(KVRC) Variante

Post here information about your own engineering projects, including but not limited to building your own car or designing a virtual car through CAD.
variante
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(KVRC) Variante

Post by variante » Tue Jun 18, 2013 2:15 pm

I created this topic to share with you the evolution of my CAD model of an F1 car, some CFD images obtained from it, and observations or explanations about how an F1 car works.

I'll try to make this topic as interactive as possible, which means that if you have any suggestion, question about the car, or request about some specific CFD images, please, don't hesitate.

BTW, Variante is one of the teams participating to the KVRC championship, an online challenge focused on the evaluation of the aerodynamics of CAD models whose design is based on FIA F1 technical regulations.

Image

variante
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Re: (KVRC) Variante

Post by variante » Tue Jun 18, 2013 2:54 pm

First, an introduction to the 2013 car:
Image
at 290km/h it produces more than 11000N of downforce, which translates into a coefficent of lift (Cl) of -3. The coefficient of drag (Cd) is 1.5
For comparison's sake, nowadays an F1 car has a Cl of 4.5 (more or less), and far greater efficiency than my car. However, keep in mind that actual F1 cars can exploit ground effect and exhausts' gases much more than us participating to the KVRC.
Also, since my car wasn't originally designed with the help of any CFD software, it doesn't take into account vortex control; this is a target for the next season.

Last round of this season is Silverstone. This is a chart of the circuit (provided by Machin of "Competition Car Engineering"). It tells us which aero configuration we need to achieve which laptime.
Image
Initially the efficiency of my car was around 2, a number represented by by that black line. What i have to do, in order to improve my laptime, is to follow that line until it reaches the maximum distance from the 1:33 laptime; and from that point i tried to increase the efficiency of the model as well, getting rid of all the bits with efficiency lower than 2.
I therefore came up with this:
Image
let's hope it does a good job...

machin
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Re: (KVRC) Variante

Post by machin » Wed Jun 19, 2013 7:28 am

Excellent work! looking forward to seeing how you get on. The only risk with taking this approach to the extreme (which I'm not suggesting that you have) is that I suspect you won't get an efficiency level of 2 at low downforce levels; as you take wing off the (in)efficiency of the open wheels/tyres will begin to dominate and your overall car efficiency will fall...
COMPETITION CAR ENGINEERING -Home of VIRTUAL STOPWATCH

astracrazy
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Re: (KVRC) Variante

Post by astracrazy » Wed Jun 19, 2013 9:17 am

you seem to have done the same as what i did in the sense of removing bardge boards. I couldn't get them to work

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Re: (KVRC) Variante

Post by RicME85 » Wed Jun 19, 2013 11:51 am

no point having parts on the car if you cant get the to work as intended.
will be interesting to see how this goes at Silverstone.

astracrazy
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Re: (KVRC) Variante

Post by astracrazy » Wed Jun 19, 2013 2:58 pm

1 thing i would say is you should prob test your car at the 100mpg 3 deg angle and improve your car from that. you quoted it produces 11000N of downforce at 180mph but to be honest its not relevant because its not where its needed.

Its just a suggestion and something i do. Obviously your car is better than mine so i can't preach, but you may find more performance where its needed if you analyse your car in the state where downforce is relevant. You'd be surprised, even at a 3deg angle, how it effects flow around some areas of the car.

you see at your rear air is being pulled back in towards the diffuser. but you need to make sure that happens at a 3 deg angle at 100mph (one side it will anyway but the other, the ways its turning, may not). I had trouble with my car to achieve this and when i got it to work, it made a good improvement.

of course you may already do this

variante
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Re: (KVRC) Variante

Post by variante » Thu Jun 20, 2013 1:22 pm

@astracrazy
thanks for the tip. I haven't done that already because the loss of downforce in the 3° scenario is only 1 or 2%, but that's for sure something to focus on next season. And i think bargeboards will play an important role for that purpose, so i guess we'll have to reintroduce them (they seem to have an enormous amount of functions anyway).
But, as Ric says, there's no point having parts that we can't get to work properly, so for the moment bargeboards are out of the game.
machin wrote:as you take wing off the (in)efficiency of the open wheels/tyres will begin to dominate and your overall car efficiency will fall...
to avoid that i took away only wings with enormous AoA as well as Gurney flaps (whose efficiency is not helped by the restrictive mesh size); on the other hand, i kept intact all those elements interacting with the wheels, such as the cascades (that i even increased in size). ...but of course the interactions are so complicated that only the CFD analysis will be able to say whether i did right or not.

(BTW, I could do a small analysis "with cascades VS without cascades". I find that comparison very interesting)

variante
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Re: (KVRC) Variante

Post by variante » Wed Jan 22, 2014 11:56 am

Hi everyone, i present you the third generation of Variante F1 cars, designed specifically for the 2014 Khamsin challenge.

It reflects 2014 FIA regulations changes, so you can have an idea on how the actual F1 cars, that will be revealed in the next days, will look like.

Image

Image

Image

Image

It was designed using Google Sketchup and with the help of the Khamsin CFD plugin, in which this full car was tested about 30 times.

As usual, if you have any question or request, don't hesitate asking!

CAEdevice
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Re: (KVRC) Variante

Post by CAEdevice » Wed Jan 22, 2014 12:15 pm

Congratulations, I can see a very detailed control of the flows. I thought it was easier to draw my version, however I still have values ​​too low downforce ...

astracrazy
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Re: (KVRC) Variante

Post by astracrazy » Wed Jan 22, 2014 12:17 pm

looks good mate. I can see one or two exploits of the rules as well

have you reduced the width of the floor?

30 times :shock:

variante
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Re: (KVRC) Variante

Post by variante » Wed Jan 22, 2014 1:45 pm

Thanks guys, can't wait to see yours!
CAEdevice wrote:...however I still have values ​​too low downforce ...
non ti buttare giù :D
too low compared to what? obviously any of our car will be far away from the actual F1 cars... Also, the new mandatory wheel/suspension complex, despite being more realistic, cuts a lot of downforce compared to last years'. With the old complex i managed to reach the same DF levels of the last season, while with the new one i'm scared of the result as well...

@astracrazy: nope, the width of the floor is the maximum allowed...must be a trick of perspective. And yes, 30 full runs in the CFD, but i wish i had the time for 300 runs... I got the chance to work on a some vortices, but the target was to get full control on all of them... Maybe next season...

CAEdevice
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Re: (KVRC) Variante

Post by CAEdevice » Wed Jan 22, 2014 1:56 pm

I don't have any other reference than this http://www.khamsinvirtualracecarchallen ... d-analysis ...
My target is (in the maximum downforce configuration) to obtain 60% of that values, but I'm quite far from it.

Complimenti ancora per la macchina :)

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Re: (KVRC) Variante

Post by CAEdevice » Wed Jan 22, 2014 2:37 pm

Hi Variante, I'm curious about the pillars that connect the nose to the front wing (by the central section): are they incomplete?

variante
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Re: (KVRC) Variante

Post by variante » Wed Jan 22, 2014 3:01 pm

The pillars are the definitive ones, unless i'll get some more time to refine them (why do they seem incomplete?).
Actually i'm proud of them because the car Force India just presented (which also has the Blanchimont nose) seems to have the very same solution.

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Re: (KVRC) Variante

Post by CAEdevice » Wed Jan 22, 2014 3:10 pm

I asked because it seems that the connection area between the pillars and the central section is very very small, from the images at least