[MVRC] Mantium Virtual Racecar Challenge 2022 (Grand Prix Cars)

[LVDH]

I agree on the fact that the noses are getting too narrow. I have a good idea, on how I will create a rule that should reasonably tame these spears without making things too difficult for us.
As some distraction, I have the full set of images for this ongoing race:

https://mantiumchallenge.com/cars-mvrc-cota-2022/

[G-raph]

Nice cars by everyone!

Lovely details on a lot of them (Rear Wing Endplate Louvres from Matteo!) and good to see the slower cars getting much more refined too. Special creativity points to HRT 2.0 for the Nose bargeboards and diffuser strakes.

Tolo Racing has to be the favourite again, with that very impressive sidepod. Same concept as my original one, but with the cooling exit and the downwashing ramp switched from inside to outside, which makes a lot of sense. Having said that, I'm sure Variante will be close.

But I secretly want Koldskaal to win, just because of the Cooling Chimney!

[Koldskaal]

I am a bit late with the preview. So lets call this an analysis

I put a lot of work into this car, so it should be a good step forward compared to the monza-spec.

I have done a lot of work on the sidepods. Earlier I had found that the side-facing louvres worked better than the ones on top. So for me the next natural step was chimneys, which worked even better. I also changed some of my lazy modelling around the sidepod inlet, and cokebottled the back. I am still not completely satisfied, but this will do for now.

The most significant changes are to the diffuser, floor inlet and fences. I increased the height of the inlet, abandoning my previous concept.


I am hoping I can hold on to a podium position, but y'all seem to have improved a lot . I think the top two will be Tolo and variante, and it will be a very close battle for 3rd between PurePower, Panthera, CAEd, Graph, Max and myself. I am very exited to see the results of this one.

I will be making a small change to the presentation, can't wait to show you guys.

[variante]

It's surprising that Tolo or CAEdevice didn't go for a more aggressive rear wing.
And it's interesting how some got closer to the RedBull sidepods, while others drifted away from that concept (like Koldskaal).

And yeah, everyone's car seems refined enough now. It's nice to have such a tight championship, where everyone is committed to it.
But i'm sure there's still a lot of optimization to do (my car included), so some hierarchies might still revert in the upcoming races.
What i'd like to work on next is vortex control under the floor and wheels wake control. But first i'll take a break and enjoy this race.

[LegendaryM]

It's surprising that Tolo or CAEdevice didn't go for a more aggressive rear wing.
And it's interesting how some got closer to the RedBull sidepods, while others drifted away from that concept (like Koldskaal).

And yeah, everyone's car seems refined enough now. It's nice to have such a tight championship, where everyone is committed to it.
But i'm sure there's still a lot of optimization to do (my car included), so some hierarchies might still revert in the upcoming races.
What i'd like to work on next is vortex control under the floor and wheels wake control. But first i'll take a break and enjoy this race.

If I went for a more aggressive rear wing, then my balance would be too far rearwards. Throughout the development I've found it much harder to add load at the front compared to the rear.

[yinlad]

I am hoping I can hold on to a podium position, but y'all seem to have improved a lot . I think the top two will be Tolo and variante, and it will be a very close battle for 3rd between PurePower, Panthera, CAEd, Graph, Max and myself. I am very exited to see the results of this one.

I will be making a small change to the presentation, can't wait to show you guys.

I'd be happy to be in the fight for third. The simulations I was able to run pre event were only showing a 1.8 CoP though, which isn't good enough. Hoping for some rearward shift over the full 5000 iterations

[G-raph]

Thanks Yinlad and Koldskaal for sharing these pictures ! That’s very interesting.

Here is my contribution to this cooling discussion, as promised. I’ve tried to keep it simple but it is still a long post (apologies!). To keep the discussion going, please ask more questions about my results and share what you have learnt too.


Cooling chimney – why ?

When I started thinking about entering this competition, I saw :
- Very open rules for the bodywork, with a big regulation box.
- Posts about how difficult it was to hit the cooling target of 3,0, having to deal with a lot of dirty flow at the back of their car.

So I immediately thought that it should be possible to send all these cooling losses above the rear tyre and outside the rear wing (where it can’t hit any useful geometry - red arrows), and/or even to get some of it to hit the front face of the rear tyre to reduce drag (red circle). So the idea of a massive pre-2009 cooling chimney became obvious, which would also make my car unique.

