Lotus E21 Renault

[korzeniow]

Look at that slotted bargeboard. Like a stairway
http://www7.pic-upload.de/03.03.13/rjgy5w4dvxz.jpg
http://www7.pic-upload.de/03.03.13/ivvo2hly19s.jpg

What's that:

http://i.imgur.com/hTXZMR6.jpg

?

[shelly]

I do not know what's that - but form the picture it seems that lotus are fairing the driveshaft too

[henra]

I wrote "footplate vortex" but I should have written "diffuser footplate vortex", meaning the vortex that develops aroud the diffuser edge, like a wing tip vortex, because of the pressure differential between upper and lower surface. Air goes down veritcally in the gap between diffuser edge and rear wheel, arounf the diffuser edge.
The vortex forme by the strake we are discussing about flows in the same gap, on the other side i.e. cloer to the wheel.
Looking at the left rear wheel from the front you would see the diff. footplate vortex turning clockwise, and the other vortex turning counterclockwise.

Ahhh, now I got you.
Agreed. That makes sense. And a fast stream from the exhaust gases flowing along the inner side of that strake will increase the strength of that strake vortex (lower static pressure on the inside, thus higher pressure differential and therefore a stronger vortex). So you probably would want a sharp stream as close as possible but strictly inside to the strake. That might be an advantage of the ramp solution vs. the bulge solution: It might be easier to prevent spreading of the plume to the outside of the strake when it hits the floorplate.

I am not sure that the vortex created by the upper part of the bargeboard lasts all the way to the back along the undercut; the vortex from the lower edge of the bargeboard goes under the floor but is more central, and I think its effect is lost half teh way down to the floor.

It would really be interesting to see actual data of this area. I suspect there would be some vortex still existing. However, you might be right, it might have shed most of its energy before reaching the ramp/strake area.

Thanks for the informative reply.

regards,
henra

[Owen.C93]

I do not know what's that - but form the picture it seems that lotus are fairing the driveshaft too

I can see the driveshaft.

[shelly]

You are right - my mistake

[CottrellGP]

Remember the regulations about exhaust pipes? The angle on horizontal axis must be no less than 10 degree pointing upward. Exhaust like this is pointing downard, so it is ilegal. I think they just wanted to see how good their actual solution is by comparing it to, probably the best possible, solution.

What exhaust is pointing downwards?

[raymondu999]

This exhaust

[MarkedOne8]

Left: Kimi's helmet from Jerez. Right: Kimi's helmet from the last test in Barcelona.

As you probably all know, Kimi has changed the manufacturer of his helmet. It was Arai last year, now it is Bell with HP7 model.
How much is that thing with changing helmets worht in performances? What do you guys think? You know, he was sticking to Arail all the career (except with Ferrari because they are sponsored by Schuberth). So, I guess there is some real gain to be achieved, but how big it acutally is or can be?

[sirexilon]

This exhaust
http://img2.auto-motor-und-sport.de/Lot ... 665423.jpg

Ok guys correct me if I'm wrong, but that cover to the usual coanda channel is not legal, that will put the exhausts exit much further back than the line FIA stipulated, I think they used it to test the difference between what they get with the coanda effect and what they get if they forced the air down. Could that be it?

[raymondu999]

It's illegal. It was just as a reference baseline for comparison testing.

[Blackout]

Look at that slotted bargeboard. Like a stairway
http://www7.pic-upload.de/03.03.13/rjgy5w4dvxz.jpg
http://www7.pic-upload.de/03.03.13/ivvo2hly19s.jpg

What's that:

http://i.imgur.com/hTXZMR6.jpg

?

Have no idea but it reminds me of the R30 EBD nozzle
http://www.servimg.com/u/f39/14/79/55/26/exh_bm10.jpg

Maybe they added it to reduce the size of that air outlet temporarily and test that...
And it seems the step between the 'ramp' and the floor has been smoothened/reduced.

[Pierce89]

https://pbs.twimg.com/media/BEdWz-kCUAAPCe2.jpg:large

Left: Kimi's helmet from Jerez. Right: Kimi's helmet from the last test in Barcelona.

As you probably all know, Kimi has changed the manufacturer of his helmet. It was Arai last year, now it is Bell with HP7 model.
How much is that thing with changing helmets worht in performances? What do you guys think? You know, he was sticking to Arail all the career (except with Ferrari because they are sponsored by Schuberth). So, I guess there is some real gain to be achieved, but how big it acutally is or can be?

The gain is monetary

[bhall]

Look at that slotted bargeboard. Like a stairway
http://www7.pic-upload.de/03.03.13/rjgy5w4dvxz.jpg
http://www7.pic-upload.de/03.03.13/ivvo2hly19s.jpg

What's that:

http://i.imgur.com/hTXZMR6.jpg

?

I think...

It's an adjustable cover that regulates flow out of the tunnel, which, I imagine, is also connected to the starter motor hole. The larger the cover on the top side of the floor, the part denoted by the arrow, the more flow is released under the floor through the starter motor hole or just in-general.

(I imagine they want the whole thing to choke at a certain speed, which could "stall" the diffuser, because a car doesn't need downforce, from neither the diffuser nor the exhaust nor anywhere else, along straights, and veritable air dam(n)s at the tunnel inlets will reduce drag, too.)

EDIT: I'm sure every ounce of this has been dissected ad nauseam. This is just me going through it for my own benefit, really. I'm never sure if I understand something until I see it.



When functioning freely, the tunnels do their Coanda business for the exhaust, a topic I --- know has been bludgeoned to bits. They also feed both the top and bottom of the diffuser so it can do its downforce thing, like a bawse.

When the tunnels choke (red), airflow is redirected from both the top and bottom of the diffuser, which upsets its aero balance and "stalls" it, reducing downforce und drag. The diverted airflow can also toy around with tire squirt to "stall" the sides of the diffuser, too. (Maybe. I dunno.)

So, yeah. The green-arrow bit helps tune that mess, because the desired flow balance is track-dependent.

(This is why I'll never be asked to give a speech and why it's not uncommon for people to ask me for the time [as if it's mine] only once or twice. Ever.)

[Coefficient]

https://pbs.twimg.com/media/BEdWz-kCUAAPCe2.jpg:large

Left: Kimi's helmet from Jerez. Right: Kimi's helmet from the last test in Barcelona.

As you probably all know, Kimi has changed the manufacturer of his helmet. It was Arai last year, now it is Bell with HP7 model.
How much is that thing with changing helmets worht in performances? What do you guys think? You know, he was sticking to Arail all the career (except with Ferrari because they are sponsored by Schuberth). So, I guess there is some real gain to be achieved, but how big it acutally is or can be?

Its pretty negligible really. The shaped helmets tend to be used in an attempt to assist air into the airbox but obviously its not going to be any great shakes especially as the head moves around constantly with gear changes, steering, vibration etc. Stil, form follows function as they say so they must be able to define the benefits.

Button used to use a heavily shaped helmet because he is 6ft 1 and has been known to block the airbox a bit. He can get lower in the Mcalren though so has reverted to a more conventional design.

[Blackout]