Reducing the drag of a two element wing through stall

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
User avatar
Poleman
1
Joined: 02 Feb 2010, 19:25

Re: Vodafone Mclaren Mercedes MP4/25

Post

That bump on the right side panel of the snorkel was on the MP4-22/23/24 as well...So i dont see that as something new this year.Also those panels have been present there since MP4-20.Scarbs theory seems too far stretched to my eyes,IMO i think hes searching something extreme through something simple as a cooling duct.

MP4-24
Image
MP4-23
Image
MP4-22
Image

User avatar
horse
6
Joined: 23 Oct 2009, 17:53
Location: Bilbao, ES

Re: Vodafone Mclaren Mercedes MP4/25

Post

The biggest flaw in the snorkel for rear wing control argument, for me, was the snorkel's late appearance in testing. If this was the original control design (and I'm sure all that pipework would need a bit of thinking about in terms of access points on the tub) then why was it not in action from the very first test (as in day one)?
Last edited by horse on 01 Mar 2010, 16:26, edited 1 time in total.
"Words are for meaning: when you've got the meaning, you can forget the words." - Chuang Tzu

Giblet
Giblet
5
Joined: 19 Mar 2007, 01:47
Location: Canada

Re: Vodafone Mclaren Mercedes MP4/25

Post

Since the rolling road wind tunnel does not get up to the same speeds as the car on track, the effect might have been extreme enough at track speed, or not worked above tested wind tunnel speeds.

That's the only reason I can think of, but I still think we are barking up a tree that we can't see, or understand at this early point, and we are starting to debate the various speculations.

Look how long the mass damper was under wraps before we even heard boo about it.

But mainly, I don't see a need for further cockpit cooling.

The other thing, is maybe it is just a distraction to send us and more so teams off on speculating, like when the interter was first seen, Mclaren hinted it was a suspension bit, long before it was figured out as what it was.
Before I do anything I ask myself “Would an idiot do that?” And if the answer is yes, I do not do that thing. - Dwight Schrute

cupidstunt
cupidstunt
0
Joined: 19 Feb 2010, 21:50

Re: Vodafone Mclaren Mercedes MP4/25

Post

Giblet wrote:
Raptor22 wrote:
Giblet wrote:Easier, harder, whatever, it doesn't remain stagnant.

Why is it on the left hand side do you think? Why not the right or center? Why not a NACA duct then?

Because by ramming air into the cockpit you can avoid much of the turbulence in this area. Now there is a steady but slow flow through the cockpit that exits around the driver and is picked up by the faster moving flow going over and aroudn the cockpit.
Its position is not in the centre because it would blind side teh driver. It can be mounted left or right depending on whether the track runs clockwise or anticlock wise and therefore has more right hand bends or left hand bends.

they could have had to move the inlet for the driver cooling because their nose cone is very thin at the leading edge and the inlet could interfere with the undernose splitter by relieving the high pressure there.
Why would they do so much testing for driver cooling? They don't need the extra cooling, the drivers have been dealing with it for years, and are not going to suddenly decide to open up the cockpit with a snorkel. When they drivers are too hot, they sweat, take a drink, or roll up their glove cuffs.

This is being over-thought.

While they were screwing with the snorkel, they were also screwing with the size of the secondary upper inlet in the intake above the drivers head. hmmmmm.

We know the blown wing slot is fed by that engine cover shark fin, as mclaren said, "it's not how it looks, it's what it does." hmmm.

We also can figure, that if the effect of this system is to make the wing less effective at speed (not just stall it, which is an extreme end of what can be done), then that effect needs to be unused at low speeds. hmmmmmmmmm.

Since no mechanical device can be used, as that is active aero, then it must be manipulated by the driver doing something, that uses no cables, or hydraulics, or electronics. hmmmmmmmm.

Maybe cooling after all, but in a sport where they paint the logos on because stickers cause too much drag and turbulence, I doubt a tall ugly snorkel for cooling when they are other means to get the air in, there, to coddle a driver who needs no coddling.

I like saying hmmmmm though :)

Nobody can know for sure, but I look forward to possibly saying I told you so when the system comes to light.

I also look forward to saying "Oh well, you were right, live and learn" if I am wrong.
I think raptor was mostly suggesting that the snorkel was there to provide flow through the cockpit to reduce turbulence.

The idea of using a knee to reduce the airflow through a duct to reduce the drag on the rear wing sounds too far fetched to me. I'm reminded of a commonly used medical analogy: "If you hear hoofbeats, think horses, not zebras".

It's probably true though that the driver's don't need extra cooling, the hole in the nose is most likely enough. Maybe it's still there to cool things in the nose also? But if this snorkel improves airflow around the cockpit, and has an added benefit of better driver cooling, that sounds reasonable, doesn't it?

Raptor22
Raptor22
26
Joined: 07 Apr 2009, 22:48

Re: Reducing the drag of a two element wing through stall

Post

This whole stall thing does not make sense from a energy balance perspective either.

forces are fporces and they need to balance. With this stall theory there is no balance unless the extra energy comes from something powerful.

butmore on that later.

User avatar
hollus
Moderator
Joined: 29 Mar 2009, 01:21
Location: Copenhagen, Denmark

Re: Reducing the drag of a two element wing through stall

Post

Raptor22 wrote:forces are fporces and they need to balance. With this stall theory there is no balance unless the extra energy comes from something powerful.
What do you mean with forces need to balance? I don't think I get your point, give a bit more detail, please.
Rivals, not enemies.

