F1 Forensics: Slats and Vortex Generators

F1 Forensics is brought to thejudge13 readers in partnership with SomersF1, Like most of us, Matthew Somerfield has a day job and his is being the manager of a car & van rental company in the Isle of Wight.

His passion is to try and bring us non-techies closer to F1 by bridging the gap between the full blown engineering publications and the simplicity of much that is provided by TV.

Ask Somers anything you want in the comments section. He’s part of the crew now and hang’s out here regularly.

And now over to Somers…

F1 – Slats & Vortex Generators

The frontal section of the Sidepod is an area of the car of particular interest to the designers this season with the need to further enhance the airflow received by the designers favoured ‘Coanda’ exhaust solutions. We saw teams sporting these devices throughout 2012 but several teams have adapted new approaches when catering them for their 2013 designs.  In a related topic I’ll also look at Ferrari’s adaptation of Rear Wing Trailing Edge Slats.

Cockpit Vortex Generator Fins / Wing Mirror Mounts

A trend started by Ferrari, these fins are placed horizontally and longitudinally between the Wing Mirror Stalk and the leading edge of the Sidepod. These fins vorticise the airflow as it moves over the Sidepod increasing downwash and reduce the boundary layer as it builds up over the length of the Engine Cover / Sidepod consequently increasing the Sidepods efficiency.

Another way of achieving this is the design of the Wing Mirror Mounts or Stalks, McLaren have this season designed their stalks in order to achieve a wing profile helping to manipulate the airflow in the region just as the combination of fins above are designed to do.

Leading Edge Sidepod Slats

Sauber employed these last season and when McLaren changed the Sidepod configuration from Hockenheim onwards they too ran some (albeit integrated into their Vertical Sidepod Airflow Conditioner) Just like the Vortex Generators mentioned above these devices are utilised in order to extract additional performance from the Sidepod itself. If we were to look at the Sidepod from the side it’s shape is reminiscent of an airplane wing and is the reason you hear Gary Anderson (BBC) refer to the region creating lift.

Leading Edge Sidepod slats we see McLaren using this season are used in order to alter the characteristics of the Sidepod to reduce this lift. The Slat enables a more efficient Sidepod by energizing the Boundary Layer whilst allowing the Sidepod to operate with a larger Angle of Attack.  Without the Slat the Boundary Layer may allow the airflow to separate resulting in the lift Gary refers to.

Vortex Generators (VG’s) – (Placed on top the Sidepod’s leading edge)

Just like the elements previously mentioned, Vortex Generator’s are used in order to trip up the airflow so as to disturb the trailing airflow. Their height usually indicates the height of the Boundary Layer which they are trying to trip up and so each version will differ to the characteristics of that teams Sidepod. A team may also employ several VG’s in order to affect a wider portion of the Sidepod or indeed if the length exceeds the height ratio of less VG’s.

Combination of the above

Mercedes have placed both Cockpit Vortex Generators and VG’s on top of the Sidepod in order to control the downwash toward their exhaust.

Rear Wing Trailing Edge Slats – Ferrari F138

This is an interesting concept and one I have been meaning to talk about since Ferrari first launched the F138. I’m also refraining from calling them flaps (as used in aviation) as they are fixed elements.

I may be making the wrong connection here but with Ferrari adopting Pull Rod Front Suspension last year and now these Trailing Edge Slats this year I have to question if Ferrari have some ex Minardi staff on their payroll. Front Pull Rod was last seen on the PS-01 and a similar Rear Wing Slat concept was used on the PS-05.

As these Slats are serving a few purposes in terms of the F138’s overall design I have decided to break it down into several elements whilst explaining the function of certain elements too:
Endplate Extension

The Endplate acts as an extension of the Mainplane, Top Flap and Beam Wing that sit between them, by increasing the size of the Endplate you can increase a wing’s effective aspect ratio leading to more downforce and less induced drag. The size of Endplates in F1 is controlled by the regulations and so Ferrari have thought outside the box.

By using Slats at the trailing edge of the Endplate they are therefore increasing the efficiency of the same area (allowing airflow to move from one side of the slat to the other) in much the same way we have seen teams use the Louvres at the front of the Endplate for many years now. This gives the Endplate a larger aspect ratio impacting on the Wing profiles between them.

