Khamsin Virtual Racecar Challenge 2015

[cdsavage]

New draft rules package available here: http://www.khamsinvirtualracecarchallen ... lenge-2015. Files will be available from the KVRC website going forward. As the competition gets started, hopefully the website will be a bit more active compared to previous years.

A number of small tweaks have been made to the rulebook, but the guide files have also been updated this time. Also included in a separate file are the wheels and actual suspension members (rather than the suspension volumes), which don't have any bearing on the regulations but these parts will be used in CFD testing.

As we're getting pretty close to the definitive rulebook release, I'm keen to get more input on the dimensions of the diffuser - it's allowed to be quite big currently, but we're undecided on whether to change this.

[MadMatt]

Sorry for being annoying, but regarding rule K2.1 you say "The side impact structures may be moved rearwards as a group by no more than 350mm, and the upper impact structure may then be moved downwards no more than 200mm."

Does that mean we can still move the upper structure down by 200mm eventho we don't move both structures rearward? It is the "then" that bothers me.

Regarding the diffuser I think it will be fairly big COMPARED TO LMP1 cars of those days, but do we want to have identical cars? I think it is good to see relatively big diffusers, rather than the cheap ones we see in F1.

I am however still a bit confused about the Surface A thing because of "the area specified by the rear bodywork height template and the flat floor template". Could you define this area a bit better? Is it viewed from above? Then it doesn't make sense because the height template and the floor template almost not overlap. This is how I understand it: "Surface A is the surface formed by any bodywork visible from below, covering the area of the rear bodywork height template. Surface A may not contain any holes and must be no more than 360mm above the reference plane."

Again English is not my native language to pardon me if I make less sense than what you wrote in the rule book!

Also one last thing, the front wheels are too wide imo to be realistic. With the bodywork clearance, turning the wheels will be impossible, so maybe for realism we could reduce a bit their width but keep the outside face at the same distance from the car centreline?

[cdsavage]

Sorry for being annoying, but regarding rule K2.1 you say "The side impact structures may be moved rearwards as a group by no more than 350mm, and the upper impact structure may then be moved downwards no more than 200mm."

Does that mean we can still move the upper structure down by 200mm eventho we don't move both structures rearward? It is the "then" that bothers me.

Good call, I need to change this wording so that the rearward movement and downward movement aren't linked together like they are.

Regarding the diffuser I think it will be fairly big COMPARED TO LMP1 cars of those days, but do we want to have identical cars? I think it is good to see relatively big diffusers, rather than the cheap ones we see in F1.

I am however still a bit confused about the Surface A thing because of "the area specified by the rear bodywork height template and the flat floor template". Could you define this area a bit better? Is it viewed from above? Then it doesn't make sense because the height template and the floor template almost not overlap. This is how I understand it: "Surface A is the surface formed by any bodywork visible from below, covering the area of the rear bodywork height template. Surface A may not contain any holes and must be no more than 360mm above the reference plane."

Again English is not my native language to pardon me if I make less sense than what you wrote in the rule book!

If you view these templates from below, the rear edge of the flat floor template lines up with the front edge of the rear bodywork height template. It's the entire area formed by theses two templates viewed from below that is used for this rule. Surface A is then whatever bodywork is visibile from below within this 2D area.

There might be some confusion caused by the fact that the rear bodywork height template is offset in Z, but for this rule you should ignore the Z position of the templates, we're only interested in the 2D outline they form when viewed from below. Would it help if we included a separate template for this?

If we didn't include the flat floor template in this rule like you wrote, then there would be a possibility to have a slot in the floor right at the junction between the floor and the start of the diffuser.

Also one last thing, the front wheels are too wide imo to be realistic. With the bodywork clearance, turning the wheels will be impossible, so maybe for realism we could reduce a bit their width but keep the outside face at the same distance from the car centreline?

Agreed there is not enought space for the wheels to turn, however we chose to ignore this aspect to keep things simple. In absolute terms I think the dimensions of the front wheels are fairly realistic, if anything the rears could be a little wider, but we want to keep plenty of free space for the diffuser.

[CAEdevice]

I think that the diffuser is well dimensioned (at first I thought it was too big, but after some simulation on a simplified model I found the car quite balanced).
Anyway I have a suggestion about it: you could reduce the maximum height from 360mm to 300-320mm but at the same time referring the "no double diffuser" rule (plane normal to X intersecting surface A) only to an area as wide as the flat floor template (= more design possibilities behind the rear wheels).

