[MVRC] Variante

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wb92
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Re: [MVRC] Variante

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I really like how you incorporated gills on the endplates on both wings.

plenty of interesting ideas.
MVRC - WBRacing

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CAEdevice
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Re: [MVRC] Variante

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It is the most innovative and original car of MVRC2020. The enhanced downwash of the sidepods is a solution I tested, but it did not produce big improvements: you must have something special in the rear part of the car to fully take advantage of it.

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variante
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Re: [MVRC] Variante

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This is a brief technical review to celebrate the car that just won the 2020 Mantium Challenge, a competition of aerodynamic design. It is the third Variante racer to achieve this result.

In 2019, a new set of regulations made the Competition shift from Le Mans inspired cars to Formula1 inspired cars. Not surprisingly, the 2020 car is based on that of the previous year. Extensive bodywork changes, however, meant that the evolutionary design approach was abandoned in favor of a bolder one, which ultimately proved to be quite successful.
Here are the highlights:

SIDEPODS
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The most predominant feature of the new car are its sidepods (which would be illegal in actual F1!). Their design philosophy revolves around venting radiators exhaust air outboards, while driving fresh and clean air downwards and towards the Rear Wing and Diffuser.

Thus, the scarcely energetic radiators exhaust flows do not interfere with the working surfaces at the rear of the car, and they also shields the rear wheels from coming in contact with fast air streams, which would negatively affect Drag. Another consequence of this oblique flow is a better sealing of the floor.

Meanwhile, the air streams over the top of the sidepods are gently turned downwards, to not only feed the Rear Wing with the cleanest air but also to feed it better flow angles. And since the car has a slotted Diffuser (also not allowed in F1), it is possible to further harvest these energetic flows by channelling the air into those gaps (more on that later).

FRONT WING
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For the sidepods to work properly, an adequate amount of air must be let through the Front Wing, hence why it features a gentle inner section, compensated by an aggressive outer section which also shields the wheels. This configuration naturally encourages outwash.

A peculiar feature introduced with this Front Wing are the Louvres on the Endplate, which virtually enlarge it, besides creating downforce by themselves.

The high rake setup chosen for this car brings the Front Wing closer to the ground, enhancing its Ground Effect and thus allowing for lower AoA for the same downforce, hence less disturbance to some of the working elements downstream.

The airfoils are custom made and organized in an elliptical fashion, and are the only actual heritage carried over from the previous Seasons.

DIFFUSER
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The raked setup of the car has the negative effect of increasing the distance between the Diffuser and the ground. Under this condition, the advantages of a concave diffuser shrink. That is why a more traditional convex diffuser was chosen, which can also make better use of the energetic airflow coming from the top of the Sidepods.

ALL IN ALL…

Besides the mentioned elements, dozens more contributed to the performance; probably less innovative or exciting, but equally important and demanding in terms of optimization. The most innovative parts did provide a considerable performance edge, crucial for the achieved results, but the car was hungry for a 360° care, being very delicate and sensitive to changes. In fact, a big upgrade package was introduced in the 4th (out of 5) race and, as promising as it was, it ultimately performed worse due little and yet crucial computational discrepancies between my tests and the official ones. The car still has a big margin for optimizations and a considerable unexpressed potential which, however, has proven to be not very easy to extract.

So, performance ultimately stabilized around these numbers:
CDA = 1.45
CLA = 3.30 (FW = 1.27 ; RW = 1.06)

What do you think about it?
Let me know if you want to see something I haven’t shown yet! Not that I’m willing to show everything, but…
A big thank you to the organizers and to the sponsors!

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machin
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Re: [MVRC] Variante

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As ever; great insight, many thanks for sharing!
COMPETITION CAR ENGINEERING -Home of VIRTUAL STOPWATCH

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variante
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Re: [MVRC] Variante

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As promised, here’s a brief analysis of the Ardore, designed to compete in the 2022 edition of the Mantium Challenge, the virtual competition of racecar aerodynamics.

INTRO
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The regulations of the Challenge are inspired by F1 regulations, while being more permissive in some aspects. The Ardore was initially conceived to comply with the stricter F1 rules, as an exercise to comprehend the aerodynamics of the real cars. But, as the season progressed, it became evident the need to bypass certain limitations present in F1, such as the maximum airfoil angle rule, in order to stay competitive.

