Khamsin Virtual Racecar Challenge 2015

[machin]

Variante, I do understand the problem, and have your sympathies that you may be one of those who has the most changes to make to their car... In truth Chris and I discussed this issue when the cars were first revealed prior to the first race, and Chris sensibly made the suggestion that a rule change would be proposed for later in the year when we made the transition from high to lower downforce rounds.

Chris originally aired the idea of a change to the sidepod rules after the first round (I forget now which page it is on in this discussion), and I don't remember anybody being against the idea (quite the contrary), which I guess is why Chris has gone a little further and proposed some actual rules with numbers.. again to see what the concensus is.

I applaud Chris for how this has been handled; always in an open way and always seeking the approval of the competitors.

A simple vote is a good way to gauge the concensus and is probably the route Chris was going to take...

(On the plus side Variante, you are clearly one of the more able competitors; a rule change half way through the season probably plays to your favour because you'll be able to come up with a good solution very quickly! )

[CAEdevice]

I'm favorable to every change to the rulebook, but I can uderstand the difficulties of Variante who has developed e much more efficient car than mine.
I think that working with a tool like SketchUp could make changes more difficult to manage, compared to a professional CAD. Anyway: for the last races (medium DF), my car needs to be completely redesigned (it has good DF but low efficiency).

I have two doubts about the draft:

PROPOSED: ​At any individual position along the length of the outer template extrusion, the entire span of the extrusion in the X­axis must either be entirely
visible from above or entirely visible from below. The front suspension templates are ignored for this requirement.

What does this mean actually?

The K4.2 outer templates are the volume(s) formed by an extrusion of each outlet surface rearwards for a distance of 1000mm. Within the first 800mm of
these extrusions (outer templates 1) there must be nothing but empty space (no bodywork or other templates). Within the last 200mm (outer templates 2)
there must be nothing but empty space or rear suspension templates. No part of either template may be located in the wheel wells, however these
templates are otherwise not required to lie entirely within the regulation volumes.
● The K4.2 inner templates are the volume(s) formed by an extrusion of each outlet surface forward for a distance of 300mm. These templates must be
entirely enclosed in bodywork and must not intersect any other parts or templates, with the exception of the rear suspension templates.

It looks odd that the internal template can intersect rear suspension and the outer (mostly) not:I think I have not understood completely the "physical" meaning of the templates.

[CAEdevice]

Two question about the last races:

1) The solver (OCCFD) will still be developed? I'm trying to use it without success for the first three races. I can consider to come back to last year solver.

2) The "lap charts" will be released?

3) Wich of the last three races will bring no points?

[machin]

Regarding Q2; I had intended on swapping the track data on the basic Virtual Stopwatch page to a more representative test track straight after the 3rd round; I presumed people may still want the high downforce track until that point?

We are also playing around with a slight power adjustment to get a nice balance between drag and downforce, so at the moment the input data isn't quite finalised....

[CAEdevice]

Regarding Q2; I had intended on swapping the track data on the basic Virtual Stopwatch page to a more representative test track straight after the 3rd round; I presumed people may still want the high downforce track until that point?

We are also playing around with a slight power adjustment to get a nice balance between drag and downforce, so at the moment the input data isn't quite finalised....

Thanks. I was referring to the graphs that where uesed last year to "tune" the cars.

[CAEdevice]

Hi everybody! I'm leaving for 3 weeks to have some training, to visit some customers and to... have a holyday week at the sea

The development of my car for the third race has been done in only two days. I had not enough time to introduce big changes (only new rear wing and new engine cover to solve some minor issues with the rulebook. My target is to confirm the 4th place of the Monaco race and then to be back with some new and fresh ideas.... and win the last three races!!!

Thank you everyone for all the fun, expecially to Chris, Julien and Machin! See you in July

Here is my latest car update:



Bye!

[machin]

Regarding Q2; I had intended on swapping the track data on the basic Virtual Stopwatch page to a more representative test track straight after the 3rd round; I presumed people may still want the high downforce track until that point?

We are also playing around with a slight power adjustment to get a nice balance between drag and downforce, so at the moment the input data isn't quite finalised....

Thanks. I was referring to the graphs that where uesed last year to "tune" the cars.

This year we won't be providing the graphs; only the Virtual Stopwatch test track... I'll do a post on my [KVRC~ish] topic on how I would go about using Virtual Stopwatch to tune my car for the medium downforce rounds.... Maybe in a week or so....

(Updated car looks good BTW!)

[TalnoRacing]

Hi guys,

Sorry to disrupt the conversation on the proposed rule changes, but I am really stuck with running an OCCFD simulation and don't know how to fix it. I continue to get the error "tool pvbatch can not be found". It then shows "block in checktools".

After the first installation I deleted all the different software and reinstalled them all, in the same sequence as what they are listed on the KVRC website and exactly in the same folders as listed on the website. I am running Windows 7 Service Pack 1, which is compatible with the different software.

I am really desperate for a solution and appreciate any help.

Arno

[cdsavage]

To decide whether this rule change proposal is adopted or rejected, we will adopt a more formal voting process, following these steps:

1. A rough rule proposal will be posted in this thread. This has already taken place in this case.
2. If the rule proposal is not strongly opposed, a proposed set of regulations will be published. This step has also already taken place.
3. Feedback on this proposal will be sought through email. We will ask for your preference for:
   a) adopting the proposal as-is,
   b) changes to the proposal, or a different rule change, and what this change would be,
   c) no changes to rulebook whatsoever.
   These emails will go out shortly. Apologies for annoying everyone through email, but it would be best to make sure we get the chance to hear from every competitor.
4. Around June 16, The proposal will be updated based on the feedback, and a final vote on the proposal will be sought through email. We will ask for a preference either to adopt the new proposal, or to make no changes to the rulebook. The vote will be open for one week, and of those who respond with a yes or no vote, the majority preference will be adopted.

