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Dr Obbs Profile picture
Dr Obbs
@dr_obbs
Engineer, PhD Fluid Mechanics, @brakingbiaspod, ✝️, Proud husband and dad, 🇹🇷/🇺🇸 lived in 🇩🇪 🇬🇧 Motorsport Tech with a side of humor.
May 28 • 8 tweets • 8 min read
Lots of talk about tyre degradation, tyre temps, balance, and the like. So I think it's time for a refresher course on tyres, grip, and degradation. I'll try and cover all of this in this thread, but stay at a high level (because it's incredibly complex) for general understanding.

Firstly, we should understand that as a car goes around a corner, the input angle of the driver to move the tyre relative to the direction of travel creates a slip angle. This slip angle creates the forces at the contact patch that act to rotate the car about the Center of Gravity (CoG) through the corner (moment).Image If we focus in on a single tyre, then we see that with increasing slip angle (with constant Normal Force), the lateral force to turn the car is increasing until a limit (sliding limit). After this point, increasing slip angle will result in less lateral force, as the tyre is no longer able to impart a force at the contact patch without sliding.

The rubber tyre behavior plays a key role in this as well. In the initial stressed region, the rubber acts as a linear elastic material with increasing slip angle (Figure in the middle). At a point, this transitions to an intermediate phase where the rubber acts non-linearly. This non-linear stress response generates a hysteresis within the material that manifests itself in a heating response. This is termed hysteretic heating, and can be a key to generating bulk tyre temperatures.Image
Mar 13, 2024 • 17 tweets • 8 min read
People often ask me, "where can I find great information on motorsports and aerodynamics?" So how about a thread of some of my favorites? And no, I don't get paid to endorse these. I just think F1 Tech is a great place to share knowledge! Also, this is NOT an exhaustive list, but some that stick out to me. Feel free to add yours as well below!

Video below by Vyssion and JJN. Let's start with some of my favorite books on car aerodynamics! "Race Car Aerodynamics: Designing for Speed" by Joseph Katz is goated. A really great book covering all types of race cars and written for anyone at any level. I highly recommend this book. Image
Mar 4, 2024 • 13 tweets • 5 min read
Is the RB20 great? Or is Max Verstappen + the RB20 great? I spent some of the weekend looking through the telemetry. And here is what I have found. In summary, Max Verstappen is a Swiss f*cking watch. Well, maybe a Dutch watch. Let's look at it in this thread. Image Looking at the macro view level lap times to gage consistency, you can see that it's incredibly consistent irrespective of compoud. Credit to Checo as well, his lap times in Bahrain were also very consistent, but also consistently 5-tenths to 1 second slower per lap. But why? Image
Jul 12, 2023 • 11 tweets • 4 min read
Was the RB19 of MV really slow on the straights compared to the other teams? Or was something else going on? We know that MV wasn't fortunate to gain any DRS or slipstream after passing LN, but what else was going on? Let's understand this more in the thread below. 🧵 If we look first at the pit straight into Turns 1 and 2, comparing LN and MV, we see something peculiar. MV never upshifts to 8th gear, but holds 7th. Thus, his engine RPM is higher and he doesn't lift into T1. He does, however, lose time slightly to LN due to the lower speed. 🧵
May 31, 2023 • 7 tweets • 3 min read
Well that helps to solve that mystery. Had also heard that this plank was painted so they could observe the wear patterns better. Looking at this, the plank wear is quite low overall. How about a thread comparing my observations of the RB, Merc, and Ferrari wear patterns.🧵 The bib looks to be running quite low. Possibly some forward rake, as most suspect. RB is able to run their forward floor very low, and still ride curbs and manage bump tracks like Monaco. A bit more left sided mid wear. 🧵 Image
May 30, 2023 • 4 tweets • 1 min read
There is a quote in here that perfectly summarizes what I have been trying to say about the complexity seeing an image of a floor, and then getting a floor to work well.

"Talking to an engineer from the Milton Keynes team, not too worried about the photographs taken of their.." "..underbody in Montecarlo, he explained to us that it is easier to work on the cross section of the channels while the slope (height) variation part inside is much more complicated to the tunnel and the simultaneous generation of eddies; an infinite job, among other things.."
May 25, 2023 • 10 tweets • 5 min read
Ok so I had questions like many about the legality of the new @MercedesAMGF1 #W14b spec floor winglet. With the help of some friends, I did a bit of digging into the regulations to understand this better. A 🧵@Formula_Nerds @AlbertFabrega Photo by Auto Motor Und Sport The regulation boxes are sometimes super confusing so it's best to start with an overview of them. The below link is a good place to start to understand the regulation boxes where engineers can design within. Each reg box is controlled differently. 🧵racecar-engineering.com/articles/tech-…
May 23, 2023 • 4 tweets • 2 min read
Amazing interview with Adrian Newey!