User avatar
Pandamasque
17
Joined: 09 Nov 2009, 17:28
Location: Kyiv, Ukraine

Re: Vodafone Mclaren Mercedes MP4/25

Post

Testing some extra driver cooling during the winter test? =D> I'd expect to see something that extreme in Sepang. The turbulence reduction idea is quite plausible though.

marcush.
marcush.
159
Joined: 09 Mar 2004, 16:55

Re: Vodafone Mclaren Mercedes MP4/25

Post

for sure the snorkel sees air almost unaffected by boundary layer buildup ,a distinct difference to a scoop or a naca duct.
So if they use this inlet to help flow through the cockpit ,they seem to have had issues with high speed ,as the boundary layer increases in thickness with speed possibly choking a bit the inlet of free streaming air into the cockpit?
To monitor the efectiveness of the mod they mapped air speed in the snorkel vs ground speed..subtle ,but everything counts.

Giblet
Giblet
5
Joined: 19 Mar 2007, 01:47
Location: Canada

Re: Vodafone Mclaren Mercedes MP4/25

Post

Reduce, nah? I'm thinking more of the knee acting as a valve in a system, allowing air from somewhere else to be diverted to the rear wing.

This is known to work in aircraft, but the rules in F1 allow no active devices. The knee hole to me might be a workaround to that rule.

The DDD fiasco / debate last year taught us one thing, holes in the floor are OK, so long as they are not holes in the plan view.

From my cigarette smoking days years ago, I like many noticed that while driving, opening both windows a crack does very little to get the smoke out. It just buffets around. If you close one window, the smoke streams out the open one with vigor.

Both sides of this discussion are based in reality, it could go either or neither way.
Before I do anything I ask myself “Would an idiot do that?” And if the answer is yes, I do not do that thing. - Dwight Schrute

cupidstunt
cupidstunt
0
Joined: 19 Feb 2010, 21:50

Re: Vodafone Mclaren Mercedes MP4/25

Post

Giblet wrote:Reduce, nah? I'm thinking more of the knee acting as a valve in a system, allowing air from somewhere else to be diverted to the rear wing.
Okay, I don't think I fully understand how you're proposing it would work. How could a driver use his knee as a valve to increase air going to the rear wing?

Even if it were possible, could it really be used usefully and reliably while driving? What if the driver accidentally moves his knee to the wrong place while going through a corner? Think he may end up going backwards slightly more than he'd like to.

nacho
nacho
6
Joined: 04 Sep 2009, 08:38

Re: Vodafone Mclaren Mercedes MP4/25

Post

I can't see why they would use the knee, can't they just use a pressure sensitive valve in that place.

Giblet
Giblet
5
Joined: 19 Mar 2007, 01:47
Location: Canada

Re: Vodafone Mclaren Mercedes MP4/25

Post

Differences in pressure. If that snorkel leads to a tube, that has a hole in it, it will outlet into the cockpit, and not channel to the wing.

Think of a garden hose, with a hole in it. Water will squire out the side, and not make it to the end. Cover the hole, and the magic happens.
Before I do anything I ask myself “Would an idiot do that?” And if the answer is yes, I do not do that thing. - Dwight Schrute

axle
axle
3
Joined: 22 Jun 2004, 14:45
Location: Norfolk, UK

Re: Vodafone Mclaren Mercedes MP4/25

Post

I take it that the official wording of the rules that cover this device go along the lines of being explcitly "controlled by the driver". McLaren wouldn't do such an elaborate system unless the driver had to control it in some way...assuming the system does work the way Scarbs has expained (whilst noting it's a rumour). Yes?
- Axle

marcush.
marcush.
159
Joined: 09 Mar 2004, 16:55

Re: Vodafone Mclaren Mercedes MP4/25

Post

Giblet wrote:Differences in pressure. If that snorkel leads to a tube, that has a hole in it, it will outlet into the cockpit, and not channel to the wing.

Think of a garden hose, with a hole in it. Water will squire out the side, and not make it to the end. Cover the hole, and the magic happens.
I don´t buy the idea of knee operation,especially when you see the guys in the corners just how much their knees and legs get tossed around ,I´m not sure if they could be sure to have it nailed or not (the tube) and in letting go you´d loose enough downforce ,as it has to net something ,that little system ) that you loose control instantly as the df is not enough for the speed you are going-df fluctuation anyone?

If this duct would have to have influence on the duct leading to the rear wing I do not get the principle .Both inlets clearly try to catch air going at full groundspeed right? so there should be no difference between the two the small snorkel can´t capture much in terms of flow volume ,so it can possibly not add much to the flow going into the wingchanneland it surely cannot add or decrease pressure.Could it cause a separtion in there by beeing blown in at a severe angle?
but would this influence the system at lower speeds or more at higher?

User avatar
Shaddock
0
Joined: 07 Nov 2006, 14:39
Location: UK

Re: Vodafone Mclaren Mercedes MP4/25

Post

I’ve read interviews with drivers when they have spoken about the heat in places like Bahrain, when it’s that hot, the air flow makes no difference, it’s like having a hairdryer in the face.

The snorkel isn’t for driver comfort.