These 2022 cars need a wide bodywork anyway, which allows a large radiator and cooling exit to be placed outboard. Then, you can have a downwashing ramp inboard of the chimney to send clean flow to the diffuser top surface, feeding the beamwing and rear tyre contact patch nicely (blue arrows).

It all sounded (too) perfect ! See picture below :



Does it work ? Sort of…

However, it then became clear that the regulation box was not tall and wide enough for my concept to work, and I should have bailed out at that point. But I didn’t and still drew a large outlet as high and outboard as possible, with a vertical exit tangency. The inboard ramp looked narrow but I hope it would be enough.

Official cooling result for Race 01 was 2,85.
For Race 02 I made the inlet and outlet larger, sacrificing the ramp width. A large vertical plate was added to stop cooling flow from spilling into the ramp. Unfortunately this only gave me 2,93 in Race 02.
See the geometrical evolution below :


The streamlines and the Cp_tot slice below are from my Race 02 car. You can see that some of the cooling flow goes to the desired region above the rear tyre. I was also able to protect the flow on the ramp with that large plate. Unfortunately, it is clear that there is still a large amount of cooling flow coming back inboard and hitting both the rear wing and the beamwing. Which is why it has only « sort of worked ».





Killing the concept – the delta.

Between Race 02 and Race 03, I got rid of the chimney and went to a more conventional cooling exit layout, removing the inboard ramp in the process. It was the only way to reach the cooling target of 3,0 anyway, but I was curious to see how much performance it would cost.

You can see the results on the picture below :

(Bear in mind that the numbers quoted come from my very unrefined setup, with a development floor and rear wing that were worse than the Race 02 spec. Both configurations have around 2,9 cooling.)

Losing the cleaner flow from the ramp is obvious on these pictures (blue circle), which ends up towards the beamwing and around the diffuser, protecting it a bit better from the tyre wake.

However, the conventional configuration improves Cp_tot towards the rear wing. As this is not a particularly efficient part of the car, I thought the trade-off would be much worse, but I was clearly proven wrong.


So why did it not work ?

Apart from the obvious failure of sending all the cooling flow away from my own rear wing, I still thought that the flowfield of the cooling chimney was better. Maybe it didn’t work because :

- I didn’t manage to get enough clean flow into the ramp and towards the beamwing to really exploit this concept ? It would have worked better with a lower cooling requirement, but would it have been enough ?
- My beamwing design is not good enough ?
- The rear suspension creates too much blockage and wake by itself that it doesn’t matter if you send clean flow into this region ?
- Maybe higher suction from the rear wing is much more important to pull on the diffuser than protecting it from ingesting the tyre wake ?


Conclusion :

If sending the cooling losses towards the rear suspension is more beneficial than towards the rear wing, then Tolo’s sidepod design is a very neat answer. It retains a ramp that will send clean flow around the diffuser.

Another way to look at it is to go for Koldskaal smaller chimney (looking very much like a 2008-spec one). If you can size it perfectly so that the flow coming out of it fully goes above the rear tyre and outside the rear wing, then it is free cooling that you don’t have to carry around further inboard.

Maybe the best configuration is a combination of these 2 cars. I will certainly try that before Race 04 !

[CAEdevice]

Here is my contribution to this cooling discussion, as promised. I’ve tried to keep it simple but it is still a long post (apologies!). To keep the discussion going, please ask more questions about my results and share what you have learnt too.

Thanks for this interesting post

I made more or less the same attempts, but in a different order (at first I tried to evacuate the flow from the radiators near the axis of the rear wheels, using the extraction effect of the rear wing, but in Monza, with a low profile wing, it did not work).

I tried the chimneys but I was not satisfied with the aesthetics and the advantages were still much less evident than I had hoped (consider that I could not imagine the great Tolo performance, so I had lower goals: I was wrong )

I am currently working on two ideas:

1) To separate the cooling air flow vertically (Z) and not horizontally (Y)

2) Worsen the aerodynamic resistance (high cooling inlet pressure) to have a relatively energized output cooling flow

I don't know which of the two is the best approach, the car for race n°3 is a compromise both for this and for many other parameters

[variante]

Here is my contribution to this cooling discussion, as promised.

Thanks, fantastic analysis.

I don't know if chimneys are better or worse than other philosophies, but i think they can surely be "made to work" competitively. And you seemed very close to that goal.
In your place, i would have tried:
- a bigger upwashing Gurney (or similar) in front of the chimney;
- a more oblique exit to encourage outwash;
- a narrower exit to increase speed;
- an outwashing turning vane.

