Parametric Racecar Aerokit design [MVRC]

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machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 2:39 pm

And there we have it; the progression from my car to Idadox to Variante and then onto Matteo (CAE Device) is really quite startling in terms of diffuser performance. Thanks for sharing Matteo.๐Ÿ‘

Matteo, your car still shows good inflow from the sides... I wonder how much more flow you could get through the diffuser side channels if you employed a nicely radiused floor edge?
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rjsa
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Re: Parametric Racecar Aerokit design [MVRC]

Post by rjsa » Sat Dec 23, 2017 2:51 pm

Just wow.

CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Sat Dec 23, 2017 3:54 pm

machin wrote: โ†‘
Sat Dec 23, 2017 2:39 pm
And there we have it; the progression from my car to Idadox to Variante and then onto Matteo (CAE Device) is really quite startling in terms of diffuser performance. Thanks for sharing Matteo.๐Ÿ‘

Matteo, your car still shows good inflow from the sides... I wonder how much more flow you could get through the diffuser side channels if you employed a nicely radiused floor edge?
Hi Richard, which edge? I have to say that my future developments are oriented to a reduction of the flow from the sides, and that the amount of air (and velocity) you see under the car is not very dependent on the diffuser performance. My diffuser is quite "raw" and I will develop it next year (see JJR diffuser as an example of a good diffuser).

Btw: In case we will switch to a an open wheels layout, I think I will have an advantage since my car is simply a covered wheels evolution of the F1-like car I used in KVRC2015.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 4:55 pm

CAEdevice wrote: โ†‘
Sat Dec 23, 2017 3:54 pm
My diffuser is quite "raw"
That's you being too modest again... :wink:

It is probably the best diffuser in the competition at the moment.... but below is what I meant (essentially a copy of Variante's floor sides)... you can see there is air flow coming from the sides on your car, despite the fact it has to navigate around your sharp floor edge... with a smoother edge to flow around you might get more flow:-

Image

What is your thinking behind reducing flow from the sides?... my understanding is that the performance of the floor is all about getting as much flow as possible (mass per second) through the "throat" area... wherever it comes from....
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machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 5:06 pm

For reference, here is the underfloor velocity distribution on my car; there is a much lower velocity of air coming from the sides of the car:-

Image

Now THAT is a proper "raw" diffuser! I just submitted something that looked OK; there was absolutely no testing or refinement at all.... :lol: :lol: :lol:
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CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Sat Dec 23, 2017 5:16 pm

Yes the diffuser of your car is less refined than mine, but mine is actually raw (it is not modesty). The side channels (140-160mm) are there only to isolate the central region from the wheel disturbing action. The front wing is the origin of the good performance of the floor and diffuser.

The shape of my front wheels cover generates an higher pressure gradient above and below the floor, this increases the side airflow but als the quality of the air that goes under the floor from above: it is full of vortices (highly energised). A rounded edge would increase the flow but would reduce the vorticity. There is not a unique strategy, the best thing to do is to choose a reasonable concept and to refine it.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 5:20 pm

...and so far you definitely appear to have the most refined design overall!
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CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Sat Dec 23, 2017 5:23 pm

machin wrote: โ†‘
Sat Dec 23, 2017 5:20 pm
...and so far you definitely appear to have the most refined design overall!
Thanks! I am proud to say that the CAD model I am using (Solidworks sldprt) is exactly the same I modeled in 2015 (that horrible and slow car), the evolution has been done "parametrically".

Before MVRV 2016 I was fashinated by TF layout and by its good 2016 performance and tempted to design the new car from zero, but I dedicate some weeks to study it and I decided to go on with the original idea (the high nose for example was in my 2015 car but not in the 2016!).

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 7:00 pm

It is interesting to compare your "Works" car to my "Intro" car... they are outwardly very similar (except the nose), but the difference, as you say, is mainly step by step evolution and refinement of the working surfaces. We saw it last year with RicME (Brooke Motorsport)'s car; externally there didn't appear to be much difference, however he made big progress by small steps.

I am interested to know on average how many different iterations you top guys try between races and also typically how much you change for each iteration?
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CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Sat Dec 23, 2017 7:08 pm

machin wrote: โ†‘
Sat Dec 23, 2017 7:00 pm
It is interesting to compare your "Works" car to my "Intro" car... they are outwardly very similar (except the nose), but the difference, as you say, is mainly step by step evolution and refinement of the working surfaces. We saw it last year with RicME (Brooke Motorsport)'s car; externally there didn't appear to be much difference, however he made big progress by small steps.

I am interested to know on average how many different iterations you top guys try between races and also typically how much you change for each iteration?
About 70-80 iterations: half of them before the beginning of the season.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 7:17 pm

So maybe... 8 between each race?
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CAEdevice
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Re: Parametric Racecar Aerokit design [MVRC]

Post by CAEdevice » Sat Dec 23, 2017 7:29 pm

machin wrote: โ†‘
Sat Dec 23, 2017 7:17 pm
So maybe... 8 between each race?
Yes, I confirm (less than the previous year).

rjsa
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Re: Parametric Racecar Aerokit design [MVRC]

Post by rjsa » Sat Dec 23, 2017 8:51 pm

I added the U near plot to my post.

machin
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Re: Parametric Racecar Aerokit design [MVRC]

Post by machin » Sat Dec 23, 2017 10:58 pm

Nice. Seeing these images is so cool. Sometimes I fear that the MVRC might be seen as a mere styling exercise... These images show just how much work goes into the cars. ๐Ÿ‘๐Ÿ‘๐Ÿ‘
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variante
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Re: Parametric Racecar Aerokit design [MVRC]

Post by variante » Sun Dec 24, 2017 1:47 am

Absolutely impressive how Matteo (CAEdevice) manages to use the central area of the diffuser... you can really see how he managed to reach those levels of aero efficiency that earned him the championship title. That zone is limited by the presence of the transmission, yet it is the one that is giving him the greatest performance. My guess is that he is pumping tons of air from the front wing, and still managing to extract it thanks to vortices that are counter-rotating to those that are closer to the wheels. I always avoided that situation, fearing that those vortices would take away energy from the main ones, for a negative net balance...but apparently I was wrong (as long as this is the right interpretation...).

Machin, it is now up to you to develope your car to that level, and showing everyone the necessary steps ;)