wieght and speed- the truth!
Joined: May 2001
Posts: 2,390
Likes: 2
From: San Francisco, CA
Originally posted by Silkworm
Depends, do you want stability? I never thought the primary attribute of an auto-x car was it's stability.
More mass, more inertia, harder for outside forces to cause it to change direction, more stability, less agile and responsive.
PaulC
Depends, do you want stability? I never thought the primary attribute of an auto-x car was it's stability.
More mass, more inertia, harder for outside forces to cause it to change direction, more stability, less agile and responsive.
PaulC
Joined: May 2001
Posts: 2,390
Likes: 2
From: San Francisco, CA
Originally posted by Silkworm
You can argue that all night long, but you'd still be wrong. 2 separate forces acting in two totally separate vectors.
PaulC
You can argue that all night long, but you'd still be wrong. 2 separate forces acting in two totally separate vectors.
PaulC
There are many types of drag however. Induced drag, which is generated by a lifting surface such as a wing, transmits momentum to a fluid such as air. This momentum is lost and becomes drag. (which still has a different vector though). Hope that clears it up...
Back to the drag vs. downforce thing: The two are related, but there are no hard and fast rules. A general rule of thumb is that more downforce will create more drag. Hence if you crank up the angle of attack on your wing, you will generate more downforce, while creating more drag (less straightline speed).
An example, however, that may not be so intuitive is the wing on the rear of a vehicle like the Audi TT. Because of the rounded rear end of the vehicle, the air stream is accelerated over the back end and creates a lift vector that points upwards and to the rear. This serves to create rear lift at speed and also a copious helping of drag, which slows the car. Adding a spoiler creates boundary layer separation (so the back of the car no longer acts like the top of an airfoil), and you get less lift, with less drag -- a win-win situation.
If this is so great, you might ask, why doesn't everyone do it? The answer is looks (some stylists don't like the clean lines interrupted by aero aids) and bucks (spoilers cost dough). In the case of the Audi TT, Bernoulli wouldn't be denied, and the stylists had to concede.
An example, however, that may not be so intuitive is the wing on the rear of a vehicle like the Audi TT. Because of the rounded rear end of the vehicle, the air stream is accelerated over the back end and creates a lift vector that points upwards and to the rear. This serves to create rear lift at speed and also a copious helping of drag, which slows the car. Adding a spoiler creates boundary layer separation (so the back of the car no longer acts like the top of an airfoil), and you get less lift, with less drag -- a win-win situation.
If this is so great, you might ask, why doesn't everyone do it? The answer is looks (some stylists don't like the clean lines interrupted by aero aids) and bucks (spoilers cost dough). In the case of the Audi TT, Bernoulli wouldn't be denied, and the stylists had to concede.
Joined: May 2001
Posts: 2,390
Likes: 2
From: San Francisco, CA
Originally posted by elwood
Back to the drag vs. downforce thing: The two are related, but there are no hard and fast rules. A general rule of thumb is that more downforce will create more drag. Hence if you crank up the angle of attack on your wing, you will generate more downforce, while creating more drag (less straightline speed).
Back to the drag vs. downforce thing: The two are related, but there are no hard and fast rules. A general rule of thumb is that more downforce will create more drag. Hence if you crank up the angle of attack on your wing, you will generate more downforce, while creating more drag (less straightline speed).
btw, while drag and downforce have different vectors, the two forces are derived the same way mathematically but using their own coefficients.
Lift = surface area x coefficient of lift x air density x (V x V)
Drag = surface area x coefficient of drag x air density x (V x V)
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