And yeah, i'd always give priority to the rear wing over the beam wing. So much performance can be extracted from it that it enables you to make further "free" gains elsewhere on the car (like on the front wing).
But, once that is sorted, it makes sense to feed some more air to the beam wing.

Last season i tried a similar approach, venting cooling air on the rear tires and letting only clean air reach the rear end of the car. No beam wing was permitted, but the nonetheless generous rules allowed me to have a wing in place of the diffuser, with good results.

A less technical reason behind this choice was to stop worrying about cooling and wake management as soon as possible (the large cooling exit worked almost right away), which didn't only prevent me from getting crazy, but also allowed me to focus on more productive areas of the car.

[G-raph]

Thanks, I'm glad you both found it interesting.

2) Worsen the aerodynamic resistance (high cooling inlet pressure) to have a relatively energized output cooling flow

Improving inlet pressure is obviously a good way to increase cooling. However, as the pressure drop through the radiator / porous media is proportional to air velocity, it might not give you a more energised flow at the exit.

For a given massflow target (= 3,0), you want to slow down the air velocity through the radiator as much as possible if you want to retain maximum Cp_tot at the exit. The only solution is to maximise radiator area. So as long as your inlet duct expansion stays under control, you should make sure that you are not leaving any space left inside your sidepod that could otherwise be used to house a larger radiator.

In your place, i would have tried:
- a bigger upwashing Gurney (or similar) in front of the chimney;
- a more oblique exit to encourage outwash;
- a narrower exit to increase speed;
- an outwashing turning vane.

I already maximised the Gurney in front of the chimney, the regulation box is limiting me quite a lot there. To get a larger one I could only drop the sidepod top surface but that would also limit my radiator size.

I agree with you that the other 3 suggestions are the obvious things to try to make it work. But that leads to your other point...

A less technical reason behind this choice was to stop worrying about cooling and wake management as soon as possible (the large cooling exit worked almost right away), which didn't only prevent me from getting crazy, but also allowed me to focus on more productive areas of the car.

Choosing the right area to spend your money on is a critical decision that even the largest F1 teams have to make. So for us it is even more important. Those strategic decisions are often much more valuable than the actual technical choices.

So yes, I agree with you, sometimes you have to pull the plug and let your concept go when it becomes evident that the time you will spend to make it work will not be efficient.

I got rid of the chimney and went beyond the 3,0 target in 2 CFD runs : the first one I posted above, and then with a simple increase in radiator and exit size. Then I found a lot a Cl by working on the floor and rear wing.

[Koldskaal]

Results for round 3

new round, new winner?



Lots of very refined cars. A real nail biter this one.

I had 4 liveries made, with appropriate "sponsors". So now the cars are not so "bare" looking.

A big thank you to our tire supplier CAEdevice for indirectly sponsoring this with the 2019 prize money.
Still lots of room on the car...
*edit: fixed the car performance table in the video

[Ft5fTL]

Congrats to Graph racing. A bit of a shocker for me i did not expected 5th after the gains i made, well done everyone.
Some windtunnel correlation issues from my side aswell . My simulations were always on the low side on the numbers untill this one.

It seems the car performances section didn't changed from Monza on the vid.

[Koldskaal]

It seems the car performances section didn't changed from Monza on the vid.

edit: managed to mess up the table twice. Max posted the right numbers on the next page

[CAEdevice]

Stunning video. Think about how fun an online race would be using the aerodynamic specifications of our cars.

Congratulations to the winner!

ehm ... are you sure about 3rd and 4th place numbers? They don't match mine (but they did in the first two sectors). It is clearly impossible I have more DF than Variante (I think it never happened)

[CAEdevice]

I had 4 liveries made, with appropriate "sponsors". So now the cars are not so "bare" looking.
https://i.imgur.com/gtd1Yq1.jpg
A big thank you to our tire supplier CAEdevice for indirectly sponsoring this with the 2019 prize money.
Still lots of room on the car...

I would be happy to be a sponsor of the final prize again, the only problem is the choice of the prize itself. A book (or cash equivalent) would be easy to be delivered. I also tried to 3D print one of the cars, but it's tricky (using a scale budget compatible), especially for cars modelled with SketchUp.

I think about it a little more, but certainly, there will be a sponsored prize, ... do you need the CAEdevice logos for the livery?