Downforce
12-18-2005, 11:50 PM
#62
Race Director
Originally Posted by Rich Sandor
No. A spoiler is a device that SPOILS airflow. Hence the name.
The duck tail on a 911RS is a perfect example of a spoiler.. it SPOILS the downward flowing air and prevents lift on the car. It doesn't actually create downforce though.
A "spoiler" on the front of a car is actually incorrect terminolgly. It should be called a splitter or an airdam, or a wing, but not a spoiler.
The duck tail on a 911RS is a perfect example of a spoiler.. it SPOILS the downward flowing air and prevents lift on the car. It doesn't actually create downforce though.
A "spoiler" on the front of a car is actually incorrect terminolgly. It should be called a splitter or an airdam, or a wing, but not a spoiler.
The bit about the "dive planes" came directly from someone with a degree in aerodynamics.
The other from Carroll Smith's "Tune to Win." I'd quote it but my copy is currently MIA.
12-19-2005, 12:22 AM
#63
Nordschleife Master
Geo, you can call it whatever you want, but a Spoiler is something that SPOILS airflow.
If you want, you can group splitters, air dans, and dive planes, all under "front spoilers", but I don't like that because of those, only "air dams" are specifically designed to "spoil" airflow.
The fact that people constantly interchange "spoiler" with terms like splitter and wing and air dam only adds to the confusion. If you ask anyone that works in the aviation industry, which is unarguably the root of aerodynamics, they will tell you a spoiler is a device that pops up on a wing to spoil downward flowing air and kill lift on a wing. This concept was copied over to cars like the 911RS and used to do exactly the same thing. However, as time went by, people starting incorrectly using the term "spoiler" for other things as well...
If you want, you can group splitters, air dans, and dive planes, all under "front spoilers", but I don't like that because of those, only "air dams" are specifically designed to "spoil" airflow.
The fact that people constantly interchange "spoiler" with terms like splitter and wing and air dam only adds to the confusion. If you ask anyone that works in the aviation industry, which is unarguably the root of aerodynamics, they will tell you a spoiler is a device that pops up on a wing to spoil downward flowing air and kill lift on a wing. This concept was copied over to cars like the 911RS and used to do exactly the same thing. However, as time went by, people starting incorrectly using the term "spoiler" for other things as well...
12-19-2005, 03:41 AM
#64
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Originally Posted by GlenL
Looking faster counts for something, doesn't it? And how about those bad boy rocker boxes. I'm getting another 5mph for those and the car is parked!
1) Almost all factory cars produce lift at speed (not lift with respect to a zero weight, but lift with respect to curb weight)
2) Aerodynamics is a myth.
12-19-2005, 09:02 AM
#65
Originally Posted by Geo
Actually, I think almost all cars generate lift.
12-19-2005, 10:16 AM
#66
Nordschleife Master
Originally Posted by patrat
You are correct in that no actual (gravitational) work is done holding the plane aloft, but power is indeed consumed; and frictional work is done. Your engines have to produce enough power to overcome the drag created by the wings, sufficient to allow the wings to create the force required to counter act gravity.
With enough power, you could make an aircraft fly with flat wings pitched at an angle. This would require a lot of power as the air in front of the wing is being physically displaced.
The airfoil is why a plane (747) with engines producing 66,500 pounds thrust can lift off weighing 960,000 pounds.
As to "spoiler" and "wing" what they really do and what they're called are separate issues on most cars. On a 944, that foam lip produces turbulence behind the car that allows air to more easily fill the void behind the vehicle. If the flow remained laminar there would be a larger vacuum back there and hence more drag.
Check out the way the exhaust swirls behind the car. Maybe without it the exhaust would not be drawn that way and make the back of my white car so nicely grey.
I think the biggest effect is looks, but what-the-hey.
12-20-2005, 12:53 AM
#67
Race Director
Originally Posted by GlenL
As to "spoiler" and "wing" what they really do and what they're called are separate issues on most cars. On a 944, that foam lip produces turbulence behind the car that allows air to more easily fill the void behind the vehicle. If the flow remained laminar there would be a larger vacuum back there and hence more drag.
