[KVRC] Khamsin Virtual Racecar Challenge 2016

[machin]

Depending on which way you look at it; the "good news" is that I don't have any involvement with the CFD side, so I could implement these changes without diverting resources away from the CFD/solver....

[RicME85]

Yes that is good news but if the CFD side of things isnt giving great or consistent results say then those changes become a nightmare for competitors

[LVDH]

The impact on you guys is simply that the "lines of equal laptime" on the chart I posted in the 2015 thread will be slightly lower gradient

That is actually very true. I did not think about it that way. I thought adding some more complexity and realism would make the whole thing even more interesting. But in the end you are just changing the gradient of the optimal design (I guess, utility function to be more accurate) we are trying to reach. So nothing would really change.

[UlleGulle]

I am not a participant of the Khamsin Virtual challenge, however, I am a huge fan. The thread about the championship is always the first I check, and sometimes the only one.

When the organizers first declared that they were leaving F1 and instead going for a LMP series I was not at all positive. That changed when I saw the cars. Indeed they were pretty. And you could see the design philosophy in a way you can interpret a F1 car.

I'd like to urge you stick with this years concept, and just change a couple of things to prevent copycat behavior. We don't want every car the next year to look the same, do we?

The first thing I would change is the engine. This is a fantasy race-car design championship. Let's put a tuned up bugatti Veyron engine in there. A huge engine with huge cooling needs, and a shitload of power. Let's have 430km/h race-duels.

Go for more aero opting. Allow covered rear wheels. Allow a bigger diffuser and bigger rear wing (if that's optimal)

One thing I'd like is to partition three different parts of three tracks each. First three street races (Monaco, Singapore and Macau?), then three medium fast tracks ( Nordschleiffe, Suzuka, Spa) and three really fast ones (Indianapolis Oval, Daytona road course, Monza) to allow for very different cars and a unpredictable championship.

[variante]

Hi, UlleGulle. Kind words! It's always nice to see that this championship is capable of drawing some attetion.

I wasn't that happy about the new formula too, when the change was announced. But i must admit that i'm really enjoying the design variety it's offering (which, from our side, translates into better understanding of aerodynamics and greater experience gained: a very important aspect of this challenge).

About this:

The first thing I would change is the engine. This is a fantasy race-car design championship. Let's put a tuned up bugatti Veyron engine in there. A huge engine with huge cooling needs, and a shitload of power. Let's have 430km/h race-duels.

I dont' think it would be the best choice: the greater the engine power, the smaller the relevance of aerodynamic efficiency. Basically, the differences between a good, refined design and a generic design would be eclipsed by the engine: this is not going to promote interesting and smart aero solutions...

Go for more aero opting.

Yes, but if we further increase variety, the newcomers and inexperienced ones may be totally disoriented... We have yet to understand which is this season's best design layout!

One thing I'd like is to partition three different parts of three tracks each.

This is a delicate aspect as well:
first, if we increase the number of races, we've got to consider the consequent increase of work required (from organizers and from competitors)
second, a longer championship might result in a boring season and a decrease of competitors, race by race.

[variante]

I could introduce a wear rate such that as the tyres get used the coefficient of friction reduces; more load on the tyres means higher wear rate, so by the end of the lap the higher downforce cars see a bigger reduction in tyre coefficient...?

Tyre management is a delicate topic... More downforce doesn't necessarily translates into more wear. Tyres work better (=more grip, less wear) at a given temperature, often studied to suit car's performance: it would be illogical to assume that the compound hypothetically chosen for this championship suits best the less performing cars...
Also, more downforce means less oversteering/drifting, less wheel locking, which translates into LESS tyre wear.
Finally, i've always got the impression that our races are more similar to qualifying session rather that proper races: would tire wear be a discriminating factor over just one lap?

Yes, i'm against the introduction of this change: too many variables we can't manage properly, as well as unnecessary added complexity.

[qwerty2459]

hey guys, ive been following this years competition and its very nice to read and follow and i can really see myself as being part of it. i registered on the site today just so that i can talk to you guys about it and im very tempted to join next years as a beginner but im not sure how to start, my problem right now is what CAD software you guys use to create, once ill know which one it is ill try to learn it so that i can have enough time to join in the competition.

[UlleGulle]

Thank you for your answers Variante. I think you have a point in all of them, actually. However, this being a Internet forum, I must stick to my opinion until I am proven wrong beyond all possible doubt.

I don't really understand your reasoning about the engine. With all cars having the same engine, and therefore power, wouldn't the difference between a good design and a bad one be the same? The only changes I could think of is a bigger challenge in terms of packaging, more bias towards streamlining and rear downforce. However, I can be totally wrong.

About the variety in aerodynamics I quite agree with you. However, refining takes a lot more knowledge and time than ingenuity. The ground effect was discovered through a melting wind-tunnel-model, not CFD calculations. Wouldn't covered rear wheels make the car more simple, aerodynamically? I thought those rotating wheels were the devil? A wing is quite uncomplicated too, unless we allow it to look like a F1 wing.

