Musing #75: Analysing the Valencia Formula E debacle

 


Some may call it exciting and others farcical. For a fledging series, Formula E certainly attracted the wrong kind of attention with the slipshod finish yesterday resulting in only 9 drivers being classified at the end. While it is easy to call out the FIA or Da Costa for the extra lap, the reality, as always, is more complex. This analysis thus aims to clarify the events as they unfolded.

The first big question that I came across on the web was about the big change in energy reduction percentage during the various SC periods. While there was only a 3% reduction during the 3-minute safety car (SC) at the 20-minute mark, the final 5-minute SC resulted in a 12% reduction. Well, this is quite easy to explain keeping in mind the starting available capacity of 52 kWh. Essentially, the percentage value displayed on the screen is a relative value whereas the absolute reduction is happening in terms of kWh, both to the usable energy as well as available energy.

At 20:38 remaining, we can see that the available energy is 61%.

Moments later, it drops to 58% after the reduction.


The reduction itself is 3 kWh for that SC period and a total of 9 kWh for the race.


This latter part is the most important as it indicates the total available energy after the reduction. Back of the envelope calculations for this scenario is as follows. Note that these calculations are based on the whole number figures displayed in the TV graphics while the actual numbers with the correct precision would be slightly different.

Usable energy before reduction: 46 kWh (52 - 6)
Available energy before reduction: 61% of 46 kWh = ~28 kWh

Usable energy after reduction: 43 kWh (52 - 9)
Available energy after reduction: 58% of 43 kWh = ~25 kWh (28 - 3)

Now let us take a look at the final SC. The available energy is 18% prior to reduction.

It drops to 6% after reduction.

The total energy reduction is 19 kWh in total and 5 kWh for that SC period.

The calculations now are as follows:

Usable energy before reduction: 38 kWh (52 - 14)
Available energy before reduction: 18% of 38 kWh = ~7 kWh

Usable energy after reduction: 33 kWh (52 - 19)
Available energy after reduction: 6% of 33 kWh = ~2 kWh (7 - 5)

As you can see above, the percentage value can be quite confusing for the viewer as both the numerator and the denominator change by the same amount and thus the change in the actual percentage value will be more drastic for lower energy values than the higher ones.

That explains the TV graphics but then why were the teams caught so unawares towards the end? For, let us go to the period just as the final SC came out.


At this point, Da Costa has 22% of 38 kWh usable energy i.e. 8.4 kWh. The fastest lap as can be seen in the office notice was about 1m 40s. It thus indicates that at this point, there was enough time to cover 5 laps.

However, when the SC came out at 5:38 remaining, there was still a part of the lap remaining. Luckily, Da Costa floored the car at about the same place after the SC, so we can easily make out the time needed to reach the finish line from that part of the track.


As can be seen from the images above, it takes about 25 seconds implying that Da Costa would have crossed the line with 5:13 remaining if there was no SC. Considering the fastest lap of the race, 3 laps would have taken around 5 minutes. Thus, if Da Costa was to complete 3 more laps in 1:44 to 1:45 minutes, he would have needed to complete only 4 laps to finish the race with about 8 kWh remaining which is perfectly feasible.

The problem then is that the SC pace was not enough to scrub off a lap and thus the cars still had to complete 4 laps to finish the race, around 2 laps under the SC and a little more than 2 laps at race pace. While the race pace target was 2 kWh/lap, under the SC, assuming a lap time of 2m 30s, the reduction would have been 2.5 kWh/lap. This implies that the cars lost around a kWh of energy behind the safety car due to the time elapsed and at the same time utilised closed to 1.5 kWh of energy following the SC.

Thus, while in race conditions, Da Costa was expected to have 4.4 kWh of energy at the point where he started the final run with 2 laps to go, in reality he had about 2 kWh. The only feasible option was to limit the race to one lap after the SC which he was unable to do so. At the same time, Mercedes seems to have a 5-lap target in mind before the SC and thus were keeping more energy in hand compared to Da Costa who was hoping to limit the race to 4 more laps at the time the final SC came out.