As a result of this development, lasted one year and 5 races, the final performance of the car clocked CDA=1.599 and CLA=4.825.
As you read these numbers, keep in mind the mandated ride-height of 50mm, rake of 0°, wheelbase of 3.6m, and the considerable mandated wheels contact patch. Many geometries, such as wheels and suspensions, were also… mandated.

The car managed to win the last race of the season, but due to a number of mishaps it could not bring home the second championship title in a row for Variante, ultimately securing the 2nd spot, 7 points away from the lead.


FRONT WING
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Being upstream of everything else, the Front Wing has a big impact on everything happening on the car. A favorable compromise between generating downforce and feeding energized air downstream had to be found.

The very demanding cooling requirements of this challenge, as well as a sensitive Rear Wing, made it difficult to use voluminous wing geometries close to the symmetry plane of the car. To compensate for such lack of available wing area, an aggressive semi-elliptical wing section was chosen. Three airfoils are enough to avoid undesired flow separations.

Outwashing Endplates together with upwashing Wheel Deflectors improve pressure distribution over the wheels, and encourage downwash in the central volumes of the car.


SIDEPODS
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Together with the Front Wing, the Sidepods required the most development effort. Almost 1/3 of all simulations were dedicated to their optimization, attempting to satisfy the demanding cooling requirements without loosing too much performance.

They are designed to be as narrow as possible to mitigate lift.
Their slope, although lift-inducing, considerably helps downwash.
Their lateral tapering is delayed to better interact with the rear wheels.

The radiator intakes catch air from the top as much as possible, rather than frontally. This solution reduces their frontal area and encourages downwash.

Radiators inclined 45° are used to ease airstream evacuation.
More vertical radiators would imply difficult intake expansion control and wider sidepods.
More horizontal radiators would imply harsher turning of the airstream.
To energize the intake flow and avoid expansion issues, a slot is used on the intake ramp.

As much cooling airflow as possible is evacuated from the rear exhaust, but a considerable amount has to be released from the sidepods gills, whose job is to feed decent quality air to the Rear Wing.


REAR WING
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The relatively few control parameters of the Rear Wing, as well as its isolation, make it quite an easy element to optimize.

A quasi-circular section with a vertical trailing edge is enough to generate the necessary rear downforce at a reasonable drag penalty. Some attention was dedicated to find the optimal slot aperture and position between the two airfoils. The chord variations are determined by the quality of the approaching air.

The endplate cuts put the wingtip vortices in better contact with the lower side of the wing, helping with airflow extraction.


FLOOR
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Most of its layout is determined by the tight regulations.

The incoming airflow is met by three bargeboards on each side of the car. The inner ones tune the mass flow towards the diffuser and generate a vortex that runs along the entire floor. The intermediate ones control the vortex shedding position on the inner boards. The outer ones control pressure gradients right behind them, as well as wheel wakes.

The Diffuser is designed to be as aggressive as possible, in a concave-convex configuration. The concave portion works together with the quasi-flat floor, taking advantage of ground effect. The convex portion, coupled with the Beam Wing, maximizes the low pressure volume behind the car, helping with suction.


That's about it.
Let me know what you think :wink:

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beschadigunc
beschadigunc
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Re: [MVRC] Variante

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Very very cool man

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LVDH
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Re: [MVRC] Variante

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Very cool renders and nice fat vortices you have under the floor. Good work =D> .

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spacehead3
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Re: [MVRC] Variante

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The extra cooling slots and ducts are nice touch, very clever.
Max Taylor

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G-raph
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Re: [MVRC] Variante

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Very nice analysis and summary! Thanks for sharing that.
I'll use some of your pictures in the main MVRC thread if you don't mind, to compare my car with yours.

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variante
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Re: [MVRC] Variante

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G-raph wrote:
Sat Jan 14, 2023 12:43 am
Very nice analysis and summary! Thanks for sharing that.
I'll use some of your pictures in the main MVRC thread if you don't mind, to compare my car with yours.
Yes, of course. Let me know if you need other images from the report and i'll provide (except certain sections...).

