shelly wrote:I think having a reduction on front wing downforce triggered by the opening of the drs is a very good idea.
The rumoured f-duct coupled with DRS pertains only to the rear wing IIRC. I find it difficult to imagine how the DRS can trigger a FW F-duct.
Fairly simple actually. If you have a pressure inside the rear wing when DRS is not activated, the pressure keeps a fluidic valve closed which feeds a pressure pulse to the front wing to keep flow going to the driver's cockpit as cooling air.
Activate DRS, the pressure is released and this trigges a fluidic switch that changes the flow from the cockpit to the front wing stalling slots to stall the front wing outer elements.
The rule loop hole is that is not driver activated but DRS activated since.
There would be a counter arguement too of course.
shelly wrote:I think having a reduction on front wing downforce triggered by the opening of the drs is a very good idea.
The rumoured f-duct coupled with DRS pertains only to the rear wing IIRC. I find it difficult to imagine how the DRS can trigger a FW F-duct.
Fairly simple actually. If you have a pressure inside the rear wing when DRS is not activated, the pressure keeps a fluidic valve closed which feeds a pressure pulse to the front wing to keep flow going to the driver's cockpit as cooling air.
Activate DRS, the pressure is released and this trigges a fluidic switch that changes the flow from the cockpit to the front wing stalling slots to stall the front wing outer elements.
The rule loop hole is that is not driver activated but DRS activated since.
There would be a counter arguement too of course.
The opening and close of the valve would be considered as moveable aero, which is banned. For a f-duct concept to work in current F1, everything has to be passive, no driver influence at all.
I tthink you do not need any moving part to get an aero switch work, triggered by a rathere big change of pressure on the rear. You need just the piping (and maybe some coanda also here? -see coanda fluidic switches)
We have already seen how without any dedicated piping the front wing of massa reacted in india to drs and braking, so with some dedicate pipe coul be fine tuned.
In the end the f-duct pressure signal travelled form the cockpit to the rw, why would travelling from the back to the front be different? And the driver covering a hole was inducing a pressure change I think smaller than that between drs opn-closed at the rear. So why not?
The only moving part is the rear flap, activated by the driver with the button. But it is not the only aero effect, and here is where a counter argument lies
shelly wrote:I tthink you do not need any moving part to get an aero switch work, triggered by a rathere big change of pressure on the rear. You need just the piping (and maybe some coanda also here? -see coanda fluidic switches)
We have already seen how without any dedicated piping the front wing of massa reacted in india to drs and braking, so with some dedicate pipe coul be fine tuned.
In the end the f-duct pressure signal travelled form the cockpit to the rw, why would travelling from the back to the front be different? And the driver covering a hole was inducing a pressure change I think smaller than that between drs opn-closed at the rear. So why not?
The only moving part is the rear flap, activated by the driver with the button. But it is not the only aero effect, and here is where a counter argument lies
Correct me if I'm wrong. The DRS is controlled electrically, not hydraulically. There is no piping, just wires. We are not going to see a sharkfin in the W03 to connect the rear wing to the rest of he car. Also to have rear aero influence front aero is completely different then front aero influence rear aero. Air simply don't travel backward
After all, what's the point of doing it? DRS is used less than 50 times in a race. And each time it is used, it is only for a few seconds. It would be much more beneficial to invest on a passive f-duct rear wing or front wing that isn't DRS driven.
shelly wrote:I tthink you do not need any moving part to get an aero switch work, triggered by a rathere big change of pressure on the rear. You need just the piping (and maybe some coanda also here? -see coanda fluidic switches)
We have already seen how without any dedicated piping the front wing of massa reacted in india to drs and braking, so with some dedicate pipe coul be fine tuned.
In the end the f-duct pressure signal travelled form the cockpit to the rw, why would travelling from the back to the front be different? And the driver covering a hole was inducing a pressure change I think smaller than that between drs opn-closed at the rear. So why not?
The only moving part is the rear flap, activated by the driver with the button. But it is not the only aero effect, and here is where a counter argument lies
I am confused!
First of all, the DRS can only be activated during the race, when the car is within 1 sec of a leading car, so a DRS activated F-duct would be pretty pointless.
