This is very interesting stuff. Look at the images labelled "velocity slice at ground plane" and "on the top side of the floor". You can clearly see the "Y250 Vortex" going between the front wheels and out around the barge boards.
This vortex structure exists because the front wing main plane needs to be flat for +/- 250mm at on the Y axis from the center line. In order to get the outwash to the barge boards and around the rear wheels, the front wing needs to generate a huge vortex right where the wing starts.
You can see the Y250 Vortex structure in this old footage from Mark Webber driving the RB9 in humid conditions where it forms a condensation trail as the air pressure drops:
https://www.youtube.com/watch?v=ZlDnd3B1rhs
As someone in the industry, please take these numbers with the biggest grain of salt you can find. The writer has both added their own components and not divulged the CFD settings used. Which is fair enough but the numbers shown could be within 10% or 1000% percent of a "ballpark".
Can’t upvote this enough. I actually include an hour of rant in my Fluids class where we dissect CFD results from blogs or LinkedIn - hypersonic reindeer for Christmas are fun and obviously a joke, but everything presented sincerely, like all the Cybertruck analyses when it was revealed, are mostly irrelevant. Don’t trust CFD results if you don’t know every aspect of them.
It’s “dangerous” now in the sense that people just have to click a button and are led to believe that meaningful results are being produced without a thorough study.
You're correct insomuch as he's not sharing CFD settings, and is bound by what I assume is a pretty strict NDA, but he still has a ton of useful content. Of course, if you want his true opinion/skills on something specific, he'll do so for a price.
One note about the aero research rules in F1 which makes this post particularly interesting: there are limitations on the amount of CFD simulation time teams can use.
> For example, each Formula 1 team is only allowed to use 25 teraflops (trillions of floating point operations per second) of double precision (64-bit) computing power for simulating car aerodynamics.
> Oddly, the F1 regulations also stipulate that only CPUs can be used, not GPUs, and that teams must explicitly prove whether they're using AVX instructions or not. Without AVX, the FIA rates a single Sandy Bridge or Ivy Bridge CPU core at 4 flops; with AVX, each core is rated at 8 flops. Every team has to submit the exact specifications of their compute cluster to the FIA at the start of the season, and then a logfile after every eight weeks of ongoing testing.
> Everest says that every team has its own on-premises hardware setup and that no one has yet moved to the cloud. There's no technical reason why the cloud can't be used for car aerodynamics simulations—and F1 teams are investigating such a possibility—but the aforementioned stringent CPU stipulations currently make it impossible. The result is that most F1 teams use a somewhat hybridised setup, with a local Linux cluster outputting aerodynamics data that informs the manufacturing of physical components, the details of which are kept in the cloud.
> Wind tunnel usage is similarly restricted: F1 teams are only allowed 25 hours of "wind on" time per week to test new chassis designs. 10 years ago, in 2007, it was very different, says Everest: "There was no restriction on teraflops, no restriction on wind tunnel hours," continues Everest. "We had three shifts running the wind tunnel 24/7. It got to the point where a lot of teams were talking about building a second wind tunnel; Williams built a second tunnel.
To level the field even more, I think the FIA should require teams to release the design of their computer hardware after X time. That way, investments by one team on improving the system architecture spread to teams with lower budgets after a while.
Also, I didn’t find it in the article, but I guess they have programmers who can work for months to speed up their software by a few percent.
>> to level the field even more, I think the FIA should require teams to release the design of their computer hardware after X time.
But that is Not what Formula One is about... it is Not a Spec series where the cars are equal to each other. It is a competition where each team builds their own race car to compete against the other iterations of race cars built by the opposing teams. It is Not meant to be fair or equitable. We have Indycar and NASCAR for that.
Ditto with the drivers: Is Max or Lewis comparable to say a Mazepin or even a Hulkenberg? No they are Not.
It's a Spectacle, it's a Circus... that is what F1 is about. And I tell you, as a racer there is nothing else that is its equal in terms of pure audacity both from a standpoint of driving talent and car performance.
