McLaren MP4-29 Mercedes

[Mandrake]

The nose is ok. It's the front wings and sidepods.
At the moment Force India have a better car, and they have a similar nose. Williams has a better car and they have a similar nose.
This is reminiscent of 2009 when they overlooked to outwash front wing design. They are going through a similar problem.
The wings are narrower this year, and they haven't gotten on top regaining the performance from it.

Note the offending coolings holes crowding out the top of the engine cover, and compare to the force India
http://img4.auto-motor-und-sport.de/Par ... 768880.jpg
removing the butterflies should allow the cooling to be better distributed out the rear of the car.
The nose can be brought back a bit like the mercedes as well. It does have a massive overhang over the wing.

The FI looks shorter and sleeker, yet they say it is overcooled. Since the components of the Merc package should be the same for both teams, I really wonder how the McLaren is not as sleek. Not to mention Williams with their tight back without cooling openings....

This might not be in any way connected to their performance issues, but from the looks the McLaren has a very obstructed cokebottle.... makes you wonder if the butterfly could work better for them if they could shrink the large cooling outlets at the back.

[PhillipM]

I would expect that's in the pipeline given the old ones started around the tubular manifolds, so there must be quite a lot of excess space there now.

[Jef Patat]

I really do not get the "build around" when it comes to internal packing and cooling. Especially as the usage of cooling air is much overrated in this forums. The main aspect in vehicle cooling is still cooling and reducing drag. Far behind there is some usage...but no one is really compromising anything for that usage except RB. Just look at the high exits in the Merc...

I think this is (at least partially) incorrect. The butterflies are IMHO functioning as a dam blocking the air, causing a low pressure zone behind them. Without going into the discussion of effectiness, drag, ... I think we can safely state they obstruct the airflow that ends up there. That is one part of the story, the other part is cooling. For good cooling efficiency you need a clean airflow. Airflow in, through and out. If the outflow is obstructed the cooling efficiency will drop, which will reduce engine efficiency, ... Combine these two ideas leads me to say that the butterflies do influence cooling. The air is obstructed which makes them to have big and high placed hot air outlets. This then again influences the shape of the covers and so on (maybe as well rear wing underflow, outwash, ...) In the end these butterflies dictate a lot of the car.

For a comparsisson check these posts:
rear comparisson: http://www.f1technical.net/forum/viewto ... 57#p482557
MCL without the butterflies: http://www.f1technical.net/forum/viewto ... 13#p503313

[basti313]

I really do not get the "build around" when it comes to internal packing and cooling. Especially as the usage of cooling air is much overrated in this forums. The main aspect in vehicle cooling is still cooling and reducing drag. Far behind there is some usage...but no one is really compromising anything for that usage except RB. Just look at the high exits in the Merc...

I think this is (at least partially) incorrect. The butterflies are IMHO functioning as a dam blocking the air, causing a low pressure zone behind them. Without going into the discussion of effectiness, drag, ... I think we can safely state they obstruct the airflow that ends up there. That is one part of the story, the other part is cooling. For good cooling efficiency you need a clean airflow. Airflow in, through and out. If the outflow is obstructed the cooling efficiency will drop, which will reduce engine efficiency, ... Combine these two ideas leads me to say that the butterflies do influence cooling. The air is obstructed which makes them to have big and high placed hot air outlets. This then again influences the shape of the covers and so on (maybe as well rear wing underflow, outwash, ...) In the end these butterflies dictate a lot of the car.

For a comparsisson check these posts:
rear comparisson: http://www.f1technical.net/forum/viewto ... 57#p482557
MCL without the butterflies: http://www.f1technical.net/forum/viewto ... 13#p503313

Sorry, but your point is not only partially incorrect. Just look at CFD data from the rear of a F1 car. Nothing in the rear like rearwing, brake ducts or beam wing has any effect on the cooling air on its exits. There are just no high/low pressure zones going so far in front of the wings and, thus there are none so far in front of the butterflies.

Your car comparison also proves my point: FI has absolutely no visible usage of the cooling air in the rear. And is fast. Cooling air usage is overrated.

[Jef Patat]

Then why are the MCL hot air exits that big and placed that high? Why don't they place them similar to other teams (Merc, Fer, ...) Read my post again, I am not saying anything on the usage of the hot air. I am saying the hot air needs to be able to go somewhere for it to have cooling efficiency. If you happen to have any CFD data on the butterflies feel free to share it, I haven't seen any and I'm quite sure those butterflies generate a higher pressure zone in front of them compared to no butterflies.

[turbof1]

I really do not get the "build around" when it comes to internal packing and cooling. Especially as the usage of cooling air is much overrated in this forums. The main aspect in vehicle cooling is still cooling and reducing drag. Far behind there is some usage...but no one is really compromising anything for that usage except RB. Just look at the high exits in the Merc...

