F1 tech special: Engines, aero and 2017 rules

Having worked in Formula 1 for more than 30 years, Williams's chief technical officer knows a thing or two about the game. Every month in F1 Racing, Pat Symonds brings his wisdom to our monthly 'Inside Tech' column, but we thought it was time he answered some of your technical questions directly.

It's our policy not to show our interviewees their questions ahead of time, but we made an exception in Pat's case - not for censorship, but rather because he was keen to research any for which he did not already have a thorough answer on the tip of his tongue. Indeed, as you will see, quite a bit of work with a calculator was needed at one point, and Pat thanked our readers for testing the limits of his knowledge.

We retreat to the middle deck of the Williams motorhome, but when we're only halfway through the questions, Pat has to leave for another engagement. "Don't worry, stay put," he reassures us. "I'm enjoying these so much I'll come back and answer them all."

Indeed, so comprehensive were his responses that this month we've devoted a little more space than usual to answer your technical queries.

Can the energy captured by hybrid engines be saved for extra seconds of power whenever the driver needs it, or must it always be used on the next lap?
Kenneth Trask, Canada

The answer to this one is that these are true hybrid power units, so the electrical energy and the energy from the normal internal combustion engine are almost one and the same thing.

When a racing driver presses down on the throttle, the system decides how much power comes from petrol and how much is electrical. In qualifying, we're using everything we can, whereas in the race we tend to be balancing it that little bit more.

Did you keep the rubber seal that failed on Michael Schumacher's Benetton while he was leading the 1993 Monaco GP?
Marc Wood, UK

I love this question! Yes, I do still have it. It now lives on the desk in my study at home. And I use it as a reminder that the smallest detail is so important.

We were leading that race comfortably and a tiny two-penny seal failed. It was on one of the actuators on the active suspension, and it cost us a race win.

Why do F1 cars have mirrors instead of a camera-operated visual display unit?
Tim Warner, UK

It's an interesting question, because in 1985 we ran the Toleman TG185 with a little camera and had two small monochrome displays that replaced the mirrors. Because we felt it was very natural for a driver to look into the mirrors we put the display in the same place, but, equally, it could have been on the dashboard.

It wasn't very successful, since the electrical systems caused an awful lot of interference so we couldn't make the display work, but today it would be a very easy thing to do.

It would definitely give better vision and it would improve aerodynamics. I can't understand why we're not doing it.

The monkey seat [the small wing under the main rear wing of the car] looks so unimportant, but it must be vital or it wouldn't be used. Why is it so significant?
Joanne Keeble, UK

Pre-2014, we were able to build a system at the rear of the car where the diffuser was aided by a beam wing that worked in conjunction with the rear wing. In 2014, the beam wing was taken out by regulation, so we now have a relatively low diffuser and a high rear wing and a big gap between them.

The monkey seat utilises a small area, 150mm wide, in the middle of the car where we don't have a restriction. It doesn't add downforce, it stabilises the rear wing and makes it better so we can push it harder.

Please could you explain what an S-duct is and how it works?
Louis Kershaw, UK

An S-duct is a device that connects the underside of the nose with the top side of the bodywork. It's called that because of its shape.

If you cut the car down the middle it would look like an S. The idea is to take air from the underside of the car - air that is building up a bit of a boundary layer - and move it to a place where it has less of a detrimental effect.

That's easier said than done, since air from a low-pressure area will flow only to a lower pressure area, which is why the S-duct opening is shaped like a letter box.

Dimples on a golf ball give it superior aerodynamic efficiency over a completely smooth ball. Has 'dimpling' ever been tried on the exterior components of a Formula 1 car?
Peter Lavigne, Canada

This is not as easy to explain as you might think. It has a lot to do with the 'Reynolds Number'.

What you want to do is to keep airflow attached to the surface, whether that is a racing car or a golf ball.

Air will build up a stagnant layer that eventually detaches, and if you don't control the way it detaches it's quite detrimental to drag.

So on a golf ball, by using the dimples you put energy into the air, excite it and keep it attached a little bit longer so that the golf ball flies further.

On a racing car you're going faster so you're dealing with higher Reynolds Numbers, and you have a slightly different flow regime.

So dimples work well on a golf ball and similarly on a shark's skin through water. Essentially they work at low speed, but at higher speeds they don't.

How far can the hybrid engine be exploited, or, better still, be made fully electric?
Mario Bernardo, Indonesia

Well Mario, you'll have to read my story on an F1 car 20 years in the future in F1 Racing in a few months' time. I think hybridisation is the first step towards full electrification in the consumer market.

There's more we can do, and we don't make enough of what we've achieved. The efficiency of the current F1 power unit is staggering, but we need a breakthrough in battery technology.

