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2010C Formula Preview
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Basic Overview
The central gist of the new formula is that chassis designers focus heavily on mass and drag. Basically, most of the options cost fundamental performance in the form of mass and drag. There are still points, but they are not really cost points against a budget anymore. They are tech points which are converted into mass and drag when the cars get baked. You get a parameter to specify how much of your tech points turn into drag, and how much turn into mass.
So the simple way to design a car is to just pick the pieces you want, then dial your aero vs mass priority. Done. This is the buffet way of looking at it. Eat what you want, but watch your weight. So in spite of all the text below, the 2010C formula is actually easier the deal with than the 2010B formula, if you want it to be.
Or you can play it the engineering way, which is what the rest of this post is all about.
Drag
Drag is pretty simple. More drag means less top speed.
Mass
Mass is more complex, and more interesting. The core car mass is at a height of around 250mm (the exact number is still being tuned). A car design with few enough tech points converted into mass will weigh less than the minimum mass (605kg). This means such a car will have ballast to bring it up to 605kg, but the ballast will be on the floor of the car, hence bringing the CG down. If lots of tech points turn into mass, the car will simply weigh more than 605kg. Therefore, the CG is never higher than about 250mm, but can be lower. CG adjustment range in the garage is also a function of ballast. More ballast, more CG range. However, that is not the only factor on CG range. Some body parts affect CG range as well, by allowing more or less distance from the core CG in which to place the ballast.
For example, the boxy sidepods have the longest lateral CG moment arm, so ballast goes a longer way with the boxy sidepods. However, since those sidepods demand more design burden to make efficient, they cost more tech points.
In these diagrams, the big circles are longitudinally where the wheels are, therefore signifying the wheelbase (technically the floor of the car is near the ground, not the centerline of the wheels, but the picture looked crisper this way).
Aerodynamics
Another major change of the new formula is that the wing aerodynamics (refer to the plot below). The aerodynamics of the wings have been corrected to be like real wings. The details are actually not terribly important, because I can summarize the new wings easily. In the middle of the range (around 30/30) the new wings will have downforce and drag very close to the current wings. High wing settings will have a little more downforce than they do now. Decreased (low) wing settings will falloff in downforce much quicker, such that a wing setting of 12 on a new wing will have about the same downforce as a wing setting of 1 on the current wings. There are more details below, but that is plenty of gist for most people's practical purposes of setting up their cars.
The black and white plot is a reference to see some proper curves, demonstrating that we are switch from incorrect to correct. The x-axis on our plot is also angle of attack, in the form of wing-setting (1 to 50), which is something less than 0.5 degrees per setting.
The first two lines in the key, "RW lift (ref)" and "RW lift", are the lift coefficients, or in otherwords, plots of the downforce level (downforce itself varies with velocity). 'ref' means the current wings, the non-ref line is for the new wing. Note that the current wings have downforce at a zero (er, 1) setting. Technically, this is not the incorrect part, since this could just mean a setting of 1 was some not insignificant angle of attack. However, while I was at it, I went to zero, so that the setting is more intuitive. A setting of 1 now means no downforce for the wing.
The next line, "RW drag (ref)" is the heart of the error with the currect wings. Real wings have significant drag at zero angle of attack, and follow a much more parabolic curve than the nearly linear lift curve. The problem then manifests in the totally busted "L/D (ref)" curve, which shows a problem we've noticed on our currect cars: we are driven towards lower downforce levels at optimal than is 'fun' for lots of drivers. This is because the L/D skyrockets with decreasing downforce, meaning the aero of the car gets unnaturally efficient. Looking at the black&white picture, we can see that L/D has some optimal angle of attack well above 0. The observant will note at this point that the current wings are not as altogether broken as that, since if interpretted as starting at some non-zero angle of attack, in fact, starting at what on the new wing is setting 12 (note match lift statement in summary), meaning the ballpark of 6 degrees, we see that the L/D curve of the current wings really starts from max and decreases. However, the decrease is significantly parabolic, where as it should be nearly linear. Bottom line: current wings are 'good enough', but we can do better, and in the process move the sweet spot of the cars to an even more fun place.