I think this is (at least partially) incorrect. The butterflies are IMHO functioning as a dam blocking the air, causing a low pressure zone behind them. Without going into the discussion of effectiness, drag, ... I think we can safely state they obstruct the airflow that ends up there. That is one part of the story, the other part is cooling. For good cooling efficiency you need a clean airflow. Airflow in, through and out. If the outflow is obstructed the cooling efficiency will drop, which will reduce engine efficiency, ... Combine these two ideas leads me to say that the butterflies do influence cooling. The air is obstructed which makes them to have big and high placed hot air outlets. This then again influences the shape of the covers and so on (maybe as well rear wing underflow, outwash, ...) In the end these butterflies dictate a lot of the car.

For a comparsisson check these posts:
rear comparisson: http://www.f1technical.net/forum/viewto ... 57#p482557
MCL without the butterflies: http://www.f1technical.net/forum/viewto ... 13#p503313

Sorry, but your point is not only partially incorrect. Just look at CFD data from the rear of a F1 car. Nothing in the rear like rearwing, brake ducts or beam wing has any effect on the cooling air on its exits. There are just no high/low pressure zones going so far in front of the wings and, thus there are none so far in front of the butterflies.

Your car comparison also proves my point: FI has absolutely no visible usage of the cooling air in the rear. And is fast. Cooling air usage is overrated.

Yes because a beam wing, rear wing and brake ducts are/were all placed in such a way the interaction with cooling air is minimized. Cooling air coming out of the rear bodywork is messy, high pressure air. You both want to to get rid of it as soon as possible while also keeping interaction between aero devices to a minimum. This year we have a weakened interaction between the rear wing and the diffuser, both because the cooling air coming out of the back is much bigger in volume, and the beam wing is gone.

Hence why mclaren clearly tries to stop the hot air and recreating the low pressure area from the beam wing. Jef Patat is right: hot air is slowed down even more due the blockade, which forces bigger cooling openings.

Also mind I don't tolerate any demands for cfd images or analyses. It's clear as day nobody has access to that and actually kills off any discussion. If you have any: good, post it. But don't demand that other people should come up with it.

[Jef Patat]

That is my reasoning indeed. And in that reasoning the butterflies 'dictate' where the hot air outlets are, which 'dictates' the engine cover, some of the packaging, ... And thus the car is 'designed around' them.

[basti313]

Hence why mclaren clearly tries to stop the hot air and recreating the low pressure area from the beam wing. Jef Patat is right: hot air is slowed down even more due the blockade, which forces bigger cooling openings.

If this is right this blockade of the butterflies has to at least reach the cooling air exits. Just to get the numbers: The butterflies are more or less at the edge of the rear tire, the cooling exits about half way between front edge of the rear tire and the center of the tire. So you can roughly estimate a distance of 40 to 50cm between butterfly and cooling air exit.

Also mind I don't tolerate any demands for cfd images or analyses. It's clear as day nobody has access to that and actually kills off any discussion. If you have any: good, post it. But don't demand that other people should come up with it.

Well, it is enough to use Google: Google -> find pictures -> "CFD".
You will find CFD pictures of F1 cars, road cars and other things. And just by looking at them you will recognize: You can pull a wardrobe at 200kph through the air and it will hardly affect the air 50cm in front of it.
So, where do you see any physical explanation, why the blockade of these tiny wishbones is strong enough to reach 40 to 50cm?
And as you said: We are not talking about "clean" air. We are talking about "messy, high pressure air" with turbulence. So even harder to affect.

[basti313]

Then why are the MCL hot air exits that big and placed that high?

If you say this is due to blocking, than how can you simultaneously solve this question: Why does McLaren have the longest hot air exits?

Regarding the size: McLaren is not using a central "tube" like Fer, Merc or RB. So I do not think their cooling exit is really bigger than the combined diameter of the exits of the contenders.

And as stated before: Force India has an even higher exit.

Why don't they place them similar to other teams (Merc, Fer, ...)

As far as I can see it nearly every team has a unique solution.

Read my post again, I am not saying anything on the usage of the hot air. I am saying the hot air needs to be able to go somewhere for it to have cooling efficiency.

So why not just shorten the exit if they have problems with the cooling efficiency?

[turbof1]

If this is right this blockade of the butterflies has to at least reach the cooling air exits. Just to get the numbers: The butterflies are more or less at the edge of the rear tire, the cooling exits about half way between front edge of the rear tire and the center of the tire. So you can roughly estimate a distance of 40 to 50cm between butterfly and cooling air exit.

