article from 'MiniWorld'

Suspension engineer Dr Alex Moulton was a fundamental part of the design team that worked on the original Mini back in the late 1950s. He gave us some insights into the development of the Car of the 20th Century - and his opinion on the BMW Mini of the 21st century

After the Second World War I was determined to move my family firm — Spencer-Moulton based at Bradford on Avon — from the manufacture of rubber suspension for railway coaches, and into automotive suspension. I had heard of Alec Issigonis by reputation and we met socially before we worked together. Issigonis was working at Alvis in Coventry at that time, on a new large car to replace their (famous but dated) “Grey Lady” model. He was given a free hand to do what he liked, more or less. He had heard of an experimental rubber-suspended Morris Minor that Jack Daniels and I had built at Cowley. It had been driven over 1000 miles on the pave at MIRA, an unimaginably tough test that the standard car would not have been able to withstand.
Following my experimental developments of the mid ‘50s. Issigonis was determined that he should have interconnected fluid and rubber suspension on his Alvis. Interconnecting front and rear suspension units with fluid in pipes meant that the pitch mode was separated from bounce and roll. As a result, the car moved smoothly over a bump in the road, giving a much higher quality ride.’ The Alvis was an interesting technical exercise, but it never reached the production line.
“Leonard Lord and George Harriman had formed BMC in tbe mid ‘50s by merging Austin and Morris. Lord was determined to make a range of new and innovative cars, and he plucked Alec Issigonis back from Alvis to design them. The Suez crisis occurred in 1957 and petrol rationing meant that tiny bubble cars, mostly of German manufacture and including some BMW-Isetta models, began to flood the roads. Lord wanted to sweep them away and so Issigonis got the order to build the smallest of his new cars first, a proper miniature four-seater. Issigonis told Lord that he wanted me to be involved with my suspensions and so I went to ‘the Kremlin’ at Longbridge to meet him. He looked at my portfolio of experimental work and said, ‘If you’ve done this, you’ll do more.’ He was very gruff but I got the OK.
“I formed Moulton Developments to work on the Mini suspension and other projects. BMC took a shareholding and paid all the costs of development. This left me free to work on the things I wanted to do. We actually developed the principles of the Hydrolastic system during the ‘5Os but it wasn’t ready for production in time for the Mini launch in 1959. I had previously designed the rubber cone suspension system — it was a specially shaped rubber and metal unit that gave a smoothly rising spring rate. This meant that, when the car cornered or went over a bump the suspension stiffened up as it was deflected. When practically undeflected (ie: the car was at rest or on a smooth road) the rate was low and so the ride was soft. We fitted this system to the original Mini of 1959. It was a parody of the interconnected hydraulic system but that simply wasn’t ready in time.
“Issigonis took Jack Daniels from Cowley and got together a small team, no more than six people. Jack had been running an experimental transverseengined, front-wheel drive Morris Minor on the road over the snowy winter of 1956/7. It performed particularly well in the wintry conditions and Leonard Lord and George Harriman were well aware of the benefits of the transverse set-up as Jack parked it outside ‘the Kremlin’ every day where he knew they could see it. Issigonis’ team designed and developed the Mini from start to production in 27 months —a fantastically short time. They had total authority from Lord: the whole of BMC was at their disposal plus all the component suppliers. The whole of the Midlands was committed to the new project.
“It is unfair to say that the Mini was undeveloped when it was introduced. OK, there were some small problems, such as the floorpan sealing, but when you think of all the technical innovation in that one small vehicle, it was amazingly right, and look how little fundamental change it then needed in the following 40 yearsl
The next suspension innovation for the Mini was the Hydrolastic system introduced to the saloon models in 1964. Hydrolastic suspension involved similar rubber cones to the “Dry” set-up, but they formed a displacer unit with an integral diaphragm and damper valves. They were filled with a water and antifreeze mixture and interconnected front to rear via pipes under the car. This gave the car a rising and falling motion rather than the sudden pitching of the rubber cone system. Alex Moulton takes up the story once more...
