New Indycar for 2012

[Jersey Tom]

Well... go for a spin in your favorite racing sim. From your standard setup... try running some laps with 5% more front brake bias from standard.. then one with 5% more rear brake bias from standard. Let us know which is more stable

I am no expert, I am merely regurgitating what I read in Motorsport. It could be wrong, but sounds legit to me.

That is the problem.

How does it even sound legit? It's a handwavy claim.. they just make a statement and have absolutely nothing to back it up.

From a vehicle dynamics standpoint it makes zero sense to me.

[Beewill]

http://www.indystar.com/article/2010060 ... ght-return

Finally something positive from the IRL. This would certainly make me want to tune in more often.

[bill shoe]

It's fairly trivial to make 550 to 750 hp reliably from a light turbo engine nowadays. The elephant in the room is how to reduce the returns on expenditure. That is, how to reduce the power gains from spending more money. The reduced returns are needed to greatly reduce the incentive to spend money, and thus greatly reduce the expenditure of money. This spending reduction is needed to increase public interest in Indycar by replacing the buy-a-ride grids with the best drivers.

The Indycar press release was an earnest wish. It had no information on how Indycar would achieve the wish in a cost effective way. There is no significance to "conceiving" a 550 to 750 hp turbo engine.

Reducing the power returns on expenditure is critical in oval racing. Penske was said to dominate Indy qualifying this year because they were ~0.5% faster than the next team. This type of advantage could be achieved in the future with an engine that was ~0.5% more powerful than the competition. The underlying issue is how to prevent large expenditures from achieving a 0.5% power advantage over the competition. If you can't prevent this then willingness to spend money rules the day.

[Pandamasque]

Well... go for a spin in your favorite racing sim.

literally

I am a sim racer, but I'm sort of Kimi-like. I just drive and let the techies figure out the technical. I'm not great at setup work. I have a lot to learn.

I'm not that good at it either. But I sometimes have to adjust brake bias on the fly and move it forwards before slow/hairpin turns. Locking the fronts if that happens is much safer than locking the rears. All you do is release the brakes slightly and turn-in later. If the rears lock you rarely have a chance to catch the oversteer and often end up facing the wrong way which is never a good thing .

That's why regardless of the weight dist. of a car the brakes are set that the fronts would normally lock up first. But in absolute numbers that would be different setup depending on the weight dist., aero balance, suspension setup. I guess in an extreme case like Delta Wing the optimum would be actually less than 50% front. But that difference wouldn't make it more stable all of a sudden, not because of the brake bias at least.

The thing is that the grip (balance) with that would be quite a lot different as well as the weight transfer. I'm actually curious to try one out in a sim. unfortunately they didn't release their rFactor model for general public.

[youtube]http://www.youtube.com/watch?v=e2mqjL2P9O8[/youtube]

PS: what happened to this concept?

[Jersey Tom]

If they're really using rFactor for "sim" work then they are truly sunk. Terrible representation of tire behavior... and without that you're hosed.

Again, there's also the issue that when they ran these "sims" no tire data existed for the new skinny front, so even if it were done professionally I'd still call BS on it.

[Pandamasque]

Well looking at the model it seems the only peurpose of that was "look! It's not falling over!".
Besides I've heard that the DW project thingy currently looks quite a lot different from the one initially presented.

[donskar]

You must be joking! There are many, many items in common use today, which owe their developement to F1. Even kers, and paddleshifts, sequential gearboxws etc etc

No, I am not joking. Are you? KERS as it was (past tense) implemented in F1 is not used in any production car. Sequential gearboxes? Likemotorcycles have used for years? Paddle shifters? Yes, I'll give you that one.

Now how about the other technologies I mentioned: Direct injection? Variable valve timing and variable lift? Suspension system that electronically vary shock stiffness? Variable rollbars? Multi-tract intake systems? Not ot mention vehicle stability control systems.

My basic point is that today's production cars employ many technologies that would actually make F1 faster. IMHO a bizarre situation. Possibly more bizarre that F1 has used some variants of these technologies, only to ban them for some reason or another.

[Jersey Tom]

+1 to that. Technology often flows from consumer markets to racing rather than the other way around.

[Scania]

You must be joking! There are many, many items in common use today, which owe their developement to F1. Even kers, and paddleshifts, sequential gearboxws etc etc

No, I am not joking. Are you? KERS as it was (past tense) implemented in F1 is not used in any production car. Sequential gearboxes? Likemotorcycles have used for years? Paddle shifters? Yes, I'll give you that one.

