Lotus E22 Renault

[mrluke]

As your analysis says, there are dozens if not hundreds of 'critical' areas in the chassis, the asymmetric nose probably being one of the simpler of them all.

I'd have to disagree with you here. I think it was Gary Anderson who commented on the fact that Mercedes have gone through multiple crash tests to produce 3 iterations of their nose this year. Why put in all that effort if it isn't important? Perhaps we might not think they are that important because they are not changed too much during the season, but the whole car is designed around the nose and front wing so changing them drastically during the year would actually be detrimental.

Sorry for OT but Mercedes revised their nose because their Plan A did not get through crash testing (Merc argued the front wing was part of the nose, FIA disagreed) so they started the season with Plan B nose, all the while working on getting the nose they had designed the car around back on the car which took lots of crash testing. Once this was achieved they have then managed to refine it and remove some of the extra structure they added to get through the test.

Could the lotus problem be a weakness in their chassis, a bit of flex or differential movement under braking?

[theWPTformula]

Could the lotus problem be a weakness in their chassis, a bit of flex or differential movement under braking?

I doubt it's flex, if it was then they could resolve it by building new ones with suitable modifications.

Grosjean said it was the issues mainly revolved around inconsistent aero - there's a link to an article on ESPN on the previous page. If the floor is stalling as the car pitches under braking then the driver lacks grip and - in my opinion, more importantly - confidence. The aero balance is also shifting from the CoP by "2%": unless anyone has clarification I presume that's 2% forwards of the CoP as the rear of the car goes light when the floor stalls.

[flyboy2160]

I've long contended that a key to getting the current stepped bottom cars' floors to work properly is designing the vortices all the way from the front of the car to help seal the floor. I even guestimate that the diversion of air outboard of the tires is also to allow vortices coming off the FW and the nose strakes to interact properly with the vortices generated locally at the lower barge board/floor corner. There is a CFD plot somewhere here on F1T that shows vortices coming of the front and feeding right into the barge board/floor corner.

RB appear to be the masters of this and thus can run more rake.

This sealing should hold even with a small change in the floor AOA due to brake pitching.

If Lotus doesn't do this well - either due to the twin tusks messing up the flow going aft or whatever - the floor could "port" (which I prefer to "stall.") Note how they admitted that their FBD diffuser was the wrong way to go. So it wouldn't surprise me that they don't have this right. Their RBD could have masked a fundamental mis-design of the floor sealing system which carried over to this year.

But that's all just F1T speculation. I wish we had Scalabrini posting here or some F1 team people posting here anonymously.

[Per]

The issue with cornering is that the tusk completely blocks off the area between the tunnel. Lotus nose works by getting air in between the tusks. This is different to the dong, where air is grabbed from the side of it.

When the dong nose is in yaw, one side isn't blocked off. With the tusks, the area where air is supposed to flow is blocked off. And seeing the importance of getting air there to make the floor work, this is quite an issue. The 50mm(or how much it is) thus makes quite a significant difference in left or right corners.

The area of the tusks also have to be pushed through the air when turning in, which also could be an issue.

I still disagree. I don't think we've seen them coming with a mirrored nose, the right rusk was always the longer one so far. (I do believe Singapore is the first counter-clockwise track this year, so if they come up with a longer left tusk this time, then I will concede my point.)

For now I don't follow your logic. "Blocked off" is way too strong terminology because the angle of sideslip (directional angle of attack, or whatever it's called) in high speed corners is probably at most ~3 degrees. Sure, the tusks will inhibit flow towards the floor a bit and consequently there will be at least a minor difference between left and right. But I simply cannot imagine that the influence is so big that it is the difference between having good downforce and "losing the floor" (- Grosjean). The flow remains attached to the tusks, there is no separation, there may just be a slight loss of pressure in the tunnel but it will occur whether you go left or right.

Here's one more question: if the longer tusk "blocks off" the flow to the floor more than the shorter tusk, why have they run a longer right tusk on all clockwise tracks so far? I do suppose the loss of pressure in the tunnel is larger in right hand corners, if the right tusk is longer.

[wesley123]

For now I don't follow your logic. "Blocked off" is way too strong terminology because the angle of sideslip (directional angle of attack, or whatever it's called) in high speed corners is probably at most ~3 degrees.