I think in the next 20 years we'll see that. Then we'll see more electrification.

Did you approve of the change in the regulations regarding what an engineer is allowed to tell their driver?
Luke Ridley, UK

F1 is a team sport and we should work together to try to win races. I can accept that some people don't want engineers coaching drivers. I have no problem with that, but I think that's where it should stop.

If we take this to the ultimate then we'll have the driver designing the car, building the car and changing his own tyres.

F1R: What about having a riding mechanic alongside the driver?

PS: That would be a driving aid! Actually today's engineers are a riding mechanic on the end of a radio, rather than hanging on for dear life in a slippery leather seat.

We should acknowledge it's a team sport, but also acknowledge that fans follow drivers more than they do teams, and I think teams should be allowed to help the driver get the best from his equipment and advise him on it - not tell him how to drive.

Bearing in mind that aero sensitivity is one of the main reasons for cars being unable to follow closely behind each other, should the 2017 regulations have included a form of limited ground effect in order to negate this problem?
Jon Harber, UK

It's true that aero sensitivity is one of the reasons that cars are unable to follow each other, but it is not a proven thing that ground effect negates this.

The work done by the Overtaking Working Group in 2008 to form the '09 regs suggested the opposite was the case. It wasn't a particularly rigorous piece of work, but people make bold assertions that ground-effect cars are much easier to follow.

I don't think anyone has proved that, and history hasn't shown that either.

F1R: A lot of people have asked whether more aero on the 2017 cars will negate overtaking and why are we doing it?

PS: It's a good question. The teams are involved in the regulations, but the formal working groups no longer exist. Working groups have no regulatory value; they are there to advise.

The philosophy comes from the Strategy Group. They had already decided - with Bernie [Ecclestone] - that they wanted to see cars that could go five seconds a lap faster.

The technical members of the team are not in a position to question that anymore. They are left in a position of: 'if this is what you want, this is how we can do it.' And in a formula where the power unit is reasonably fixed, it's therefore necessary to add tyre and aerodynamic grip.

Is it the right thing to do? Time will tell.

If you could write F1 technical rules by yourself, what would they be like?
Uros Kobal, Slovenia

This is a tricky one and I probably won't give the answer Uros is looking for.

The technical rules can't live in isolation from the sporting rules. There are two main objectives in F1. The first is to improve the cars and the second is to improve the racing. Then F1 teams have to be a sustainable business and that isn't mutually compatible with the first two objectives.

What I'd like to do is to combine the technical and sporting regs. That way, we'd free up the tech regs, but we'd ensure it doesn't become a spending war by having some form of cap on how we develop.

Other sports have financial regulations. We all have to fill in forms to say how much tax we have to pay, so it can be done.

Can you explain why the rain lights flash when it's not raining?
Paul Lychako, USA

We call them rain lights, but these days they have two functions. They are there for visibility in the wet and they flash to attract another driver's attention, and pre-2014 that's all they did. Now they have another use.

There's only a certain amount of electrical energy we can use during a lap. Don't confuse energy and power. Power drives the car and energy is the amount of time that you can have that power. So the electrical systems can deliver 120kW until we reach the energy limit for the lap. When we reach that limit we have to turn off the electrical drive.

120kW is 160bhp and that's a lot of power to turn off; if you're following a car closely and it loses 160bhp suddenly, you'll run into the back of it. So as that happens, the rain light flashes. That's what you see into the approach to corners in the dry. It's not a brake light, it's just that the electrical systems have been de-rated and the driver has lost 120kW of driving power.

I have read articles about diffusers but what does 'attached flow' mean?
Tony Geran, Australia

Attached flow isn't necessarily used in relation to diffusers; it's also used for one of the many flow regimes around the car.

If you imagine a car going through the air at 200mph, the free air that is stationary has a speed of 200mph relative to the car. But on the car itself there is a little layer of air that is attached to the car and that is travelling with the car. So the relative speed of that molecule of air and the car is zero.

That layer of air, which is known as the boundary layer, builds up in thickness - starting at the molecular level and building up to a few millimetres - and if you don't add any energy to it, it will eventually detach.

So then your attached flow will become a detached flow. When it detaches in an uncontrolled manner, it adds a lot of drag to the car.

What qualities separate great drivers from merely good ones?
Michael Barnes, UK

Good drivers can drive fast. Great drivers can also drive fast, but they add to that experience.

It's intelligence, tactical awareness, mental capacity and dedication. Then there's self-esteem. Great drivers believe they're the best, and that drives them to go further.

If you'd asked me 20 years ago, when Michael Schumacher first came along, I would have included fitness, but these days it's a given that they are fit.

