Secret to Red Bull's Q3 Pace - Engine Mapping

[alelanza]

Is this too ridiculous to believe?

In order to maintain constant air flow through the diffuser during low revs, the teams look to the ballast for the answer. Constructors normally use a tungsten ballast located at the lowest point on the car to maintain the lowest possible center of gravity. With a 620 kg minimum, a pre-ballast car weight around 420 kg, and factoring in driver weight ~70 kg, Red Bull saw around 130 kg of weight to deal with the rev-dependent air flow through its diffuser. Instead of a solid tungsten ballast, Red Bull may be utilizing computer controlled, variably discharged according to engine rev, highly compressed air tanks where the ballast is normally located. Although there is no possible way to make this method last a whole race, it is possible for two or three laps in Q3.

Then it wouldn't be ballast. The car would need to still be above minimum weight post quali. If you were blowing your ballast into the air then you wouldn't pass inspection. Unless you're suggesting they use the engine to refill the tanks during the in lap, now that would be one wild idea. Plus i doubt the regs allow for any thrust to come from anything other than engine/kers.

[xpensive]

Boy, that's a wide..opening...

...but I'm still not entirely convinced, if you wanted the xhaust to pass thru the "upper deck", there should be a more efficient way to place the xits. I'm leaning more towards the idea being to use the xhaustgases to isolate the lower diffuser from the rear-wheel turbulence?

[imightbewrong]

Boy, that's a wide..opening...

...but I'm still not entirely convinced, if you wanted the xhaust to pass thru the "upper deck", there should be a more efficient way to place the xits. I'm leaning more towards the idea being to use the xhaustgases to isolate the lower diffuser from the rear-wheel turbulence?

I think that would be the main idea yes. But apparently you can also gain something by having part of the high speed flow going in to the upper deck, otherwise there would be no window there (and they wouldn't have recently increased the size).

[xpensive]

Again, from the pics, it still looks as if the exits are located on the sides of the body's waist and not thru anything at all?

Here you go, the hole into the upper deck of the diffuser. The size of the window was recently increased.

Come to think about it, which window are you referring to, not the large dark part just behind the xhaust I hope, that's just the shadow from the rear-wheel, isn't it?

But there's something further back, but way to far away to feed the "upper deck", no?

[marcush.]

it is 2nd deck opening ..it can be seen from behind the car..i think on scarbs site are some pics..

[xpensive]

it is 2nd deck opening ..it can be seen from behind the car..i think on scarbs site are some pics..

Kindly be a tad more specific marcush, please take your time to enlighten an ignorant?

[FW17]

Is this too ridiculous to believe?

In order to maintain constant air flow through the diffuser during low revs, the teams look to the ballast for the answer. Constructors normally use a tungsten ballast located at the lowest point on the car to maintain the lowest possible center of gravity. With a 620 kg minimum, a pre-ballast car weight around 420 kg, and factoring in driver weight ~70 kg, Red Bull saw around 130 kg of weight to deal with the rev-dependent air flow through its diffuser. Instead of a solid tungsten ballast, Red Bull may be utilizing computer controlled, variably discharged according to engine rev, highly compressed air tanks where the ballast is normally located. Although there is no possible way to make this method last a whole race, it is possible for two or three laps in Q3.

Then it wouldn't be ballast. The car would need to still be above minimum weight post quali. If you were blowing your ballast into the air then you wouldn't pass inspection. Unless you're suggesting they use the engine to refill the tanks during the in lap, now that would be one wild idea. Plus i doubt the regs allow for any thrust to come from anything other than engine/kers.

Moving ballast of any kind is not allowable, if it was teams would have been pumping mercury in an active manner.

[gridwalker]

Is this too ridiculous to believe?

In order to maintain constant air flow through the diffuser during low revs, the teams look to the ballast for the answer. Constructors normally use a tungsten ballast located at the lowest point on the car to maintain the lowest possible center of gravity. With a 620 kg minimum, a pre-ballast car weight around 420 kg, and factoring in driver weight ~70 kg, Red Bull saw around 130 kg of weight to deal with the rev-dependent air flow through its diffuser. Instead of a solid tungsten ballast, Red Bull may be utilizing computer controlled, variably discharged according to engine rev, highly compressed air tanks where the ballast is normally located. Although there is no possible way to make this method last a whole race, it is possible for two or three laps in Q3.

Then it wouldn't be ballast. The car would need to still be above minimum weight post quali. If you were blowing your ballast into the air then you wouldn't pass inspection. Unless you're suggesting they use the engine to refill the tanks during the in lap, now that would be one wild idea. Plus i doubt the regs allow for any thrust to come from anything other than engine/kers.

