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newtonsfirstlaw
EcoModding Apprentice

Join Date: Dec 2007
Location: Melbourne
Posts: 152

The Mighty Mira - '92 Daihatsu Mira
90 day: 61.32 mpg (US)
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Quote:
 Originally Posted by DifferentPointofView well, I was just thinking of the lift problem because the whole car is shaped like an airplane wing, and since there is more down force towards the rear of the vehicle...
If anything happens, that is the most likely of anything. But in most vehicles, there is downforce generated at the front of the vehicle (because the majority of air is pushed up especially with basjoos' car, and that generates an equal but opposite force on the front of the car downward. Because of that, it would be unlikely to tip over that way IMO. It might get equal, but there is also the weight of the car (remember that the rear wheel would be the pivot point, and most of the mass of the car is right at the front end, exerting larger torque).

Most cars generate lift at the back, because there is a low pressure area from the rear window backwards, and that rear window is pointed primarily in an upwards direction, so that component of force (Force = Pressure * Area) is large. I thought this was what you were getting at, but evidently not.

Quote:
 Most every car creates lift because of it's similar shape to an airplane wing, uneven raised surface on top, flat surface on bottom. The air going over the top has to go a lot faster than over the bottom so that the air meets up at the back at the same time as the bottom. This creates a high speed, low pressure on top and a low speed, high pressure on bottom, creating lift.
Third grade (and often, unfortunately, higher) level science textbooks have a lot to answer for in their attempts to teach aerodynamics by their mangled interpretation of Bernoulli.

There is no miraculous force that tells one molecule next to another molecule that it must somehow meet up at the other side of a vehicle at exactly the same time. None. To carry that meme to its logical conclusion, consider an inverted "T" shape - pretty much the ideal wing, because of all that distance and hence speed the air must travel around the top to reach the other side at the same time. Well no.

Please note that my ridicule is not aimed at you, it is aimed at ignorant publishers, science writers and teachers that credulously parrot these explanations. To help understand aero, spend a few hours googling "Newton" "Bernoulli", and aerodynamics in general.
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"Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed." - Isaac Newton

Last edited by newtonsfirstlaw; 12-24-2007 at 12:06 AM..