Lotus E21 Renault

[raymondu999]

Trackside impressions by Gary Anderson, from the latest edition of Autosport:

The Lotus looks very consistent on track. What’s most impressive is that the front end seems very strong and the drivers can place the car where they want. Having watched it over long runs it doesn’t appear that the car has any understeer, which potentially could hurt over a stint on a set of tyres. Lotus has a good little car that is working well.

[korzeniow]

- stall behaviour: If I suppose that stall is achieved by blowing out of the slot, after stalling the suction peak on the wing is lost, so the pressure is higher and the hypotetical blowing is less effective, which could lead to reattachment. That seems undesirable. By sucking instead, the higher the pressure on the lower part of the wing, the greater the suction effect

-flow viz: though I am not an expert in interpreting flow viz, in the picture above that shows the separated wing I did not recognize a separation pattern on the slotted pillar, which I expected if the slots were blowing. )But maybe I have wrong expectation - this is not a strong point)

You don't have to be an expert to see patterns on flow visibility paint. "L" shaped vertical pipe blows rear wing's main plate. The flow pattern is in line with the slots on "L" pipe (see pink arrows).

-pipe sizes: when I took a look at renault's f-duct on another thread here http://www.f1technical.net/forum/viewto ... 0&start=15, I noticed that the pipes were sized very differently:
http://www.formula1.com/wi/full/ta_arti ... le_785.jpg
the ears were much smaller, the pipe blowing on the wing and the other pipe discharging between mainplane and beamwing had more or less the same section. On the drd there are much bigger ears, that feed a big main duct, with a much smaller pericope duct - if the working principle is the same, expect for the "passive" switching instead of driver operated, why are the pipes' sizes that different?

F-Duct operated diffrently than DRD, because the driver was switching the air. The stall was achievent diffrently because rear wing's main plate had slit in it (which made the wing 3 parts in general), air from -Duct was bowing the main plate and exiting trough the slit and stalled bottom of the main plate.

I would imagine to achieve passive fluid switch you need more air, hence bigger intakes.

-fluidic switch: I have seen no hypotesis about how it could work, and it is difficult for me to imagine one. If I suppose that the periscope is drawing air in, there is no need for a fluidic switch, you need just a venturi section (from there comes the analogy with a mr proper spray)

In this scenario the wing would be stalled all the time, wouldn't it? Because always there would be lower pressure in the venturi tube.

-monkey seat on the outlet: if the periscope is blowing above a certain speed when the main pipe cannot expel any more flow, why is the big monkey seat needed? In 2013 lotus have got rid of the big monkey seat, but they still need the tongue after the exit of teh main pipe to drive the fluid. If the periscope is sucking and there is a throat in the main pipe to achieve the lower pressure needed, then the monkey seat is necessary to pull the flow out from the throat

How do you know that they got rid of monkey seat? For me more sense makes the idea that they didn't have time to fit it, they were using very old (from the middle of the 2012 season) rear wing after all.

-shape of the periscope / main pipe junction: it seems consistent with a 90° connection between periscope and main pipe, which is not necessary if the slots are blowing, whereas it is if the slits are sucking it is needed. But it is difficult to detect the exact shape of teh joint, so this is not a strong point either.

The "L" shape (as Scarbs is calling it) is the result of the rules that banned the use of shark fins. On the image below, the yellow colored colored area must be free of any aero gizmos

[Matt Somers]

The F Duct worked to increase both downforce and reduce drag as the slots were able to cross the length of the Mainplane as mentioned above by increasing the Wing's AoA / Efficiency (by effectively making it a 3 plane wing) when the driver interrupted the airflow the AoA became too much to sustain and stalled. (Well that's how I have always perceived the F Duct/RW80)

Although my original theory was based on the same idea it's apparent that the slots aren't able to blow far enough across the wing to make this possible let alone the fact that without driver involvement there isn't a way of interrupting the flow.

