost and complexity meant that ultimately, it was a system that wasn’t perservered within BL.

The techniques employed in the Permabond process.

The techniques employed in the Permabond process.

In December 1982, this reseach was fully underway when the ECV3 was introduced, and although its aluminium structure was regarded as a flight of fancy by the press, the ASVT – Aluminium Structured Vehicle Technology system was pursued well into 1985, and was sold to the dealer network as the construction medium for the upcoming AR6 supermini. However, with time, money and market share slipping, the outcome was inevitable: cancellation.

According to the book, Materials for Automobile Bodies by Geoff Davies, they were tested quite stringently – Torsion, 1000-mile cobbled Belgian pave test, pothole braking, accelerated corrosion and finally the 30mph impact test. Given that the bare body in white weighs half that of its conventional pressed steel alternative, it’s a shame that the first supermini to employ these production methods was the loss-making Audi A2; a car that Spen King openly acknowledges to be the ‘son of ECV3’…

As far as British manufacture goes, it wasn’t until 2003, with the arrival of the X350 generation Jaguar XJ, that the results of this research bore fruit.

As always, if you know more, please get in touch or leave feedback below.

The Aluminium MG Metro survives at the Heritage Motor Centre at Gaydon.

The Aluminium MG Metro survives at the Heritage Motor Centre at Gaydon.

No clues here...

No clues here...

Keith Adams

About the Author:

Created www.austin-rover.co.uk in 2001 and watched it steadily grow into AROnline. Is the Editor of Classic Car Weekly, and has contributed to various motoring titles including Octane, Evo, Honest John, CAR magazine, Autocar, Diesel Car, Practical Performance Car, Performance French Car, Car Mechanics, Jaguar World Monthly, Classic Car Weekly, MG Enthusiast, Modern MINI, Practical Classics, Fifth Gear Website, and the the Motoring Independent... Likes 'conditionally challenged' motors and taking them on unfeasable adventures all across Europe.

12 Comments on "In-house designs : Aluminium Metro"

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  1. Paul Taylor Paul Taylor says:

    Did they ever collate any performance data on this car? It would be interesting to know how it compared in terms of 0-60mph time and top speed with the shell being so much lighter than the steel equivalent

  2. Ryan Antell says:

    I would love that metro would never have to worry about rust.

  3. Graham says:

    It was to me a sign of the back to front thinking in BL to put so much effort into doing a lightweight metro which was always going to be too expensive to make, while the Range Rover which could have used this technology to real advantage lumbered on with a ladder chassis and massive panel gaps.

  4. mm says:

    You need to be a rich and prosperous car company to dabble in aluminum construction for your cars, a cash strapped company should have stay with material it knows,

  5. Richard16378 says:

    Citroen looked into building the 2CV out of aluminium, but decided against when they found the cost of it compaired to still was about double, mostly due to the more energy used in the smelting.

    • mm says:

      The engineers on the 2CV could not master the welding techniques for alumiinum for production, this information ame from the Equinox docu8mentary anout the 2CV.

      Steel has many benefits, easily repaired, those “supermarket car park” dents can be easily fixed, not so with Aluminium, a slight knock causes the metal to stretch, very hard to panel beat back into shape again. I have owned an all aluminium car for many years, modern steels are so corrosion resistant, the advantages of aluminium over steel are not significant in the context of the motor car

  6. stevo says:

    Obviously i didnt have an aluminium version, but the picture of the interior took me back to my MG Metro, RCU 52Y. Both the best and worst car I have ever owned. Nippy,stylish (I loved that chunky ssteering wheel!) and fun too, but in addition to being an unlucky car it had a shocking set of faults which cost me a fortune to repair. After a year off the road to replace the engine and front subfranme it was nicked.

    Regardless a great car, worthy of the metroname if not the MG badge. Always felt a fraud driving it as it was not a real MG but a great, great car. ( am i confused about this car or what!)

  7. Greg says:

    To build an aluminium car the same way as a steel car means to waste a lot of the positive characteristics of aluminium. If pressed steel panels are simply replaced by pressed aluminium panels a lot of unneccessary material has to be used because aluminium is pretty soft. Therefore a car designed that way is unneccessarily heavy, just as Honca proved with their equally designed NSX.
    Properly done, an aluminium body would use extruded aluminium structures attached to cast nodes by glue, which make the best of the material’s characteristics and save a lot of weight. Just like an Elise or the respective Audis.
    To achieve this, it took a non-cash strapped company like Audi with their A8 D2, because you not only have to adapt existing production processes to a new material but to develop completely new production processes. I doubt whether a company as close to bankruptcy as AR would have been able to do this.

  8. Adrian says:

    And look how much money Audi lost on the A2….. i have one and its great but advances in steel technology are such the same car could now be built from steel at the same or even less weight. It will not however rust away….

    • mm says:

      The failure rate of the A2 body tub at manufacture was very high, it is believed at certain points of production to be 100%. such are the difficulties of forming Al into complex shapes

  9. Richard16378 says:

    Citroen & Panhard both did a lot of research in the 1930s & 40s on using aluminium for car bodywork.

    At the time the cost of suitable sheet aluminium was twice that of steel, due to the amount of energy need to produce it, especially in pre-nuclear power France.

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