The Urbee

There is much about Urbee that is highly innovative. However, the innovation does not lie in expensive 'start-of-the-art' technology, the use of expensive materials, or complicated manufacturing processes. Urbee's innovation is that it uses widely available materials and components in original ways.

The designers of Urbee have attempted to maximize the distance that can be traveled per unit of energy consumed by minimizing seven important properties of the car: weight, coefficient of aerodynamic drag (Cd), rolling resistance (Crr), frontal area, maximum speed, maximum acceleration.

COEFFICIENT OF DRAG

The Coefficient of Drag (called "Cd") for a vehicle is one of three things that affect how much energy is required to overcome aerodynamic resistance. It is a number that describes the 'slipperyness' of a shape as it passes through the air. Urbee is being designed to have a Cd about half that of a traditional sports car.

COEFFICIENT OF ROLLING RESISTANCE

We have attempted to make the coefficient of rolling resistance of Urbee as low possible by using large diameter motorcycle tires inflated to high pressure. As well, the cross sectional profile selected for the tire has a very small contact surface with the road.

FRONTAL AREA

The frontal area of a vehicle is approximately equal to its width multiplied by its height. We decided to make the roof of Urbee as low to the ground as the lowest production car ever made, the Ford GT-40, which was 40 inches above the ground. We also tried to minimize the width by placing the two occupants as close as comfortably possible to each other.

MAXIMUM SPEED AND ACCELERATION

By reducing the maximum speed and acceleration of Urbee compared to what many other cars are capable of, we can dramatically reduce the maximum horsepower required to power our car. The smaller motor/engine size in turn decreases the weight of the vehicle and increases the range.