Vodafone McLaren MP4-27 Mercedes

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Just_a_fan
251
Joined: Sun Jan 31, 2010 7:37 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by Just_a_fan » Fri May 04, 2012 10:50 am

I think the idea here is to introduce flow that is contrary to the expected vortex direction hence the cut out's shape. As there is a low pressure area behind the wing between the endplates, the the flow will want to vortex one direction behind the flap and the other direction rolling off the ednplate. The shape of the cut out will determine how that forms.

I'm guessing that the sum of the drag from the two vortices formed this way is less than the drag from one big vortex and so is considered preferential.

Don't forget that the louvres in front of the flap in the endplate will allow some high pressure bleed outwards which will reduce the pressure differential at the end of the flap. This will also reduce the resultant vortex and so improve efficiency.

That's how I see it anyway, for what it's worth.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools."

JMN
4
Joined: Sun Aug 29, 2010 1:45 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by JMN » Fri May 04, 2012 2:17 pm

Might actually have been posted previously, but watch the two videos below for illustration purposes:
No modification of wingtip vortex - go to 5mins 11s.
[youtube]http://www.youtube.com/watch?v=Yy5S9pa_nVk#t=5m11s[/youtube]
Reducing effect of spillover via winglet
[youtube]http://www.youtube.com/watch?v=MYsxXXYrh4I[/youtube]

McMrocks
37
Joined: Sat Apr 14, 2012 4:58 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by McMrocks » Fri May 04, 2012 3:21 pm

i saw the video and i think McLaren also must have the effect of spillover.
But i can't believe that McLaren makes RWs with vortices, because there is no downforce but drag. But we sometimes saw a vortex at the McLaren RW. So why they do this?

i mean we ofthen saw things like this: http://scarbsf1.files.wordpress.com/201 ... tices1.jpg

JMN
4
Joined: Sun Aug 29, 2010 1:45 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by JMN » Fri May 04, 2012 3:46 pm

The vortices from the RW on the MP4-26 was noticably more visible due to the larger flap. It's all in the article related to the picture you posted, including how the current aspect ratio of the RWs simply doesn't make it feasible and much less optimal to mitigate the vortices to a point where they are hidden from the naked eye.

hardingfv32
28
Joined: Sun Apr 03, 2011 6:42 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by hardingfv32 » Fri May 04, 2012 5:31 pm

Just_a_fan wrote:That's how I see it anyway, for what it's worth.
What you propose does make sense.

The louver designs sure have been progressing over the last couple of years. I wonder why it takes so long to max out such a theme?

Brian

Huntresa
54
Joined: Sat Dec 03, 2011 10:33 am

Re: Vodafone McLaren MP4-27 Mercedes

Post by Huntresa » Fri May 04, 2012 5:40 pm

McMrocks wrote:i saw the video and i think McLaren also must have the effect of spillover.
But i can't believe that McLaren makes RWs with vortices, because there is no downforce but drag. But we sometimes saw a vortex at the McLaren RW. So why they do this?

i mean we ofthen saw things like this: http://scarbsf1.files.wordpress.com/201 ... tices1.jpg

You cant make a RW without vortices, so how do you propose they would make one without them?

Just_a_fan
251
Joined: Sun Jan 31, 2010 7:37 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by Just_a_fan » Fri May 04, 2012 7:19 pm

McMrocks wrote:i saw the video and i think McLaren also must have the effect of spillover.
But i can't believe that McLaren makes RWs with vortices, because there is no downforce but drag. But we sometimes saw a vortex at the McLaren RW. So why they do this?
All of the cars make rear wing vortices. It's a natural result of using a wing. Even wings with endplates make vortices. I've got some poor pictures of cars other than McLarens making rear wing vortices at Silverstone last year.

The important thing is to make the L/D as good as possible. Having 100kg more downforce is no good if it comes with 100kg of drag, for example, because you'd get destroyed on any long straight. Getting 75kg more downforce but with only 25kg extra drag, on the other hand, is worth it. Sure you'd be marginally slower on to the straight from the corner (assuming the corner exit speed is downforce limited) but you'd be quicker for most of the straight (think China's long straight here as a good example).