F1 is definitely trying to make the teams and their engineering more similar than different, why do you think the whole regulation part exists even? [1] If they were to be allowed to build whatever they want, F1 would have looked very different than how it looks today.
F1 (FIA really) has been using regulation to improve the sports safety, but lately they also used regulation in order to regulate how much each team spends on engineering, both money-wise and time-wise. This is to make things more equal between the teams.
>> F1 is definitely trying to make the teams and their engineering more similar than different, why do you think the whole regulation part exists even?
I agree, especially under the new owners. And for sure the cars are built according to each teams interpretation of the rules (which are of course subject to scrutineering). But that still leaves massive room for innovation.
Lewis is sitting in the same cockpit as Bottas is... their results are frequently vastly different due to their individual interpretation of events.
The problem is the sloppy use of technical terms. MIPS means "millions of instructions per second" so the "p" is "per" and the "s" is "second". So it is natural for people to use FLOPS in the exact same way, but it is more correct for this to be "FLoating point OPerationS" where the "s" is used to indicate a plural.
That makes MIPS the equivalent of power (Watts) and FLOPS the equivalent of energy (Jouls). In that case limiting each Formula 1 team to a maximum of 25 teraflops of computation does make sense.
If instead you use teraflops as the equivalent of "trillion floating point operations per second" as many people do then it indeed makes less sense.
Unfortunately doing CFD is not a question of running ./cfd carmodel and waiting for a day. You need to ensure you are correlated with real life i.e. the wind tunnel.
If Williams outsourced their CFD with that leak, they might gain an unduly advantage over teams like Haas or Alfa. These teams compete over several millions in price money.
Ironically, the allowance for CFD time is scaled based on the reversed world championship points order, and Williams was dead last, so they should have the most CFD time of any of the F1 teams.
Interesting point, which a little bit implies that Williams would have the best aerodynamics by now. But clearly that is still not the case. So I am quite skeptical, whether CFD time has indeed the effect it aims to have. We all know that knowledge which you build up over time as a developer pays in long term. So even thou teams like Mercedes may have shorter time for CFD, they have the knowledge base build up over time which they use heavily.
Also, keep in mind that this year the rule is only in a demo mode. The first team has 90%, the last team has 112.5% of the dedicated time. From the next year this will change to 70% and 115%. (The time for the teams between is defined in steps of 2.5% this year, next year 5%)
Exactly CFD time does not necessarily correlate to effectiveness. The saying "all models are wrong but some models are useful" definitely applies and if you make incorrect assumptions your CFD will not be that usefel
The limit is in FLOPS but CFD is memory bound. To get round the limit, AMD made custom CPUs with restricted floating point performance to allow quadrupling the number of cores.
Each team has to submit an audit of CFD runs at 8 week intervals throughout the year. An FIA inspector can also turn up on premise to review simulations run. The full details are in Appendix 8 of the sporting regulations [0].
Yes, but that comes with a pretty heavy asterisk - driver salaries are not included in the cap for example (which will be extremely significant for the top teams), nor is marketing. Still, I think it's a step in the right direction for the sport - having a cost cap in place now lays the groundwork for tighter restrictions in the future.
As another comment mentions above, there are now budget caps, which affect every decision a team make. For instance, one of the Mercedes drivers had a really nasty crash recently and the cost to build him a new car is putting budget pressure on Merc.
This reminds me of the invented sport Paced Badminton. It’s badminton, and also the players have pacemakers and are only allowed a fixed number of heartbeats per match.
IIRC it was mostly to reduce overall expenditure on aerodynamics. Before FIA restricted resources, teams would use wind tunnels 24/7, up to 70 days per year. This was crazy expensive so the restrictions were implemented (and they happened to include CFD limits too).
Most teams have their own dedicated wind tunnels and they are fairly expensive installations. As an example, the artificial lake you see in front of the McLaren Technology Center at Woking [0] is the cooling liquid reservoir for their wind tunnel.
These are big industrial installations which need highly specialized staff to run them. Even if the facility exists, keeping the "wind on" costs a lot of money per hour.
