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Wednesday, 13 June 2012

KERS & DRS - What They Are & What They're For

11/6/12, 10:48, 21617 views (when posted)

The above video is double world champ Sebastian Vettel on an American talk show hosted by an old bloke trying desperately to be funny. That's not the interesting bit of this article by any means, but in the interview - which includes an F-bomb and the mentioning of "balls" - David Letterman asks him several times at once to explain Formula 1's KERS and DRS gadgets, and makes it needlessly complicated. So, just in case you're new to the sport and/or haven't quite worked it out yet, I'm going to explain it in a way that hopefully is not complicated, because really, they're not that hard to explain. You just have to be given half a chance before some shouty pensioner butts in yet again...

Kinetic Energy Recovery System (KERS)
KERS is Formula 1's hybrid system, and their first attempt to make it easier to overtake in cars with so much downforce that many corners only really have one line and don't require significant deceleration. It works in two phases, the first of which is essentially the same as "Regenerative Braking", like you get on a pious hybrid road car. Kinetic energy that would otherwise be wasted during braking is "harvested" by a Special Thing on the rear axle, which transmits the energy into a battery - or a flywheel - as electricity. On electric cars, this is/would be a particularly useful addition. Need a sip of extra juice? Slam the brakes on at high speed. The insurance companies will understand...

Once you've topped up the battery, the energy is there to be used as an 80bhp (60kW) power boost. Each lap, you're entitled to 6.7 seconds of boost. When you cross the line, you're allowed another 6.7 seconds' worth. Commentators sometimes say that the battery graphic shows the KERS "recharging" as they cross the line, but of course it's actually harvesting electricity every time you brake, regardless of how much you've used or got left - until it reaches the maximum storage capacity of 400kJ of energy - and the graphic actually just shows how much of the allowed amount they've got left, which resets as they cross the line.

So it saves up energy to give you a momentary-but-noticeable power boost. Use it coming out of corners rather than halfway down the straight for maximum effect. Simple.

Drag Reduction System (DRS)
As the video shows, DRS can get more complicated the more you explain it, so to put its general purpose simply, I'll do it Q&A-style:

What's The Point? Wings on an open-wheel car create a lot of downforce, giving extra grip and thus allowing higher speed in corners, but they also create lots of drag, which is basically air resistance. That affects the straight-line speed and lowers the top speed. Also, the air coming off the car is very turbulent, so F1 cars can't follow each other closely, because while slipstreaming (like in NASCAR) does work up to a point, when they get to a certain distance to the car ahead, the turbulent air coming off the back of an F1 car stops them drawing in any closer. DRS solves this by "stalling" the rear wing.

How Does It Work? In a DRS Zone, the top part of the rear wing is raised up, stopping it from making any downforce, and minimizing drag. This adds about 10-15mph of top speed (depending on how long you use it for and how long your 7th [highest] gear ratio is), allowing you to catch up to and draw alongside the car ahead. This hopefully puts you in a prime position to pass the other car at the next corner. The difference in acceleration is noticeable when it's activated, and in contrast to KERS, it works best at high speed (when much more air is hitting the car).

How Do They Use It? Currently, in practice and qualifying sessions, you can use it whenever you want (i.e. all the straights and some very easy/mild flat-out corners), but in the actual race, you have to be less than a second behind the car in front when you go over the DRS "Detection Line" on the track. When this happens, you're entitled to activate the system using a button or switch once you go over the "Activation Line". The wing flap closes automatically when you brake (unless it fails, like Michael Schumacher's did during the Canadian Grand Prix this year thanks to a hydraulics issue). DRS is allowed when it's dry, and after lap 3 during Grands Prix. If it was allowed on the first lap, 23 out of 24 cars would use it and the whole thing would be pointless, and royally piss off the race leader. If it was allowed in the wet, everyone would spin out. You can't use DRS in corners because cutting out drag also cuts out rear downforce, meaning the car would just spin out backwards as soon as you turned in.

Visual Explanation
Some argue that these overtaking devices - particularly DRS - has made the racing "artificial". Sure, there were teething problems, and the idea of a "Double-DRS Zone", where there are two consecutive activation points one, did lead to two cars swapping places and then swapping back again at circuits like Abu Dhabi, which was annoying, but the major pro is that it allows faster cars to get past slower cars without being held up for lap after lap. For example, at the 2010 Abu Dhabi Grand Prix, Fernando Alonso came out of the pits behind Vitaly Petrov, and was stuck behind him from then on, allowing Sebastian Vettel to win on points and secure his first Formula One World Driver's Championship. If DRS had existed in the sport back then, then Fernando would've got past Petrov in one lap and could very well have got to a championship-winning position and secured his third WDC. The FIA have learned a lot from last year, and aim to set it at each track so that you have enough space to set yourself up for a pass, but not complete the entire manoeuvre before you even brake, which would arguably be "artificial" as you've just breezed past someone by pressing a button.

So there it is. Was that so hard? I hope not. Now you can tell your friends and watch their faces... get bored.

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