View Full Version : And so it begins... McLaren protest unlikely
First practice hasn't even started and it begins. ;)
Red Bull Racing team principal Christian Horner has played down the possibility of his team deciding to officially protest the McLaren over its ingenious aerodynamic devices. (http://www.autosport.com/news/report.php/id/81998)
This thing entails the driver moving his legs to cover a hole in the cockpit tunnel that changes the air flow. :confused::saywhat:
opinionated ow
03-11-10, 10:01 PM
First practice hasn't even started and it begins. ;)
Red Bull Racing team principal Christian Horner has played down the possibility of his team deciding to officially protest the McLaren over its ingenious aerodynamic devices. (http://www.autosport.com/news/report.php/id/81998)
This thing entails the driver moving his legs to cover a hole in the cockpit tunnel that changes the air flow. :confused::saywhat:
I'd love somebody to explain to me how a "stalled wing" produces less drag. Conventional wisdom and the official aviation theory (which I am licensed to teach) dictates that beyond the critical (stalling) angle the separated turbulent airflow produces enormous amounts of induced drag.
I'd love somebody to explain to me how a "stalled wing" produces less drag. Conventional wisdom and the official aviation theory (which I am licensed to teach) dictates that beyond the critical (stalling) angle the separated turbulent airflow produces enormous amounts of induced drag.
http://www.langleyflyingschool.com/Images/CPL%20Aerodynamics%20and%20Theory%20of%20Flight%20 Part%201/Drag%20Curve.gif
I agree with what you are saying, but your graph doesn't seem relevant to the discussion since it deals with stall from too slow of a speed, there is no angle on the chart.
http://lh5.ggpht.com/slimjim8201/SE7WA9E3Z1I/AAAAAAAAASQ/jaSixIplwNE/s800/Lift%20and%20Drag.jpg
I was checking out the discussion at autosport, and here is what I think. Horner said the wing was being put into stall, but Horner isn't an engineer. I think they are taking in air in a high pressure area (rumored to be in front of cockpit) and using a swith or drivers knees to move a flap, they can let the air route through the engine cowling, through the wing and out the back. Simply put, they are routing high pressure air from the front and using it to fill the low pressure area on the bottom and backside of the rear wing. Higher pressure air vented there reduces drag and downforce. Remove the high pressure air, and downforce and drag returns. Still sounds like a movable aero device is incorporated to me.
opinionated ow
03-12-10, 02:20 AM
I agree with what you are saying, but your graph doesn't seem relevant to the discussion since it deals with stall from too slow of a speed, there is no angle on the chart.
Yeah you're right, I didn't actually look at it I just linked to it :rolleyes:
However the same principles of separation and transition apply because as you correctly point out, the aerodynamic stall is a function of angle of attack and not airspeed.
Link to Autosport thread. (http://forums.autosport.com/index.php?showtopic=125295)
It's all a bit too much for me to understand, especially on a friday night after a couple of beers. :gomer:
opinionated ow
03-12-10, 07:30 AM
I was checking out the discussion at autosport, and here is what I think. Horner said the wing was being put into stall, but Horner isn't an engineer. I think they are taking in air in a high pressure area (rumored to be in front of cockpit) and using a swith or drivers knees to move a flap, they can let the air route through the engine cowling, through the wing and out the back. Simply put, they are routing high pressure air from the front and using it to fill the low pressure area on the bottom and backside of the rear wing. Higher pressure air vented there reduces drag and downforce. Remove the high pressure air, and downforce and drag returns. Still sounds like a movable aero device is incorporated to me.
That's a conceivable consideration at 10:30 after just having spent the last two hours supervising 20 children. I'm gonna have to draw myself some diagrams to see if I can get it right in my head. It makes much more sense than that autosport thread where some have the idea that a stalled wing produces less drag...
This thing entails the driver moving his legs to cover a hole in the cockpit tunnel that changes the air flow. :confused::saywhat:
Apparently, air comes in though a snorkel on the nose of the car, down a duct that runs down into the footwell, along and up though the car and out the hole in the shark fin, where it disrupts the air flowing under the wing reducing the downforce and lowering drag which raises the speed of the car by 3-4 kph.
There is a hole in the duct near the drivers feet that lets the air out to "cool his feet." When it is open, no air flows on to the wing. When the driver covers up the hole with his foot, it send the air flow up the duct and on to the wing. The only moving part is the drivers foot, which makes it all legal. For the moment.
Craig Scarborough explains it better on his blog. Link (http://scarbsf1.wordpress.com/)
Where he also says:
This is what F1 aerodynamicists term a ’stalled’ condition, although this is different to the term ’stall’ used in aeronautical aerodynamics.
:)
There is a hole in the duct near the drivers feet that lets the air out to "cool his feet." When it is open, no air flows on to the wing. When the driver covers up the hole with his foot, it send the air flow up the duct and on to the wing.
:)
I caught a bit of practice this AM. According to their explanation and my early AM understanding - it was the opposite.
There is some sort of bladder or bag. When the driver enters the straight, he presses the bag with his leg to block the hole - blocking the hole stops the air from entering the rear wing creating this "stall" effect and lowering drag on rear wing.
