Aston Martin

The V8 Vantage story – VH platform

The aluminium chassis, cornerstone of the Gaydon era Aston Martin range, was used for the first time in 2003. This allowed the brand to secure its future and greatly reduce costs by developing all its models based on the same platform.

Aston Martin has named this chassis “Vertical Horizontal Platform (VH)”. In spite of what it may seem, its name does not have any relation to its geometric disposition. Vertical represents the use of the platform in the entire range, from the Vantage to the second generation Vanquish, and horizontal represents the wide range of components that can be shared between the different models. The platform is designed in a modular way so that parts of it can be adapted to any need.

The lineage of this family of aluminum chassis has its origins in 1996 with the structure designed for the Lotus Elise by engineer Richard Rackham. The design took into account the possibility of replacing complete sections of the chassis, greatly facilitating their repair. Lotus was later responsible for designing the chassis for the Opel Speedster and later for the Aston Martin Vanquish.

Back in 1996, in the original chassis, the different components were bonded using an epoxy glue cured at high temperatures and applied with absolute precision by robots. Once the adhesive was applied, the pieces were held together using aluminum screws to ensure the accuracy of the assembly. Another feature is that the edges of each piece have ribs that keep the perfect alignment between them, while also keeping the glue in place. Once assembled, the whole chassis is cured at 180º in an oven.

23-Lotus-Elise-Chassis
Lotus Elise chassis. Source: Lotus Cars

An example of the tough resistance tests made to this structure are the 1000 hours of spraying with saline acid at 52º Celsius. According to Lotus, a steel chassis under those conditions would completely disintegrate.

With such technology, Aston Martin turned to Lotus for the design of its Vanquish chassis.

While the Elise has a mid-engine arrangement, in the Vanquish the engine is placed in front of the passengers, so the gearbox and the transmission bar had to be accommodated in the center of the structure. For this, the Vanquish has a carbon fiber tunnel running its length that forms a rigid spine, something that did not exist in the chassis designed for the mid-engine models.

It also has plastic impact absorption structures both in the front and rear, also manufactured by Lotus in Hethel.

in the late ’90s the plan was to offer a range of three models: Vanquish, a new two-seater mid-engine sports car and a front-engine four-seater GT.

When Dr. Ulrich Bez joined the company in July 2000, in order to cut development costs, it was decided to use a modular platform shared by the entire range, thus ditching the two-seater mid-engine idea.

The sports car known at that time as project code AM305 could have a shorter wheelbase than the larger GT (project AM803) and still share the vast majority of components.

vhv8side

Aston Martin would then independently develop the VH platform for the DB9 and Vantage models. Its construction and design are very similar to those of the Vanquish, although both chassis do not share any element and the steel parts in the Vanquish were now made using aluminum.

The components are glued using epoxy adhesive strengthened by the use of rivets. The adhesive was applied by the only existing robot in the Gaydon factory until 2008, hilariously nicknamed James Bonder. According to Aston Martin the use of adhesives not only improves the structural rigidity, but also helps in the vibration mitigation.

The body panels are bonded using the same epoxy resin. Opposite to what happens in the vast majority of cars, as these are not structural components, variations in the design of the body can be made much easier and with a much lower cost.

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The C pillars are assembled using an innovative ultrasonic welding technique. The high frequency (20KHz) vibration creates a molecular bond 90% more resistant than normal welds. This process is, so far, unique at Aston Martin. Its biggest advantage is that by not generating heat during the process, no deformation is caused in the parts.

The rest of components are also manufactured in lightweight materials. The windshield frame is casted in a single piece of aluminum, the steering column and interior door frames in magnesium and the roof and rear panels of the body are made of superformed aluminum (aluminum takes the form of the mold by applying vacuum). Both the front wings and the bonnet are made of composite materials and the torque tube is made in carbon fiber.

The suspension is also manufactured in lightweight materials; thus, the suspension arms are made of forged aluminum and both at the front and rear are joined to the chassis by aluminium subframes.

Achieving a perfect weight balance was one of the priorities in the design. Placing the engine in amid-front position (behind the front axle), the gearbox on the rear axle, and the fuel tank in front of it, the Aston Martin engineers achieved a front / rear mass distribution of 50 / 50 in the DB9 and 49/51 in the Vantage, with a very low polar moment of inertia. The torsional rigidity of this platform is 29kN / degree, twice that of the DB7.

In the next article we will talk about another of the key parts of the Aston Martin V8 Vantage, its engine.

Bibliography:

astonmartins.com

Definitive Guide to New Gaydon Era Aston Martin, Grant Neal, 2017

Aston Martin: Power, Beauty and Soul, David Dowsey, 2010

Aston Martin, Richard Loveys, 2015

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