Wing Tip Vortices

When we see cars operating in damp conditions it’s easy to see the drag at work on the Rear Wing. Tip Vortices are the spiralling air we see expelled from the edge of the top flap where it meets with the Endplate (Air moving from the high pressure to low pressure side causes the air to rotate (Vortice).

In the case of the Slatted F138 images from Jerez captured the wing tip vortices in a strange position much further outbound. This to me donates the fact that the increased aspect ratio of the Endplate (as mentioned above) has also resulted in the reduction of drag. (The farther a vortex is shed from the wing the less influence it has on it)

Attachment Issues: Gary Anderson spoke on several occasions last season in regard to Ferrari suffering re-attachment issues when using DRS. This is when the airflow takes too long to re-attach to the wing. This is a complex scenario bought on by the team trading off their DRS delta for a high speed gain resulting in an instability when the DRS is closed by the driver. The team looked to offset the time differential last season by operating DRS with a foot pedal rather than using a steering wheel button.

The movement from the foot pedal DRS button onto the brake pedal would start the process of the top flap moving into a closed position before the brakes were applied gifting the team a little more leeway. This however didn’t seem to be enough to overcome their problems and left them with 2 choices, suffer the consequences of a little lateral movement in the braking phase or adjust their DRS delta by adjusting the size of the Mainplane / Top Flap combination.

It’s a cat and mouse scenario where neither really directly solve the problem of trying to force a better lap time for qualifying and then have a balanced car during the race. The problem didn’t hurt Ferrari as badly during the race as DRS usage was limited and so the re-attachment issue only occurred when trying to overtake someone.

Cause and Effect: By making this area more efficient the slats have to be splayed at an outward angle, acting like a perforated Gurney flap. This means the airflow that would ordinarily be travelling along the outside of the Endplate will have to find a way outward and as these slats sit behind the wheel the expelled air is pushed into the region behind the wheel. The Endplate Slats and Strakes become vertically shorter the further back they reach inline with the expansion of the Diffuser.

Overall the Rear Wing Endplate Slats are a neat solution to overcome a problem that the F138’s predecessor suffered whilst also increasing the operating window the Rear Wing operates within. We may see other teams adopting similar solutions throughout the season as teams search for more downforce.


9 responses to “F1 Forensics: Slats and Vortex Generators

  1. Excellent piece Somers!
    Two thoughts strike me on reading at first run through:
    We may see many things nowadays that were tried in the past and didn’t work, because now they have the means in CFD and better wind tunnel modelling/correlation to see why they did not work originally and find out if in fact they could have been made to work years ago if only they had had access to the information.
    Secondly the slats remind me very much of documentaries on flight/wings, wing warping etc (nod to Stringfellow of Chard) and the way large birds use their wingtip feathers like fingers to control aspects of their flight.

    • The only thought I have which – for me – might improve these articles, is a few footnote references to further reading. That’s selfish of me, because I’m looking for ways to slowly restart learning physics, and I always had a problem that I’d get things conceptually, but not practically in any detail. Like my Latin master pointed out “John, you translate Lain well, not because you know Latin, but because you know English.” I had the worst grammar scores ever and bluffed well enough to con lesser teachers.

      Sometime I used to encounter a chap on a photography forum, who worked for Ford at Dearborn, designing industrial optics, pointed out that every three years the number of calculations completed which are new exceed the previous total. That may be a estimate, or his rule of thumb, but it seems to hold well to scrutiny, at least my scrutiny.

      What I don’t expect happens in F1 is that engineers publish papers to announce their work!

      If that has any effect on the rate of advancement, I don’t know. Feynman described quantum physics as watching a chess game but without knowing the rules. So you have to guess behavior, and I think there’s a lot of sussing out and reverse engineering in F1, with some understatement.

      What I mean is, that I cannot identify any outlet from F1 that reaches publication that describes novel technique.

      That leaves me with a rather tricky question: to what extent does F1 push the envelope, and to what extent does it derive other fields?

      I can explain that better: Adrian Newey is a undoubted talent. But is his genius in comprehending, applying and adapting known aero design, or is he advancing the fundamental art?

      The thing is, if he is pushing the envelope, it’s unlikely we’ll find out. Maybe even pushing the envelope” is a poor expression here, because a envelope usually means a set of known parameters, and only implicitly that you challenge them, or the combination of them, rather than set to redefine the expectations of limits.