My point was not to have nine races actually. My apologies for not being clear about that, but to partition the season into a high downforce part, a medium downforce part and a low downforce part. There can be three, six or nine races. A competitor with limited time and resources could opt for a low-drag low-downforce design and leapfrog for a good last part of the season.

[variante]

I don't really understand your reasoning about the engine. With all cars having the same engine, and therefore power, wouldn't the difference between a good design and a bad one be the same? The only changes I could think of is a bigger challenge in terms of packaging, more bias towards streamlining and rear downforce. However, I can be totally wrong.

Let's bring the problem to the extremes: an engine with infinite power would allow us to design cars without taking care of drag at all; we would run maximum downforce setup even at Monza. Instead, an engine with ridicolously low power would impose us to look for the most efficient solution and study for smarter ideas.
In the first scenario a car with huge amount of downforce produced in an extremely inefficient way would win over another car which lacks just a bit of downforce but is remarkably efficient...not very fair! All the season would be similar to Monaco!
(BTW i don't want the ridicolously low powered engine either...let's look for something in the middle)

In fact, for the final three races of this very season it's been decided to decrease engine power in order to enhance cars' efficiency!

hey guys, ive been following this years competition and its very nice to read and follow and i can really see myself as being part of it. i registered on the site today just so that i can talk to you guys about it and im very tempted to join next years as a beginner but im not sure how to start, my problem right now is what CAD software you guys use to create, once ill know which one it is ill try to learn it so that i can have enough time to join in the competition.

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.

[UlleGulle]

Let's bring the problem to the extremes: an engine with infinite power would allow us to design cars without taking care of drag at all; we would run maximum downforce setup even at Monza. Instead, an engine with ridicolously low power would impose us to look for the most efficient solution and study for smarter ideas.
In the first scenario a car with huge amount of downforce produced in an extremely inefficient way would win over another car which lacks just a bit of downforce but is remarkably efficient...not very fair! All the season would be similar to Monaco!
(BTW i don't want the ridicolously low powered engine either...let's look for something in the middle)

Damn it. Through simple logic you proved me wrong. By internet forum rules I must now resort to name calling. You... you ... Honda Power Unit!

[MadMatt]

I could introduce a wear rate such that as the tyres get used the coefficient of friction reduces; more load on the tyres means higher wear rate, so by the end of the lap the higher downforce cars see a bigger reduction in tyre coefficient...?

Tyre management is a delicate topic... More downforce doesn't necessarily translates into more wear. Tyres work better (=more grip, less wear) at a given temperature, often studied to suit car's performance: it would be illogical to assume that the compound hypothetically chosen for this championship suits best the less performing cars...
Also, more downforce means less oversteering/drifting, less wheel locking, which translates into LESS tyre wear.
Finally, i've always got the impression that our races are more similar to qualifying session rather that proper races: would tire wear be a discriminating factor over just one lap?

Yes, i'm against the introduction of this change: too many variables we can't manage properly, as well as unnecessary added complexity.

This is incorrect. If you have more downforce you are just pushing further the limit but when you drive, you drive at the limit. We were at Monza last week (I say we, but I mean F1), even at 350km/h you can lock wheels and yet at 350km/h they generate huge amount of downforce. Its just a matter of moving the limit further or earlier.

One thing that is for sure is that the greater you push an object to the ground and the move it along a normal axis, the greater the friction.

[variante]

If you have more downforce you are just pushing further the limit but when you drive, you drive at the limit. We were at Monza last week (I say we, but I mean F1), even at 350km/h you can lock wheels and yet at 350km/h they generate huge amount of downforce. Its just a matter of moving the limit further or earlier.

Yes, good consideration!
I was thinking about real life conditions, where a pilot with less downforce will always make more mistakes (i.e. more oversteering, locking,...) trying to catch up with the more performing cars (whose pilots, in turn, will be more confident of their position and less prone to mistakes).
But, since our cars are driven by computers, you're right!

[MadMatt]

If you have more downforce you are just pushing further the limit but when you drive, you drive at the limit. We were at Monza last week (I say we, but I mean F1), even at 350km/h you can lock wheels and yet at 350km/h they generate huge amount of downforce. Its just a matter of moving the limit further or earlier.

Yes, good consideration!
I was thinking about real life conditions, where a pilot with less downforce will always make more mistakes (i.e. more oversteering, locking,...) trying to catch up with the more performing cars (whose pilots, in turn, will be more confident of their position and less prone to mistakes).
But, since our cars are driven by computers, you're right!

Exactly, and I quote myself from the previous page: "Plus having more downforce makes things easier for the driver (your car is not sliding all the time)."

[machin]

it would be illogical to assume that the compound hypothetically chosen for this championship suits best the less performing cars...

In reality Virtual Stopwatch is "supplying" the tyre, so there is no "assumption"; currently we're running a tyre model that was decided (Or "designed") by me without any input... but I could "design" any tyre characteristics we want... drop off at high loads due to overuse, drop off at low loads due to low temperature, etc. etc.....
I'd make sure that the drop off in tyre performance meant that higher downforce meant cars are still at an advantage, just less of an advantage than currently... if the majority agree that's the way to go....