Ironically, as a response to the newly introduced cost cap measure, the teams are building new facilities like crazy right now, with many teams building a bigger wind tunnel so they can have it in the books before the accounting for the cost cap starts.
A car size wind tunnel that can do 250 mph will be moving 400kg of air each second, and requiring a 2.5 megawatt fan. That costs ~$500k in electricity annually to run half a working day. That motor from China costs $30k. Imagine it's the same again for the fan, same again for wiring and control systems, and double that for fiberglass moulded side panels, foundations etc. We're talking £150k, and that's for a very budget wind tunnel.
It looks like 14-17 cents per kilowatt hour is about the going rate as of Q3 - Q4 2020.
I’m a little surprised this doesn’t lead to more such facilities being strategically located based on availability of cheap power, e.g. by building near to hydro, and where power costs can be ~2c/kWh. See: https://www.seattletimes.com/business/technology/sunday-buzz...
I’m forced to conclude the power costs are a marginal expenditure versus other costs involved in running such a facility, and benefits from having R&D, testing and validation, and production all on the same campus?
The onus is on the teams to prove it. If you cheat in formula 1 and they feel like punishing you a fine of one hundred million dollars is not unprecedented.
Honestly, even without outright cheating, a manufacturer team has so many advantages it's kind of pointless.
Imagine a scenario where a brake duct needs to be redesigned to account for some change in regulation or a performance tweak. At someone like Mercedes the conversation would probably start with ok, let's dig out all of the CFD we did for this when we designed this in 2007, let's also grab the data on the changes we made on the GP2 last year, also weren't the LeMans team doing some work on this last month? From there they would be in a much better place to identify the points where they have to concentrate their efforts without expending a minute of new CFD time.
At a small new entrant team none of this data is available to them.
I wish they’d release all data for currentMinusX years ago.
There could be so much fun playing with that data. Could make an accurate iRacing model, could compare teams historical downforce levels, could make tiny 3D models to paint
I remember reading a friend's "owner's manual" for a honda road-racing (only) motorcycle years ago and it was amazing.
A normal motorcycle owner's manual is almost 100% propaganda by weight.
it's basically legalese regarding injury, legalese regarding warranty type stuff, a few specificaitons, a bit of sort of fantasy maintenance which mostly segways into... "contact a dealer", then lists dealers
In comparison the road-racing honda manual talked about reality. written by engineers, not lawyers.
For example, I recall it told you how to gear the bike for different speeds (the kinds that would lose your license, wallet and prospects on the street)
It also had carb (yes) settings for different track temperatures and all the maintenance intervals were in hours of use.
I think this kind of stuff is a goldmine, and can really educate.
Regulations always change and what was legal today might be banned tomorrow and be legal again (like Williams active suspensions from the Mansell era)
It doesn't make sense to make all data public when there might be something the FIA or other teams didn't know about and might be useful in the future.
F1 is all about living on the edge of what's allowed by the rules, and more often than not crossing that line and hoping not to get caught by the FIA. There's a fantastic interview with Ecclestone, Withing and Piquet (1) where they reminisce the olden days and have a laugh admitting their Brabham car was so illegal they would have been disqualified by the FIA had they knew that. 2019 Ferrari had an amazing engine and then they got caught doing tricks with the fuel sensors.
It makes sense to release all data. Not for the teams, but for FIA. They could require teams to release it after some time, so that teams with smaller budgets can learn from the work done by teams with larger ones/better engineers.
That would level the playing field a bit and, I guess, limit the amount of bending the rules (even if the FIA would give amnesty on any infringements found, which it probably should do)
Yes, but then you'd find that the FIA cut deals with teams in the past to wipe various infringements off the books so they wouldn't be embarrassed. Take for instance the way Ferrari performed after changing 'absolutely nothing' from one day to the next they were in the midfield or even at the tail. If they released everything it might show how Ferrari might have to hand in all of their points in 2020, and quite possibly 2019 as well. And/or be disqualified.
F1 is a media circus, not a sport and 'fair' and 'level playing field' are things that are not on the books unless they happen to drive up the bottom line.