OR I could have misheard the whole thing. :gomer:
Maybe I am wrong, but I don't believe the air going through the cowling is blowing over the wing at all. I believe the air is routed internally in the wing and expelled out the back. Reading the Autosport link, I think they are saying essentially what I said above as to how it works.
When air pressure is the same on both sides of the wing, that's a stall. No lift. No drag. Increasing pressure under the wing on the straight, reduces downforce. I bet they're "compressing" the air as it flows through the chassis to increase its pressure.
There is some sort of bladder or bag. When the driver enters the straight, he presses the bag with his leg to block the hole - blocking the hole stops the air from entering the rear wing
If you change one phrase in what you said "entering the rear wing" to entering the cockpit, then you and Badger are saying the same thing.
If you change one phrase in what you said "entering the rear wing" to entering the cockpit, then you and Badger are saying the same thing.
I thought it was both?
My understanding from Speed (perhaps mistaken - it was early) was that air entered the cockpit via the new scoop and somehow onto the wing via an internal duct. Blocking the duct while on the straight prevented air from reaching the wing thus lowering drag somehow.
Maybe Machett has it wrong?
I'll listen again on the DVR tonight.
Link to Autosport thread. (http://forums.autosport.com/index.php?showtopic=125295)
It's all a bit too much for me to understand, especially on a friday night after a couple of beers. :gomer:
But, but...it's Friday morning...did you come from the future. :gomer: :D
-Kevin
When air pressure is the same on both sides of the wing, that's a stall. No lift. No drag. Increasing pressure under the wing on the straight, reduces downforce. I bet they're "compressing" the air as it flows through the chassis to increase its pressure.
I bet not since you would need a compressor to "compress" the air. You don't need to compress it, air taken in at the front will be higher pressure than air under a wing anyway.
I thought it was both?
My understanding from Speed (perhaps mistaken - it was early) was that air entered the cockpit via the new scoop and somehow onto the wing via an internal duct. Blocking the duct while on the straight prevented air from reaching the wing thus lowering drag somehow.
Maybe Machett has it wrong?
I'll listen again on the DVR tonight.
It is both. In the cockpit on the corners. Under the wing on the straight. but it is not reducing drag by reducing airflow. It adds airflow to balance pressure which reduces drag. : I.e. increasing pressure under the wing on the straightaway.
I bet not since you would need a compressor to "compress" the air. You don't need to compress it, air taken in at the front will be higher pressure than air under a wing anyway.
An engineer can jump in, but the speed of the air is important. All a wing really does is slow down air on one side of the wing, creating a pressure differential. For downforce, you slow down the air on the top of the wing. pressure builds on top of the wing, pressing the car down, giving it more grip in the corner. To remove downforce, you need "faster air " underneath. I think the air moving through the chassis would need to be going slower than the air going over top of it. Therefore, I'm guessing, the channel probably narrows as it moves towards the back of the car, which increases the air pressure.
So I think it works this way. Air is forced through a narrow channel under the car, and released under the rear wing. The high-pressure airs lift the rear wing, reducing its angle, reducing drag. remove your foot, the back of the car sinks and you get the downforce you need for cornering.
chop456
03-12-10, 01:33 PM
How long before Ferrari asserts that air is a moveable aerodynamic device? :gomer:
TrueBrit
03-12-10, 02:18 PM
How long before Ferrari asserts that air is a moveable aerodynamic device? :gomer:
Countdown begins in 5...4...3..
An engineer can jump in, but the speed of the air is important. All a wing really does is slow down air on one side of the wing, creating a pressure differential. For downforce, you slow down the air on the top of the wing. pressure builds on top of the wing, pressing the car down, giving it more grip in the corner. To remove (add) downforce, you need "faster air " underneath. I think the air moving through the chassis would need to be going slower than the air going over top of it. Therefore, I'm guessing, the channel probably narrows as it moves towards the back of the car, which increases the air pressure.
So I think it works this way. Air is forced through a narrow channel under the car, and released under the rear wing. The high-pressure airs lift the rear wing, reducing its angle, reducing drag. remove your foot, the back of the car sinks and you get the downforce you need for cornering.
I'm BS Engineering Mechanics so I think I can commment. When you force air through a narrow channel, air pressure does not build, it decreases. That is the Bernoulli principle and that is the way ground effects work. I'll overly simplify what I think McLaren is doing. Take a square board and hold it out against an oncoming wind velocity. Lots of drag. Now, take the same board, and cut a hold in the middle. Less drag. I think that is what McLaren is doing, they are filling the low pressure air (which causes drag) with high pressure air routed from the front. I don't really consider that "stalling" the wing in the traditional sense, but that appears to be how the f1 engineers are referring to it.
