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Cd · 10-20-2012, 08:51 AM

Why Don't Pint-Sized Cars Get Better Gas Mileage? - Popular Mechanics

QUOTE : "The Spark's windshield angle is about 33 degrees. While that design yields more interior space, it also increases aerodynamic drag and reduces highway fuel economy."
"The Spark's short length impacts the drag in two main ways," explains GM's small-car development manager, Dan Molnar. "First, the grille and windshield are more upright to allow greater passenger space, and second, there's simply not enough length to smoothly guide air around the car."

The drag occurs at both ends: the air hitting the front of the car, and the vacuum created as the turbulent airflow spills off the car's rear. Longer cars may weigh more, but they can better approximate a teardrop shape, resulting in slightly less resistance as they travel, which helps highway mpg. Engineers attempt to reduce drag on shorter cars with various body features, such as smaller wheel openings and sometimes a rear lip spoiler, but there's only so much that can be done. The Spark's drag coefficient is a few percentage points higher than the Sonic's. "

The first thing that comes to mind when i see these comments is the Mercedes Benz A-Class, with it's excellent .27 Cd

Just look at the length . Look at the windshield angle .

Also the Mercedes Benz Bionic car with its excellent .19 Cd - just look at that steep windshield !

And the Sonic : Correction - Spark

10-20-2012, 08:51 AM	#1 (permalink)
Cd Ultimate Fail Join Date: Feb 2008 Location: Austin,Texas Posts: 3,585 Thanks: 2,872 Thanked 1,121 Times in 679 Posts	Older Article : Why Don't Pint-Sized Cars Get Better Gas Mileage? Why Don't Pint-Sized Cars Get Better Gas Mileage? - Popular Mechanics QUOTE : "The Spark's windshield angle is about 33 degrees. While that design yields more interior space, it also increases aerodynamic drag and reduces highway fuel economy." "The Spark's short length impacts the drag in two main ways," explains GM's small-car development manager, Dan Molnar. "First, the grille and windshield are more upright to allow greater passenger space, and second, there's simply not enough length to smoothly guide air around the car." The drag occurs at both ends: the air hitting the front of the car, and the vacuum created as the turbulent airflow spills off the car's rear. Longer cars may weigh more, but they can better approximate a teardrop shape, resulting in slightly less resistance as they travel, which helps highway mpg. Engineers attempt to reduce drag on shorter cars with various body features, such as smaller wheel openings and sometimes a rear lip spoiler, but there's only so much that can be done. The Spark's drag coefficient is a few percentage points higher than the Sonic's. " The first thing that comes to mind when i see these comments is the Mercedes Benz A-Class, with it's excellent .27 Cd Just look at the length . Look at the windshield angle . Also the Mercedes Benz Bionic car with its excellent .19 Cd - just look at that steep windshield ! And the Sonic : Correction - Spark Last edited by Cd; 10-20-2012 at 05:01 PM..