Fastskinz MPG-Plus: Golf Ball-Like Dimples Won't Improve Fuel Efficiency
Golf balls are covered in dimples because of one simple fact: the irregularities in the ball reduce wake, allowing the ball to travel farther. Using this logic, a company called Fastskinz created a full-vehicle vinyl wrap called MPG-Plus that it claims increases fuel economy by 18 to 25 percent.
Popular Mechanics' Ben Stewart tested the skin on a 2009 Ford Flex. Stewart obtained two fully loaded Ford Flex crossovers decked out in Limited trim, each with about 8000 miles on the odometer and a full tank of gas. He outfitted one with the Fastskinz MPG-Plus wrap, and left the other one alone.
Predictably, Stewart found the MPG-Plus had no effect on the fuel efficiency of the Flex. If the fuel economy gauges in the vehicles are to be believed, the Flex without the skin actually achieved better mileage. After 430 miles, Popular Mechanics measured mileage of 24.52 mpg for the wrapped Flex, while the naked Flex returned 24.55 mpg. The dash displays read 24.8 for the Fastskinz Flex and 25.6 for the normal Flex.
Popular Mechanics speculates that the full-skin wrapping is overkill -- it may actually have a negative effect on airflow.
Steve Ogg, the president of golf ball research and development for Callaway, explains how the dimples work on a golf ball: "A golf ball is a bluff body and most of the drag is due to airflow separation -- the flow cannot close behind the ball and stay attached. The dimples transition the flow from a smooth laminar state to chaotic turbulent state. The turbulent mixing increases the momentum of the air at the surface of the ball, allowing it to stay attached longer."
The Fastskinz MPG-Plus would have to be more discreet about where it tries to break up airflow. In some places, the MPG-Plus may actually smooth out turbulent airflow, which would ultimately decrease fuel mileage. Ford's supervisor of aerodynamics, Bill Pien, says the skin friction accounts for no more than1 percent of the total drag, anyway -- the shape of the vehicle is the most important factor.
Even though the Fastskinz MPG-Plus probably won't improve your fuel efficiency, it may still be coveted by polka-dot lovers seeking a unique look for their vehicles. Head on over to Popular Mechanics to read Stewart's full procedure and analysis, or check out the FastSkinz website for more information about the MPG-Plus.
Source: Popular Mechanics