Wing Downforce Specs?
Originally posted by u00mem9
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**blah blah blah has been deleted by SC**
Last edited by Secret Chimp; Jan 24, 2004 at 11:34 PM.
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From: Turkey Town (Gobble-Gobble)
i have a quiestion, does the cut away of the EVO VIII spoiler reflect that of an aircraft wing?.... if it in anyway doesn't then your theory doesn't hold water... the only reason aircraft wings function as they do is due to their design... Not trying to prove anyone right or wrong just trying to throw out questions that might contradict things
It was merely to point out the way air flows - an aircraft wing is much more complex than our spoiler, as was pointed out. My point there was that we have two areas of pressure vs. one with an aircraft wing. I'm done trying to help out...
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From: Riverview, FL
Originally posted by djsbadger
If the wing is generating 70 lbs of downforce at 60 mph, that equates to :
194 lbs at 100 mph
280 lbs at 120 mph
437 lbs at 150 mph
As far as the wings effectiveness, one of the magazines (Autoweek?) noted the RS felt less stable than the standard
EVO on the fast corners and attributed it to the wing.
If the wing is generating 70 lbs of downforce at 60 mph, that equates to :
194 lbs at 100 mph
280 lbs at 120 mph
437 lbs at 150 mph
As far as the wings effectiveness, one of the magazines (Autoweek?) noted the RS felt less stable than the standard
EVO on the fast corners and attributed it to the wing.
In the recent Rally of Jamaica, a driver lost his rear wing (Evo 5)and replaced it with one from his road car... he had to as the back end was VERY NERVOUS, after fixing it... we went on to win 5 stages.
On the road... well I guess its mostly for style as you should not be driving that fast
hehehe
On the road... well I guess its mostly for style as you should not be driving that fast
hehehe
Last edited by jemm; Jan 24, 2004 at 05:31 PM.
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From: Orange County, CA
Originally posted by Chris in HB
BTW, I don't think the downforce will be that high. At least not net downforce. Keep in mind that as speed increases, underbody lift does, as well. This is why I mentioned in my original post that the Evo's wing doesn't really provide pavement-sucking downforce in the sense that most people think. It merely negates the lift in the rear end, not that this is a bad thing. To generate true downforce (and in this application, it would upset the car's balance), there would have to be some type of diffuser tray under the rear (similar to the front). Before someone does this, consider that if you have smooth airflow at the front, and then smooth out the airflow at the back, you'll end up with a pressure area in the center of the car. This is why many sports racers have full flat-bottom or venturi-bottomed cars - to eliminate any pressure areas and have smooth underbody flow. Ideally, we would have someone construct us a panel that would attach to the rear of the front panel, travel the length of the car between the wheels and mate up to a panel at the rear to diffuse the airflow cleanly out the back. If we had that, then any canards (at the front) and wings (at the back) would have true aero effect at high speeds (not just negating lift). Hope this helps...
Chris
BTW, I don't think the downforce will be that high. At least not net downforce. Keep in mind that as speed increases, underbody lift does, as well. This is why I mentioned in my original post that the Evo's wing doesn't really provide pavement-sucking downforce in the sense that most people think. It merely negates the lift in the rear end, not that this is a bad thing. To generate true downforce (and in this application, it would upset the car's balance), there would have to be some type of diffuser tray under the rear (similar to the front). Before someone does this, consider that if you have smooth airflow at the front, and then smooth out the airflow at the back, you'll end up with a pressure area in the center of the car. This is why many sports racers have full flat-bottom or venturi-bottomed cars - to eliminate any pressure areas and have smooth underbody flow. Ideally, we would have someone construct us a panel that would attach to the rear of the front panel, travel the length of the car between the wheels and mate up to a panel at the rear to diffuse the airflow cleanly out the back. If we had that, then any canards (at the front) and wings (at the back) would have true aero effect at high speeds (not just negating lift). Hope this helps...
Chris
When can you have it ready...
Thanks for your contribution. Dont get discouraged.
Sean
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From: Virginia Beach, VA
Originally posted by u00mem9
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blah blah blah has been deleted by SC**
Speaking of pulling things out of thy rectum - maybe you should heed your own warning.
What these guys are talking about isn't coming out of their asses. It IS physics.
Go troll somewhere else.
Last edited by Secret Chimp; Jan 24, 2004 at 11:36 PM.
