Quote:
Originally Posted by donee
Hi All,
I think we can all agree that parachutes work. And parachutes do not have air flowing through them.
The front grill of a car , with the grill blocked from behind is a parachute. But, in the overall drag of the car, its not that big a percentage. It takes energy to form the air bubble. Otherwise, skydivers would die.
Letting air flow through the non-aerodynamic spaces of the engine comparment is going to have allot of drag too.
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If I understand parachutes correctly, they work by increasing the surface area. The shape of the parachute is secondary and works twofold. The cup shape is better at catching air, but that takes me to the second point, it has to be cup shaped to stay inflated, i.e. it has to be inflated to maintain the surface area... If you could make a parachute that was flat and rigid of equal area, (and weight and was aerodynamically stable) you would fall faster, but it would still slow you down almost as well. I will argue that the surface area is king here. So I will agree, the front grill of a car with the grill blocked from behind is parachute shaped, but not of a greater area.