The Morris 1100 was introduced in 1962 with the first Hydrolastic installation. It was a great success, and Ford in particular were very upset by it. Dunlop and Moulton Developments took some time to make a unit small enough to fit in a Mini, but it was done by the early 1960s. The majority of the Mini’s racing and rallying success was achieved with Hydrolastic cars. The whole Mini racing thing was started by John Cooper. We never thought about racing during the design phase; we were worried about safety, particularly when the car was overloaded with lots of students aboard or such like.”
The final phase of the Moulton suspension system evolution was the Hydragas system. In this later version of the interconnection principle, the rubber cone was replaced by using a gas under pressure. Hydragas was introduced with the unloved Austin Allegro in the 1970s and is still in use on roads today fitted to the MGF. Hydragas was never fitted to a production Mini, but Alex Moulton has some fascinating prototypes in his stable: a 1966 Cooper S fitted with Hydragas suspension and a 1980 Metro fitted with a more developed, fully interconnected and refined version of the system. We were able to take a short trip in both of these cars, and the sophistication of ride and handling has to be experienced to be believed.
“The prototype Metro installation I have is the ultimate expression of interconnection for a small car. I showed the Mini Cooper S with Hydragas to BMW during the early development of their new Mini and I am certain they were impressed. We then worked with Rover on the Minky 2, a one-off based on extended Mini sheetmetal that was essentially a test rig for a potential suspension set-up for their new car. However, there was a major personnel change at board level. Bernd Pischetsrieder, with whom I had had encouraging discussions left and the decision was taken that the new Mini should be wholly conventional in its suspension.”
Alex Moulton has some forthright views to share on the BMW Mini: “It’s enormous. The (original] Mini was the best-packaged car of all time this is an example of how not to do it. The interior space is not much bigger than the old Mini, but it’s huge on the outside and weighs the same as the Austin Maxi! The crash protection has been taken too far. I mean, what do you want... an armoured car? Princess Diana was killed in a two-tonne Mercedes: you can have a fatal accident in anything if you drive fast enough.
With the original Mini, we set out to prevent any accidents by having excellent handling, not by cushioning people from the consequences of their own folly The old Mini was the absolute apogee of this philosophy of built-in safety via the handling —people avoided accidents by driving around them. The suspension of the [BMW] Mini Cooper is set far too stiff, giving a most uncomfortable ride. To he honest, it’s an irrelevance in so far that it has no part in the Mini story.
We were also able to get a second opinion on the BMW Mini’s handling from Doug Milliken, an American suspension engineer who happened to be visiting. After his first drive in the BMW Cooper he confirmed Alex Moulton’s opinion that the suspension was too hard for comfort and that it was overdamped. His conclusion was basically that he would not want to drive it on anything other than dead-smooth tarmac.
What is the future for Dr Moulton’s innovative interconnected suspension systems which were first demonstrated in the Mini and other BMC cars of its generation? I can do no better than to paraphrase his published thoughts:
“There will he a new breed of small cars, sufficient in size for the typical [urban] journey, but with the convenience in driving on crowded roads for the longest journey, provided they have big car ride comfort and absolute security of handling. I suggest that these cars will have the Issigonis layout of transverse engine and front wheel drive. Their suspension could comprise fore and aft fluid interconnection to separate pitch from bounce and roll. These cars could have uncompromised damping which, with the wheel at each corner layout. gives the [ultimate] handling capability.” (Moulton Suspension. Past and Future — Institution of Mechanical Engineers. Automobile Division, 2000)
Amazingly. 42 years on from the production of the most enduring of his and Sir Alec Issigonis collaborations — the Mini, of course — Dr Alex Moulton is still thinking about the development of suspension for small cars. No doubt the Mini’s eventual successors, whatever they may be, will benefit from his highly original thinking.

Sir Alex Moulton passed away on 09.12.2012. R.I.P.

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