PROPOSED: ​At any individual position along the length of the outer template extrusion, the entire span of the extrusion in the X­axis must either be entirely
visible from above or entirely visible from below. The front suspension templates are ignored for this requirement.

What does this mean actually?

The wording here is not very clear, I'll post an image to show what I mean. If this change were to go ahead I think it would need a lot of input from everyone. It might require removing both side impact structures. It's an attempt to regulate against some possibilities under the current rulebook where the inlet can be unrealistically 'shrouded', which would become more relevant in the lower downforce rounds - this hasn't been a big problem so far, but the general concept has been used on one entry.

The K4.2 outer templates are the volume(s) formed by an extrusion of each outlet surface rearwards for a distance of 1000mm. Within the first 800mm of
these extrusions (outer templates 1) there must be nothing but empty space (no bodywork or other templates). Within the last 200mm (outer templates 2)
there must be nothing but empty space or rear suspension templates. No part of either template may be located in the wheel wells, however these
templates are otherwise not required to lie entirely within the regulation volumes.
● The K4.2 inner templates are the volume(s) formed by an extrusion of each outlet surface forward for a distance of 300mm. These templates must be
entirely enclosed in bodywork and must not intersect any other parts or templates, with the exception of the rear suspension templates.

It looks odd that the internal template can intersect rear suspension and the outer (mostly) not:I think I have not understood completely the "physical" meaning of the templates.

The logic is that there's not really any difference in the local drag penalty whether the outlet surface is 300mm rearwards of the suspension templates, or 5mm rearward - in either case, the templates can be contained inside the bodywork. The inner template in this case just represents (mostly) empty space within the bodywork which the outlet flow will pass through.

The outer template has no real physical meaning, it is to ensure that the outlet is not obscured by bodywork or other parts. I think we could either make the outer template shorter, or the region which can intersect suspension templates could be longer. It would be good to get some more feedback on this.

Wich of the last three races will bring no points?

http://www.khamsinvirtualracecarchallen ... lenge-2015: Points will not be awarded for round 4. Rounds 5 and 6 are normal rounds.

[CAEdevice]

Thank you for the explanation.
For the next year I think we could work on much more detailed template of the internal parts, it would make easier to obtain realistic cars. I'm thinking about product configuration tools (es. the online cataloque of rexroth hydraulic cylinders ).

For this year, I think that Chris proposal is a very good idea (I would have liked to apply similar changes after the first race), but I'm going to choose the "no vote" option, since Variante is one of my direct opponents... and I'm not a fan of democratic management of technical question : )

[CAEdevice]

Hi guys,

Sorry to disrupt the conversation on the proposed rule changes, but I am really stuck with running an OCCFD simulation and don't know how to fix it. I continue to get the error "tool pvbatch can not be found". It then shows "block in checktools".

After the first installation I deleted all the different software and reinstalled them all, in the same sequence as what they are listed on the KVRC website and exactly in the same folders as listed on the website. I am running Windows 7 Service Pack 1, which is compatible with the different software.

I am really desperate for a solution and appreciate any help.

Arno

Try with Paraview 3.8 and check each version of the installed tools.

[RicME85]

I would definitely like to see an image or two of what these rules are proposing

[LVDH]

Hi,

my opinion on the cooling thing:

I have worked on various motor sport projects and always wondered about the cooling duct design.
After a certain period in Europe many aircraft engineers went to design race cars. These cars then had good duct design. The principles are now only found on few cars like F1.
So what is going on on modern cars now? For one people would be surprised to see how few engineers design and create race cars. If we are not talking about F1 or Le Mans it is very little. It seems there are guide lines on how to design the cooling ducts. These seem to be similar to what we see in the KVRC competition. Maybe after trying to follow these guidelines everything gets thrown overboard because of packaging reasons. In the end you have strange cooling ducts with massive separations, maybe even rearward airflow.

Here is a good link to get an idea on how a duct could be designed:
http://www.ch601.org/resources/cooling_systems2.htm

So what does this mean for KVRC?
Well maybe we could just define the radiator as a porous volume or baffle. Everyone has to design a cooling duct around it. The CFD tool monitors the air mass flow through it. Engine power then gets set according to the mass flow as a better cooled engine would be able to use more power.

We could do the same for the engine inlet as well. Monitor either total pressure or mass flow. More equals more engine power.

I think these suggestions make everything more complex, but it should help to create good and realistic designs.

[variante]

Well maybe we could just define the radiator as a porous volume or baffle. Everyone has to design a cooling duct around it. The CFD tool monitors the air mass flow through it. Engine power then gets set according to the mass flow as a better cooled engine would be able to use more power.

We could do the same for the engine inlet as well. Monitor either total pressure or mass flow. More equals more engine power.

I think these suggestions make everything more complex, but it should help to create good and realistic designs.

That would be simply great.
But yes, it would be much more complex. First, Julien should verify the feasibility of the thing and eventually implement a few things to the CFD tool. Then, someone should bother doing calculations about the impact of such air masses (and relative quality of) on engine performance.
If the two things are feasible, the competition would make a huge step forward.

[LVDH]

I am wondering what we will do during the winter anyways.
Maybe some cool futuristic vehicle and only something like three races.
There we could test the idea of setting engine performance related to cooling performance and lets say intake pressure.