2012 Stalled wings, F/ W ducts & DDRS

[ecapox]

You may do so unless the particular system is prohibited by other means and regulations. AFAIK movable elements of front wings are absolutely prohibited. So your interpretation isn't legal IMO.

Agreed. Totally illegal but i was just using it as an example to show that he is contradicting himself. In one case, something (DRS) can be used against it primary purpose and in another case (suspension), it cannot.

[radosav]

Brawn also said there was no way that F-ducts could have been banned, because there is no official definition of what one is.

"It is not a debate," he said. "What is an F-duct? People talk about an F-duct but I don't actually know what an F-duct is. And if you ask the FIA what is an F-duct they don't know. So, what we are doing we are completely comfortable and we believe the FIA is happy with, so we will see."
i agree with Brawn here. we should test all openings on every car to see if they help to stall wings and then call them F/ W ducts. this is aerodynamic phenomenon that can be caused by many factors , intentionally or unintentionally.

[hardingfv32]

Totally illegal but i was just using it as an example to show that he is contradicting himself. In one case, something (DRS) can be used against it primary purpose and in another case (suspension), it cannot.

The rules do NOT state a primary purpose for the DRS. There is mention of improving overtaking in the race, so this rear wing stall system would meet the letter of the rule perfectly. I assume stalling the main element is going to 'improve' overtaking.

3.18.2 The adjustable bodywork may be activated by the driver at any time prior to the start of the
race and, for the sole purpose of improving overtaking opportunities during the race,

Brian

[hollus]

A driver moving his hand to close a hole is a driver affecting aerodynamics, hence prohibited.
A driver moving his hand to push a button that moves a flap that opens a hole is not a driver affecting aerodynamics, hence legal.
I'd like to point out that the driver has the option of activating the DRS flap or not (when allowed), which goes against the very definition of passive.

We must thus conclude that the critical difference is then between closing a hole (illegal) and opening a hole (legal). Kermit the frog would be proud.
(Just nitpicking and being ironic here).

Interesting. I also smell a "would be good if Mercedes/Schumacher won a race" here. It will become illegal if they win 5 of the first 7 as Brawn did, though.

[Ral]

A driver moving his hand to close a hole is a driver affecting aerodynamics, hence prohibited.
A driver moving his hand to push a button that moves a flap that opens a hole is not a driver affecting aerodynamics, hence legal.
I'd like to point out that the driver has the option of activating the DRS flap or not (when allowed), which goes against the very definition of passive.

We must thus conclude that the critical difference is then between closing a hole (illegal) and opening a hole (legal).

No, I think DRS is the only permissible exception to the rule that there can be no driver affected aerodynamics on the car. Closing or opening has nothing to do with it.

[King Six]

A driver moving his hand to close a hole is a driver affecting aerodynamics, hence prohibited.
A driver moving his hand to push a button that moves a flap that opens a hole is not a driver affecting aerodynamics, hence legal.
I'd like to point out that the driver has the option of activating the DRS flap or not (when allowed), which goes against the very definition of passive.

We must thus conclude that the critical difference is then between closing a hole (illegal) and opening a hole (legal).

No, I think DRS is the only permissible exception to the rule that there can be no driver affected aerodynamics on the car. Closing or opening has nothing to do with it.

When you think about what DRS main purpose is, it's to reduce drag. So if Mercedes are using DRS in an f-duct sort of manner, they're simply improving its main purpose by increasing its drag reduction capabilities. Which is why it's legal, compared to having suspension or exhausts for aero benefit.

Also yes, DRS is sanctioned moveable aero for the teams. So those rules don't apply to it either...

[Pup]

The issue of legality is settled, I think, whether you agree with Charlie or not. The question now is what bit of the car, within the rules, would benefit from being blown:

Rear wing - I think it's out because the rules are strict enough to prevent any hollow areas with a slot. Plus the benefit of blowing the wing with the DRS flap activated would be minimal.

Front wing - Maybe. It seems quite a chore to get even a pilot flow of air to the wing, and I'm not convinced at all of the benefit. As I said earlier, the only element of the front wing you could blow is the main element, which doesn't have all that high of an angle of attack. For a switched f-duct to work, the wing has to be designed to stall when the flow is cut. So if they were blowing the front wing, I think you'd see a steep single-element wing instead of the multi-element wings we're used to seeing.

Diffuser/Floor - No idea how that would work. And again, I don't think the diffusers are steep enough under the current regs to stall.

Beam wing - This seems the most logical to me. It has a high angle of attack that might benefit from being blown and is outside of the rules limiting slots on the main wing. Plus, it's got this honking duct attached to it, which is sort of a giveaway if you ask me.

[PlatinumZealot]

This is what I think is happening.. DRS rear wing and DRS air box. The air box is large source of drag at high speeds.

I think the DRS also vents the engine airbox at high speeds - when the air box pressure is already saturated. Even if you use it at low speeds it will not affect the engine. This is because the absolute pressure in the air box will be slightly less. At higher speeds when the engine is running at full power and it cannot pump in enough air into self the excess pressure can be bled off. If this is not true and the engine does lose power... the reduction in drag will make up for it.

