Build This Classic Urban Car and get 55 mpg at 60 mphWhen UrbaCar was featured on the cover of Mechanix Illustrated magazine in the mid-seventies it set off a build-it-yourself car boom that would last for over ten years. It was the first in a long series of alternative cars that would be featured by Mechanix Illustrated magazine. Ultimately it would lead to a series of unique car designs following a minimalist alternative car theme. UrbaCar was envisioned as an in-town runabout that would help reduce dependence on imported oil, but in reality it was a precursor to today's super-mileage cars like Smart Car and hybrids UrbaCar is an ideal father/son project.
Instant DownloadThe plans are available for instant download and include ten 24 x 36 inch drawings in PDF format, a 36-page booklet in PDF format, and 2D CAD plans supplied in AutoCAD R12 level dxf format.
The original prototype, as it appears in Mechanix Illustrated, was powered by a 12 kW (16 hp) single cylinder industrial engine mounted in the rear. It delivered a top speed of 95 km/h (60 mph) and fuel economy on the order of 23 km/l (55 mpg). Using today’s automotive technology, it could easily reach 100 mpg. The design featured removable gull-wing doors and a 10 gallon fuel tank that would hold enough fuel for nearly 965 km (600 mi).
UrbaCar tips the scales at a mere 295 kg (650 lb). Because of its low curb weight, the small 12 kW (16 hp) engine still gives it a power-to-weight ratio about equal to that of the early VW Beetle. And more powerful engines can be installed. The simple drive train uses a continuously variable transmission (CVT), which transfers power to an oil-bath chain drive and then through a differential to the rear wheels. A standard automotive starter motor drives the car in reverse. The integral power train (engine, transmission, and final drive mounted on a sub-frame) is suspended from the rear of the chassis at four points using soft rubber mounts. This allows for easy removal of the drive package, and it effectively isolates vibrations.
Ultimately, UrbaCar went through three generations of improvements. The perfected version was slated for production in Kitchener, Ontario, until public interest in high fuel economy vanished as the oil market stabilized. Plans offered here include the previously unpublished and vastly improved production chassis. It is still classified as a “1975 UrbaCar.” A non-functional UrbaCar is on display at the American Museum of Science and Energy at Oak Ridge, Tennessee.
UrbaCar’s body is built of FRP/urethane foam composite. For more information on the body construction method, click on One-Off Construction Using FRP/Urethane Foam Composite. Click here for more on the history of UrbaCar, published on the Forgotten Fiberglass website. Be sure to follow their link to a video of the pre-production prototype on the road in Canada (incorrectly labeled as the “first electric car”).
ABOUT THE PLANS
Plans are based on an upgraded chassis design and done in 2D CAD. These revised plans include improvements to the chassis and power train that were developed over three generations of prototypes. The frame and final drive package is the pre-production design that went to Kitchener, Ontario, in anticipation of production. The body is the original fiberglass-over-foam body on the vehicle that appeared in Mechanix Illustrated Magazine. Until this revised plan-set was published, the new chassis design was not available to the general public. The vehicle is designed to 1975 motor vehicle code, so exemptions may be required, depending in the DIY vehicle code in your state.
A pre-production prototype was sent to a start-up group in Kitchner Ontario. They made modifications, many of which were good. Their biggest mistake was to install a 2-cycle engine, which was a disaster for fuel economy.