Lotus E22 double-tusk nose during cornering and lateral wind

[Gusgus]

I saw some French media state that the Lotus E22 nose causes turbulences, but the arrows on their expliainatory illustrations seem like, to me at least, they are drawn quite randomly but don't have much theoretical basis.


(C) Bill Suserg/ToileF1.com


(C) Canal+

So I wanted to hear your opinion, confront it with mine and see what's journalist guesswork and what's true fluid dynamics.

I think in straight line, this causes no particular turbulence problem that a traditional "single appendix" solutions wouldn't have, the flow separates itself quite smoothly between each side of each tusk. But I'm guessing that under cornering or strong lateral wind, ie. when the flow is not strictly parralel to the car center line, there's more truth to what those media say, because the inside tusk blocks a little the flow from entering the central channel, preventing it from going smoothly under the monocoque.

What do you think ?

[Holm86]

Scalabroni talked about this several weeks ago.

Of the images of 2014 Formula 1 cars so far released by teams, Lotus has the most unconventional front nose design of all with the E22 concept resembling that of the Williams Fw26 ‘walrus’ which, according to well respected technical guru Enrique Scalabroni, will generate a great deal of understeer.

Speaking to Omnicorse, Scalabroni, formerly with Ferrari, Williams, Lotus and Peugeot Sport, observed, “The solution is original and interprets the restrictive front end regulations in a very particular way. This is very reminiscent to that of the 2004 Williams FW26 walrus nose. Also interesting is that the two ‘teeth’ of the nose are asymmetrical.”

In 2004 Williams used a similar concept, devised by Antonia Terzi, but it was ditched early on in the season for a more conventional solution.

“Of course from an aerodynamic point of view this could have some advantages. Patrick Head [Williams technical director at the time] told me that the data in the wind tunnel was excellent when compared to a more conventional nose, but the same results did not happen on track.”

Scalabroni predicts, “The front end [of the Lotus E22] will generate strong understeer, which will make the car unstable in rapid changes of direction. Both face plates are very long and will create a high moment where the driver will feel a strange reaction when turning the steering wheel. It will have an effect like a fin…”

Lotus are set to miss the first official F1 testing of the season at Jerez, but should be present at the Bahrain sessions next month with Romain Grosjean and necomer Pastor Maldonado on duty.

http://grandprix247.com/2014/01/26/lotu ... tech-guru/

[Jersey Tom]

Scalabroni predicts, “The front end [of the Lotus E22] will generate strong understeer, which will make the car unstable in rapid changes of direction.

I'd love to hear the reasoning behind that one...

[tomazy]

Scalabroni predicts, “The front end [of the Lotus E22] will generate strong understeer, which will make the car unstable in rapid changes of direction.

I'd love to hear the reasoning behind that one...

Scalabroni predicts, “ Both face plates are very long and will create a high moment where the driver will feel a strange reaction when turning the steering wheel. It will have an effect like a fin…”

Here you go

[Jersey Tom]

That would be the opposite of understeer then.

I don't buy it either way. To be honest, Scalabroni seems hit or miss with his technical analyses.

[Holm86]

That would be the opposite of understeer then.

I don't buy it either way.

How is that the opposite?? He is saying that the E22 nose has a large side area. Just like the FW26. Which maybe good when going straight ahead. During yaw the larger surface creates a bigger air pressure to overcome when turning. And as pointed out the FW26 should work according to CFD. But we all know it didn't and they had to switch to another more traditionally nose later in the season.

I'm not saying the E22 nose wont work. Only what Scalabroni predicts.

[shelly]

I disagree with Scalabroni. The lateral surface of the double task is not bigger than last year's full-height, fulle length pillars that most teams used. Plus, the wide and round leading edge can cope with a even wider range of yaw angles than a thinner pillar; and there are 3d effects on top of that (conceptually similar to the ones maentione din the Op, but very difficult to determine by eyesight).

I do not know if the "incredible numbers" that Chester mentioned about E22 are related to this nose design, but I do not think it would cause understeer issues

[Lycoming]

Scalabroni predicts, “The front end [of the Lotus E22] will generate strong understeer, which will make the car unstable in rapid changes of direction.

Isn't understeer the opposite of unstable?

Scalabroni predicts, “ Both face plates are very long and will create a high moment where the driver will feel a strange reaction when turning the steering wheel. It will have an effect like a fin…”

But they have such small side profile area... by the same logic, shark fins should have an absolutely disastrous effect on handling.

[Jersey Tom]

As has been said.. the guy is making nonsense claim as he's saying it will create understeer (increasing stability) but that somehow the car will be unstable because of it.

All cars are going to have some non-zero gain of Fy and Mz from aero as a function of yaw. Whatever the tusks contribute to that will IMO be fairly trivial in the grand scheme of things compared to rest of the body, tires, etc. Plus, as Shelly points out, the side view area really isn't that big.

[DaveKillens]

The Lotus does not possess perfect bilateral (left/right) symmetry because one tusk is slightly longer than the other. Because of this, airflow moving laterally across the nose will have different values, depending on the direction. Thus the car's center of aerodynamic pressure will differ depending on which side the airflow comes from.

IMO this will probably be negligible, but on fast left-right corners, such as Maggotts and Becketts, the car should seem to be balanced in one direction, and have slight understeer or oversteer in the other direction.

[ringo]

Sometimes turning is misunderstood to be like a sidewide. That's not the case with planes or cars.
Turning is the same as a headwind. What is different however is the rate of turning relative to the air speed; ie the transient.
The transient is where you would start to make you analysis. The transients in turning also is the relative difference in speed with the turning rate and the speed of the car. If this is small or doesn't last long enough for any meaningful flow development as the air passes over the car, then symmetry won't be super critical.

[shelly]

It is not really like that - even in steady state the flow angles are different in cornering - so different that, for example, a cfd vendor developed some function of its software specifically for testing steady cornering condition

[ecapox]

I'd hardly call Scalabroni "this guy" and I'd hardly call ANYTHING he says "nonsense".

Disagree if you'd like as we are all entitled to our own opinions. But as he has decades of F1 experience over multiple teams, I'd give him the benefit of the doubt. It is possible that he misspoke or since English isn't his native language, maybe he chose the wrong word.

[idfx]

Is a new project, it is normal idea and arguments are different. This enriches the development work of the project.

[Lycoming]

It is possible that he misspoke or since English isn't his native language, maybe he chose the wrong word.

Sure, or maybe he made some error in somehow simplifying the subject matter.

Be the as it is, what he's saying doesn't make sense. The reasons why it doesn't make sense have been pointed out in this thread. If you can offer an alternative interpretation of his words or point out some error in our reasoning, I'm willing to listen, but as it stands, it is nonsense.