While it was a shambolic end to the race with the FIA shifting blame to Da Costa for not controlling the pace, the FIA is not without blame. They had never made a provision for such a scenario and the fixed reduction of 1 kWh/min applied by the FIA is excessive when the usable energy is low.

One way of tackling such a scenario could have been to reduce the energy allocation for a race lap over a SC lap duration (i.e. ~2 kWh reduction over a 2:30m SC lap). This results in a reduction rate of 0.8 kWh/minute. If this seems too low a reduction, then the rule can be changed to apply this limit only for the final 10 minutes of the race.

The other option could have been to not deduct the energy consumed by the car behind the SC which seems to be about 0.3 kWh/minute (can be calculated from the fact that usable energy reduced from 22% to 18% behind the 5-minute SC with 38 kWh available energy). However, this would result in a reduction rate of 0.7 kWh/minute and thus even more benevolent that the previous approach which is in fact more practical as it takes in to account the energy consumption by the race car and SC for a specific track.

Will this situation be addressed? That is anybody's guess as Formula E certainly seems to be quite disorganised at present. However, the solution to the problem is available as highlighted above and all it needs is the FIA to act on it. Most probably though, I think the teams will adjust the software to account for the SC loss going forward and we might see a slow but secure finish if such a scenario arises in the future.

Musing #51: The philosophical difference between Formula 1 and Formula E


Compared to last year and the year before, I have decided to change tack and throw Formula E in to the mix this year. While the renders were shared in January, Formula E physically unveiled its Gen2 car at the Geneva Motor Show earlier today. I find it to be an attractive design, specifically as it is something that Formula 1 is unlikely to mimic anytime soon; unless its American owner, Liberty Media, manages to miraculously convince the teams that the show is more important than the performance.

This brings me to the point of why Formula E finds it favourable to adopt such a radically different design compared to Formula 1, marketing reasons aside. I cannot profess to be an aerodynamicist but over two decades of following motorsports has led me to be more appreciative of its technical aspects. Also, it feels satisfying to be able to tap in to my years of studying physics and engineering, and leverage it to satisfy the curiosity of a random commenter on the Internet.

Formula 1 is considered to be the epitome of motorsports and rightly so. It is all about harnessing the ultimate performance from the machine and achieving the ultimate lap time, much of which is accomplished by being fast through the turns. Hence, F1 cars are set up to have the highest possible downforce so that the turns can be taken as fast as possible while ensuring that the high drag that comes with it doesn't impact the straightline speed as much.

Unfortunately, most of the downforce in modern F1 cars is generated using aerodynamic structures and appendages which leaves a significant disturbed air flow for the car following behind. A consequence of this approach is the poor racing that we see in F1 these days. The much-maligned Drag Reduction System (DRS) overcomes this specific obstacle for the following car, though it seems the wider cars and even more intricate aerodynamic structures have rendered it less powerful (and thankfully so).

On the contrary, Formula E being a spec chassis series, isn't focused on ultimate performance. The philosophy here is to accelerate quickly out of the corners using the instant torque from the electric motors, reach the top speed as quickly as possible down the straights and then coast for the remainder of the straights, before breaking hard while already cornering to aid the charging of batteries using the Kinetic Energy Recovery System (KERS). The power absorbed by drag increases with the cube of speed increase, so less drag results in less energy expense over a lap, while ensuring higher top speeds along the straights. The less disturbed air of a low drag/downforce setup certainly helps the following car but a side benefit of this, coupled with the low-grip, all-weather Michelin tyres, and instant torque is that the cars are incredibly difficult to handle around the corners due to which we see a lot more driver errors in Formula E compared to F1's cornering on rails.

I hope Season 5 of Formula E brings in better uninterrupted racing, made possible by having a single car complete the race. However, I hope that some strategic element of a pit-stop is retained, e.g., allowing for quick, short recharges for additional power at the expense of lost time. Formula 1 and E aside, 2018 is looking to be another cracking year for motorsports with a competitive MotoGP field littered with manufacturers and the the new low-downforce IndyCar.