I actually posted earlier that F1 is a "circus"... I agree. It is however a Very Real Sport insofar as the drivers are World Class Elite Athletes... especially the few who can run at the front.
Maybe, but the IP holders are never going to agree to this. You have not only the entrants themselves, but also engine manufacturers and so on. I really believe the manufacturers would leave the sport first; many of them are on a hair trigger anyways given the shift in consumer R&D to electric.
Speaking of Honda and 2000s, the S2000 engine is a pretty remarkable piece of engineering. It would be really interesting for them to publish data for a car that's reasonably obtainable on the used market. Both engine and aerodynamic fluid models would be interesting to play around with.
> Tyre data is literally worth its weight in gold unfortunately
The minimum amount of energy to flip a bit at the temperature of the cosmic background radiation, converted to equivalent mass via E=MC^2, is minuscule. (The mass of a black hole with one bit of entropy at its surface is also minuscule.) So any data worth storing is literally worth several orders of magnitude more than its weight in gold (assuming the gold and the data are weighed under the same gravitational acceleration).
Edit: apparently people are taking my response as being more snarky than I intended. I just find it interesting that bits actually have mass. Information is incredibly expensive on a per-mass basis.
Thanks for the clarification. I think we all understood what you meant. A more literal interpretation just reminded me of a tidbit of physics I find very interesting.
Previous commenter did write "literally". A word which, IMO, is ridiculously overused and abused by people with a bit of a chip on their shoulder. I'd say they asked for it! :)
Photons have no resting mass, but my understanding that they still distort spacetime. It's not only mass that generates gravity. We're talking about weight, and it's mass-eneregy that warps spacetime/generates gravity.[0]
My understanding is that none of the virtual interactions in the Feynman path integral for that photon traveling through spacetime (such as spontaneously becoming a particle-antiparticle pair) affect the far-field gravitational field generated by the photon.
Also, 99% of the mass of your body is not electrons and quarks, but the binding energy between quarks. The mass of a proton is ~938 MeV/C^2, but the masses of its quarks sum to about 9 MeV/C^2. The rest of the proton's mass is the binding energy of the quarks. You get a similar ratio for the neutron. The electron's resting mass is roughly 0.5 MeV/C^2.
I think the Higgs mechanism is responsible for the rest mass of quarks, leptons, and neutrinos, but the majority of mass in atoms is due to nuclear binding energy, not the Higgs mechanism.
Though, my formal physics education didn't go beyond Freshman year E&M, so I could be way off.
CFD settings
Indeed, without proper information on the CFD settings, it's difficult to judge the quality of these results. This includes:
- Mesh resolution: smallest cell size, refinement strategy, ...
- Mesh type: hexagonal? Prism layers? ...
- Solver: which solver was used? Steady or unsteady? RANS or LES or ...? Were the results averaged? Were wall functions used? Y+ values?
- Wheel rotation: which technique was used for wheel rotation? Just a "tangential wall velocity", or MRF, or a sliding mesh, or ...?
Judging by the resolution of the flow pattern at the bottom, by the fact there is enough mesh to capture the details & gaps between wing elements, ... I'd say there is at least a decent amount of cells. But then again, that's just a very indirect estimation :)
3D model
- Rake: the car is running at quite a high rake. This is just one of the "infinite" number of possible combinations for rear and front ride height and so on. So to get a full aero map, you would need to run the car at various positions.
- Tyre compression: the tyres seem to have been cut-off at ground level, which is a common technique to add in the effect of compression. But the "height" of cut-off is subjective and has a large effect on the aerodynamics, as it influences the ride height and thus the underfloor aerodynamics. Also, there is no tyre deformation in the 3D model (or perhaps I missed it, difficult to tell from the screenshots).
Analysis versus optimization
This is an analysis, which tells us quite a lot. But it doesn't teach us how the team interprets results or, even better, how it translates this into improved designs. It would be cool to see how an adjoint solver would improve this car towards more downforce for example!
(if you don't know what adjoint is, check this video - https://airshaper.com/videos/aerodynamic-shape-optimization-...).
