Parametric Racecar Aerokit design [MVRC]

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CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Wed Dec 20, 2017 7:25 pm

Yes, I think you are right. There are two possibilities: to lower the diffuser (especially at the sides) reducing drag or to find a way to feed it with more air (the high nose helps the central channel, but not very much for the side channels).

Zynerji
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Re: Parametric Racecar Aerokit design [MVRC]

Post by Zynerji » Wed Dec 20, 2017 8:16 pm

If this had a TensorFlow plugin, the possibilities would be utterly astounding.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Wed Dec 20, 2017 8:31 pm

CAEdevice wrote:
Wed Dec 20, 2017 7:25 pm
Yes, I think you are right. There are two possibilities: to lower the diffuser (especially at the sides) reducing drag or to find a way to feed it with more air (the high nose helps the central channel, but not very much for the side channels).
Was Variante working on trying to feed the diffuser side channels from the side of the car?
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rjsa
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Re: Parametric Racecar Aerokit design [MVRC]

Post by rjsa » Wed Dec 20, 2017 10:16 pm

Yes, he has a rounded floor edge amid ship. Did nothing for me but choke the front diffuser.

I have a pair of "horns" protuding from the rear diffuser edge that brought some flow into the side channels. And a whole lot of very twisted streaks within the diffuser volume.

Let's see if I can post a picture later.

variante
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Re: Parametric Racecar Aerokit design [MVRC]

Post by variante » Wed Dec 20, 2017 11:40 pm

machin wrote:
Wed Dec 20, 2017 8:31 pm
Was Variante working on trying to feed the diffuser side channels from the side of the car?
Yes, and I find it surprising that not many people are using this approach. Sure, it takes a while to get it to work, but it looks like a better way (at least, it looks so to me).
The biggest downside is what rjsa mentioned: you must deal with the front end airflows, somehow.

The "recipe" that I found is this:
- front wing airflow is evacuated in a dedicated channel which ends just above the diffuser, where there is quite a low pressure
- the leading edge of the floor is a splitter that takes front wing airflow away from the diffuser
- therefore the diffuser is forced to take air from elsewhere: slantwise, from the sides of the car
- that airflow happens to be of good quality, and its oblique motion helps creating strong vortices inside the diffuser itself

I'll post some images too, and a more detailed analysis

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Thu Dec 21, 2017 1:16 am

More pictures of both your cars would be cool. 😎

Matteo is far too modest and self-deprecating though; he may have a conventional car layout without any fancy front wing evacuation ducts, but let's not forget he also designed the most aerodynamically efficient car... it makes me wonder; what could you guys all achieve if you worked together to design one ultimate car?!?! 🤔
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schwepes
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Re: Parametric Racecar Aerokit design [MVRC]

Post by schwepes » Thu Dec 21, 2017 7:12 am

machin wrote:what could you guys all achieve if you worked together to design one ultimate car?!?! Image
I'm not sure if too many "technical directors" in one team would lead to any constructive result :-k .

Sometimes I cannot even make compromise with myself regarding some solutions :lol:
Last edited by schwepes on Thu Dec 21, 2017 6:06 pm, edited 1 time in total.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Thu Dec 21, 2017 9:43 am

Yes, I do agree! And I think that personal glory (as opposed to shared glory) is a big motivating factor!
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rjsa
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Re: Parametric Racecar Aerokit design [MVRC]

Post by rjsa » Thu Dec 21, 2017 1:10 pm

variante wrote:
Wed Dec 20, 2017 11:40 pm
machin wrote:
Wed Dec 20, 2017 8:31 pm
Was Variante working on trying to feed the diffuser side channels from the side of the car?
Yes, and I find it surprising that not many people are using this approach. Sure, it takes a while to get it to work, but it looks like a better way (at least, it looks so to me).
The biggest downside is what rjsa mentioned: you must deal with the front end airflows, somehow.

The "recipe" that I found is this:
- front wing airflow is evacuated in a dedicated channel which ends just above the diffuser, where there is quite a low pressure
- the leading edge of the floor is a splitter that takes front wing airflow away from the diffuser
- therefore the diffuser is forced to take air from elsewhere: slantwise, from the sides of the car
- that airflow happens to be of good quality, and its oblique motion helps creating strong vortices inside the diffuser itself

I'll post some images too, and a more detailed analysis
I also have the air extracted from the diffuser to the back. My duct is a tad shorter though, just long enough to cover the rear suspension.

Here the bottom:

Image
Image

The genie is out of the bottle now machin, the front diffuser you were curious about. This isn't the highest downforce version however...
Last edited by rjsa on Sat Dec 23, 2017 8:11 pm, edited 1 time in total.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Thu Dec 21, 2017 1:51 pm

Wow, that is some seriously nice underbody design.... 😳 👍
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rjsa
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Re: Parametric Racecar Aerokit design [MVRC]

Post by rjsa » Thu Dec 21, 2017 8:50 pm

:oops: tks!

variante
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Re: Parametric Racecar Aerokit design [MVRC]

Post by variante » Fri Dec 22, 2017 6:01 pm

I was't sure about showing so much of the car, but rjsa did and hopefully all the other MVRC guys will follow this path.

When I was a beginner, I really struggled to find any valuable information about aerodynamics, and today the web and most of the books are still full of misconception or partial explanation about the functioning of aerodynamic devices (...not to talk about university courses, because those are too generic and totally fail to form a competent class of aerodynamicists...at least in Italy).

So let's make this altruistic move and show something. A detailed article will follow on the Variante thread.

Image
Image
I'll quote myself for a brief description of what's going on under this car:
variante wrote:
Wed Dec 20, 2017 11:40 pm
The "recipe" that I found is this:
- front wing airflow is evacuated in a dedicated channel which ends just above the diffuser, where there is quite a low pressure
- the leading edge of the floor is a splitter that takes front wing airflow away from the diffuser
- therefore the diffuser is forced to take air from elsewhere: slantwise, from the sides of the car
- that airflow happens to be of good quality, and its oblique motion helps creating strong vortices inside the diffuser itself
I envy rjsa's front end, and especially the central part of the front wing, which has been giving me headaches during the whole season.

rjsa
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Re: Parametric Racecar Aerokit design [MVRC]

Post by rjsa » Fri Dec 22, 2017 6:42 pm

That's a lot of work done by that rear diffuser. I have a lot to do there.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 12:53 am

Nice one Variante, so cool, you can really see nice flow from the sides of the car on the velocity plot.

My personal opinion is that the championship should release more CFD pictures of the cars... I know that you guys want to win and don't want to give away secrets... but I don't think that isometric underfloor surface pressure plot gives too much away (especially if done at low resolution). But it would show the relative aero performance of the cars...

I think it would also help to grow a bigger "spectator" base for the championship.
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CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Sat Dec 23, 2017 8:26 am

I am not sure about publishing the CFD data/images: I think that realism should be the guideline, and in real races is not possibile to see pressure and velocity plots. On te contrary, it is possibile to see the more geometric details of the car.

I would agree about showing more CAD data and better renderings. Sometimes it is impossible to understand details that would be clear if watching a real race.

It would help to see pictures of gray streamlines running around the car or coming out from the diffuser, as it happens in the track when it rains or the car crosses a stretch of gravel or dust.

Anyway, the 2017 season is over and "the emperor has no clothes" so here are some images of the underfloor of the MP005B.

Image