Moving ballast of any kind is not allowable, if it was teams would have been pumping mercury in an active manner.

I find that somewhat doubtful; you would need A LOT of mercury to make a significant difference in ballasted weight (without even taking into account the piping and pumping mechanism).

Mercury is also highly toxic, which adds an additional element of risk in the event of a crash : I would refuse to be a marshal if there was a chance I would have to help clean up a crash that spilled litres of mercury.

Incidentally, the weight of the pressurised gas cylinder would be far greater than that of the air being blown, so I doubt that it would count as "movable ballast" in the unlikely event that such a system was being implemented.

Using exhausted retards to blow on the diffuser is much more probable

[autogyro]

Here is a guess that gets away from the direct blowing of exhaust gas over the diffuser.
On full throttle, the mass 'exhaust gas' flow increases from the engine due to burning fuel. This flow alters the direction of airflow into the rear 'coke bottle' area. The main airflow is directed outside of the diffuser and upwards.
The result is slightly reduced diffuser DF and reduced drag.
Under braking the 'exhaust gas' flow reduces in volume with less fuel burnt and the airlow redirects inboard over the diffuser and lower wing section increasing DF into corners.
On high speed 'throttle on corners' the flow is of much higher mass airflow and the result is a neutral DF effect.

[myurr]

Here is a guess that gets away from the direct blowing of exhaust gas over the diffuser.
On full throttle, the mass 'exhaust gas' flow increases from the engine due to burning fuel. This flow alters the direction of airflow into the rear 'coke bottle' area. The main airflow is directed outside of the diffuser and upwards.
The result is slightly reduced diffuser DF and reduced drag.
Under braking the 'exhaust gas' flow reduces in volume with less fuel burnt and the airlow redirects inboard over the diffuser and lower wing section increasing DF into corners.
On high speed 'throttle on corners' the flow is of much higher mass airflow and the result is a neutral DF effect.

Not saying that isn't part of what's going on, but in and of itself it doesn't explain why Red Bull are quicker in Q3 than any other session of the weekend, and usually by a significant margin. A throttle map that provides additional down force at the expense of component life does explain this, as the team can only run in this mode for a limited period and thus limit themselves to Q3. It also has a nice tie in with Vettel's spark plug failure in the first race, with the loss of power and apparent change in balance of the car that made it difficult to drive (it took him many laps to get his pace under control).

Not saying that this explanation is the right one, merely that your explanation right or wrong does not cover the subject of this thread - namely Red Bull's Q3 pace.

[Richard]

if you wanted the xhaust to pass thru the "upper deck", there should be a more efficient way to place the xits. I'm leaning more towards the idea being to use the xhaustgases to isolate the lower diffuser from the rear-wheel turbulence?

I think that would be the main idea yes. But apparently you can also gain something by having part of the high speed flow going in to the upper deck, otherwise there would be no window there (and they wouldn't have recently increased the size).

I presume that they wouldn't want the exhaust feeding more directly into the DDD because that would be too throttle sensitive? Also there could be benefits from using an exhaust vortex to protect the DDD exit. It looks like the exhaust is used for two purposes.

Just to complicate it, I wonder if the split between those two functions can be tuned? At slow speed the exhaust shoots out the back and only a small amount diverts into the DDD.

At high speed, the general air flow traps the exhaust gasses closer to the bodywork, so a higher proportion feeds into the DDD?

However the above relates to the general functioning of the diffuser, not specific to Q3.

Back to the OP, ride height is the most mystifying part of the RB in Q3.

[xpensive]

I still cannot find the slot, hole or window on the RBR6 where the xhausts are supposed to enter the diffuser's upper deck from the outside, not even in the car's formidable Q3 guise?

OK like that Richard?

[l4mbch0ps]

I still cannot find the slot, hole or window on the RBR6 where the xhausts are supposed to enter the diffuser's upper deck from the outside, not even in the car's formidable Q3 guise?

It's in the last posted picture. To the left of the wheel, and directly under the lower most suspension arm. Very clear.

[ringo]

blue is air coming from under the floor, red goes through upper deck, orange goes to the sides.

[ringo]

That upper deck hole is exaggerated just so you can see it. It's possible behind this hole has a ramp under neath (to reflect the exhaust up against the roof off the DDD). Air from the floor is entrained in the jet flow of the exhaust gasses; similar to a natural draft cooling tower.