[KVRC] Khamsin Virtual Racecar Challenge 2016

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machin
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Re: Khamsin Virtual Racecar Challenge 2016

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variante wrote:BTW, do you have exact data about tyres behaviour at different loads?
As I say, I have created a tyre model from many hours of testing real cars which I'm happy with and I think is suitable for the formula we're talking about. It is not meant to replicate a specific manufacturer's tyre... but I feel compelled to tell you that this tyre model already includes a slight decrease in coefficient of friction with increasing load which is quite common for pneumatic tyres (see link below for example)...

https://en.wikipedia.org/wiki/Tire_load_sensitivity

....So we already have a tyre which you could say is less kind to the high downforce configurations (although it is not that drastic a drop off in coefficient). What we're suggesting here is that there could (note emphasis) also be a load and time-based reduction in the coefficient to represent wear/tyre temperature over the lap. Is that more or less realistic than what we currently have? Well I would say its neither more nor less realistic, it just represents a different type of tyre than the one we're currently using which could simply be said to be one with a wide operating window and good wear characteristics..... as opposed to one with a narrow operating window and poor wear characteristics...

At the end of the day, it doesn't really change the challenge for you guys, it just changes slightly the "optimum" aerodynamic coefficients that you're aiming for and for that reason I don't think it is something that we need to worry too much about....
COMPETITION CAR ENGINEERING -Home of VIRTUAL STOPWATCH

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CAEdevice
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Re: Khamsin Virtual Racecar Challenge 2016

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Thanks again Machin!

I have a new suggestion. What about including the inlets/outlets of the brakes cooling ducts? I noticed that they are significantly large in lmp1 cars (especially the front ones).

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RicME85
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Re: Khamsin Virtual Racecar Challenge 2016

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I think adding in more tyre wear and engine changes (other than the idea for inlet/outlet size having an effect) isnt the right thing to do, think it would put KVRC into the realms of the jokes Formula Sketch and more GPRO than what KVRC was set out to do.
If you want to do those ideas I think it would need to be a few years down the line with a proper team that produced something like the front end of GPRO which utilises our cfd data to do full race distances along with pit stop selections so we can try and produce a car kind on tyres and push the laps done on a set.

Really i dont want to see KVRC go that way but its the only way i can see the ideas raised being a worthwhile inclusion.

Matteo - i like the brake duct idea. There inclusion in the supplied parts in previous seasons was a disappointment, i wanted to design them during the F1 rulebook years.

qwerty2459
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Joined: 09 Sep 2015, 02:51

Re: Khamsin Virtual Racecar Challenge 2016

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variante wrote: Hi!
I'm using SketchUp. It's free, very intuitive and lets you design very fast. I think it's the ideal choice for those who have never touched a CAD program. You'll need some plugins, however.
CAEdevice suggested the student edition of CREO, a serious CAD... Look for his post on the last page.
thanks for the reply! i do work as a structural draftsman, but i dont want to get too serious about it (i already see too many models in one day) :lol: so ill use sketchup. what plugins do i need btw?

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machin
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Re: Khamsin Virtual Racecar Challenge 2016

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RicME85 wrote:I think adding in more tyre wear and engine changes isnt the right thing to do, think it would put KVRC into the realms of the jokes Formula Sketch....
I'm not sure it does... regarding the fuel usage idea; the actual LMP1 rules already have a fuel flow per lap limitation: if the drivers exceed that fuel usage in any given lap then that lap time is cancelled (see table APPENDIX 4 – Article 65. E of the WEC Sporting regulations). That means you can pretty much guarantee that on the final straight before the finish line all cars will be increasing power output to ensure that the full fuel allocation is used (minus a little margin of course!); what we're suggesting as an option is that we could do the same thing: to make the KVRC more in line with the real LMP1; i.e. make it more realistic....

I just want to make another attempt at explaining how this actually affects the competition though, as it really isn't the big change that people think it would be:- Virtual Stopwatch has a whole host of different parameters "behind the scenes", all of which are used to determine the lap times when you add in your aero coefficients... When we moved to the second half of the season we decided to "play" with these parameters slightly; obviously the track data changed, but we also changed the engine power curve; this was done to promote a slightly more efficient car design than we would have had with the track change alone. Would people consider that to have been unrealistic? Many real racing series already impose power restrictions for different tracks (a direct air restrictor in Indycar at Speedways and slightly less directly via a change in fuel allowance per lap in the WEC for example) so it had a precedence set by real life, and therefore could be considered to be "realistic".

At the end of the day tyre characteristics, fuel usage, power curves, gear ratios, etc, etc, are all parameters that are open to us to achieve a desired trade-off between the aero-coefficients and lap time (Just as in real life; governing bodies such as the FIA, the ACO etc write rules and regulations to ensure that the cars achieve lap times within a certain performance bracket).

To the competitors it doesn't really matter which one (or more) parameters we change to achieve that desired trade-off between the aero-coefficients (instead of reducing power for the second half of the season, we could have changed the tyre characteristics to achieve the same effect in terms of aerodynamics vs lap time and the competitors would have been none-the wiser)....

