Oxford Press

DETROIT — Ford Motor Co. on July 16 showed off the aerodynamic qualities of its boxy new 2009 Flex, which was designed to let wind sail with ease over its bumper, hood and pillars — despite its square shape — in an effort to improve fuel economy.

"It's amazing what the little details can do," Richard Gresens, the chief designer of the Flex, said at a wind tunnel testing facility in Allen Park, Mich., where a Flex was on display.

The Flex, which has been arriving in showrooms since early June, achieves 24 mpg/highway and 17 mpg/city.

Ford's communications team has been talking up the vehicle lately in an effort to promote the new model name to the public.

Although it's still early, dealers are reporting a mixed reception for the full-sized crossover in the increasingly gas- and cost-conscious environment, which has consumers seeking out the most efficient, affordable models. The Flex starts at $28,295.

At the wind tunnel, Ford executives demonstrated how much attention they gave to the vehicle's aerodynamics to make it more fuel-efficient.

To determine the ease with which a vehicle travels through the air, engineers measure the coefficient of drag.

The smaller the number, the less energy the vehicle needs to glide through the air.

Flex tests at 0.355 coefficient of drag, while competitors are at 0.375, Ford said.

One of the most important factors for reducing the drag of the Flex is the vehicle's low-riding stance, which prevents air from slowing down the vehicle in the underbody and also adds to the hip, low-slung look of the vehicle.

"The closer the vehicle is to the ground, the more airflow goes over the top, creating less drag," said Wayne Koester, an aerodynamic development engineer in Ford product development.