BlueCheetah66
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Re: [MVRC] Variante

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The new W14 somewhat reminds me of your car

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variante
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BlueCheetah66 wrote:
Wed Feb 15, 2023 2:50 pm
The new W14 somewhat reminds me of your car
Yeah, mine is chunkier, but similar in concept (aside from the vertical air intakes).
I also tested the RedBull sidepods (sort of) that everyone is adopting, but these were better for my car.

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variante
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Re: [MVRC] Variante

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About time for an update!

The 2023 MVRC season has come to an end. Despite fighting hard and winning the last race, the Candore ultimately managed to achieve a mild 2nd place in the final standings.
Not much more could be done against a G-raph in great shape.

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Let's focus on the differences with the previous model, the Ardore, as well as the shortcomings that will have to be addressed.

Thanks to rule changes and intensive development, from 2022 to 2023, performance was increased considerably.
Drag (CDA): from 1.599 to 1.534
Downforce (CLA): from 4.825 to 6.114
With Centre of Pressure and Cooling kept within the ideal ranges.

Design philosophy
No much has changes on this front, characterized by an aggressive search for downforce, achieved by harmonizing high angle of attack wings and 3D flow structures. The rules mandate strict constraints, and I self-imposed additional ones like the 75mm radius rule to make things more interesting. So, just like in Formula1, there isn't much room for design variations. Still, small details may be massively influential for flow structures and performance. A good half of the development was, in fact, dedicated to such optimizations.

Front Wing
The inner sections have been unloaded as much as possible to keep inboard flows energized, mitigating the never-ending struggle for rear downforce. However, more loaded outer sections are necessary to compensate for the loss of front downforce. The drawback of this approach is the induced inwash that draws Front Wheels wake toward the Floor, compromising its performance.

Floor
Diffuser volumes have been brought forward, given more three-dimensionality, and maximized to enhance ground-effect. As a consequence, more powerful vortices were needed to stabilize it, shed by higher angle of attack Strakes. Despite their power, such vortices are still unstable and susceptible to unpredictable interactions, which are hard to tame due to different and delicate CFD simulation settings. But, once all pieces will start falling into place, a lot of additional performance will be unlocked in this area.

Sidepods
The general layout has been revolutionized to follow the outwash-to-downwash philosophy, which will provide better airflow to the Rear Wing. Radiator intakes are now conventional, to maximize cooling rather than downforce. Radiator ducts have been narrowed to minimize recirculation. Sidepod outlets have been moved as further out as possible, to minimize interference with the Rear Wing.

Rear Wing
A number of optimizations resulted in more sculpted and extreme wing profiles. But Rear Wing performance is much more reliant on upstream flows rather than shape optimizations. Not by chance, a large downwashing winglet has appeared around the Airbox.

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The 2024 season will begin in a couple of months, and development must restart.

One of the main areas of interest is the Floor. Many of my adversaries are using relatively gentle Strakes and a convex Diffuser, and still achieving good performance. I need to investigate how. At the same time, I'll have to stabilize and harmonize the 2 principal vortices running along the Floor, one shed by the Strakes and the other by the Diffuser walls.

I'd also like to optimize cooling to decrease air intake and outlet size, and use the gained volumes to produce downforce.
Once that's achieved, testing 2024 Formua1 style sidepods would be the next logical step.

But, most importantly, i need to manage the Front Wheels wake. Somehow.

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As always, criticism and questions are welcome!

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G-raph
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Re: [MVRC] Variante

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Nice summary!

I have a couple of quick questions for you...

1 - Do you run every design iteration (including wing profiles) with the standard MVRC settings? Do you ever run with the Fast settings?

2 - Is your front wheel wake really that bad compared to mine? Can you see it compromising your underfloor vortices?

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variante
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G-raph wrote:
Wed Feb 21, 2024 11:17 pm
I have a couple of quick questions for you...
I ONLY run simulations on the Fast setting.
In this challenge, due to the number of variables involved, I value number of simulations way more than accuracy.
Also, I can't really keep my little computer busy simulating for too long #-o

Correlation with official / high-accuracy results isn't too bad.
Differences can be accounted for, up to a certain degree.

As for Front Wheels wake, it's somewhere in between your 2022 car and your 2023 car.
I reckon there's a good amount of Floor performance to be gained from cleaning such wake (elegantly...).
Underfloor vortices may be influenced, but the wake rather damages the outer Floor Vanes, which don't shed vortices.