... So when people say "could we allow a low drag car to make use of the extra fuel they are saving?", what they are in effect saying is "can we have a track (or tracks) which promote an even more efficient design than we currently have?". If that is the desire then the organisers and I will work together to achieve that desire: whether it be via selecting different tracks, or a change to one or more of the "hidden" parameters then it is up to us to achieve that, but rest assured that we won't do any changes to the parameters without giving the competitors sufficient time to take account of those parameters (most probably via the Virtual Stopwatch Test Track), and we won't change the parameters in such a way that we end up with counter-intuitive results (such as a low drag design being faster at Monaco than a high downforce one).

EDIT: and one thing I think we're all dead against is adding any kind of "randomness" to the results, so I'll never introduce random engine failures, tyre blow outs, or driver mistakes to Virtual Stopwatch, the lap time will always be a direct correlation to the technical inputs.

I hope that is sufficient explanation on this issue and we can now take it off-line.

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Gridiot
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Joined: 23 Jun 2015, 23:41

Re: Khamsin Virtual Racecar Challenge 2016

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As many already mentioned, keeping the current regulation through next year with only minor changes would be totally fine according to me, as I really think that there's plenty more to come from it.

For a more distant future, I would be in favor of tending towards what would be basically a total freedom. Just keep what makes the cars technically realistic (templates for cockpit, engine or suspensions, requirement for cooling, visibility volume, etc.) and then just define maximum dimensions with a box and leave all the rest totally free. No rule for the underbody/diffuser, no rear wing box or profiles limitation, no rule about covering or not the wheels or suspensions... I mean, it's an aerodynamic competition and there's no need to imitate any of the existing formula. It would be very interesting to see how cars could evolve without all the current rules which sole purpose is to avoid cars being too fast.
KVRC Team Kineuton

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CAEdevice
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Re: Khamsin Virtual Racecar Challenge 2016

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At the moment, the most important news/request about KVRC2016 would be... a stable masher and accurate solver!

@Julien: is there any news about the solver? I've found some windows porting for OpenFoam 2.3 or 2.4 (and I heard that OpenFoam 3.0 could be officially compiled for windows).

(https://sim-flow.com/download/openfoam-windows/ - http://www.cfdsupport.com/download-open ... ndows.html)

When you have something to test on a (local) hardware, I have an i7+64gb RAM waiting!

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variante
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Re: Khamsin Virtual Racecar Challenge 2016

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qwerty2459 wrote:
variante wrote: Hi!
I'm using SketchUp. It's free, very intuitive and lets you design very fast. I think it's the ideal choice for those who have never touched a CAD program. You'll need some plugins, however.
CAEdevice suggested the student edition of CREO, a serious CAD... Look for his post on the last page.
thanks for the reply! i do work as a structural draftsman, but i dont want to get too serious about it (i already see too many models in one day) :lol: so ill use sketchup. what plugins do i need btw?
Sorry for the late answer: i wasn't at home these days.
The only necessary plugin is called "Curviloft" from "Fredo6 Collection". While not as good as lofting tools you find on professional CAD, it does its job (if you like compromises...). I'm still waiting for an improved version of that plugin...it would make SketchUp much more enjoyable! Still, that's the way to go.

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RicME85
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Re: Khamsin Virtual Racecar Challenge 2016

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Curviloft is a good tool if you can get it to produce shapes that you are envisaging in your mind.
Sometimes it does some bizarre things, other times it doesnt lay the surfaces in the best way for a smooth surface because of the way it triangulates.
Still, wouldnt be without it and I find it much easier to work with than a proper CAD drawing software.

MadMatt
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Re: Khamsin Virtual Racecar Challenge 2016

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Having looked at the current 2015 regulations, my thinking is that for 2016 the design of the car will greatly depend on the cooling requirements. At the moment I think we are right between a "group C evo" look and a LMP1 look, but change in cooling sizes will move the balance on one side or the other! :)

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CAEdevice
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Re: Khamsin Virtual Racecar Challenge 2016

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Cooling and front suspension visibility will be very important...

I hope cooling will be more free, but with limits about the delta p*Area of the inlets/outlets

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RicME85
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Re: Khamsin Virtual Racecar Challenge 2016

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I find the boxy nature of the internal space if the cooling requirements can be really awkward when trying to produce a nice shape sidepod etc

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CAEdevice
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Re: Khamsin Virtual Racecar Challenge 2016

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I was thinking that the wheels are quite wide: what about 10% wheels width reduction, balanced by 10% reduction of the total mass and of the engine torque and power? Narrower wheels would allow more design freedom, expecially for the front axle.

MadMatt
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I disagree with reduction in wheel size, I think we have enough to play with already, but that's just my opinion :)

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CAEdevice
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MadMatt wrote:I disagree with reduction in wheel size, I think we have enough to play with already, but that's just my opinion :)
I agree, maybe only the 90% of the possible efficiency will be reached untill the end of the season, and only by 3 or 4 teams, but the option of changing the rules depends on wich car shape we would like to have in the future: LMPx or something like the Redbull/Mazda/Hyundai (virtual) prototypes.

Also consider that some advanced detailed design solutions (related to the vortex management) would be impossibile with the present mesh size (around the car and below the floor) and solver (steady state, not transient).

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