Now how about the other technologies I mentioned: Direct injection? Variable valve timing and variable lift? Suspension system that electronically vary shock stiffness? Variable rollbars? Multi-tract intake systems? Not ot mention vehicle stability control systems.

My basic point is that today's production cars employ many technologies that would actually make F1 faster. IMHO a bizarre situation. Possibly more bizarre that F1 has used some variants of these technologies, only to ban them for some reason or another.

the hold KERS in not use in road car, but its technology make the battery management & motor contorl get better efficiency, this improvment was bring to road car system.

[bill shoe]

Jersey Tom, Giblet, et al-

Interesting discussion about braking stability. Here is a Ben Bolby quote on the car in question:

"What we discovered," Bowlby explains, "was that if we had the weight more rearwards in a straightline competition we can out-accelerate the current car because more of our weight is on the two rear tires that are powered and that gives us greater acceleration capabilities. Under braking we discovered that we had created a unique condition--in racing car terms--where more than fifty percent of the braking came from behind the center of gravity. Normally, more than fifty percent of the braking comes from in front of the center of gravity and that is an unstable condition where you have to be terribly careful not to lock the rear brakes."

http://gordonkirby.com/categories/colum ... no222.html

I think there is some logic to what he says.

Imagine a car with 70% rear static weight and freely rotating casters (yes, shopping cart casters) for the front wheels. The front wheels provide no lateral influence. If the brake bias is 100% rear then this car will be stable during braking because the C.G. inertia will pull the car straight anytime there is a slight disturbance that would start to rotate the car in yaw. This continues to be true even if the rear brakes are locked.

Now lets keep the 70% static rear weight but put normal front tires on and assume the driver holds the steering straight during braking (or at least can't correct fast enough to matter). Now the front end has the potential to generate lateral force. If the brake bias is still 100% rear and we lock the rears then the car will have the same previous natural stability under braking but the front wheels will now have a lot of potential to rotate the car in yaw if they start to get even a little sideways. Bowlby's natural stability is now fighting against the instability from the front lateral capacity. Not sure which is stronger, it would depend on the front tire lateral gain at low slip angles and various car geometry, etc. It's entirely plausible that the natural stability wins.

Here's where I don't understand. The Bowlby car will in fact have brake bias that is very rearward, but it also has a very rearward C.G. If the front and rear tires have grip capacity that is roughly proportional to the static weight distribution then under braking the optimum brake bias will always be in front of the C.G. due to forward load transfer. Let's assume Bowlby's car has 70% static rear weight and 60% rear brake bias. Therefore, according to my understanding, the Bowlby natural stability is gone because the brake bias is forward of the C.G. In contrast to my understanding, Bowlby implies that the natural stability is still there because the rear bias is greater than 50%.

I could ramble on but I'll stop here and request feedback.

[rich1701]

Would introducing splitters on indycars reduce their tendency to take off so easily when an incident occurs? as seen at the the Indy 500 this year.

[Jersey Tom]

I'm definitely not following the "natural stability" thing.

[autogyro]

I'm definitely not following the "natural stability" thing.

I just love listening to the American ideas on motor racing.
They are always so far removed from practical reality you cannot stop yourself laughing.
You are absolutely correct JT, what stability?

[Jersey Tom]

What's with the attitude?

[bill shoe]

I'm definitely not following the "natural stability" thing.

"Natural stability" is an informal term I used for this discussion. If a more specific definition is helpful then try this-

Natural stability: Braking stability that does not depend on maintaining a sufficiently high ratio of rear to front lateral capacity. The practical significance is that this type of braking stability does not depend on brake balance.

Here is my first example again. Do we agree this car is stable under braking even though it has full rear brake bias?:

"Imagine a car with 70% rear static weight and freely rotating casters (yes, shopping cart casters) for the front wheels. The front wheels provide no lateral influence. If the brake bias is 100% rear then this car will be stable during braking because the C.G. inertia will pull the car straight anytime there is a slight disturbance that would start to rotate the car in yaw. This continues to be true even if the rear brakes are locked."

Let me try new wording to explain where this stability comes from. Think of the car in plan view during braking. If the braking force is coming from behind the C.G. then anytime there is a yaw disturbance the C.G. inertia will pull the car back to zero yaw. If the braking force is in front of the C.G. then anytime there is a yaw disturbance the C.G. inertia will pull the car around in yaw MORE.

Previous brake stability discussion on this thread has only focused on front:rear brake bias. I am bringing this "natural stability" concept up because I think it's what Bowlby is getting at.