Don't forget that powered absorbed by drag is a cubic relationship with respect to velocity ( bhp absorbed = (Cd . A . v^3)/1225 ) so anything you can do to reduce drag at high speed is good - the teams can't get any more power from the engines so they have to concentrate on drag in order to get decent straight line speed. After all, this is what the DRS is all about - letting the teams dump a good chunk of drag.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools."

Just_a_fan
251
Joined: Sun Jan 31, 2010 7:37 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by Just_a_fan » Fri May 04, 2012 7:21 pm

hardingfv32 wrote: The louver designs sure have been progressing over the last couple of years. I wonder why it takes so long to max out such a theme?

Brian
Presumably the louvre designs change to match changes elsewhere in the package. Change the front wing and you will alter the flow getting to the rear wing so you'd need to adjust accordingly, for example.
Turbo says "Dumpster sounds so much more classy. It's the diamond of the cesspools."

PlatinumZealot
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Re: Vodafone McLaren MP4-27 Mercedes

Post by PlatinumZealot » Fri May 04, 2012 8:52 pm

McMrocks wrote:i saw the video and i think McLaren also must have the effect of spillover.
But i can't believe that McLaren makes RWs with vortices, because there is no downforce but drag. But we sometimes saw a vortex at the McLaren RW. So why they do this?

i mean we ofthen saw things like this: http://scarbsf1.files.wordpress.com/201 ... tices1.jpg
You see, McMrocks, they don't choose to make the vortices. the vortices is a physical phenomena that happen at the corner of the wing where you have a high pressure gradient and a tripping surface. It is all a consequence. Vortices in this area make drag so team try to reduce them, by making fancy gills and vertical gurney flaps on the side of the RW end plates.
"Raindrops .. drop top!"

AnthonyG
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Joined: Sat Mar 03, 2012 12:16 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by AnthonyG » Sat May 05, 2012 9:32 am

JMN wrote:Might actually have been posted previously, but watch the two videos below for illustration purposes:
No modification of wingtip vortex - go to 5mins 11s.
[youtube]http://www.youtube.com/watch?v=Yy5S9pa_nVk#t=5m11s[/youtube]
Reducing effect of spillover via winglet
[youtube]http://www.youtube.com/watch?v=MYsxXXYrh4I[/youtube]
Question: why if the problem is air comming from beneith the wing, does the winglet tries to cut off the top and not the bottom?
I understand how the "current" solution works, but it seems more logical to tackle the bottom.

Sorry for the off-topic
Thank you really doesn't really describe enough what I feel. - Vettel

Matt Somers
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Joined: Thu Mar 19, 2009 10:33 am

Re: Vodafone McLaren MP4-27 Mercedes

Post by Matt Somers » Sat May 05, 2012 11:54 am

Perhaps this old picture I have of a flo-viz'd McLaren rear wing will help show how the flow moves across the endplates?

Image
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Huntresa
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Joined: Sat Dec 03, 2011 10:33 am

Re: Vodafone McLaren MP4-27 Mercedes

Post by Huntresa » Sat May 05, 2012 12:09 pm

Well the part nearest the wing isnt there now, cause they have a cutout there aswell meaing the fins is more inwards and the side is outwards.

hardingfv32
28
Joined: Sun Apr 03, 2011 6:42 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by hardingfv32 » Sat May 05, 2012 5:57 pm

AnthonyG wrote:Question: why if the problem is air comming from beneith the wing, does the winglet tries to cut off the top and not the bottom?
I understand how the "current" solution works, but it seems more logical to tackle the bottom.
The low pressure region (distance from wing surface) on the low pressure side of a wing is many times larger than the high side of a wing. Is that on point?

Brian

hardingfv32
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Joined: Sun Apr 03, 2011 6:42 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by hardingfv32 » Sat May 05, 2012 6:01 pm

In the above end plate photo, what is happening to the flow behind the second element/flap? Does this look correct or could the test have been done with the flap up?

Brian

Lycoming
133
Joined: Thu Aug 25, 2011 9:58 pm

Re: Vodafone McLaren MP4-27 Mercedes

Post by Lycoming » Sun May 06, 2012 7:26 am

This looks like the wing they ran in the beginning of 2011, the one with the most prominent vortices....