Secondly, even if used in practice or qualifying, opening the DRS would provide just as much if not more freedom from drag, and an F-Duct would also be pointless.
I just cannot see how an open DRS , coupled with an F-Duct, would be any more beneficial than just the open DRS.
Raptor22 wrote:.
The rule loop hole is that is not driver activated but DRS activated since.
.
And 'what' activates the DRS....
Read the regs, all the driver can do is activate DRS. they specifically ban any secondary effect. Any aero device activated this way would be deemed illegal.
shelly wrote:I tthink you do not need any moving part to get an aero switch work, triggered by a rathere big change of pressure on the rear. You need just the piping (and maybe some coanda also here? -see coanda fluidic switches)
We have already seen how without any dedicated piping the front wing of massa reacted in india to drs and braking, so with some dedicate pipe coul be fine tuned.
In the end the f-duct pressure signal travelled form the cockpit to the rw, why would travelling from the back to the front be different? And the driver covering a hole was inducing a pressure change I think smaller than that between drs opn-closed at the rear. So why not?
The only moving part is the rear flap, activated by the driver with the button. But it is not the only aero effect, and here is where a counter argument lies
I am confused!
First of all, the DRS can only be activated during the race, when the car is within 1 sec of a leading car, so a DRS activated F-duct would be pretty pointless.
Secondly, even if used in practice or qualifying, opening the DRS would provide just as much if not more freedom from drag, and an F-Duct would also be pointless.
I just cannot see how an open DRS , coupled with an F-Duct, would be any more beneficial than just the open DRS.
+ Had the F-Duct (or whatever) been independent of the drs system it could have been used in other places on the track to get closer to the car ahead and then used the DRS to overtake.. But all this talk of F-Ducts is mere speculation and will have to wait till Australia till Charlie Whiting examines the cars in Park Ferme and discloses the secrets.
With f-duct I refer to the device that, by blowing a small flow in a key area of the wing, reduces its downforce (and induced drag).
IIRC, such a device is banned geometrically on the rear wing (where it was applied in 2010) plus there is nothing that driver can activate with his body having effect on aero except for the button opening the drs.
Merc have been rumored of running a passive (no driver intervention) f-duct on the front wing; I would say it is quite sure they have run it in the final races of 2011, to solve some issues with the w02.
Now on the w03 there was a first rumor about the w-duct, a front wing f-duct with no driver intervention, but more sophisticated because supposed to be reacting to yaw condition. It has been discussed in this thread also.
The last, different, rumor is about a drs activated front wing f-duct.
I now try to put some order into what I wrote confusely.
When I read about this last rumor, I thought it could be a good idea if true.
I thought that because the drs when it opens reduces rear downforce and increases front downforce (this point specifically could seem strange , but if you thik that the center of pressure of the rear wing is behind the rear axle becomes clear).
Both by reducing rear downforce and increasing front downforce, the opening of the drs pushes forward the center of pressure fo the car - i.e. shifts balance to the front, and this affects the performance of the car and its driveability.
So it makes sense to have a system that, when the drs gets opened, reduces the downforce on the front wing also. This would reduce (or even overshadow) the balance shift to the front, leaving the center of pressure where it should be in design condition, or even pushing it slightly towards the rear.
We almost know for sure that the w02 had a system that made the front wing lose load under certain conditions(over a certain speed?), triggered by a fluidic switch(no moving parts- "passive")
Now how can this system be triggered by the drs?
The key is that in subsonic field, pertubation in the flow field propagate in every direction. So opening drs has an effect on the pressure field in front of the rear wing. We have seen on massa's ferrari in India an undesired side effect of that, when the front wing started to vibrate after the drs closing.
So it is reasonable to imagine that the pressure at the back of the car, for example at a point just outside tha central "cannon" exit, will be different between the two conditions of drs closed and open.
If there is a pipe inside the car that connects this point at the back to a fluidic switch (a switch with no moving parts) inside the car, the difference in pressure can trigger the deviation of the flow inside the nose and cause the stall of the front wing.
In the 2010 rear wing f-duct it was the body of the driver which caused the pressure variation and triggered the switch. Now this is banned, but a delta pressure elsewhere on the car (especially at the rear) can be picked and used as trigger.
