The Gordon Murray Design iStream carbon structure of the TVR Griffith, now being developed for production. (TVR)
Gordon Murray calls new iStream Superlight chassis concept a paradigm shift
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High-profile automotive engineer and designer Prof. Gordon Murray is utterly confident of the potential for his company’s latest iStream Superlight manufacturing system—and says so forcefully: “It is a breakthrough that will deliver the lightest chassis technology for decades to come.” He also believes Superlight manufacturing to be “a paradigm-shifting” innovation.
But it isn’t just his established chassis-lightening program that saves the kilograms; Gordon Murray Design (GMD) also has designed a seat that weighs less than 12 kg (26.5 lb) and is said to need only “ultra-low” tooling costs for simple and quick assembly.
Established in 2007, GMD benefits from Murray’s time as a Formula One technical director with Brabham and McLaren. The iStream Superlight, suitable for “all vehicle segments” from city cars to SUVs and light commercial vehicles, follows the previous iStream manufacturing system that has demonstrated the novel thinking of Murray and his team. It uses a high-strength aluminum thin-wall tubular frame and honeycomb recycled carbon composite chassis panels.
It will be used for GMD’s own T.43 sports car project, which is now in development. The car will have an overall weight of around 850 kg (1874 lb) and will be powered by a 1.5-L turbocharged 3-cylinder delivering 164 kW (220 hp).
Salient points claimed for the iStream Superlight are a 50% weight saving over conventional stamped-steel bodies in white (BIW); a “high degree” of flexibility in optimizing aluminum section shapes; cold-metal transfer welding to reduce distortion and manufacturing time; improved frame stiffness via aluminum section and carbon panels; a carbon sandwich panel cycle time of 100 s and use of recycled carbon fiber. High levels of torsional rigidity and durability are targeted.
The T.43 initial build will be by GMA (Gordon Murray Automotive), formed in late 2017. The iStream technology has been available to the auto industry for several years via a licensing program; now, a new dimension involves licensing automotive platforms alongside iStream licenses.
The forthcoming (2019) production V8 TVR Griffith sports car uses iStream technology and achieves torsional stiffness of 20,000N/o.
Light seats: not easy
Meanwhile, with the need to achieve acceptable levels of comfort, safety and aesthetics, successful design of genuinely lightweight seats has long posed a challenge.
But Andy Smith, GMD’s R&D Director, said of GMD’s lightweight seat concept: “Developed as part of the Innovate UK-funded project (backed by the U.K. government), the 4-way composite seat weighs less than 12 kg complete, a 30% saving versus conventional modern automotive seats.”
Based on what he terms an “innovative” sandwich construction for the seat’s base and back, the design is said to significantly reduce the part count found in competitive designs and has passed the relevant automotive safety standards.
“Costs are expected to be comparable with conventional technologies—and certainly cheaper than previous composite designs,” said Smith. The seat is stated as satisfying all applicable European automotive safety requirements (UN ECE), including luggage retention.
GMD also sees potential for the weight-optimized seat within the aerospace and rail industries.
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