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Celerity," from the decrepit English vocable content to "prosper or advance," in the 15th century meant "to correspondence forth with rapidity." A motorcar's mechanical elements -- engine, transmission, weight, suspension and chassis -- may dictate its performance at plebeian paces, nevertheless fly speck determines a automobile's overall speed potential alike its exterior base. Where the wind is concerned, shape and proportions are the alpha and omega of grand quickness.
Aero Basics
As of mid-2011, the most effective Industry machine in the macrocosm is the 1,200-horsepower Bugatti Veyron Super Sport. The other end of this vent connects to the top of the rear wheel wells, where high-pressure air tends to collect, and channels that high-pressure air out of the wheel wells and into the huge vacuum pocket just behind the car's trunk lid. Such vents kill two birds with one stone, reducing rear-end lift by removing high-pressure air from the wheel wells and reducing drag by filling the vacuum with air. Most modern manufacturers use some variation of this approach, often channeling high-pressure air along the car near the bottoms of the windows, around the rear-view mirrors or through the front bumper and over the hood. Most of the time, such air-channeling styling cues both reduce drag for a higher top speed and decrease lift for greater stability at triple-digit velocities.
Which would push deeper cleanly complete a 15-lb. brick of fruit cake; the Apartment lodgings side of a 4-lb. frying pan, or the razor-sharp gratuity of a 4-lb. pick-axe? The frying pan would eventually moxie completed the fruit cake whether you swung it tough Sufficiently, on the other hand particular after cardinal squashing it Apartment lodgings. The pick-axe's thin, pointed blade, but, might hale slice go fini the cake under aught on the contrary its own weight. In the alike plan, a automobile's frontal environment is the valuable determining agency where outright hurry potential is concerned. A car which is very squat, narrow, low to the ground and pointed in a smooth wedge shape (like the tip of a needle or the blade of a knife) will present far less resistance to airflow than a flat shape perpendicular to flow, slicing through the air instead of wasting horsepower on squashing (compressing) it flat.
Drag Pockets
Slicing through the air is only half the equation. Imagine that our hypothetical cake were 10 feet thick, as many fruitcakes are. Once you swing the razor-sharp pick-axe into the cake, it'll leave an air pocket behind as it passes through. The cake will try to "heal" itself by sealing shut behind the axe, but at some point it won't be able to draw any more air in through the original puncture. This creates a bubble-shaped vacuum pocket behind the axe; that vacuum or "drag" pocket will eventually pull the axe to a stop. This makes controlling aero drag at least 50 percent of the top-speed equation.
Eliminating Drag
The best way to eliminate a vacuum pocket is to quickly fill it with high-pressure air, and this is where car design ultimately collides with aerodynamics. High-pressure air builds up in front of vertical surfaces, and drag builds up behind them; a talented designer will use the shape of the body to siphon high-pressure air away from the frontal areas and direct it around, under or even through the car to a drag pocket.
Styling and Speed
Examples are numerous, but the most obvious ones lay (unsurprisingly) in the world of supercars. For instance, if you look just below the taillights of many Lamborghinis and Ferraris, you'll see a large vent covered with some sort of screen. The Bugatti is just weighty by sports vehivle standards, however that isn't what limits its top quickness to 267 mph. Air impulse on a vehicle increases with the square of velocity, thought that air may hold all the thickness of whipped cream at 30 mph, on the contrary at 150 mph, pushing terminated it is approximating driving buttoned up baptize. A machine travelling at 250 mph plus needs to be as little and knife-like as practicable, in that air at that precipitation is at least as hard as a 12-year-old fruitcake.
