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A D V A N C E D M A T E R I A L S & P R O C E S S E S | A P R I L 2 0 1 9 2 0 and production, with a goal of a low to mid-volume range-topping vehicle. They would eventually explore other structural concepts, but the first pub- lic manifestation of their alliance was an aluminum model of the Audi 100 displayed at the 1985 Hanover Motor Show. An affordable manufacturing solution that could bring an affordable material substitution to the automotive mass market would require a different approach, focused on aluminum as a system. PROGRESS AT BRITISH LEYLAND The unlikely proponent of that ap- proach was British Leyland, beset with a dwindling European market share of its struggling volume brands Austin and Morris. British automakers had under- gone a progressive consolidation that culminated in the formation of a sin- gle entity in 1968, uniting Leyland’s trucks, buses, and car makers includ- ing Austin, Morris, MG, Triumph, Rov- er, Jaguar, and Land Rover under the single corporate umbrella of British Leyland (BL). But a lack of fresh prod- ucts and the first oil crisis brought the company to near collapse, resulting in partial nationalization in 1975. After further reorganization in late 1978, the formerly independent R&D depart- ments were consolidated as BL Tech- nology (BLT) in early 1979 under the direction of the famous Spen King. Charles Spencer “Spen” King was the chief engineer for the Rover 2000, 2200, and 3500 sedans (1963), along with the Range Rover (1970), and he also led the teams that delivered the Tri- umph TR6 and TR7. The new organiza- tion was based at the Gaydon Proving Grounds and was soon working on fu- ture concepts. If the 1973 oil crisis, rise of the envi- ronmental movement, and emergence of safety regulations had prompted a reevaluation of the car of the future, the oil supply shortages created by the 1978 Iranian Revolution further high- lighted the West’s vulnerability to polit- ical unrest in the Middle East. To Spen King, this realization dictated that the focus of BLT’s efforts would be a step improvement in fuel economy. He re- cognized that fuel economy depended not only on improving the powertrain and the aerodynamic performance, but also on a substantial reduction of mass. Because the largest and heaviest com- ponent in a car is the body structure, it was only natural to make it the focus of advanced research and development. David Kewley was BLT’s chief ma- terials engineer and he recognized that any consequential mass reduc- tion would require a switch to an alumi- num body structure. The question was not whether aluminum was suited to structural applications: It had been the structural backbone of the aerospace industry for decades. Rather, the issue was how to devise a manufacturing and design concept that would meet the cost and productivity requirements of the automotive industry. He knew that one of the main de- sign challenges of an aluminum body structure was stiffness and that struc- tural adhesives could solve the prob- lem. But the best structural adhesive systems had been developed for the aerospace industry and were not read- ily transferable to high-volume produc- tion. There were two main issues. First, the adhesives required special surface conditioning before application. Sec- ond, they needed a lengthy curing cycle in dedicated curing ovens that would add a crippling level of investment to any automotive body shop. Rather than translate such prac- tices to the automotive sphere, Kewley decided to imagine the ideal automo- tive process plan for an aluminum body structure, from the mill to the paint shop. His original sketch is shown in Fig. 1. Four key points of Kewley’s con- cept as shown in Fig. 1: 1. Applicable to the three alloy fam- ilies in use at the time: 2xxx, 5xxx, and 6xxx. (1) 2. Stable surface pretreatment at the mill before applying any protective/ forming lubricant. (3) and (4) 3. Structural adhesive compatible with the stamping lubricant(s); no intermediary part cleaning. 4. E-coat bake oven performs triple duty: Cure the E-coat, cure the adhesive, and offer a possible heat treatment. (11) Kewley was clearly conflicted about the possibility of a separate thermal cure for the adhesive, but his industrial experience comes through in the question mark on item (8) – “Sepa- rate thermal cure?” – after the adhesive application. Charles Spencer “Spen” King. Courtesy of Range Rover and www.influx.co.uk.