I also have a question about the physics of the car: wich COP value will be considered? How is COP computed in the CFD simulation?

[MadMatt]

I also think there should be a maximum distance from the FWCL where the rear view mirror has to be, because in the current situation it could be placed at the rear of the side window which doesn't really make any sense

CAE already simulating, there will be some challenge hehe

[cdsavage]

referring the "no double diffuser" rule (plane normal to X intersecting surface A) only to an area as wide as the flat floor template (= more design possibilities behind the rear wheels).

The x-axis intersection rule is gone, it's now just specified that surface A cannot have holes or overlaps (since an overlap would 'shadow' part of the surface, so it would produce a hole in surface A).

Let me think about your suggestion. There shouldn't be too many restrictions on the area behind the rear wheels since the rule only applies to bodywork visible from below.

I also have a question about the physics of the car: wich COP value will be considered? How is COP computed in the CFD simulation?

All of this will be detailed after the final rulebook release, but the COP calculation method should be no different to 2014.

I also think there should be a maximum distance from the FWCL where the rear view mirror has to be, because in the current situation it could be placed at the rear of the side window which doesn't really make any sense

Are you using the latest guide file release? I made a change to bring the rear of the visibility template forward a bit for this reason.

Are the rules on surface A clear enough? I will try to re-word this rule if it's still confusing.

[MadMatt]

Yes Chris now surface A is clear enough.

Regarding the mirror, is that correct to say we cannot move the template you've provided? K2.1 says we cannot move that mirror template. I think the confusion is with the "reflective surface". Is it the mirror (cover)? The 4th rule says we can position it freely (with 2 exceptions) but it has to enclose the provided mirror template, right?

[cdsavage]

Regarding the mirror, is that correct to say we cannot move the template you've provided? K2.1 says we cannot move that mirror template. I think the confusion is with the "reflective surface". Is it the mirror (cover)? The 4th rule says we can position it freely (with 2 exceptions) but it has to enclose the provided mirror template, right?

K2.1 isn't stating that the mirror template can't be moved - maybe the confusion is the sentence at the end, "These parts may not be moved, rotated or altered in any other way" - emphasis on the word "other", meaning you can't move or alter these parts other than what's allowed in the bullet points above. The mirror template, exhaust templates and cooling inlet templates can all be moved according to their individual rules. Maybe it would be best to remove that last sentence in K2.1.

The mirror template that we provided is the minimum area for the reflective surface. There are no templates or special rules for the mirror 'cover', this is just considered as bodywork.

[RicME85]

I have just started to put together the supplied parts into my own file and started to work on a basic shape for my challenger.
Just to clarify, the floor, is it only the green area that has to be flat? Can I raise the floor in the other areas, like at the leading edge like current LMP cars to get air underneath?

[cdsavage]

I have just started to put together the supplied parts into my own file and started to work on a basic shape for my challenger.
Just to clarify, the floor, is it only the green area that has to be flat? Can I raise the floor in the other areas, like at the leading edge like current LMP cars to get air underneath?

Correct, only the green floor template has to be flat.

[RicME85]

Can anyone remember the official FIA regulation for the front of the floor of an LMP car in recent years?
IIRC they included a rule which gives that raised central section.
Just wanted to have a look at some actual LMP regs for that part of the car to make it look realistic

[RicME85]

Ok, now I am a little confused by K3.1.
I know it was reworded slightly recently but it still confuses me
"the shape(s) must be at least 24000mm^2 in total area. The shape(s) must be at least 100mm wide and at least 100mm  high." 

I dont get why it says at least 100mm high and wide as that is less than the permitted area.
Or am I reading this wrong?

[cdsavage]

Ok, now I am a little confused by K3.1.
I know it was reworded slightly recently but it still confuses me
"the shape(s) must be at least 24000mm^2 in total area. The shape(s) must be at least 100mm wide and at least 100mm  high." 

I dont get why it says at least 100mm high and wide as that is less than the permitted area.
Or am I reading this wrong?

The width can't be less than 100mm and the height can't be less than 100mm. So a shape 80*300mm or 300*80mm would be illegal, but 100*240mm or 240*100mm is ok, even though they all meet the minimum area.

[RicME85]

Ok, thanks

[cdsavage]

Just a heads-up since you're working on the front of your car - in the next release the minimum front crash structure area will be 25,000mm^2, and the plane is at 750mm ahead of the FWCL instead of 700. We hopefully wont be making too many more changes from here on.