      At the crudest, my analogy is you are making a recipe, which sounds almost demeaning. The pity is that if say Newey devises a whole new technique, or discovers a new theoretic approach, I am guessing that would be too hot to publish. I can imagine that some very bright academic minds might not consider F1, for fear they cannot take credit. Mind you, the kind of person who wants to work on theory, is not going to have much time for that in F1. But I can counter that also, and say that friends of mine dedicated to their subject practically have their mind in automatic, think about their work 24/7, and for some of them, they have found it very difficult to find any place practical enough, sufficiently resourced, to run any experiment. I’d further argue that the mind does not function on starvation rations, and lifetime research grant chasers such as my brother, have lost too much time to that process, and the frustration shows.

      I said further reading, because a list of Wikipedia links is of little value. But suggestions for books or papers that are pertinent and well written, would be a genuine service. My diversion into thoughts about F1 and academia is because if we can expand the conexions, we can maybe get more people interested. Ambitiously, I think that some books on fields I know better are sufficiently well written they literally open doors to understanding. Sadly I cannot make any suggestions in this application, but maybe collectively, we could.

      = = =

      Thanks Somers, super work!

      ~ joj

    • p.s. Rpaco, meant to email you but been sleeping off a epic and uncompromising work stint, but I thought of you first about the possibility of doing some book reviews. Will drop you a line anyhow.

      If anyone tuning in might be so disposed, as to pitch in with book reviews, I’d very much like to hear.

      Thing is, I can sculpt a layman’s view of any book, but a good review needs more specialist insight than I can bring. If of engineering, I clearly have not the experience, even if I may have impressions and could certainly report if I was able to learn from the work. But also of F1, I do not possess encyclopedic knowledge of history. I am confident however that I would be a very good sub editor and assistant to anyone who has a take on any book we ought to hear about, and despite my writing in comments may seem egotistical, or at least it is in fact indulgent, I’ve spent a lot of professional time ghosting others’ styles: it’s a essential part of my work. You’d not be shoved about by my ego.

      My offer to pay forward a supply of books, if we can get this started, still stands.

  2. Just a random thought further: with the limits on testing, I think we are being deprived of seeing some aspects of the car development. If you only have so much time to run a test, to baseline a new part or configuration, then so much more of the work is behind closed doors, estimating what can be tested that can evaluate factors you need to understand. I mean that the tested cars are far more research machines than development machines. This thought was prompted by looking at those toothed fins, and wondering if the idea is not to run a wing like that, but to evaluate e.g. the effect of turbulence behind close configurations of fins. (In turn, o doubt, any measurement of those fins / slats feeds data of more front components)

    My amateur understanding is that in a tunnel, discovery of flows encountered in turns or in crosswind, or in following air behind a leading car, are not doable. So my amateur mind is thinking that we all know getting airflow precisely directed around a car is critical, from the tires to the exhaust, undertray and so on. Why have such a garden rake of fins? The random thought is that what’s being studied is the close interaction, and the limits of placement of such a array, not necessarily a racing design.

    I’m (cough, splutter) winging it, with derived logic, not learning. The thought is it would be less cool if we are seeing less of actual car development, because inside a brief opportunity, the teams need to run experiments much differently from the way they would if there was more time.

    My apologies I am thinking out loud. Damned fine article, got me thinking, and though I expect my thinking quite wrong, I think at least I may have something in the difference of what is being tested under the restrictions.

  3. J(oJ) – very interesting thoughts on the main article. One of the beauties of this site is how so many of you chaps (rpaco included) add to what has been given (in this case by Somers) rather than mindlessly pulling it apart… As someone who last studied physics in 1960 I find these discussions challenging – and occasionally enlightening…

    • 🙂 It was 62 or 3 I think (I could never do the maths, in fact it was calculus that killed my HND Electronics, not that calculus is involved in the date )

    • Thank you, BJF, I will happily settle for “occasionally”!

      Quite a compliment to someone with only A Level Physics. Thank you again.

      I wish it felt right to say the name of my teacher, but she opened my eyes in ways I realized my mind was being expanded only years later. She was using her sabattical year from RR Aero to expand her interests, and frankly had us mesmorized. One thing to be taught how a jet engine works, another to have that taught from who helped design them. In a school stuffed with teaching talent, there was one math teacher with serious aero background, and a Physics master with City finance in his veins, a amazing variety of people who could not get a job in a sate school* that for a teacher to stand out was a awesome thing. I’m increasingly tempted to look up how her career continued. In the 80s still, there most certainly was a glass ceiling, though I imagine she was not a management type, but I hope when or if I do find out, she attained what she plainly deserved. My school could be demoralizing for new teachers, because there were kids there who were capable of posing serious challenges. I was given A level papers for practice aged 12. I was very very average for my peers.