[shelly]

@somers: I have ready your original theory at the link you gave, but it seems the opposite of mine, as in your hypothesis the periscope pipe blows, ie air comes out of it. I think air goes into the pipe instead

[Owen.C93]

The F Duct worked to increase both downforce and reduce drag as the slots were able to cross the length of the Mainplane as mentioned above by increasing the Wing's AoA / Efficiency (by effectively making it a 3 plane wing) when the driver interrupted the airflow the AoA became too much to sustain and stalled. (Well that's how I have always perceived the F Duct/RW80)

Although my original theory was based on the same idea it's apparent that the slots aren't able to blow far enough across the wing to make this possible let alone the fact that without driver involvement there isn't a way of interrupting the flow.

Pretty sure it was the opposite. It acted as a normal wing until it was blown which caused it to stall.

[korzeniow]

@somers: I have ready your original theory at the link you gave, but it seems the opposite of mine, as in your hypothesis the periscope pipe blows, ie air comes out of it. I think air goes into the pipe instead

Kudos for thinking out of the box, but you have no proof to that

Pretty sure it was the opposite. It acted as a normal wing until it was blown which caused it to stall.

This. When the main plate was blown it bowed which opened the slot that stalled the wing by detaching the flow from under the wing.

[Matt Somers]

You 2 of course are right (Regarding the F Duct), I dunno why I wrote that post in the way I did (Must be the lack of sleep over the last few days). Always helps if you use the words could have in a sentence where you meant to place them. *Slopes off to go and get some sleep.

[Lurk]

#WhatnottosayonValentinesDay... Hey E21, we never said you NEED a nose job. We just said it wouldn't hurt to consider it.

Vanity panel soon?

[Neno]

#WhatnottosayonValentinesDay... Hey E21, we never said you NEED a nose job. We just said it wouldn't hurt to consider it.

Vanity panel soon?

They said if they find vanity panel who will gain them aero advantage, they will use it. In other case, it will remain less or more how it is.

[Lurk]

I know, I saw the presentation and Allison also nearly said they found something tricky with it .

[stefan_]

Don't know where you heard that, it's purely your speculation. This is exactly what Allison said at the launch:

"We have not done it yet [mounting a vanity panel] because the cosmetic panel would weigh a few grams and with a Formula One car, putting a few grams on it you don't need to *couldn't understand the word*(...) However if we find a cosmetic panel that looks nice but, much more importantly and crucially, develops a little bit of downforce then we'll pop it on as quick as you like."

[shelly]

@korzeniow: I find some of your objections reasonable, other come from the fact the fact my post lent itself to misunderstanding. I go in the same order as your points:
- flow viz: what I meant is that the separation apparent on the wing is much less noticeable on the pillar
-f-duct: agree on the functioning summarized, but that does not explain why the periscope is that small
-the wing would not be stalled all the time, the pressure difference between throat of the pipe and wing would not be constant with car's speed due to internal losses in the pipe tuned with wire mesh screens - agree that this type of switch is debatable
-in 2012 there was a special monkey seat for drd, in 2013 it has been replaced by the engine cover "tongue" to have the same effect with less drag
-I read scarbs abou the leaglity box, but I was not referring to that, I was thinking of the curve near the juction between the two pipes.

Anyway, I liked the discussion and I hope that we will find out something more about this gizmo in the future

[Forza]

1st Barcelona test
Permane: The first Barcelona test is largely concerned with improving the car from the initial lessons learnt in Jerez, so we’ve worked on anything which didn’t quite operate as expected or any components which need beefing up. This means there are minor updates to make the car more robust and raceworthy, which can be done in conjunction with performance work. Many of the updated parts are not necessarily performance parts, but more concerned with reliability, so a performance assessment can be conducted in parallel.

2nd Barcelona test
Permane: Some more of the same, but we’ll have aerodynamic updates such as a new front wing, a new floor, a new rear wing and most of the Melbourne package to evaluate. This means performance is more the focus. That said, even when we’re focused on performance testing, reliability evaluation is a welcome by-product whenever we run the car.

Back in from first lap of E21 chassis #2

F1 test 02 - Barcelona - day 1

[korzeniow]

[madly]

Some changes visible. Different top camera mounting. It's on the main axis. Good shoot!

On this photo tee tray looks like it is bending vertically at the edge. Looks different.