Khamsin Virtual Racecar Challenge 2014

[RicME85]

Shifty you have no idea what is what and just spouting rubbish.

Julien created the Khamsin plugin for Sketchup and takes no money, he gives his time to putting the cars through their simulations with cloud computing as well as giving us 1 to 1 advice on how to use his plugin and the associated software.

Luke aka astracrazy takes no money, he gives his time for free to check the submitted designs for legality before passing them to Julien.

Why is there no sponsors this year? No idea but I bet its not for want of trying. Cant expect from CPU time donated from a cloud company every year.

[Schifty]

Have you never ask to yourself why the best designer never join the challenge? Because yes a lot are in this forum, i saw a lot of great 3d design of speculation of 2014 nose design... or just here in this categorie the Ferrari 2014 was modelled? They know its not needed to put any money to calculate anything... thats why they didnt join this challenge

[RicME85]

No I havent asked myself that because I know not everyone has the time or interest to participate.
Not everyone has a computer at home capable of running the software to an accurate enough level so cloud computing IS need.

Oh and the F14T in Maya is completely different. Its one thing modelling something in 3d using reference images, its another designing something from scratch to the millimeter.
A lot of 3d models arent to scale because of the way they are drawn against images, this can be seen with cars from mod packs for games like Grand Prix 4.

[CAEdevice]

I think that al least two high level designer are taking part to the challenge.

I'm not obtaining great results, but I can define myself an expert designer, FEM and CFD analyst: I've never designed a F1 car, but I have exprience with some complex machinery, in industrial and aerospace field (even more complex than a f1...).

[Schifty]

If he want money to pay his cpu time, its need to be as donation not has entry fee...

[cdsavage]

Have you never ask to yourself why the best designer never join the challenge? Because yes a lot are in this forum, i saw a lot of great 3d design of speculation of 2014 nose design... or just here in this categorie the Ferrari 2014 was modelled? They know its not needed to put any money to calculate anything... thats why they didnt join this challenge

On this point I can speak from experience to some degree... last year I modeled a number of very complex aerodynamic pieces, which by my own testing, were giving me a benefit. The limit on computation resources though means that the mesh size for the competition has to be fairly low (which I didn't take into account in my own testing), and as a result any small details just get meshed over and have no real effect on downforce and drag. As a result there's no point in modelling to a very high level of detail.

One other thing I have experienced is that a complex model works against you in the ability to make quick changes. It pays off to have a simple model, with which you can easily make many variations and test each of them, rather than spending time on one, complex model.

[Schifty]

No I havent asked myself that because I know not everyone has the time or interest to participate.
Not everyone has a computer at home capable of running the software to an accurate enough level so cloud computing IS need.

Oh and the F14T in Maya is completely different. Its one thing modelling something in 3d using reference images, its another designing something from scratch to the millimeter.
A lot of 3d models arent to scale because of the way they are drawn against images, this can be seen with cars from mod packs for games like Grand Prix 4.

Easy to get our own reference image and after that modelling it. Took a paper, with a rule, draw your car has you want, scan it or take a picture of it. Put it in your 3d software and use your drawing has a reference to modeling your our car....

[RicME85]

still just clutching at straws there mate and not noting what Im saying

[Schifty]

still just clutching at straws there mate and not noting what Im saying

You said that F14T is completly different because he use reference image to get this result. You can do the same thing, like i said, you think how was maded first F1 car before the computer was enough strong to carry any kind of modeling or calculation....

[astracrazy]

What are you actually doing here?

If julien wanted money for doing it he would of wanted it last year. If he wanted money we wouldnt offer the remaining back as a prize

If it was a donation it would imply its not required. It was required so its an entry fee. Everyone had the option to pay per race or up front.

The cost was one of the first things discussed about 2014 and even test calculations were given on the 2013 thread. Everyone was happy. It was made clear costs would be involved. We expected $50 but julien got it down less. Why would he do that if it was for him when we already had interest?