Musing #25: F1 2017 Preview


I can't believe it's been over a year since I had last contemplated the state of Formula 1. Much has changed since then, at least as far as ownership is concerned. Unfortunately, it seems Bernie's legacy will live on for some time, at least through 2017, even as Brawn seems to be presenting a more pragmatic view of the future of F1. Another shock that came through late last season was the retirement of Rosberg, but I am glad to have my wish of a new F1 champion fulfilled prior to it.

A year back, I had expressed concerns for the 2017 rules and true to form, F1 managed to pin the cow with the blindfold on, just not where it's intended. Hence, we might be getting cars that will end up being the fastest around most race tracks but might end up ruining the show. The 2017 rules were in the least intended to "make the cars beautiful again" but that can't be deemed to be a resounding success. Force India managed to still give rise to an ugly duckling (or platypus) while McLaren seems to have picked up the inspiration for their colours from backmarkers of yesteryears (Virgin, Arrows). In a way, it should suit them since that is most likely where they will end up this season.

Quite dreadfully, Mercedes seems to have picked up from where they left last season. However, Ferrari posted impressive lap times on harder tyres which offers some hope of a duel with Mercedes, though no one knows for certain what each team is up to. The Red Bull looked deceivingly simple at the first test, so one must assume (or hope) that Newey has something up his sleeve. Whatever be the pecking order, it doesn't seem that the general pattern will be any different from what we have already seen in the V6 era. If it ends up being a bore fest, at least now it will end sooner now with the faster lap times.

I am still looking forward to the new season as any change is worth the attention, at least initially. It might sound a bit cynical to expect the drivers to work harder to earn their money this season but it is more so with the expectation of seeing drivers make mistakes and throw up surprises. Lance Stroll has already indicated that things are not going to be easy with his multiple spins in the first test and while his raw talent seems to be far from Verstappen's level, there is an expectation that even the best will not be invincible. Clutching at straws we may be, but all will be revealed when the lights go out on March 26th.

Musing #22: F1 2016 (prior to season finale) in graphs

My opinion of Formula 1's 2016 season remains pretty much the same 9 months later and has in fact been reinforced by the on-track action. 2016 has again been a two-horse race or rather "two jockeys on one horse" race as the other "horse" in the race has miserably failed to prance. Even as the driver's title stands on a cliffhanger, the inevitably of it falling in Mercedes' hands is not enticing to say the least. The title fight going to the last race does not justify the largely boring on-track action throughout the season. Races like Brazil don’t happen too often and even then Pirelli’s rubbish wet weather tyres nearly managed to spoil the show. Having grown up in awe of Senna’s and Schumacher’s driving prowess and personalities, I think Verstappen’s drive has given me a reason to get behind someone since the vacuum left behind by Schumacher. Few great personalities have arisen in F1 since then and I have filled the void by devoting greater allegiance to Rossi as MotoGP has become the motorsport to beat.

Coming back to F1, this time I have decided to present the 2016 season in graphs based on public available statistics from f1.com and f1fanatic.co.uk, both of which are great resources for any F1 fan. The statistics can be said to mostly favour Rosberg because all things considered, he has been the consistent one. Keeping Hamilton’s engine gremlins aside, he still qualified outside the front row on few instances, something that Rosberg hasn’t done all season. Also, the fluffing of the starts can’t be put down to the car alone, so Hamilton must take his fair share of the blame even as his race pace has been better on most occasions. Having said so, even Rosberg has been untouchable once he’s in the race lead, so one can draw one’s own conclusions. Perhaps, having a new champion might be a welcome change going in to a new F1 era in 2017. I have always been on the “more power, mechanical grip and less downforce” camp, so the 2017 rules are not far reaching as far as I am concerned. But I guess anything will do to disrupt the status quo.

While all the other websites will judiciously update the stats following this Sunday's race, I am going to let this one be as it stands to put forth the perspective going in to the season finale, irrespective of who wins it all.

Qualification: (Click on the images for an enlarged view)



Race: (Click on the images for an enlarged view)