The World gets this, and the US gets wedges and new mirror stalks. :shakehead
I'm BS Engineering Mechanics so I think I can commment. When you force air through a narrow channel, air pressure does not build, it decreases. That is the Bernoulli principle and that is the way ground effects work. I'll overly simplify what I think McLaren is doing. Take a square board and hold it out against an oncoming wind velocity. Lots of drag. Now, take the same board, and cut a hold in the middle. Less drag. I think that is what McLaren is doing, they are filling the low pressure air (which causes drag) with high pressure air routed from the front. I don't really consider that "stalling" the wing in the traditional sense, but that appears to be how the f1 engineers are referring to it.
OK. So I got the shape of the tunnel backwards. But if the air pressure doesn't change as it moves through the car, that's probably why it's not considered an aerodynamic device.
Where is the high pressure air coming from? Above the front wings? Then, aren't they just moving the high pressure air above the front wing, underneath the back wing?
Steve99
03-12-10, 04:07 PM
This is very interesting. That snorkel looks really tacked on, I'm surprised it's not more integrated into the nose of the car.
This could be really fun at Malaysia if there is another late race downpour. I wonder how much water an F1 tub can hold.
I'll overly simplify what I think McLaren is doing. Take a square board and hold it out against an oncoming wind velocity. Lots of drag. Now, take the same board, and cut a hold in the middle. Less drag.
I may suck at the Bernoulli principle, but engineers suck at oversimplification. In your example, you're just reducing the area that creates downforce/drag. That's not what McLaren is doing. They're moving air, without changing its speed, which would - as you point out - change its pressure and therefore be an aerodynamic device. Right? The turbulent air, which creates drag, is caused by unbalanced pressure on the rear wing. They're moving high pressure air under the rear wing on the straights.
I should also point out it is dangerous as hell, which is one reason why movable aerodynamic devices are banned. The best drivers are the ones who change the weight on each tire very subtly: driving school, dayone. When the downforce/drag ratio changes quickly the car becomes unstable. That isn't a problem if you're the only one who has the advantage and you can take your foot off the "hole" well before the corner. But, if everyone has the device, and everyone waits to see how long they keep the hole covered....
oddlycalm
03-12-10, 05:12 PM
This could be really fun at Malaysia if there is another late race downpour. I wonder how much water an F1 tub can hold.
That's what I was thinking, what happens in a real frog choker? How fun would it be to see both McLarens slow to a crawl with water sloshing out of the cockpit...:laugh: :thumbup:
oc
OK. So I got the shape of the tunnel backwards. But if the air pressure doesn't change as it moves through the car, that's probably why it's not considered an aerodynamic device.
Where is the high pressure air coming from? Above the front wings? Then, aren't they just moving the high pressure air above the front wing, underneath the back wing?
Air pressure could change as it moves through the car, it all depends on the area of the tubing. Smaller tubing increase velocity, decreasing pressure, larger tubing lowers velocity, increasing pressure. However, they probably wouldn't want the pressure to change since they want the higher pressure air at the front of a car and some energy is lost when air gets moved around. The internal flow would be as clean and free of bends as possible.
On a street car, air at the grill and at the base of the windshield would be high pressure regions. You have to realize, the magnitudes of the air pressure differences are quite small, so when I say high pressure, its not that the pressure is like pressurized air to fill tires, it's only slightly higher than the air behind and below the rear wing. The difference is small, but with enough area, you create downforce.
In my example, if you create the snorkel, mount it offset of the hole so frontal area isn't changed, and then route it to the hole, you would still be feeding the higher pressure air to the hole and redecing drag. Take that same board with the large area facing the wind, and put your hand behind that board. That area is a low pressure region, which causes air to swirl around as it flows past. Now let some higher pressure air come out the middle. The high pressure air smoothes the flow going around the board, reducing the swirling effect and the resultant drag.
I think I can describe this in a way that everyone understands that is actually technically correct.
Air moving at different speeds has different pressures. Downforce/drag is created by the air above the car, moving at a different speed than the air below the car. In the straights, McLaren takes air from above the car and transfers it underneath the rear wing. Therefore, the air is moving at more or less the same speed above and beneath the wing. Therefore, there is less drag.
Air moving at the same speed above and below the wing of the plane is a stall. But because the plane is freaking heavy, a stall happens before airspeed above and below the plane are identical. (The heavier the plane, the smaller the wing, etc. the more differential you need to fly.)
And I think that that is what Badger is staying with the board example. You are - more or less - equalizing the airspeed on both sides of the board. Correct?
I'm out! :laugh:
Yeah? Are you gonna make it all 220?
Yeah. 220... 221, whatever it takes.
http://i42.tinypic.com/2mn21qp.jpg
I'm out! :laugh:
http://i42.tinypic.com/2mn21qp.jpg
*****.
Wonder how it affects turbulence behind the car? I assume with equal pressures, the vorticies that create dirty air would be diminished.
Would it help with braking? I guess more drag would slow the car down for the corners like an air brake.
How can it be applied to production cars? Luxury sports cars with optional floor holes. Do you feel a draft? :gomer:
Wonder how it affects turbulence behind the car? I assume with equal pressures, the vorticies that create dirty air would be diminished.
vortex magnitude decreased, and since it's for use on straights and not corners, the trailing car doesnt receive the benefits of clean laminar air while cornering, and the decreased wake might result in more drag for the trailing car as well
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