That's still a bit of blockage on the single path under the nose.

Sure, the tusks will inhibit flow towards the floor a bit and consequently there will be at least a minor difference between left and right. But I simply cannot imagine that the influence is so big that it is the difference between having good downforce and "losing the floor" (- Grosjean).

The issue is there that the floor needs clean air to work properly, clean air that comes from under the nose. Influencing the intake of this clearn air will influence the airflow further down. And with such limited rules on the floor, you want to push it as hard as you can, making them unstable to a loss of this clean air.

This issue can be limited to a side, because a side of the tunnel will be "choked" under yaw, this would also mean that a side would suffer more downforce loss than the other. Making downforce levels overall just unpredictable.

Their use of the "bowling alley" under the nose imo shows that they have issues directing the airflow properly under yaw. I believe theWPTformula has a article on it.

Another issue is that the nose now is on the height where it is in the front wing area. We all know the use of the front wing shedding tip vortices. Both for use further down, as well as to shield the tire wake. I'd say that under yaw, the nose will too influence flow around the front wing, and thus influence the vortices, which then influence tire wake.

I agree that the tusk in itself doesn't pose much of an issue, but if you look further than the nose in itself, this design just adds small issues overall.

Here's one more question: if the longer tusk "blocks off" the flow to the floor more than the shorter tusk, why have they run a longer right tusk on all clockwise tracks so far? I do suppose the loss of pressure in the tunnel is larger in right hand corners, if the right tusk is longer.

When I saw their assymetry I always assumed they would switch this around for tracks with more left-hand corners. This did not happen.

Lotus had the issue where their car hardly lasted half a race, which needed fixing. After it was solved they could truly develop, and that is where the problem is found.

It could very well be that they just did not bother crash testing twice(remember, they were already late to the party) as their car had bigger issues.

[stefan_]

Singapore 2014 (Thursday 17.09.2014)

[Per]

Counter-clockwise track, still right tusk longer than the left. I stick to my view on the asymmetric nose not being of crucial importance to the car's overall (lack of) performance. Yes Lotus had a lot on their mind lately but no, it is not an insurmountable task for a team their size to mirror the design, make the moulds, manufacture the new noses and crashtest them. If it really made a difference, they would have gone for that, surely.

[wesley123]

If the tusks are the issue here then there is no point in mirroring them, because you'll just end up with the exact same issue.

[Per]

Hold on a sec, this conversation we had in this topic started with theWPTformula suggesting that the 50mm difference between left and right tusk might be the root cause of Lotus's problems, not the existence of the tusks in and of itself. That's what I was reacting to. Perhaps the twin tusk nose is a bad concept, I would even say it's highly likely. But whether they are equal length or 50mm different, to me it doesn't seem like a big deal.

[chuckdanny]

"No offence to the team because it has been the case for three years, but with the blown diffuser on the car and more downforce on the car we had before it was invisible to everyone. When it is invisible you don't know it, but with the new regulations and harder tyres and less downforce and the loss of the blown diffuser - everything that made us strong in the past - it is now our weakness"

this phrase from RG tends to prove that the problem doesn't come from the nose because it has been the case for 3 years and it was hidden by the level of downforce they had plus more mecanical grip from the tires, so we should look for something else.
It raises the question : "how do they know now that this aero instability from the floor was there too with the E20 and E21?
With the bunch of sensors they use, they didn't get the floor stalling on there screen?
With such a massively different nose this year (creating a substantial downwash with this steep underside right before the air intake of the floor, at least before they add this strange air filter) that create a very different condition for the air intake, they are able to sort this out and tell it's due to something else that already existed on the E20 and E21 ?
This air filter completly negate the effect ?
Or perhaps it just that realising the problem on the E22 they've gone back to the data of the year 2012 and 2013 realising that the floor finally wasn't working so well? So that this instability was of the order of 0.5 to 0.7% of aeroshift instead of the 2% for example so that it was not such a problem.

It seems like they had to give an answer to the boss for the problem and i'm not sure they really found it...
I mean, surely now they know the problem, floor stalling, but now they need a solution, which seems not that simple and maybe one of the holly graal they are all looking for... Newey!

The last sentence, "everything that made us strong in the past - it is now our weakness" seems related to the tires, they were gentle on tire and now you need to work them harder.