[N12ck]

@Schifty May I comment upon this subject, I myself have experience in designing racecars and working in CFD for a few years now, can I just add that last year when the challenge was ran, it was ran with CPU time supplied by sabalcore as a sponsorship, this sponsorship is no longer existent, to run simulations on a HPC suite costs money, you only have to research this yourself. CFD simulations of this quality can take many hours as I myself experience day to day in my own CFD activities.

To continue the challenge without any sort of HPC sponsorship would leave the people who spend their time working on it day by day at a loss, so there would be not much point in simulating other peoples ideas with yourself loosing money, so to allow HPC to be used for the simualtions to allow the fast turn around time, an entry fee needed introduced as if the people who are in this competition wanted to simulate their own cars on a HPC suite it would cost anyway, and not all computers/ laptops can run these sort of simulations very quickly.

So I would say to your prejudice that the people who run it are gaining money from this is on a very very wrong assumption indeed and seems to be from someone with not a lot of experience in CFD, that is OK, however please double check everything before sounding your mouth off on a forum page which is intended to allow people to learn about other peoples designs, what works and what doesn't.

You yourself are not happy to pay the entry fee, but just because you aren't happy doesn't mean others aren't, so please, stick to technical content about this than abusing those who run it.

[variante]

You said that F14T is completly different because he use reference image to get this result. You can do the same thing, like i said, you think how was maded first F1 car before the computer was enough strong to carry any kind of modeling or calculation....

That F14T is an awful example... It looks cool, and it's clearly the product of an expert 3D modeller. However, looking at the details, it is clearly noticeable how relatively poor the aero effectiveness of that model is (i don't know if that was made on purpose...maybe it's simply an aesthetics exercise...). An example? It has no airfoils...
Basically, that model would never win this challenge. Thus the equation "nicely designed model=winning model" is not necessarily true!

[astracrazy]

So moving on and back to positive stuff

[RicME85]

Thanks to Julien I can now run simulations remotely so I can carry on working on my pc without lag

[machin]

Thank you for the detailed answer!

Yes, I'm just extimating the maximum speed for fun (to compare my car to the real 2014 GP cars). I mean an absolute max speed (imagine to have an infinitely long straight and flat road).

I used to extimate it with this formulas:

Power@MaxSpeed = Drag_Force * MaxSpeed (I should consider also a trasmission/wheels efficency, about 90%)
Drag_Force = 0.5 * Cd.A * MaxSpeed^2

MaxSpeed = (Power@MaxSpeed / (0.5 * Cd.A))^(1/3)

Considering that Monza principal straight segment is very long (and the initial speed, after the Parabolica, is quite high) I wondered if real F1 will plan to use the electric power at the end of this straight segment or during the acceleration.

Nearly there... the drag equation should include the air density (rho), i.e.

Drag_Force = 0.5 * rho * Cd.A * MaxSpeed^2

Personally I account for the rolling resistance of the tyres using another equation and keep it separate from the transmission efficiency:-

Rolling_Res = Crr.W

where Crr is the coefficient of rolling resistance and W is the weight of the car (incl. downforce).

Is there a chance we might see more data than the lap time? What's the chances of a speed/acceleration trace being made available? Admittedly, it doesn't tell more than the graphs you've produced, but it's some data to mull over.

My version of Virtual Stopwatch (which is excel based) does this, but the version I have made available to the championship (which is html based) has a pure lap time output; mainly because I haven't learnt how to generate graphs in real time using html (yet!). In all honesty whilst a speed trace might be cool to look at I think it could simply add to confusion; as you say; the goal is best lap time and the best tool to determine the set-ups is the (relatively) simple charts I've produced showing Cd.A and Cl.A vs laptime.... It is worth noting that the google-maps generated lap animation on the KVRC website is only accurate for the time when the cars cross the finish line; all the car positions from start line up to the finish line are not generated by Virtual Stopwatch and have been created by the KVRC guys with some randomisation to add suspense to the final result, i.e. the mid-lap positions are essentially random.

How are people's cars coming along for Monza? Anyone trying anything different?