Finally, i've always got the impression that our races are more similar to qualifying session rather that proper races: would tire wear be a discriminating factor over just one lap?

At the moment the tyre model I'm using is one I developed for predicting the performance of cars competing in the UK sprint championship; which is for short distance events and shows no drop off; I think its OK for our purposes. However, I remember times not so long ago when drivers in F1 would report that the tyres were "going-off" at the end of one qualifying lap. For me adding this characteristic is just a few taps of the keyboard away (Ok, a little more than that, but not too bad...) if we want to go that way....

Yes, i'm against the introduction of this change: too many variables we can't manage properly, as well as unnecessary added complexity.

As with all of these things being suggested (e.g. the ability of more efficient cars to run with less fuel, or to have a slightly increased power output to use up any remaining fuel), the only outcome for you guys as competitors is that it changes the shape/gradient of the lines of equal lap time (that I've labelled "Medium" "Fast" and "Faster" in the diagram below): you'll still put your aero coefficients into Virtual Stopwatch and get a lap time out: all these tyre degradation formulas/fuel saving formulas will be automatically considered... So the additional work is only for me on the programming side really....

This contrasts quite a bit with the desire to introduce engine power output modifications based on airflow/pressure on the inlet and cooling intake surfaces: that request certainly adds complexity and more variables for both the competitor and the organisers to handle....

On the flip side you could argue that the fact that since the tyre degradation has no real impact on the method competitors should use to design their cars (and therefore no increase in the "enjoyment" a competitor gets from adding this feature), there is also no real advantage in adding this tyre degradation feature either, since we can also change the shape/gradient of these lines of equal lap time by increasing/decreasing engine power, changing gearing ratios, changing engine inertia, or simply choosing other tracks to visit....

e.g: current curve:


e.g. curve with tyre degradation at high loads:-



...You can see that Config 3 is still fastest, but now a little closer to the "Fast" lap time curve than it was before, i.e. a little slower than before.... LVDH put it quite nicely:-

I thought adding some more complexity and realism would make the whole thing even more interesting. But in the end you are just changing the gradient of the optimal design (I guess, utility function to be more accurate) we are trying to reach. So nothing would really change.

If you have more downforce you are just pushing further the limit but when you drive, you drive at the limit

That is exactly how Virtual Stopwatch works: it drives at the limit of the tyre with the least amount of relative grip at all times unless some other variable is the limiting factor (e.g. during acceleration engine power, drag, gearing etc. are the limiting factors most of the time, with tyres, the forces on them and the transmission configuration (FWD, RWD or 4WD) only the limiting factor to acceleration at low speeds), so in essence there is no extra "margin" or "less sliding" with more downforce in the Virtual Stopwatch simulation, only more speed due to the higher limit.

[variante]

In reality Virtual Stopwatch is "supplying" the tyre, so there is no "assumption"; currently we're running a tyre model that was decided (Or "designed") by me without any input... but I could "design" any tyre characteristics we want...

Ok, then: it would be illogical to "decide" that the compound hypothetically chosen for this championship suits best the less performing cars...
The consequence of that "decision" would be a performance leveling of the cars. And i would ask...why??
We already have CoP adjustemt. If we are further seeking leveling we could adopt less artificial solutions (ie smaller diffusers, tracks that don't require such efficiency refinements,...)
Otherwise, if the only interest is just leveling laptimes, just make a formula about that without calling it "tyre wear, fuel thing, pitstop issue,...": let's just say that is an artificial way to make the championship more enjoyable for the less performing guys.

BTW, do you have exact data about tyres behaviour at different loads?

About tyre wear rate, I know that in MotoGP qualy tyres barely last one lap (but at least they do last one lap without significant drops). Obviously you could bring it to the extremes and impose even higher degradation rate... But, again, that would be such an artificial solution...
Let's not forget that we've discussed for months about the best ways to improve realism.

On the flip side you could argue that the fact that since the tyre degradation has no real impact on the method competitors should use to design their cars (and therefore no increase in the "enjoyment" a competitor gets from adding this feature), there is also no real advantage in adding this tyre degradation feature either, since we can also change the shape/gradient of these lines of equal lap time by increasing/decreasing engine power, changing gearing ratios, changing engine inertia, or simply choosing other tracks to visit....

Indeed. BTW i could even say that tyre degradation could be an enjoyable challenge for us, but not a realistic one (unless we want to simulate a full GP).

This contrasts quite a bit with the desire to introduce engine power output modifications based on airflow/pressure on the inlet and cooling intake surfaces: that request certainly adds complexity and more variables for both the competitor and the organisers to handle....

No, it's not in contrast. Competitors dealing with engine/cooling inlet to get extract more performance from the engine is totally normal in real world (while i've never seen a car decreasing downforce to preserve its tyres...maybe the opposite, especially during qualy laps), and that rule would elegantly get rid of other restrictive and artificially imposed rules governing inlets position.