[turbof1]

"No offence to the team because it has been the case for three years, but with the blown diffuser on the car and more downforce on the car we had before it was invisible to everyone. When it is invisible you don't know it, but with the new regulations and harder tyres and less downforce and the loss of the blown diffuser - everything that made us strong in the past - it is now our weakness"

this phrase from RG tends to prove that the problem doesn't come from the nose because it has been the case for 3 years and it was hidden by the level of downforce they had plus more mecanical grip from the tires, so we should look for something else.
It raises the question : "how do they know now that this aero instability from the floor was there too with the E20 and E21?
With the bunch of sensors they use, they didn't get the floor stalling on there screen?
With such a massively different nose this year (creating a substantial downwash with this steep underside right before the air intake of the floor, at least before they add this strange air filter) that create a very different condition for the air intake, they are able to sort this out and tell it's due to something else that already existed on the E20 and E21 ?
This air filter completly negate the effect ?
Or perhaps it just that realising the problem on the E22 they've gone back to the data of the year 2012 and 2013 realising that the floor finally wasn't working so well? So that this instability was of the order of 0.5 to 0.7% of aeroshift instead of the 2% for example so that it was not such a problem.

It seems like they had to give an answer to the boss for the problem and i'm not sure they really found it...
I mean, surely now they know the problem, floor stalling, but now they need a solution, which seems not that simple and maybe one of the holly graal they are all looking for... Newey!

The last sentence, "everything that made us strong in the past - it is now our weakness" seems related to the tires, they were gentle on tire and now you need to work them harder.

Lotus has been trying to explain the problem, without actually giving away any data to the competition. The end result is that we have several pieces of non-specific info, much like a puzzle where half of the pieces are missing. It's anyhow difficult to recreate the assembled puzzle.

I think RG's comment on the blown diffuser is interesting. He mentions the last 3 years: 2011, 2012 and 2013. He said that it masked the issues that are currently visible these days. But Lotus mostly didn't have a good history with EBD in the very first place!

-2011: Lotus (Renault) utilised Front Exit Exhausts: http://scarbsf1.com/blog1/2011/02/01/re ... explained/
In the wind tunnel, it proved to be quite advantageous. However, development of it stalled very quickly. Renault also had overheating issues with it. Do note that while this solution was inferior to normal EBD due the latter having more overall performance and peak downforce, FEE was more stable.
-2012: Lotus was one of the few not running any coanda or semi-coanda ramps for much of the year. Again this misses out on downforce, but is more stable. They introduced a semi-coanda ramp in Korea, albeit relative simple compared to the competition. It did prove succesfull though: http://www.formula1.com/news/technical/ ... /1015.html
2013: Lotus copied the full coanda ramp from Red Bull: http://www.f1technical.net/f1db/cars/1000/lotus-e21. This too proved to be succesfull.

He's saying downforce surpressed the imbalances. EBD is foremost a low-speed downforce generator. So one could assume there were and are issues with the mechanical grip, masked off by downforce. However, 2012 does not fit in that picture.

An other piece of the puzzle is that it's structural: they can't fix it this year. Based on that, I can come up with two options:

-Either they are having pure aero issues with the floor and diffuser. Mclaren did last year, with the floor and diffuser stalling. However, mclaren was able to fix this! Near the end to the 2013 season they seemed to have cracked it, ending up with more downforce on the rear then they could possible extract from the front (a very rare given in modern f1). So maybe it's not the same problem.

-A reiteration of a point made earlier on, but there could be issues with the overall packaging. Too much weight either to the left or right side of the car could very much lead to instability. This could explain why they aren't able to get it fixed this year, but does not explain the relation to EBD.

[trinidefender]

Maybe their cars throughout the "blown diffuser" days were unstable in terms of aero and as far as they were aware the main contributing factor to that was the EBD that they thought was giving them good but inconsistent downforce.

Come this year the car is designed with the same methodology as before (by a very similar design team as far as I'm aware) and only when the car hit the track did they realise that it wasn't only their EBD that gave them the instabilities.

[emmepi27]

Beautiful pics from Tobias Gruener (amus)

[FrukostScones]

[PhillipM]

Seems like a very abrupt angle at the collectors there.