There are no moving parts: as the drs is opened, pressure at the back of the car changes. A pipe connects a point at the rear to a switch inside the car where the pressure difference makes a small flow go on the front wing when drs is on, stalling it, or go elsewhere in a "neutral" point when drs is closed and full effectiveness of the front wing is needed.
Now that we have devised a reasonable implementation of a system that reduces front wing downforce concurrently with drs activation, without in principle breaking any rule, what could be its possible advantages?
My opinion is:
-first of all no balance shift to the front when drs open
-reduced drag (maybe ) when drs opened
-reduced sensitivity to loss of downforce when following another car, since the front wing is already stalled
First two advantages play into merc hands especially in qualifying, when drs use is free.
I hope that I have been less confused now - sorry for the long post but when trying to be concise I was confusing.
PS Maybe the odd pipes spotted inside w03 "cannon" are related to this gizmo.
The DRS is used primarily in the straights for overtaking. The passive front wing f-duct will dump drag off of the wing at a given speed down the straight. It will already be working by the time the DRS is opened. The only way it would be beneficial to have the DRS and front wing f-duct work at the same time is for certain turns. The cars didn't seem to have much of an issue with balance last year though.
Something funky is certainly going on at the back of the car though.
While I do understand what you describe Shelly, I think it is not doable and the theory of the system falls apart when I am trying to picture it:
- I have heard often enough that on windy days the aero balance of F1 cars get influenced. If this already makes an impact, the entire approach falls apart.
- The rattleing of Massa's Wing you describe is probably a result of change in forces onto the support wing structure as the load changes with or without DRS are probably significant.
- The pressure changes as a result of the DRS being active vs closed are likely there, but likely to be very local, around the rear wing main elements. Probably influence by more factors than just the DRS, such as wind?
- The tubes at the 'cannon' exit are not even close to the rear wing main element. They are almost what?, 500 mm (?) straight below the main wing element. I doubt there will be any change in pressure, DRS active or not. Look at the pictures there is nothing behind the exit.
- Even if all that would be solved, which way or rather medium would transfer the pressure changes to the front? Cannot be air....(compressible), than you got a long distance of travel over the entire car length, probably with windings and turns, signal distortion, etc. So, would it have to be an electronic signal?
- Besides that I wonder what the time delay of the measurement system would be before the signal would trigger something at the FW.
- In addition, as the DRS can only be used if within 1 sec behind another car, during the race, would the entire air flow and pressure regime not be different if you are in a distance that close behind another car? That in turn would means different pressures, and velocities for the FW fluid switch depending if behind another car or not?
I think that whole discussion is just a hoax when I think about all of the above....
The last, different, rumor is about a drs activated front wing f-duct.
[snip]
Stop right there.
There wasn't ever such a rumor!
Helmut Marko (Redbull btw.) said they think Mercedes has a DRS activated rear wing F-Duct. He said no word about a front wing connection.
BTW, wouldn't such a system have an impact on the driveability of the car? Wouldn't it make the car more nervous to drive having varying levels of downforce on the front-wing in different corners, and indeed, different parts of a corner?
The last, different, rumor is about a drs activated front wing f-duct.
[snip]
Stop right there.
There wasn't ever such a rumor!
Helmut Marko (Redbull btw.) said they think Mercedes has a DRS activated rear wing F-Duct. He said no word about a front wing connection.
Exactly what I said above. Where is the source for the DRS-FW F-Duct rumour? I agree with gilgen.
shelly wrote:I think having a reduction on front wing downforce triggered by the opening of the drs is a very good idea.
The rumoured f-duct coupled with DRS pertains only to the rear wing IIRC. I find it difficult to imagine how the DRS can trigger a FW F-duct.
Fairly simple actually. If you have a pressure inside the rear wing when DRS is not activated, the pressure keeps a fluidic valve closed which feeds a pressure pulse to the front wing to keep flow going to the driver's cockpit as cooling air.
Activate DRS, the pressure is released and this trigges a fluidic switch that changes the flow from the cockpit to the front wing stalling slots to stall the front wing outer elements.
The rule loop hole is that is not driver activated but DRS activated since.
There would be a counter arguement too of course.
Yes, a very simple counter argument. DRS is driver activated. DRS activated IS driver activated
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