      It’s very rare that people do not think I am boasting when I talk about this. But I am not. I left all that behind very firmly, flunked out, and only much older, now look back with fondness. You cannot boast of giving up privilege that was bestowed on you. Not with a “what could have been” attitude. (OK, I’ll admit that once, when I first let myself think about that past, it did strike me how much easier life could have been. I was just sad how much disappointment my father experienced, though after long incommunicado, the year before he passed, we reconciled properly.) Rather with a curiosity because I was ruining so fast away from my school and family the next years were a blur. About the next 20 years!

      A big reason I flunked out was I just felt I had experienced the best there was on offer, at the right time for me, and wanted anything but more of the same. (Possibly, simply being average for my set demoralized me, made me want to strike out, but friends felt the same, still went through the paces of Uni. I’m still arrogant, in many ways, but the arrogance I encountered, coming from a very lowly prep school in a small town, also made me want to move away fom that.) My only regret is I never tried to get a apprentice job, when I as young enough, because I would have loved the practical. I could punch that young me, if I had a time machine. Woodwork was by far my passion at prep school. No metal shop, sadly. And at my last school, despite a huge budget to build a science facility, to the enduring scorn and anger of our electronics master (who wrote the main Biology texts, we had that kind of crossover, I was taught Biology by a Classicist . . ) there was no machine room. The good Doctor (who was built and looked like you’d not want him in the room in a brawl and was equally no nonsense) was right. Maybe half of my contemporaries might never need a job, but kids need a passion, and building things is a lifelong passion for who enjoy that. Even if the kids turn out from the trust fund cookie cutter, passion passes to another generation more often than not.

      Why did I end up a ad man, then? Because working on trade magazines let me talk to any variety of people in industry. I couldn’t get bored.

      My mission now is to get trade magazines of virtue exposed to education and vice versa, in particular lower education. Kids absorb very fast wen young, even when they do not have the ability say to o stock cal, they can nevertheless absorb huge piles of information. There is a highly febrile point in time of the mind, and that time is much earlier than the structure of education systems think. Early exposure can mitigate bad teaching, also kids can know they have other sources to check upon. And school is not cool, but building big things, or fast machines, or smart machines, is cool. Exams suck, but a book on racing engines will get read by tor light past bed time.

      It’s not a small game, trade publishing. But to convince publishers to expand circulation to unlikely customers requires more efficient economic models. It is not easy to change a entire industry’s habits, but that is my aim, and why this school dropout spent his life working on economic models and learning the means to apply them. But with a purpose, which I summarize as giving kids like I was what they wanted: the stimulus of the real world’s business in a copy in their hands.

      As a kid I invented a company, to get on the circulation lists.

      You may say, but we have the internet. up, but you can’t google for things you never heard of, and this is why magazines still work, and why pint advertising is still massively larger trade than online.

      Ironically, though I am too close to being on my uppers, just function of having to divert my work to building a new setup before going ahead again, my biz partner long gone, my new partners simply brilliant but they cannot just show one day with the passion of a decade of knowing me and my singular pursuit, and I’ve not the lightness of youthful energy I had, this now is about the best opportunity I have had to pursue my dream. My late partner and I joked we wee not doing the right rain dace . . . we needed a recession for there to be enough pressure to make people look at more efficient models, because if one business is strug up and all too static, it’s pint publishing. The tricky bit is that by averting lesser recessions, TPTB built up the actors which led to this almighty mess we are in now.

      Fairly obvious why I love F1, in he context, I expect.

      Those of you who’ve written me, know I don’t hide behind pseudonym, save for habit online, but the difficulty I have been struggling with, is I do prefer to be a very private person, and yet to make a real attempt to do what I dream of, will strip from me that privacy. I took multi year diversions developing productized ideas simply to circumvent the necessity of pitching the main game. When I sell, it’s so personalized, I don’t get some customers (publisher customers, I loathe the word client, think only whores and solicitors have clients) ad in fact I chose to be a salesman to overcome innate shyness, that job I reckon accomplished. The actual fear is that I am so connected with my work, it’s in my most private thought I get real work done. So I have a big hangup about delivering a incomplete product, because to sell that, I have to trade my time. Therefore I delayed a lot. If ever I’ve been in the financial cooler, there’s your reason. But I shall have to bite the bullet on this, soon enough.

