The three-wheeler Dymaxion introduced front-wheel drive, rear steering and rear engine mounting. It was 18 feet long and an elongated tear-shape, not unlike other flying cars of the time, (it was intended to fly in final form) and with the capacity to carry eleven passengers it anticipated the “people-movers” of later decades. It had one eighth-inch-thick aircraft-glass windows, a chassis of chrome-molybdenum steel, wraparound bumpers, and an aluminum body. It could park in a tight space and spin a graceful U-turn on its own length. Furthermore it was fuel-efficient for its time, running on 30 miles to the gallon, and Fuller claimed it had reached speeds of 128 mph.
Only three were ever built. A crash involving the son of a politician doomed the project. The second prototype survived in a Reno collection and has been loaned to a restoring team of engineers and fanciers.
Like the first prototypes, the shell of Dymaxion #4 is built with an ash frame sheathed in hand-beaten aluminum sat backwards on the chassis of an old 1934 Ford Tudor Sedan and is strikingly painted in racing green with a white roof. Similarly the V8 Ford engine is rear-mounted and steered by the same single rear wheel, which acts like a boat's rudder, calling in mind Fuller's final epitaph “Just call me Trimtab”. In gratitude for the lending of Dymaxion #2 Foster offered to restore it, though the interior has been left hollow as they did not know what it was like. As of September 2009 the interior of #2 is being partially restored with the help of fans asSynchronofile.com.