I've got to find my copy of Tune to Win. Unfortunately we rearranged the area of the house where I had it in my bookcase and it's currently MIA. I'll try to find it this weekend.
I cannot say I have any direct knowledge, but I try to get my information from quality sources such as Carroll Smith or Racecar Engineering.
12-21-2005, 12:04 PM
#68
Nordschleife Master
The trick is to move from general into the specific. The use of terms is also suspect. I don't think the 944 spoiler functions much like the recent NASCAR spoilers, for example. Better to start with the similar and extend the behavior.
12-21-2005, 12:34 PM
#69
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Originally Posted by shiners780
Good thread. 
However, I'm beginning to get flashbacks to that damn "interesting question" thread regarding the airplane being able to take off....AAAAGGGGGHHHHHH!!!!!
However, I'm beginning to get flashbacks to that damn "interesting question" thread regarding the airplane being able to take off....AAAAGGGGGHHHHHH!!!!!
The 951 doesnt fly, the conveyor belt keeps the wheels rolling at a static rate.
end of discussion.
12-21-2005, 01:54 PM
#71
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Originally Posted by streckfu's951
Hitting the Chronic already, Juan? It's a little early there isn't it?
Que Pasa, Eh?! that's Juan-Sized, right there.
12-21-2005, 03:18 PM
#72
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www.en.wikipedia.org/wiki/downforce.
^^^^^^^^^^^^^^^^^^^^^^^^^^ This IS NOT A VALID SOURCE FOR ANYTHING EVER!
Anyone with an account can add or subtract any info they wish from or too that data base regardless of qualification or proof. Try using it as a source in a college setting.
Back to regular programming.
^^^^^^^^^^^^^^^^^^^^^^^^^^ This IS NOT A VALID SOURCE FOR ANYTHING EVER!
Anyone with an account can add or subtract any info they wish from or too that data base regardless of qualification or proof. Try using it as a source in a college setting.
Back to regular programming.
12-21-2005, 03:41 PM
#74
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meet kettle
This thread contains multiple refernces using wikipedia. It is not a vlaid source, therefore what I posted is infact quite germain to the converstaion at hand. As this has been a mostly quality tech thread, it should be important that we keep our reference sources of quality as well. It was not intended as a negative comment toward any person, but rather a comment seeking to define the validity of a source.
Next time you'dlike to acuse someone of post whoring, look in the mirror.
Location: Fishers, IN (Indianapolis)
Posts: 11,163
Pot^
meet kettle
This thread contains multiple refernces using wikipedia. It is not a vlaid source, therefore what I posted is infact quite germain to the converstaion at hand. As this has been a mostly quality tech thread, it should be important that we keep our reference sources of quality as well. It was not intended as a negative comment toward any person, but rather a comment seeking to define the validity of a source.
Next time you'dlike to acuse someone of post whoring, look in the mirror.
12-21-2005, 03:50 PM
#75
I wasn't calling you a post a *****. Sorry for the mis-understanding. I meant to back up your assertion that Wikipedia is usless by creating that page in about 2 minutes.
<<--------- Look. I am THE Post *****.
<<--------- Look. I am THE Post *****.
Originally Posted by ehall
Join Date: Jul 2002
Location: Fishers, IN (Indianapolis)
Posts: 11,163
Pot^
meet kettle
This thread contains multiple refernces using wikipedia. It is not a vlaid source, therefore what I posted is infact quite germain to the converstaion at hand. As this has been a mostly quality tech thread, it should be important that we keep our reference sources of quality as well. It was not intended as a negative comment toward any person, but rather a comment seeking to define the validity of a source.
Next time you'dlike to acuse someone of post whoring, look in the mirror.
Location: Fishers, IN (Indianapolis)
Posts: 11,163
Pot^
meet kettle
This thread contains multiple refernces using wikipedia. It is not a vlaid source, therefore what I posted is infact quite germain to the converstaion at hand. As this has been a mostly quality tech thread, it should be important that we keep our reference sources of quality as well. It was not intended as a negative comment toward any person, but rather a comment seeking to define the validity of a source.
Next time you'dlike to acuse someone of post whoring, look in the mirror.