Overall, I find it very interesting - even if the model, CFD setup, ... aren't an exact match with what the guys at Williams are doing, it does provide a lot of interesting insight into existing flow structures on such cars - which is an interesting tool for learning.
Since Williams defines the very bottom of the race grid, they don't have much to hide in terms of technology. So releasing a 3D model of their car in this form is nothing that would harm the team at this time.
It is possible that their aerodynamics are good or even best of all F1, while the motor, the suspension, the tires, etc lag enough to nullify this advantage.
It seems to me that the aerodynamic picture of an F1 car would also have to account for all the air getting sucked into the engine and blown out the exhaust, no?
Similarly, a lot of the tricky aerodynamic effects in F1 come off the tyres (tyre squirt etc.) so without modelling those you're not getting a great view of the bigger picture.
In a similar vein I remember reading that one of the reasons for the CFD restrictions was because the bigger teams were starting to spend a lot of money modelling the aerodynamics of the tyres as they oscillated in corners (because F1 tyres have a relatively high sidewall they deform a lot through corners, then if a wheel lifts a little e.g. bouncing over a curb, then the whole tyre starts oscillating laterally.) Sounds very interesting but a bit of a CFD nightmare!
I wonder if this is one of the reasons why they will switch to bigger rims in 2022. The explanation given was that the wheels would look more like those of road cars; making the cars more relatable to prospective car buyers I guess. Anyway, if you can reduce the side wobbling with larger rims then teams have it easier to meet the cost cap without having to spend money there.
Another justification I've heard for the larger rims is that the current, smaller rims make it difficult to make any meaningful adjustments to the car's suspension. Ideally, suspension adjustments will become a bigger part of the setup for each race, which could help differentiate teams that are able to get the ideal settings for each track.
That certainly was the case in the past with the whole 'blown diffuser' situation which led to cars' engine maps being specifically created to allow lots of volume of air through the exhausts even when they weren't generating much power to take advantage of this - listen to the exhaust sound in mid corner of this era F1 car and you'll hear what I mean (I think it was around 2011 and Red Bull were the best at it, but I think many did it to a degree).
For anyone that follows F1 it’s not a surprise that the numbers show a draggy car, although they might be higher than the real ones. For three seasons now, high drag to downforce ratio has been Williams’ no. 1 problem.
I was wondering, how much different the simulation would be from stock models from Turbosquid: https://www.turbosquid.com/3d-models/formula-1-season-2020-3...
The article mentions there were some problematic areas in the extracted model. So I am quite skeptical that the model is indeed more accurate than what you can easily get from legal sources.
Organizations where the big $ is on intel property and R&D wouldn’t be dumb enough to give the actual schematics to some random intern building an app. There are some serious security controls and mNDA around that data, for all internal parties, external parties and suppliers. Think about it, they must collaborate with dozens if not hundreds of parties to get to a finished products, and some amount of information must be circulating to achieve the purpose of their relationships. If those were to leak - they’d leak to the competitors first and it’d be a disaster for the entirety of the upcoming year(s) as the improvements tied to their new designs would now be considered available on all cars. It doesn’t take two dummies to think about that, soooo.. to avoid losing hundreds of millions, what do you do as an organization? Data classification, risk assessments, tight security controls, procedures, and finally mNDAs for the instances when data do have to be shared.
Furthermore, as it was pointed out on Reddit, the model appears to be made of parts that are valid for 2020 regulations, some parts for 2021.. in other words, it’s just scrap.
You can get quite detailed timing data from the F1 app. If you have the speed and time data for a sector that's completely full throttle and straight you can calculate quite a lot.
Based on a Reddit thread, the model was 100% rigid - it would be interesting to see how the CFD changes when surfaces are allowed to bend and respond to different air densities at different spots.
the suggested article in the series at the bottom is even more interesting, outlines a 'fantasy f1 championship' but for aereodinamicists to compete with their car concepts
The Netflix series on F1 got me interested in the current rule sets and it's mostly just kind of depressing.
It occurred to me that a professional racing series becomes boring at about the time that the car isn't built by a dozen (or less) mechanic/fabricators in a commercial space at an airport.
