The 1973 Chevrolet XP-898 concept car was built with a frameless fiberglass foam sandwich body and chassis. This two-seater sports coupe offered a unique look at alternative engineering approaches to future techniques in design and manufacturing. The entire body consisted of four lightweight fiberglass outer body panels, the floor pan, firewall, upper front, and upper rear with a rigid urethane foam filling the designed clearance between the panels.
The structure and appearance of the car were designed so that the body could be assembled using four lightweight molded outer skin sections. With the outer skin panels placed in a foaming mold, liquid urethane was injected between the panels where it expanded and bonded the body into a single, rigid sandwich structure.
The result was a vehicle body virtually free of squeaks, rattles, and vibrations. Once the urethane hardened (which took about fifteen minutes), the suspension, drive train, hood and doors were bolted to reinforcing plates, which were bonded to the fiberglass panels.
The XP-898 was a front engine, rear wheel drive design and used many components from the Chevrolet Vega. The vehicle had a 90-inch wheelbase with an overall length of 166 inches. A key consideration in the engineering design of the XP-898 was the advantage of improved crash worthiness of the sandwich construction technique. The energy absorption characteristics of the vehicle enabled engineers to simulate crash conditions for the vehicle at speeds up to 50 miles per hour without catastrophic failure to the structure.