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Originally posted by Chris in HB
The net result of the wing is not positive downforce, but zero lift at speed. For genuine downforce (above the lift negation), the angle of attack on the wing (the slant) would have to be greater. Also the shape of the back edge of the roof plays a big part as to where the air flows (ie over or under the wing element - the center part).
However on a full-size race track, the wing will help keep the car stable coming into the braking zones.
The net result of the wing is not positive downforce, but zero lift at speed. For genuine downforce (above the lift negation), the angle of attack on the wing (the slant) would have to be greater. Also the shape of the back edge of the roof plays a big part as to where the air flows (ie over or under the wing element - the center part).
However on a full-size race track, the wing will help keep the car stable coming into the braking zones.
To say that surface (rear trunk) would be influenced some by the wing is correct. That is the very reason that given the chance, a race car designer will mount the wing behind all body work. Since the underside of a wing is a low pressure area, the air pressure on the trunk on an EVO (under the wing) with the wing would likely be lower than the pressure on the trunk of a wingless evo. However, the loss of downforce (or lift) on the trunk is not as large as the increase in downforce that the wing gives. That is why racing cars still have wings, even when they must mount them over bodywork. Also, the higher the wing is mounted, the less it will affect the air flowing over the trunk, and the more efficient it becomes.
While downforce has no mass, it is a force and weight is a force as well. The beauty of downforce is that it pushes down on the car (like a weight) but it does not have to be accelerated and stopped. For purposes of calculations, downforce which is due to pressure acting over an area, can always be converted to a resultant force acting at a specific location. Because the wing is mounted behind the rear tire, it can reduce the load on the front tires in the same way that a see saw works.
The weight is not pressing down *edit* solely *edit* on the wing, it is pressing down on the car in the area under the wing... And besides, as someone else earlier mentioned, downforce is not mass, so it cannot be equated with putting the same amount of mass on the wing. It is simply a way to measure an equivalent number in relative figures. Think about it - F1 cars can produce over 3000 pounds (1500kgs) of downforce at speed. Why doesn't the car break apart?
the wing is inverted which means the low pressure area would be above the trunk(which means nothing). the incidence of the wing is great enough that were it right side up the rear end of the car would get lighter, when driven at speed. as installed it pushes down
the fact that it is an airfoil simply means the designer was trying to reduce drag. you tuner nuts might try shaping the trailing edge knife edge sharp. litigation and manufacture prolly why it is blunt.
the turbulence of the roofline negates a lot of downward pressure, that is why it is as large as it is and as high as it is, to find clean air. nevertheless it will push down on the back of the car.
the underside of the car might benefit from a smooth skin, drag wise, but it would be suited best with as little air under it as possible.
that is why race cars have very low body moldings- to keep the air out.
just an opinion, bruce
the fact that it is an airfoil simply means the designer was trying to reduce drag. you tuner nuts might try shaping the trailing edge knife edge sharp. litigation and manufacture prolly why it is blunt.
the turbulence of the roofline negates a lot of downward pressure, that is why it is as large as it is and as high as it is, to find clean air. nevertheless it will push down on the back of the car.
the underside of the car might benefit from a smooth skin, drag wise, but it would be suited best with as little air under it as possible.
that is why race cars have very low body moldings- to keep the air out.
just an opinion, bruce
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From: Clovis, New Mexico USA
Originally posted by nothere
the fact that it is an airfoil simply means the designer was trying to reduce drag. you tuner nuts might try shaping the trailing edge knife edge sharp. litigation and manufacture prolly why it is blunt.
the fact that it is an airfoil simply means the designer was trying to reduce drag. you tuner nuts might try shaping the trailing edge knife edge sharp. litigation and manufacture prolly why it is blunt.
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Originally posted by djsbadger
The overall car likely produces lift, much like a Porsche 911 does. However, to say the wing is not producing downforce but only zero lift is wrong. Probably not as bad as calling it a spoiler though, spoilers only flow air above them for downforce. If you are producing zero lift, the wing is doing nothing for stability and only creating drag. The wing on the evo has a downward angle of attack aprox. 3-5 degrees. Additionally, the top is flat and the bottom is curved so it is a cambered wing which even at a 0 angle of attack, would produce downforce.
To say that surface (rear trunk) would be influenced some by the wing is correct. That is the very reason that given the chance, a race car designer will mount the wing behind all body work. Since the underside of a wing is a low pressure area, the air pressure on the trunk on an EVO (under the wing) with the wing would likely be lower than the pressure on the trunk of a wingless evo. However, the loss of downforce (or lift) on the trunk is not as large as the increase in downforce that the wing gives. That is why racing cars still have wings, even when they must mount them over bodywork. Also, the higher the wing is mounted, the less it will affect the air flowing over the trunk, and the more efficient it becomes.
