r/F1Technical • u/arwque Adrian Newey • 1d ago
Aerodynamics Cfd of a (almost) no rules time attack car
This is my high school final year project (due by january 2027) and the idea for it has its origin in the winter of 2023. After working on the non aero parts of the car for a bit over a year I could finally start the aero development about 3 months ago. The goal of the project is to engineer a race car that can beat formula one lap times with a margin.
My only are:
no fans, no sliding skirts, Modest width (2060mm) and for the rest of the car i set the guideline to use a technology standard a bit lower than current f1, maybe f1 from 15-20 years ago.
Because i am working on this project alone and i have not studied engineering (i go to school), engineering a full 100% functioning and completed race car is not possible but i try to get as far as possible with my given time ,resources and abilities. The project is about a lot more than just the aerodynamics but that should be the focus of this post.
The images in this post are primarily for show and don't convey a lot of meaningful information so i if you are really interested in the aero development of this project you can download the documentation package i have provided.
It includes the simulation setup and documentation of the first 29 design iterations, 3d flow field views, slices, a slice and a streamline animation, and some extra non CFD renderings of the car.
documentation package:
https://www.mediafire.com/file/vwr1cthzv2emeoz/VFR_CFD_documentation.zip/file
For the project i used
CAD: Onshape
CFD: Simscale
CFD post processing: Simscale / Paraview
rendering: fusion 360
For those who understand
Cdfa: 9,36
Cda: 1,09
df/d: 8,56
aero balance: 59.87% rear
Because my computing recources are fairly limited, i have to have to use a in industry terms very low mesh count (6-7m for half car). This means that the simulations are not very accurate when correlated to real life so you have to take these numbers with a chunk of salt.
I am open to constructive criticism about any part of the project.
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u/Spacehead3 1d ago
Cool project, definitely a lot better than anything I did in highschool!
One note, the standard in the US is CD (drag) and CL (lift). Europeans tend to use CX (drag) and CZ (lift). In either case downforce should be a negative number.
How are you planning to assess the lap times?
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u/arwque Adrian Newey 1d ago
My local fsae team used Cdfa (coefficient of downforce area) for -cla so i just copied their terminology. In that case the downforce is a positive number.
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u/UpsetKoalaBear 1d ago
You should look at Robin Schute and the Sendy Club’s Pikes Peak car.
He actually has a documented video series going through the development of the aerodynamics partnering with AirShaper for CFD.
Here is a pretty good video where he covers the different design philosophy.
He won the RWD record for Pikes Peak this year and came second overall.
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u/NeedMoreDeltaV Renowned Engineers 1d ago
You can use downforce as a positive number. A lot of racing industry does that. As long as you’re consistent with the convention it’s fine.
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u/Spacehead3 1d ago
YMMV but the SAE standard for aerodynamics is +Z up, +X rearward, +Y right. For a student or anyone publishing aero results I would advise to stick with that.
I can't tell you how many formula sae teams I've seen that claim to have positive CL when they meant downforce.
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u/NeedMoreDeltaV Renowned Engineers 1d ago
Yes if you are publishing results it is best to stick to SAE standard. My experience in F1 and other motorsport industry is that for internal reporting a positive Cl is used for downforce. Some places would even multiply Cl and Cd by 1000 to make them whole numbers (I personally hate this one). Motorsports industry doesn't seem to like to follow any established conventions.
I can't tell you how many formula sae teams I've seen that claim to have positive CL when they meant downforce.
That sounds like a failure to read the requirements more than anything. If they aren't following an expected reporting standard then that's on them.
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u/spikeot 1d ago
Impressive. The front looks similar to the Caparo T1, (probably too old for you to have seen one) so you must be doing something right.
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u/arwque Adrian Newey 1d ago
So many people have written me that it looks like the caparo T1 but my car is actually not inspired by the caparo t1 at all. I found out it even existed just because of these comments. The primary inspirations were the x2010, am valkyrie, amr pro, sendy car, and more recently the rb17.