      It’s in this context that I devote time to TJ13’s project, and firmly support Joe Saward’s effort, so that F1 may be illuminated. I’m indulging my passion for the sport, at the same time as furthering my goals, by learning from all you guys and gals. I’d not trade these opportunities for any other occupational past time.

      What I do want, without becoming a burden, in any way, is to see this blog become really serious as a media entity. That will require not just time, but money to support it – websites do cost money to host, and TJ already puts in full time hours – because making a impact simply requires it. TJ13 has already made a impact, but I think in more ambitious scope, what it takes to make a impact on MSM – main stream media, also. (I also want Joe and David’s GP+ to hit the main market, in print, and to become a genuine hit in their niche) but TJ’s idea embraces far more in modern media, and I see it as a compliment to Joe’s GP+, not as a competitor. I would like, and think this possible, that here could be the go – to venue for social media in F1. Doing so will take resources, and I’m “in the rear wit the gear” at least with a store of thinking and experience to aid and assist. (and I anticipate, very soon, the germ of some features that will help expand the possibilities) I am certain the efforts already portend the possibility to transcend the normal ambitions of a blog, and in the background, I’m formulating the what where and why and the technical underpinnings of how.

      So his is no merely a hobby, and I’m not motivated to bloviate and stroke my ego, and tough socially it is cool very cool to have discussions offline with top minds, but it’s about utilizing the store of knowledge and observation I accumulated about the online world of media, all of which I ope can be leveraged. I’m a self declared print man, ink in m veins, since a little boy, naturally skeptical of what’s on the internet, but a lifelong geek, programmer since double digits in age, and I kept up, because even selling print, customers expect you to be absolutely current and correct, on he ball, ahead of the curve if possible. To sell print, I have to be good at the rest. Consider it like I am of a different race or religion, in a country with prejudices. As a independent competing indirectly with vast agencies, I have to be as good, or better, and if not full service, nothing gets sold now without the consideration of the internet world.

      The reward for the time I spend considering what I can do to help, is precisely this environment, an to read latices like Somers’, here above. But directly or indirectly I hope to have the back of supporting TJ13 grow, and when the time is right, make the possibility to reward the contributors beyond my gratitude.

      All this long story is just my way of underlining that, for as long as I am tolerated and given leave to support and influence and act where I may be of use, I am at least for about 2 days a week, plus inevitably a lot of other time thinking, dedicated to making this place, a notable, known, and fully functional part of the F1 media, to the best of my efforts and the extent to which it is possible to shake up what I fear is otherwise a moribund, lame, or tamed, or even hostage, landscape of journalistic output.

      If you’re reading this, and thinking you can pitch in, in any way, TJ’s email is there to be used.

      all best to all,

      ~ joj

      *Infamously, a later headmaster of my school was point blank refused a job in a state school when he decided he should give something back to kids without rich parents. He was not considered qualified. Honestly, fff the system, it’s things like that that really set me out to fight to be independent in my life.

      • sorry for my typos, due to see a specialist for my nerve damage, it’s not clearing up very fast, and not typing is not a option I can choose right now with work plans. Speccl check in Chrome is driving me mad. Goggle are so good with their lexicons (they actually bought most of their language tech from a outside firm, something I know because of my own work in advertising) but I am convinced their browser is not using the same thing, Word is so much better. Having to rely on spell check, because with one hand turned into a pecker, the other doesn’t flow either. Just about to shove a nw SSD ito my main box. I chose this one, otherwise identical, for a fresh install of everything, the other just had a SSD transplanted into is) at which point Dragon dictate will work much better (lookups like small queries benefit enormously from SSD, but I have to decide which to put in, 335 or 520 Itel, must look up which has the best small read profile) and in theory they have a plugin so i can use the browser by voice also. I’m interested how my writing style will change, but my late BP, who was no mean writer himself, taught me to write as I would speak. What happened was I stated to write as I used to speak, and then my speech changed entirely to a different mode. That change fascinates me to try to learn how things happened ad to what extent . .

        Google Crome spellcheck plain sucks, I omitted the “n” from “facinaes” (as i typed that) and it came up with “fattest”, ugh!

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