It always is a game of compromises - there's a lot to take into account: cooling, weight, aero, regulations. The solution clearly does not reduce the influence of the cooling air to the pre-2014 level, nor will the aero benefit be as big as the beamwing. I can't give you a clear cut answer on that; there are too many variables. Hency why mclaren had to test it without the butterfly suspension: even they couldn't tell if it was reaching its goal.

You will find CFD pictures of F1 cars, road cars and other things. And just by looking at them you will recognize: You can pull a wardrobe at 200kph through the air and it will hardly affect the air 50cm in front of it.
So, where do you see any physical explanation, why the blockade of these tiny wishbones is strong enough to reach 40 to 50cm?
And as you said: We are not talking about "clean" air. We are talking about "messy, high pressure air" with turbulence. So even harder to affect.

Nothing pre-2014 is representative since cooling was way different. Again, if you find one, feel free to post it, but I doubt you'll find anything on 2014. And again, I don't tolerate demanding it from others. Often this is a strategic use in conversations to discredit the other person's theory since he can't bring it to the table. Trying to pull the conversation in its totality to cfd is fine, but if you want so, you'll need to make that first step, bring in cfd analyses and try to explain with pictures where it doesn't hold. In my opinion a waste of time, as again I doubt we'll have anything representative on this. Not only the aero is different, cfd has issues with higher temperature flow.

And sorry, but could you get some calculations on how you determined that the gap of 50cm (hardly true, but anyway...) makes it insignificant? By my knowledge, fast moving, high energy low pressure is much more difficult to control. The hot cooling air is much slower then even mainstream air. Granted the air has to go somewhere, hence why mclaren shaped their rear crash structure, but still I find this making no sence what you are saying there. I could be wrong of course, but elaborate on it.

About your reply on jef patat I only want to say this: again, it's a game of compromises. Shortening the exits would probably lead to other disadvantages. Probably the packaging and engine cover aero made them place it there.

[Jef Patat]

The FI outlet is smaller and not higher, check the exhaust position / rear crash structure which are fixed.

I think you need to look at it in another way. For the hot air exits to work efficiently they need pressure behind them that is as low as possible, to virtually suck the messy air out of them, if possible. They have those air outlets longer and higher to reach that goal. If they lower them they end up in the messy 'higher pressure' air. If they shorten them they feed the lower part of the rear wing with messy air. That has been my point from the beginning.

If we can't agree that the butterflies obstruct the air then there is not point in discussing their influence. I cannot backup my feeling with data. Also, don't over exagerate with the 200kph wardrobe thinking, the air at the back bottom is not that clean anymore. It passed the sidepods and whatever in front of them.

http://www.f1technical.net/forum/viewto ... 42#p263642
http://www.f1technical.net/forum/viewto ... 37#p386737

[turbof1]

If we can't agree that the butterflies obstruct the air then there is not point in discussing their influence. I cannot backup my feeling with data. Also, don't over exagerate with the 200kph wardrobe thinking, the air at the back bottom is not that clean anymore. It passed the sidepods and whatever in front of them.

It's this. Whether you 2 agree or disagree, there's no point in asking cfd. Mclaren didn't have fully confidence in it, and they have better tools.

There's nothing wrong going from intuition. Basti, so far you've discussed what it doesn't do. Then what's your opinion what it actually does?

[basti313]

If this is right this blockade of the butterflies has to at least reach the cooling air exits. Just to get the numbers: The butterflies are more or less at the edge of the rear tire, the cooling exits about half way between front edge of the rear tire and the center of the tire. So you can roughly estimate a distance of 40 to 50cm between butterfly and cooling air exit.

It always is a game of compromises - there's a lot to take into account: cooling, weight, aero, regulations. The solution clearly does not reduce the influence of the cooling air to the pre-2014 level, nor will the aero benefit be as big as the beamwing. I can't give you a clear cut answer on that; there are too many variables. Hency why mclaren had to test it without the butterfly suspension: even they couldn't tell if it was reaching its goal.

The discussion we are in is only about one simple question: Are the butterflies affecting the cooling. If we keep it that simple we may find a solution. There is no need for other variables.

You will find CFD pictures of F1 cars, road cars and other things. And just by looking at them you will recognize: You can pull a wardrobe at 200kph through the air and it will hardly affect the air 50cm in front of it.
So, where do you see any physical explanation, why the blockade of these tiny wishbones is strong enough to reach 40 to 50cm?
And as you said: We are not talking about "clean" air. We are talking about "messy, high pressure air" with turbulence. So even harder to affect.

Nothing pre-2014 is representative since cooling was way different.

CFD here should not solve any pre- or post-2014 question, but only one question:
How big is the high pressure zone in front of an obstacle?

Again, if you find one, feel free to post it, but I doubt you'll find anything on 2014.

Again: It is not about a 2014 F1 car. It is about simple physics, you can take a road car, a bike, a tire or a wardrobe as an example. It is just about the question how big the pressure zone in front of this item can be.

the gap of 50cm (hardly true, but anyway...)