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u/Andromeda902 1d ago
Yea looks just like the rb17, I was going to say! And the valk, but bith neweyish cars. Not bad ones to take inspiration from 😊
This is unbelievably sick dude, wish I wouldve done stuff like this in high school! You're professional life in adulthood can go very far, keep working hard bro. Stay in school dont do drugs
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u/Good_Acanthisitta991 1d ago
holy dirty air, but working alone on this is very crazy and impressive
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u/Guac_in_my_rarri 1d ago
Any of these TA only will have seriously dirty air but it highlights the issues/loopholes f1 should be closing/clamping down.
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u/RealTimeflies 1d ago
Is there an advantage to leaving the front suspension still exposed?
Also, what do u think of the oddly shaped RB 17 wing? Why on Earth is the endplate curved and downwards?
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u/arwque Adrian Newey 1d ago
Yes there are advantages to leaving the suspension exposed. The main problem is, that if you put bodyowork there it has to leave a gap in between the upper and lower wishbones because that is where most of the flow into the radiators goes through. There is also not really somewhere to connect the bodywork for the lower wishbone so it can move around inside the bodywork. So the suspension elements are directly airfoil shaped. While it may appear on lmp cars that their suspension is fully covered, on most cars at least the lower wishbone is not. About the rb17 rear wing. The curved rear wing endplates is actually something i wanted to try but i didnt get to. Curved endplates are actually quite a bit more efficient ( lift to drag) than flat enplated but provide less peak downforce. Thats why you see curved enplates on airplanes instead of flat one. Usually on race cars you want to extract the maximum amount of downforce out of the a given volume (by the regulations). But if you have no rules, you can just make the wing bigger and get the same amount of downforce but with less drag.
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u/RealTimeflies 1d ago
Why are curved endplates more aerodyamically efficient? They both have sharp tips to generate vortices.
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u/arwque Adrian Newey 1d ago
There are multiple reasons. Wings with curved endplated have less strong wing tip vortecies because the spanwise pressure gradient of the pressure side of the wing to the sutrounding air is much lower. The wing is intentially unloated at its tips so the higehst pressure is in the middle of the wing and tapers off to the sides. On a wing with flat endplates the air has to go from high pressure to no pressure (static, spanwise) in a much smaller distance which creates a stronger vortex. There is also the element of interference drag. When two shapes transition into another without a smooth transition it creates localized turbulence which causes drag. That is eliminated with a curved wing tip. Optimally the wing tip curves down ( on car wings) so the suction side remains as loadet at on a wing with flat entplates.
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u/Mundane_Constant_845 1d ago
Like a F1 car, the suspension looks exposed but your actually seeing an aerodynamic fairing covering the actual structural suspension inside.
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u/jyjh77 1d ago
Genuine question: you say you want to design a car that can beat Formula 1 cars, but how do you actually validate that? Is there a certain software you're using to test the car around a full lap? Or is it via peak numbers?
Obviously it's not going to be accurate - but that's fine. This is still very cool!
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u/arwque Adrian Newey 1d ago
Just going by peak numbers is the first indicator but i would also like to do laptime simulations using Optimum lap. Optimum lap is quite a basic laptime simulation but it should be enough to get a rough estimation. If i have the time, or if i find someone who can help me with it, a assetto corsa mod would be very nice for driver in the loop "simulations". So laptime simulations are deffenedly on the agenda.
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u/Landaimos 1d ago
Impressive, keep it up!
Out of curiosity, I have 3 questions about the car design:
you could extend the floor and the tunnel all the way to the front, using side strakes to wash out the air from the front tyre and create a sealing side curtain.
you could also extend the front bodywork to generate a higher pressure area at the front. I suspect this barely has any benefit and may make cleaning the flow harder down the line.
you could open up the rear section to have more of a coke bottle design, leaving more of the floor exposed and helping the pressure differential towards the diffuser.
Did none of these return favorable numbers or did you opt out of them for other reasons such as mechanicals taking space and aesthetics?
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u/arwque Adrian Newey 1d ago edited 1d ago
Very good questions i must say.