The "body (lo)" and "body (hi)" lines show an approximiate level of really low and really high drag from the tech point built formula. In other words, it is the approximiate drag window of the car body in our formula, shown here just to put the wing drag levels into perspective. This shows that a 50/50 winged car will be approaching 3 times the drag of a 1/1 winged car (there are two wings on a car). In yet other words, wing settings are a big deal.
The rest of the lines show drag and L/D for a (lo) variant wing (lo meaning optimal at lower speed, hence higher wing setting) and a (hi) variant wing. Note that the drag curves are properly parabolic, and the L/D curve are of proper shape and have a max other than at the lowest setting. These wing variants will be available as the A and B wing styles for both front and rear. This means the RW choice is no longer just aesthetic, and it means the FW choice is no longer flexi vs rigid.
Note that with reduction of the lift curve at lower angles, oval applicability has significantly increased for the GPs. They are no longer automatically glued to the ground at oval speeds.
Gearbox
One new change for 2010C that may interest a lot of people is the expansion of gearbox options. We are expanding the number of gears available, which has long been one of the most requested changes, and the choice between seamless and normal (base) shift times. The gearbox options are:
- RB4 -- RWD, Base shift speed, 4 speed (0 tech points)
- RB5 -- RWD, Base shift speed, 5 speed (2 tech points)
- RB6 -- RWD, Base shift speed, 6 speed (4 tech points)
- RS4 -- RWD, Seamless shift speed, 4 speed (1 tech point)
- RS5 -- RWD, Seamless shift speed, 5 speed (3 tech points) -- this one is exactly the same as helotek
- RS6 -- RWD, Seamless shift speed, 6 speed (5 tech points)
Ah that's better - I can see the diags now I've logged in.
So with all these extra choices, I wonder if Club Engineer, Arthur "Two Sheds" Jackson is going to need a bigger, or even a third shed.
Just to make sure I understand the gist of the 10C budget system. We are free to choose any option we want when building our cars. There's no budget limit for that the way there's been in past seasons. However, every option has a point value. Once we've chosen our various options, we add up the point value and the resulting total must be portioned out on what is essentially either a mass penalty or a drag penalty?
As an example, let's take the the various brake options. Going from memory and not checking the actual formula, the steel brakes currently have no cost; MKI, MKII, and MKIII brakes cost 2 points each; and nanotech brakes cost 3 points. With the old system, if I chose the MKII brakes, 2 points would be deducted from my available point budget. Once my point budget reached zero, I was done 'buying' options. With the new system, the 2 points would be added to my mass/drag budget with, effectively, no upper limit to that budget. Once all my options have been chosen I must then 'spend' my mass/drag budget on mass and drag settings, either increasing mass or increasing drag. If this is so, do I have a choice in how those points are apportioned to both settings? Or is the point cost per category fixed? In other words, do those same MKII brakes cost 2 points that can be spent in either or both categories, or do they have a fixed cost of 1 point in each category, or 2 points in one category - or whatever the case may be - and I have no choice in which category the points are spent? Note: I'm in no way assuming the point cost for the brakes will still be 2, I'm just using that as an example, nor am I making a case for or against either method of distributing the mass/drag points....I'm just making sure I understand the concept.
If I've got it right, I must say this is certainly an interesting way of handling things. One that I approve of. I like the idea of potentially trading speed for flexibility. I get the idea that a faster car will end up being harder to setup, the options that make a care more flexible, with more setup options, generally cost more under our current budget system. I can only assume that means they'll come with a correspondingly higher mass/drag cost under the new system. So to design a car with a low mass/drag penalty, you're going to end up with a car that has fewer setup options. This generally means that a driver will probably not be as consistent from week to week since a car with limited setup capability will usually favor one track type over another. Whereas someone that opts for a design that's a bit more flexible will end up with a car that may not be quite as fast due to the mass/drag cost, but has the potential to be more consistent from week to week as the driver will be better able to adjust the car to fit a particular course's quirks...that is if the driver has the time to spend on tweaking the setup to get the most speed out of the car that he can....very interesting indeed. frankly I'd rather have consistent 6th-place finishes than 2 or 3 podiums with the rest being sub-8th-place or even DNF's...not that we're likely to see that sort of extreme, but still.....