[hardingfv32]

This is what I think is happening.. DRS rear wing and DRS air box.

This is idea has potential.

1) The air box is tuned for a precise RPM. I would say that normally it is tuned for max power and max RPM. There is no saturation. I am not sure there is much drag, as all flow is being used.

Now that is not to say we could not lower the the target to a lower RPM and then have over saturation at max RPM. Then you could correctly bleed off excess flow. This would mean having a intake opening that is larger than last year. Do you think that is in fact the case?

2) What kind of flow performance can we expect from the slot/opening that is uncovered by the upper element? Positive or negative pressure?

Design Optimization of a Two-Dimensional Subsonic
Engine Air Intake

http://www.southampton.ac.uk/~nwb/lectu ... 23-118.pdf

Brian

[skgoa]

I just had an epiphany: the holes in the RW endplates simply CAN'T be inlets. Because the air rushing over them will suck air OUT. It's pretty basic aerodynamics.

This is what I think is happening.. DRS rear wing and DRS air box. The air box is large source of drag at high speeds.

I think the DRS also vents the engine airbox at high speeds - when the air box pressure is already saturated. Even if you use it at low speeds it will not affect the engine. This is because the absolute pressure in the air box will be slightly less. At higher speeds when the engine is running at full power and it cannot pump in enough air into self the excess pressure can be bled off. If this is not true and the engine does lose power... the reduction in drag will make up for it.

[urk]http://img.photobucket.com/albums/v626/ ... switch.png[/url]

Uhm, at high speed the air box is already sucking in air very very strongly. You would not gain anything by reducing pressure in there even further.

[Just_a_fan]

1) The air box is tuned for a precise RPM. I would say that normally it is tuned for max power and max RPM. There is no saturation. I am not sure there is much drag, as all flow is being used.

Actually the problem with the air intake is when the driver lifts off the throttle. Then the air intake has excess flow and will shed the excess outwards and this will then be flowing back towards the rear wing. I'd be interested in whether this has an effect on rear end stability under braking.

I remember reading that the circular style intake favoured by RedBull is better in this regard because of the way it overflows. The triangular intakes preferred by some teams are not so good. Indeed, one of the functions of the undercut and strakes etc. seen below the intake help to channel this overflow.

[PlatinumZealot]

I just had an epiphany: the holes in the RW endplates simply CAN'T be inlets. Because the air rushing over them will suck air OUT. It's pretty basic aerodynamics.

This is what I think is happening.. DRS rear wing and DRS air box. The air box is large source of drag at high speeds.

I think the DRS also vents the engine airbox at high speeds - when the air box pressure is already saturated. Even if you use it at low speeds it will not affect the engine. This is because the absolute pressure in the air box will be slightly less. At higher speeds when the engine is running at full power and it cannot pump in enough air into self the excess pressure can be bled off. If this is not true and the engine does lose power... the reduction in drag will make up for it.

[urk]http://img.photobucket.com/albums/v626/ ... switch.png[/url]

Uhm, at high speed the air box is already sucking in air very very strongly. You would not gain anything by reducing pressure in there even further.

how do you know what pressure is inside the air box at 200mph may I ask?

It will reduce drag both ways. on the wing and on the airbox. do your calculations.

[hardingfv32]

how do you know what pressure is inside the air box at 200mph may I ask?

It will reduce drag both ways. on the wing and on the airbox. do your calculations.

You should read the paper I referenced. They are lucky to get 95% pressure recovery at the intake ports when compared to the scoop inlet. A larger opening does not create more pressure. Air is considered generally non-compressible under Mach .3 . Essentially the intake scoop will only accept what the engine is using. There is no ram affect!

Brian

[Pup]

A little primer on how the f-ducts worked...

First, remember that on a blown wing the blowing prevents the stall - it doesn't cause it to stall. The wing is built in a way that would ordinarily stall, and then the blowing is introduced to prevent it. So on the old McLaren, when the driver 'activated' the f-duct on the straight, he was actually cutting the flow. The gist of this is that there's really no way that the wing duct is involved in the actual blowing, since it opens when you'd want it closed and so would be doing the opposite of what it should. That's why I say that it has to be the switch.

Which brings us to the second point, which is how a fluidic switch works. Basically, it uses a small flow of air (the pilot flow) to control a large flow (the main flow). It doesn't do this like an on/off switch, but rather it directs the flow in one direction or another. So the main flow is always moving, but the pilot flow sends it down one pipe or the other. The gist of this is that the pilot flow is pretty flexible. It doesn't have to be upstream or downstream and it doesn't have to be open or closed to send the main flow where you want. It can be set up however best makes sense. It just needs to have enough flow when its circuit is closed to trip the man flow from whichever direction you chose as the default, and the switch just needs to be placed somewhere on the circuit - in this case, on the rear wing, and 'open' sends the main flow to open air, and 'closed' sends the main flow to whatever bit is being blown.

[PlatinumZealot]

The Static pressure will increase at high speed depending on the flow rate being sucked in by the engine. Ram air effect is very real in moving cars - static engines on test beds is a different story.

The BMW s1000r's horsepower increases as it goes faster and faster. It gains over 10hp (or was it 20?) at 200mph. I wish I could find the article.