Why? Can you make a better estimation? And I would say it is in the range of 40 to 50cm, not 50cm.

And sorry, but could you get some calculations on how you determined that the gap of 50cm (hardly true, but anyway...) makes it insignificant?

I do not do calculations. I use the CFD pictures available by googling and just look how far the high pressure zone of an obstacle can get.

For example this one: http://www.f1technical.net/forum/viewto ... 46#p284846
Absolutely no high pressure zone in front of the nose and no high pressure zone in front of the front wing. so I find it hard to believe that there is a big high pressure zone in front of the butterflies reaching the cooling air exits.

By my knowledge, fast moving, high energy low pressure is much more difficult to control. The hot cooling air is much slower then even mainstream air. Granted the air has to go somewhere, hence why mclaren shaped their rear crash structure, but still I find this making no sence what you are saying there. I could be wrong of course, but elaborate on it.

I do not know what you mean with the rear crash structure. But you are absolutely right with the slow cooling air. And if the air is slower the high pressure zone in front of the butterflies is even smaller.

About your reply on jef patat I only want to say this: again, it's a game of compromises. Shortening the exits would probably lead to other disadvantages. Probably the packaging and engine cover aero made them place it there.

So they are not placed there because of the butterflies?
Well, this was my point....but never mind....

[basti313]

If we can't agree that the butterflies obstruct the air then there is not point in discussing their influence. I cannot backup my feeling with data. Also, don't over exagerate with the 200kph wardrobe thinking, the air at the back bottom is not that clean anymore. It passed the sidepods and whatever in front of them.

It's this. Whether you 2 agree or disagree, there's no point in asking cfd. Mclaren didn't have fully confidence in it, and they have better tools.

One last answer to this one:
1. Of course the butterflies obstruct the air. But this obstruction, as any obstruction of this size can not move far forward. That is just simple aero.
2. Every wing produces an obstruction, but always the obstruction is compensated by a high pressure and low pressure side. Only a high pressure side in front would be rather stupid and I see no need for that and no reason coming from the shape of the butterflies. They should rather act as a wing with high and low pressure compensating each other in front of them, so absolutely no effect on the cooling.
3. If we are not talking about "clean" air, then the obstruction will be smaller as distinct pressure zones building up are compromised by turbulent air.

There's nothing wrong going from intuition. Basti, so far you've discussed what it doesn't do.

Isn't this useful? I mean, when physically impossible guesses about the butterflies compromising the cooling are taken for real this is rather "F1sciencefiction" than "F1technical".
If we go on with this butterfly discussion as it was, then after the next race someone comes and says the butterflies compromise the front wing...

Then what's your opinion what it actually does?

What part do you mean? Butterfly or cooling?

[turbof1]

So they are not placed there because of the butterflies?

The butterfly solution is there to have interaction with the cooling air, to a degree of course. Overdo it and you remove more performance then you add - hence why it's a game of compromises.

The discussion we are in is only about one simple question: Are the butterflies affecting the cooling. If we keep it that simple we may find a solution. There is no need for other variables.

Well you were the one trying to discuss the placement of the suspension, which in turn complicates the discussion. This happens anyhow with such discussions anyway: the more we discuss the more variables will be brought in. If it were that simple we wouldn't be having this discussion right now.

CFD here should not solve any pre- or post-2014 question, but only one question:
How big is the high pressure zone in front of an obstacle?

And the pressure is influenced by the temperature of the air which has been used to cool components. CFD has a very hard time with that.

Why? Can you make a better estimation? And I would say it is in the range of 40 to 50cm, not 50cm.

More like 10-20cm. to put in perspective: 50cm is the length of the neutral section of the front wing.
Just to visualise everything:

My neutral section of the front wing would have to be very flexible to be able to squeeze it into that gap. Would I be able to pass the deflection test? (yes, this is sarcasm)

I do not do calculations. I use the CFD pictures available by googling and just look how far the high pressure zone of an obstacle can get.

Then do please show them?

For example this one: viewtopic.php?p=284846#p284846
Absolutely no high pressure zone in front of the nose and no high pressure zone in front of the front wing. so I find it hard to believe that there is a big high pressure zone in front of the butterflies reaching the cooling air exits.

What the hell? Are you trying to compare the front wing, which hits unaffected mainstream air, with the cooling air hitting the butterfly suspension? I think this is the f1sciencefiction you mentioned: mainstream neutral pressure air = hot, high pressure and very turbulent air. In a world where increasing AoA will reduce drag .

What part do you mean? Butterfly or cooling?

. What do you think I am asking: the purpose of cooling ? Common man, it's not like I believe cooling is the fuel for the engine.