Mclaren Mercedes MP4-25

[Pup]

Also as a previous poster said, it's damaging at low speeds, where you would infact want a sucking slit, and we have seen that extra mystery outflow on the back of the car (although it could just be an exhaust). Nobody's come up with a mechanism for how it could be done, but it doesn't seem beyond the bounds of possibility.

My guess is that it's just a venturi effect going on inside the engine cover, and that black exhaust is the exit for the fast moving, low pressure body of air (B.)that's "sucking" on a slightly higher pressure body of air (A.), which is itself drawing air through the slot.

I really think you guys are barking up the wrong tree with a vacuum slot. Just look at the example of a vacuum wing given previously - there are multiple slots, all located toward the trailing edge - past the point of maximum thickness, where pressure begins to rise. Blown wings have single slots on each element, located at the leading edge, which is what we see here.

I believe that vacuum slots are used when a designer is trying to maintain a laminar flow across more of the wing, whereas a blown slot is meant to disrupt the flow earlier on, much as a turbulator would. So a vacuum slot would be good for creating a slippery wing with a low AoA, where a blown wing would be draggy, but better suited for high lift wings.

[Pup]

I think Vodafone is raking in the cash after this discussion...

more than 3x the number of posts than any other car.
What an extremely successful marketing campaign

Think of how the Santander boys must feel, after pulling their logo from just above this mystery.

[Pup]

Just a question on the rear wing, everyone is concentrating on the slot in the rear of the wing. At the top front front they may also have a full length slot across the entire wing. Is that likely and does that explain the black strip along the top as it doesn't look like a guerney flap.

I looks like just a small gurney flap to me.

[meves]

Cheers Pup.

[ringo]

Yaw control provided by the end plates??? Perhaps a 2ndary effect of their purpose yes. Yaw control is provided by the tyres.

When the wng falls off, a large portion of the energy required to draw the air along the underbody is removed. The air flow under the car slows down dramatically resulting in a higher pressure wave now moving underneath the car. It reaches the exit at the rear and destabilises the rear, reducing the grip.
A the shark fin won't stop fish tailing under these conditions. Slowing the car down to rebalance the underbody flow is what is required.

I think Vodafone is raking in the cash after this discussion...

more than 3x the number of posts than any other car.
What an extremely successful marketing campaign

Not yaw control, i meant yaw stability. The distribution of surface area when viewed from the side is important when it comes to yaw stability.
Similar to aircraft, the vertical tail area and position factor into it's stabilty and how quick it can change direction.
The end plates have other purposes as well, mainly to reduce vortex formation and increase the effective span of the wing.

[Poleman]

McLaren planning bodywork changes as well as aero for Barcelona.

The team decamps to Barcelona next week for the fourth and final test of the winter. Both drivers will spend alternate days in the car evaluating the new bodywork and aerodynamic components ahead of the season-opener in Bahrain on March 14.

[cornermarker]

Also as a previous poster said, it's damaging at low speeds, where you would infact want a sucking slit, and we have seen that extra mystery outflow on the back of the car (although it could just be an exhaust). Nobody's come up with a mechanism for how it could be done, but it doesn't seem beyond the bounds of possibility.

My guess is that it's just a venturi effect going on inside the engine cover, and that black exhaust is the exit for the fast moving, low pressure body of air (B.)that's "sucking" on a slightly higher pressure body of air (A.), which is itself drawing air through the slot.

I really think you guys are barking up the wrong tree with a vacuum slot. Just look at the example of a vacuum wing given previously - there are multiple slots, all located toward the trailing edge - past the point of maximum thickness, where pressure begins to rise. Blown wings have single slots on each element, located at the leading edge, which is what we see here.

I believe that vacuum slots are used when a designer is trying to maintain a laminar flow across more of the wing, whereas a blown slot is meant to disrupt the flow earlier on, much as a turbulator would. So a vacuum slot would be good for creating a slippery wing with a low AoA, where a blown wing would be draggy, but better suited for high lift wings.

Previous implementations have always had the blower low on the wing, where the transition in aoa is dramatic, just like on an aircraft. You see it on last year's McLaren slot and BMW, and this year's Sauber. This shows us that most of the wing is actually treated as a flap. The MP4-25's slot is located much closer to the trailing edge, and in an area where the change in profile is minimal. This convinces me that it's not a blown flap. Along with that, shots from above and behind show no difference in "height" before and after the gap, i.e. there's nothing to indicate that the air is being directed upward (and we've seen some good shots from above the garage) along the surface of the wing, it just seems to be an opening.

Whereas I used to think it was about pressure, now I'm pretty convince that the slot is there to interfere with the boundary layer in some way. I keep going back and forth between blowing and sucking, and feel that it could be, should be both. Suction at low speed to keep the layer attached for higher df (perhaps also a small benefit in lower pressure), blowing at high spd for a early and controlled (lower drag) release of the boundary layer.

I'd always imagined that it would be passive, but imagine the potential if active (which should also be relatively simple). Through the last turn the driver has the switch in it's up position, the slot is sucking, producing high df. Some distance out of the turn and down the straight, he puts the switch in a down position, releasing the boudary layer early, and reducing drag. Would such a control be legal? If not, it could be activated by the gear the car is in, sucks up to 4th, blows above that. The particular gear of course could be determined by the track. *shrug*

Kelpster

[outer_bongolia]

I really think you guys are barking up the wrong tree with a vacuum slot. Just look at the example of a vacuum wing given previously - there are multiple slots, all located toward the trailing edge - past the point of maximum thickness, where pressure begins to rise. Blown wings have single slots on each element, located at the leading edge, which is what we see here.

I believe that vacuum slots are used when a designer is trying to maintain a laminar flow across more of the wing, whereas a blown slot is meant to disrupt the flow earlier on, much as a turbulator would. So a vacuum slot would be good for creating a slippery wing with a low AoA, where a blown wing would be draggy, but better suited for high lift wings.

Hmm.. Horse's paint picture on page 82 definitely suggests some blowing of air, and no flow separation until pretty much the far tip of the wing. The flow for sure looks laminar, but it is accomplished by high speed air coming from the slit.

I think we were able to go one more time around the circle.

[gibells]

At last we'll see what difference it makes on a decent straight like Barca.

[TheMinister]

At last we'll see what difference it makes on a decent straight like Barca.

We'll finally come to the realisation that it's just some line that a mechanic with a malicious sense of humour drew on in black pen.

[Hangaku]

At last we'll see what difference it makes on a decent straight like Barca.

We'll finally come to the realisation that it's just some line that a mechanic with a malicious sense of humour drew on in black pen.

"This is really gunna get that lot at f1technical talking, haw haw haw", etc. =D>

[bonjon1979]

There seems to be blown wings on the Sauber and the Williams which are fed from an opening on the front of the wing. However, the slot on the back is clearly visible. Could it be that Mclaren haven't put their wing with a slot in it on yet?

[axle]

There seems to be blown wings on the Sauber and the Williams which are fed from an opening on the front of the wing. However, the slot on the back is clearly visible. Could it be that Mclaren haven't put their wing with a slot in it on yet?

I thought the opening was the black line in the upper element?!

[bonjon1979]

There seems to be blown wings on the Sauber and the Williams which are fed from an opening on the front of the wing. However, the slot on the back is clearly visible. Could it be that Mclaren haven't put their wing with a slot in it on yet?

I thought the opening was the black line in the upper element?!

Well, there have been some who have said it looks more like a ridge! On the williams and the Sauber it's really clear what it is. I don't know though!

[mstar]

the next test be great to see the latest upgrades i think mclaren bring some bits and so will ferrari etc. anybody know which ones mclaren might have?