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Speed Traces – Mercedes and Haas – 2017 Bahrain Grand Prix Qualifying

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This is the speed trace of the Haas VF17 driven by Romain Grosjean, compared with the Mercedes W08 driven by Valtteri Bottas at the final part of qualifying for the 2017 Bahrain Grand Prix. Bottas’ lap was the pole lap (1m28.769s), and Grosjean’s the Q3 lap (1m30.763s).

2017 Bahrain Grand Prix Qualifying

An interactive plot of the above graph can be found here

I found this comparison interesting because, there were rumours that the Ferrari power unit was running in a conservative state as they had experienced some issues through the race weekend, and the works Ferrari team was surprised by the larger than usual gap to Mercedes in qualifying. Lack of Ferrari onboards made it difficult to make a direct comparison, however, an overall look at the speeds in the acceleration zones, suggests that the Mercedes is only pulling ahead significantly at speeds above 250 km/h. It could be due to increased drag from the Haas car and/or higher power produced by the Mercedes M08 PU in qualifying trim. Data is inconclusive.

The 2016 Haas car showed well in Bahrain relative to the front runners, so it’s interesting the form has carried through to the new 2017 regulations, with Grosjean driving the car to a P9 start and finishing P8. A few highlights between the Haas car and the Mercedes;

Low Speed Corners

2017 Bahrain Grand Prix Qualifying t8_10

Turns 8 and 10, Grosjean’s apex speeds were 5 km/h and 10 km/h respectively, slower than Bottas.

The Mercedes car seems to carry much higher apex speeds in the low speed corners at this circuit compared to Haas, and this is one where significant gains can be made relative to the midfield for Haas. I would guess that the Renault and Williams are probably better than Haas in these corners, although Grosjean suffered a lock up into T10. Bottas’ lap had the telemetry missing till turn 1 (a low speed corner), but from what I can work out, Bottas was probably carrying 4-5 km/h better apex speeds than Grosjean.

Medium Speed Corners

Several corners could come under this heading, but interestingly the Haas is matching the Mercedes in Turn 4, with Grosjean carrying as much speed as the Mercedes into and even enjoying a slightly better apex speed, but losing out in the exit:

2017 Bahrain Grand Prix Qualifying t4

Turn 4

As the lap goes on, however, the Haas is not able to maintain this level of performance relative to the Mercedes in the medium speed corners:

2017 Bahrain Grand Prix Qualifying t11_t14

Turns 11, 13 & 14. Grosjean’s apex speed deltas to Bottas in these corners were +2 km/h, +5 km/h and +15 km/h, respectively.

Turn 11 seems to be a reversal of T4, where Bottas is able to carry a lot more speed on entry than Grosjean, and out-accelerate Grosjean in the exit quickly. In turn 13 they have similar speeds on entry but apex and exit speeds were much better for Bottas. Grosjean didn’t make a mistake in T14 from the onboards as best I can work out, for such a big apex speed difference. If I were to make a guess on the reason for this performance, I’d suggest the Haas unable to get as much out of the tyres as the Mercedes over a lap (or previous front lock up costing him?).

High Speed Corners

I think a real snapshot of how much downforce the Haas car is missing relative to the front running Mercedes is the speed difference in turn 7 & 12.

2017 Bahrain Grand Prix Qualifying t6_7

The Mercedes is carrying a huge amount more speed through turn 7 than Haas, almost flat out! Very reminiscent of the Mercedes performance in turns 7 & 8 in China. The Mercedes seems to do very well in high speed direction changes, losing a lot less speed in these transitions than the competition.

It’s difficult to display the differences between Haas and Mercedes in turn 12, but the speed trace looks like it has a more flatter profile (slope) than the Mercedes on first glance. This corner is different to turn 7 in China in that, the cars are continuing to accelerate through it under full throttle, but the acceleration rate is somewhat determined by what the chassis can cope with.

To analyse the differences between these cars when cornering forces are limiting the chassis, along with helping evaluate the drag/downforce of these cars, we bring another car into the equation. The RB13, supposedly designed with less drag in mind. I was only able to obtain data from Ricciardo’s first run in Q3, so I plotted the cubic fit of data for acceleration through turn 12 (unbroken lines), along with acceleration from turn 13 to 14 with no DRS assist (dashed line) and acceleration between turns 10 and 11 with DRS assist (dotted line):

BotL

Unbroken line = cars approaching and accelerating through turn 12, dashed line = acceleration along the straight (without DRS) between turns 13 & 14, dotted line = acceleration along straight (with DRS) between turns 10 & 11. All data under full throttle.

Now, different deployment strategies and peak power of the PUs of these cars will have an effect on these data, however it is generally accepted that the deployment variable doesn’t have a marked effect on the lap time differences among the three PU manufacturers I have plotted.

It is clear that the opening of DRS has a much bigger effect on the speeds of the Haas car than the RB13, suggesting that the Haas car is generating a lot more drag than the Red Bull. The Haas VF17 was gaining 11 km/h with DRS compared to without DRS at 0.4 km in the plot above, whereas the RB13 gained only 7 km/h. This perhaps, confirms that RB13 was designed with less drag in mind, and that the Haas car with the 2017 Ferrari PU is generating downforce that comes with an increased drag penalty. The RB13’s performance in turn 12 is matched by the Haas car, suggesting that the RB13 chassis is lagging behind the front running Mercedes in the high speed corners too.

The Haas’ performance in turn 12 compares well to data from China turn 7, of McLaren and works Renault chassis performance. The McLaren and Renault’s deficit in high speed cornering performance was also 4-5 km/h to Mercedes/Ferrari.

 

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  1. A note about the RB13. There were rumours in the off-season that RBR had designed a car to exploit asymmetric movement of it’s suspension components so that, the rake of the car would be reduced as the car accelerated along the straights, to help boost straight line speeds but maintain a bigger rake angle in the corners for better cornering performance/downforce. They were apparently doing this to some extent with the RB12. However, the rumours were that the team took this concept to more extreme interpretations that fell on grey areas of the technical regulations with the RB13–an avenue subsequently closed on short notice due to Ferrari’s request for clarifications. It could also be that, RBR had been forced to run a compromised car in the early fly away races as a stop gap that met FIA’s rule clarifications on suspension systems that precluded the kind developed for the RB13. This could also explain the RB13’s performance compared to Haas/Mercedes above. A heavily revised RB13 is set to debut at the Spanish GP.

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