I see F1 as high budget soap-opera/reality-TV with a racing series setting. I can't relate to the people in the same way as you might with the "dirty dozen" approach but the drama is there nonetheless.
I used to love F1 as an engineering research unit for the world. But once regulations started banning technologies - and even relatively simple tweaks! - left right and centre it lost that shine.
I wish F1 would largely throw away the regulations again.
Keep general safety regulations, a safety cell and 4 wheels, set the physical parameters for the car like size and weight with an 80kg driver, maybe specify some aerodynamic condition for trailing air and limit the unobtanium material use.
I think limiting $ spent should be done by full specifications of cars to be released after 3-5 years. It is only worth spending money to get an advantage. If all your competitors are going to have your research in a few years then why spend so much? Also, ALL the engineering fanciness is released for the world to benefit.
Then, when cars get too fast. Reduce the size/weight of the car, while keeping safety cell and wheels the same.
"Oh, your 2m wide car goes too fast? Try it next year at 0.8 the size."
Eventually it will be go-karts again. But of the most brilliant engineering.
It's worth noting the current rule set is trying to optimize for spectator moments, safety and budget constraints. An F1 series unruled at this point would be a case of biggest pockets wins, and the racing wouldn't be close at all. I like to think of F1 as just a big go-cart race. The cars are obviously on the edges of performance inside the rules, but the cars are still homologated.
The really interesting racing has been in Time Attack and grassroots leagues in my opinion. I forsee an end to F1 soon enough, the budgets are big and it's no longer a good platform for R&D given manufacturers will start to ditch consumer ICE anyway. Whereas Time Attack and other leagues are more about developing enthusiast level performance fabrication shops and parts which is something that will go on in to the future.
To each their own perhaps, but I find F1 very exciting. Even despite Mercedes's recent dominance, there is plenty of great midfield action, strategic decisions, uncertainty due to safety cars or weather, and teammate battles that make each race a fun watch.
To be fair, scarcely any HN readers (and a vanishing amount of the general population) remembers when racing hadn't gone down the rabbit-hole of infinite cost and technology.
The post-war period of extremely common amateur racing morphed into pro racing some time ago. Most organized series became impossible for the dozen-guys-in-a-garage to compete probably sometime in the 1980s. We'll never see the likes of the Herb Adams 'Grey Ghost', Smokey Yunick small block Chevrolet Indy car, or (I suppose) Hesketh ever again.
Like most endeavors in the era of mass media consumption and mass production/distribution, you end up with a handful of utterly dominant players with everyone else simply a consumer.
Does anyone know of a (preferably free) API for live F1 timing data? I would love to put together a custom dashboard for races, but haven't been able to find a source for the data.
If you subscribe to F1TV you get timing data in form of additional screen which you can view. Apart of that, there were several attempts in the past to extract timing data from from live streams, which stopped around 2016 when the API was changes. So to my knowledge, there is no free API for that. If there was payed version, I would be also interested, but I don't know about it either. The thing is that F1 considers this traditionally very sensitive information and is unlikely to make it public any time soon.
I read an article[1] a while ago where some people made a dashboard with all streams and data. Never tried it though.
The application is called race control and is opensource [2]. If the app is not what you mean, their reverse engineered api client might help?
Do you model this with spinning tires? That that make a difference? I would think that the amount of vortices, etc would be significantly different when the tires are in motion.
I wonder if the computation was done taking into account that the wheels are rotating. I also wonder how much of a difference it would make in the output anyway.
Under what authority / jurisdiction would the author get in trouble for doing these computations?
Surely the FIA doesn't have any authority over random civilians.
This vortex structure exists because the front wing main plane needs to be flat for +/- 250mm at on the Y axis from the center line. In order to get the outwash to the barge boards and around the rear wheels, the front wing needs to generate a huge vortex right where the wing starts.
You can see the Y250 Vortex structure in this old footage from Mark Webber driving the RB9 in humid conditions where it forms a condensation trail as the air pressure drops: https://www.youtube.com/watch?v=ZlDnd3B1rhs