While downforce has no mass, it is a force and weight is a force as well. The beauty of downforce is that it pushes down on the car (like a weight) but it does not have to be accelerated and stopped. For purposes of calculations, downforce which is due to pressure acting over an area, can always be converted to a resultant force acting at a specific location. Because the wing is mounted behind the rear tire, it can reduce the load on the front tires in the same way that a see saw works.
The car doesnt break appart because the load is distributed over the entire car. Would you rather have a hundred pound blanket placed over you, or a knife pushing with 20 lbs force? How the load is disributed makes a huge difference. Finally, if someone is producing fences to direct air away from the underside of the rear wing, then they are hurting the wings effectiveness, not helping it.
The overall car likely produces lift, much like a Porsche 911 does. However, to say the wing is not producing downforce but only zero lift is wrong. Probably not as bad as calling it a spoiler though, spoilers only flow air above them for downforce. If you are producing zero lift, the wing is doing nothing for stability and only creating drag. The wing on the evo has a downward angle of attack aprox. 3-5 degrees. Additionally, the top is flat and the bottom is curved so it is a cambered wing which even at a 0 angle of attack, would produce downforce.
To say that surface (rear trunk) would be influenced some by the wing is correct. That is the very reason that given the chance, a race car designer will mount the wing behind all body work. Since the underside of a wing is a low pressure area, the air pressure on the trunk on an EVO (under the wing) with the wing would likely be lower than the pressure on the trunk of a wingless evo. However, the loss of downforce (or lift) on the trunk is not as large as the increase in downforce that the wing gives. That is why racing cars still have wings, even when they must mount them over bodywork. Also, the higher the wing is mounted, the less it will affect the air flowing over the trunk, and the more efficient it becomes.
While downforce has no mass, it is a force and weight is a force as well. The beauty of downforce is that it pushes down on the car (like a weight) but it does not have to be accelerated and stopped. For purposes of calculations, downforce which is due to pressure acting over an area, can always be converted to a resultant force acting at a specific location. Because the wing is mounted behind the rear tire, it can reduce the load on the front tires in the same way that a see saw works.
The car doesnt break appart because the load is distributed over the entire car. Would you rather have a hundred pound blanket placed over you, or a knife pushing with 20 lbs force? How the load is disributed makes a huge difference. Finally, if someone is producing fences to direct air away from the underside of the rear wing, then they are hurting the wings effectiveness, not helping it.
And regarding F1 cars, just as one example, the rear wing is mounted to the f*****g gearbox, not a trunk or some other peice of thin metal.
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From: NR Reading PA
Originally posted by SOF
This is the only post in this entire thread that has any resemblance of correct information.
And regarding F1 cars, just as one example, the rear wing is mounted to the f*****g gearbox, not a trunk or some other peice of thin metal.
This is the only post in this entire thread that has any resemblance of correct information.
And regarding F1 cars, just as one example, the rear wing is mounted to the f*****g gearbox, not a trunk or some other peice of thin metal.
Speedlimit...
sorry, the low pressure above the trunk does nothing, it is the wings force through the mounting points that is pushing down.
tape a piece of paper to the rear window at it's base, so that it covers the trunk (or use pieces of yarn). go for a drive that piece of paper is going to float up. there is just to much "bad" air behind the roofline.
havn't you guys seen models laying accross car hoods or trunks before, they have to weigh at least 90 lbs each.
almost any car body will make lift at speed, heck a pimple on a nats back will make lift if he is going fast enough.
the wing is there to counteract the lift. it prolly also helps to cut the airstream some, same as a spoiler. but, just guessing again, I wouldn't think that is a big factor.
tape a piece of paper to the rear window at it's base, so that it covers the trunk (or use pieces of yarn). go for a drive that piece of paper is going to float up. there is just to much "bad" air behind the roofline.
havn't you guys seen models laying accross car hoods or trunks before, they have to weigh at least 90 lbs each.
almost any car body will make lift at speed, heck a pimple on a nats back will make lift if he is going fast enough.
the wing is there to counteract the lift. it prolly also helps to cut the airstream some, same as a spoiler. but, just guessing again, I wouldn't think that is a big factor.