It's his plastic bodied car, not the plywood one. although they look quite similar
'summer 1941, when he built a plastic-bodied car, Russell’s plastic car used a framework of welded steel tubing to support a wire mesh contour, to which he applied ethyl cellulose plastic up to 1/8-inch thick with a modified caulking gun. The envelope body styling might have been considered revolutionary, but the 1942 Chrysler-like grille bars suggest Russell had his eye on the latest Chrysler designs, including the envelope-bodied Thunderbolt''