Tuesday, 16 August 2011

DRS - 1954 style

I really liked the article in F1 Racing recently about DRS 40 years ago (Thanks for that, Jimmy, Hans et al) especially as I was around in the 60s to see the cars running with ludicrous wings - I'm especially thinking of Jo Siffert at Brands Hatch here.

At the Nürburgring, by the entrance to the paddock, Mercedes were displaying two W196 cars from 1954. One was in standard open wheel form, the other was fitted with pristine "slipstream" bodywork. This was the German company's strategy for dealing with drag on the faster circuits like Reims and Silverstone. The two cars were both beautiful, but it's the streamlined one I'd drive, given the choice.

While you can't really call it DRS, as it's not operated by the driver, it was one of the first attempts in F1 to deal with the different aero needs of various circuits. Then, as now at Monza, the main reason for this is to reduce one of the forces that are reducing the acceleration of the car - in this case: aerodynamic drag.

As drag rises with the square of velocity, at high speed circuits with long straights it's very important to minimize drag where possible.

On a more typical circuit, the exit speed of a corner is more critical at determining the amount of time spent to cover the length of a short straight, so teams focus more on increasing that exit speed by using maximum downforce.

On an infinitely long straight, you would not run any more downforce than is necessary to keep the car from lifting at speed, and the car would accelerate more quickly along the straight than if it had a High Downforce set-up.

So the question becomes - where is the crossover between focusing on corner exit speed as opposed to Vmax - maximum speed (Velocity also includes the concept of direction, but as we are talking about a straight line it's ok to use the terms interchangeably. Well, I think so!).

In this totally fictitious example, let's look at two extreme set-ups, comparing the speed of a car exiting a given corner and accelerating down a straight (all other things being equal). You can probably imagine that the Low Drag set-up will start to bring dividends if the straight is about 700m long, or longer. But if there is only one long straight at the circuit, like Shanghai, the advantage on the straight will be more than negated by the time gained by using a high downforce setting over the rest of the circuit.

Which is why it's only at circuits like Monza and Montreal that we start to hear about "low downforce" settings; although I'd really prefer to talk about "low drag", as that's what we are aiming for. We would still want to maximise corner exit speed, but not at any price. Increasing downforce increases drag with any given wing, hence the need to reduce downforce - but we'd keep it if we could.

In the 1950s and 1960s, Reims and Silverstone were both circuits consisting of long straight pieces of tarmac where the corners were defined by where the straights crossed. And Mercedes' response to this was to build special bodywork. It wasn't until the late 60s that focus switched to increasing corner exit speed.

As usual, nothing is straightforward. At Silverstone, oil drums were used to mark the edge of the circuit. But Fangio could not see exactly where they were, so on his way to winning the race, he would occasionally get too close and tap one of the drums, denting the bodywork and almost certainly reducing the aerodynamic advantage. So it goes.
Sorry, I don't know who to credit for this photo, if someone does, please tell me!
Finally, if you've got this far and are wondering what sort of biscuit to reward yourself with, go for a chocolate digestive


  1. Great article! Enjoying your blog (I click all your links from Twitter). That last picture is tops too!

  2. Blah blah blah blah BISCUITS! Okay, the chocky digestive is way up there on the list, but can it ever really beat a Ginger Snap or the fabled Jaffa Cake (unless you class it as a cake of course)? This is presuming we're on Brit biccies only, of course...

  3. I was only given a choice of three biscuits (for a competition). If it was called a Jaffa Biscuit that would be tops, but it's a cake, so it's not. I'm open to non-Brit biccies, but someone would have to send me some...

  4. Well, that's exactly what http://www.nicecupofteaandasitdown.com/ aims to do (get free biccies). It is THE top site of the internet.