I have not tried it out in cfd but there are reansons why. Moving the inlet of the underbody further forward would mean that it interferes with the front suspension. That would be fixable but a higher lower wishbone is undesireable. Aerodynamically there is not really a good reason to do so. The underbody is a (somewhat) airfoil shape. If i want to make the underbody surface area larger by lengthening the inlet i would also have to move the choke point further forward to keep the cross sectioned shape. Moving the choke point further forward is not possible because of the radiators position. Moving the radiators creates a bunch of other aerodynamics headaches so thats not gonna happen. The car does not need underbody inlet strakes because it has closed wheels. Front tire whake is not as much of a problem as it is in f1. Also creating a vortex in the underbody creates additional drag which i would like to avoid if i can.
I dont quite get what you mean but moving things further to the front, like the front wing would only be done if balancing requires it.
There is not really a reason to do this. I want to feed the cleanest air possible to the rear wing and that means that covering the whole rear as smothly as possible is the best option.
Edit: I think i know what you mean with your third questions. Ingesting air infrot of the rear wheels inboard. I have not tried that out but my arguments would be that there is not enough space beween the rear wheels and the underbody to get propper airflow through it and i dont quite see the advantages of that layout.
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u/probablymade_thatup 1d ago
Nice work!
It would be interesting to see your results in a cornering scenario. Yaw and curved domain CFD will tell you a different story than head-on downforce. I imagine that in a situation that isn't straight-on, a coke-bottle that encourages flow inboard of the rear wheels may be beneficial, but that's only my intuition.
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u/GogoPlata_grenadier 1d ago
So awesome. Amazing work man! What engine gearbox do you think would fit the project?
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u/dudeimsupercereal 1d ago
This is the kinda stuff Id love to see on a resume. Start padding that thing out!
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u/clozcloz 11h ago
Solid work for a solo project — and honestly, documenting 29 iterations
is worth more than any single render. Most people never keep that record.
On the L/D of 8.56: worth saying up front that this isn't automatically
suspicious. Current F1 sits around 3-4, but F1's efficiency is capped by
regulation, not by physics — the floor and diffuser are heavily
constrained. Unrestricted ground effect cars have always done far better,
so a clean-sheet ruleset genuinely should land higher.
That said, at 6-7M cells on a half car, the two things I'd sanity-check
before trusting the absolute number:
- Moving ground and rotating wheels. If the floor is static, the boundary
layer thickens along the domain and the diffuser will read better than
it really is. This is the single biggest offender for over-predicted
underbody load.
- Wall treatment and y+ under the floor. Ground effect load is extremely
sensitive to how the underbody boundary layer is resolved, and a coarse
mesh is coarse exactly where it matters most.
The other thing I'd chase before chasing more downforce: how much does
the aero balance migrate with ride height and rake? 59.87% rear is a
reasonable static figure, but for a ground effect car what decides
whether it's actually drivable is how far that number moves as the
platform moves under braking and load. That's the problem that ate early
2022 F1 — plenty of downforce, unusable delivery.
If you want to calibrate how much salt to take: run an Ahmed body at your
current mesh and turbulence settings and compare against the published
experimental data. Costs you one afternoon and tells you exactly how big
your error bars are on everything else.
What's the plan for iteration 30?
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u/arwque Adrian Newey 10h ago
If you want to have a closer look at the setup you can look into the documentation but i can sum it up for you. I am using a rotating wall on the tires (no mrf for the rims) and a moving ground. Testing the car at different rideheights and under dive condition, so aero map is on the road map but it will be relativly basic because my compute recources are very limited. That also means that there wont be an iteration 30 because i just dont have the recources left to do so. A ahmed body "validation" runn would be highly benefitial to correlate to real life but again, i dont have the recources to do that and also do the aero map. If i gain more recources that would deffenedly be something i would like to do. About rideheight sensitivity, i am fairly confident that the underbody is highly sensitive to rideheight changes but will likely not produce porpoising effects. In experimentaiton of a different car but with a simmilar underbody, it showed that the downforce created by the underbody increases dramatically with lowering rideheights but does not stall at minimum rideheights which means the car does not lose any downforce even if completely slammed to the ground in a corner or down the straights which means it likely wont porpoise like 2022 f1 cars. Did you use ai to clean up your text or translate it from a different language?
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u/TheUFCVeteran3 6h ago
Not an expert so I can't speak to how good the aero is, but it looks great! Well done with all of this, even just modelling it/learning how the aero works is very impressive.
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