*RB have gotten on top of the tyre "switch on" issues they had in AP
*More freedom than thought in these regulations
*Ferrari concept broadly similar to RB
*Never clear on what the potential of a concept is initially
*RB19 evolution of RB18 *CFD now gives engineers better understanding of flow details on a car
*RB team minimizes meetings and encourages communication in flat organization
*Focus on creating a culture of innovation
*overall complexity of packaging components in current F1 cars is driving larger cars Image
May 8, 2023 • 9 tweets • 4 min read
There is this narrative going around that Checo wasn't informed enough of what Verstappen was doing, so let's dive into it and see what's what. Lap 21 Checo Pits for Hard Tyres. HB tells him on exit MV's last time on hard tyres "32.2." Lap 22 a few minor setting changes 🧵 Lap 22 SP 1.31.5, MV1.32.27. Checo asks HB on lap 23, what is MV's last lap?" HB tells him "Max was a 32.2." Lap 24 HB comes on the radio and tells SP "Max a 31.9." Checo did a 31.86 on lap 23. 🧵 Image
May 7, 2023 • 4 tweets • 2 min read
Thoughts on the race & grid for the #MiamiGP

-Rubbered in racing line side (P1 & behind) should be grippier than the other
-Alonso had the inside of T1 if he can launch well
-Perez should be ahead after short run to T1, but launch will be everything.. (cont) Image -KMag at P4, a bit high, but has some real pace this weekend
-Gasley could pip KMag early, and develop a bit of a train behind him
-Russel on the slippery side needs to watch out for Leclerc who is faster.
-Both CL and MV need good starts. Could jump a place each right off… Image
Apr 27, 2023 • 4 tweets • 2 min read
My thoughts on this,

@KyleEngineers was the first I saw to mention that this decoupled underbite scoop could be “tuned” for specific conditions in the future, and I think that’s exactly what RB have done here. Cont.. The leading edge has been raised to potentially allow you to pressurize the undercut more for better mid wake control.

With the underbite, a raised LE doesn’t necessarily mean sacrificing cooling either, as you still have upper intake pulled back to pull in mass flow. Cont..
Apr 27, 2023 • 5 tweets • 3 min read
Good shot of the @ScuderiaFerrari double mouse hole. @KyleEngineers did a good video on how this might work to cast smaller discrete vorticity into the diffuser edge to help clean up the edge flow. Tom Talks also did a good video on this. I will link both below ⬇️ Image Here is the reference for the video from @KyleEngineers explaining this. Typically, smaller more discrete vortices are less prone to burst when they experience an adverse pressure gradient having their axial velocity reduced.

Feb 22, 2023 • 6 tweets • 3 min read
Just going to say this..

You can NOT seal a ground effect floor with vortices. Without sliding skirts, you WILL get inflow.

So there is no such thing as floor sealing vortices. There are, however, ways to use this inflow to your advantage. Rear floor edge structures are created to bring some inflow vorticity into the rear floor to help stabilize and clean up the diffuser. So what can these pronounced forward edge structures do?

CFD from Latios (F1Technical)
Feb 20, 2023 • 4 tweets • 3 min read
It's very interesting when you look at a teams carbon footprint, however. @McLarenF1 produced a FANTASTIC sustainability report in 2022 highlighting some of their top carbon emitters. It was not logistics or travel. For them it was scope 3 emissions from development and mfg. Image Scope 3 emissions are indirect emissions from suppliers for purchased goods, and fuel and energy related activities. For McLaren this number includes all of their racing series.

media-cdn.mclaren.com/media/sustaina…
Oct 11, 2022 • 11 tweets • 7 min read
Let's talk about F1 front tyre wake!!

For open wheel race cars, the wake from the front tyre is a very important thing to understand. It can impact many of the aerodynamic elements downstream. The complex structures around the tyre are 3D, and very complex #F1Tech 🧵 https://www.racecar-enginee... There are many research papers and articles studying this very phenomena. What you should know is that the wake is not stagnant but influenced by many factors like tyre rotation speed, wheel covers/no covers, tyre deflectors, etc.. #F1Tech 🧵 "Race Car Aerodynamics...
Mar 31, 2022 • 16 tweets • 11 min read
@DANIELEALOFAN Made a great overlay of what the #LasVegasGP track layout could be like in 2023, so I decided to use this as a go-by and add some turn numbers. Let's take a Google Maps tour of the circuit! #F1 The starting line and T1-T3 section looks to be in a currently vacant field where tarmac will surely be laid down. This could change, but interesting nonetheless and has lots of potential. #LasVegasGP
Mar 30, 2022 • 6 tweets • 6 min read
During Pre-season testing many people wondered how powerful the slipstream might be with these new wake friendly aero regulated cars. Some also wondered how powerful the DRS might be following in the slipstream. I did a post on this some time ago.#F1Tech The battle between @Max33Verstappen and @Charles_Leclerc was really fun to watch. Not only did we see the new regulations working quite well, but we saw just how powerful DRS still is. #F1Tech

📸 (@XPBImages) #AMuS
Mar 9, 2022 • 11 tweets • 9 min read
The rumors about the @MercedesAMGF1 being updated without a side pod and comments to @ScarbsTech mad scientist Merc drawings, showed me some explanation of the aero influence side pods have is worthwhile. So let's dig more into this #F1Tech thread.

📸(Stefan Baldauf) #AMuS For open wheel racers, one especially problematic geometric element is the front tires. A source of drag, and wake turbulence, the control of the front tire wake is essential for aero efficiency. A great study of this can be found below racecar-engineering.com/articles/wheel…

#F1Tech