You've got to be able to drive a car flat-out using only 80% of your mental capacity. The other 20% is for storing away information and adding to the data acquisition. Then you need to be intelligent enough to get all of that information across to your engineer.

F1R: What if you're brilliantly quick during testing, but can't handle the pressure to repeat that performance over a race weekend?

PS: That's what I meant by tactical awareness. Some drivers can test, but they can't race. I'm going back a few years but I'm going to mention Teo Fabi. In a quick corner all by himself, no one could touch him. Qualifying in Austria with a 1300bhp engine, he'd be on the front row.

But when he had other cars around him, he didn't have the spatial awareness to know what to do.

How does the increased rake on a Formula 1 car actually work?
Matthew Lumley, UK

If you increase the rake of the car, you're lifting the rear and dropping the front. The latter is always a good thing because the closer you get the front wing to the ground, the more downforce it produces.

The diffuser is an expansion device, so if you can lift it off the ground you can get it working better. Go too high and you lose downforce again. There is a sweet spot and the current regs do drive us to use quite a lot of rake at the moment.

What effect does ambient temperature have on F1 lap times? What is the approximate expected difference between, say, 10°C and 20°C?
Andrew Philips, USA

This is probably my favourite question. This one made me work because I didn't know the answer! [Pat pulls out his A4-sized notebook, which has numerical scribblings on it]

So, if we go from 10C to 20C, the air density drops from 1.247kg/m3 to 1.204kg/m3. So there's a 3.6% change in air density as it gets hotter.

What that means is that you lose some downforce, but you also lose some drag.

At a typical circuit - think Barcelona - the change in downforce would slow you down by 0.45s, but the change in drag would speed you up by 0.28s, so the net answer in terms of aerodynamics is 0.17s faster when it's colder.

Back in 2013 you would have had an engine effect too, because when it was colder the engine would have given you more power. But with the current power units, because we're limited on the amount of fuel we can put into them rather than the amount of air we put into them, it doesn't make a difference. The compressor has to work a bit harder on a hot day or at high altitude, but we can still get enough air into the engine to use our 100kg/hr fuel.

But the third thing we need to think about is tyres. If the ambient temperature has gone up by 10°C, then the track temperature may well have gone up, too, so does a hotter track make the car faster or slower? The answer depends on which tyre compound you're using and the operating temperature of that tyre.

How does the exhaust system convert heat into electrical energy?
Brian Squires, UK

A turbocharger consists of twin turbine wheels. One sits in the exhaust system and is driven by the flow of gas into it. The other one sits outside and compresses air before it goes into the engine.

In a current F1 car, there is an electric motor generator between the compressor and the turbine. We can use that either as a motor or a generator, and therefore fill the battery up.

The interesting thing is that we can also use it to limit the turbine speed, hence the boost, so we really no longer need a wastegate - although we do still use one because it's a slightly more efficient way to use the engine in qualifying mode.

And the other thing is that you often hear of turbo lag, where you put your foot down and have no power until the turbocharger spools up.

We don't have to wait for that to spool up - we can use the electric motor to spin it up. So turbo lag is a thing of the past.

Why is it that IndyCars can race on ovals whereas Formula 1 cars don't?
James Manzano, USA

I think that Formula 1 cars would be able to race on ovals, but you have to bear in mind that the loads on the tyres are immense on an oval.

An IndyCar tyre is a very different thing to a Formula 1 tyre. I don't think it would be very difficult to change an F1 car, though. It would be no more out of the ordinary than setting up an F1 car for Monaco, for example.

You would have to do a bit of strengthening on certain parts of the car to deal with the different loading conditions, but the main thing is that we would need a special tyre for it.

Why aren't dual clutches used in F1?
Mehran Irdmousa, USA

The reason we don't use dual-clutch gearboxes in Formula 1 is because of a slightly obscure technical directive from some years back, which banned the use of dual clutches on the grounds that they could be considered an additional braking system.

That was never reflected in the rules that the public could read, and this is one of the stranger aspects of Formula 1: you need an encyclopaedic knowledge of these technical directives that go back years.

In 1999, on the Benetton B199, we did run a dual-clutch gearbox and it was a fine device. It was heavy, but the reality is that with a dual-clutch box you can get a seamless gearshift - well, we have that on F1 cars now.

It's complicated and requires a lot of precision in both the electronics and the machining of the parts, but there would be no advantage in torque transmission by having a dual-clutch gearbox.

Why during heavy rain does the cockpit not fill up with water?
Dani Damaa, Lebanon

Well, the answer is that it does. In Malaysia 2009 when the storm hit and the red flag came out, the cars were so full of water that the KERS warning lights came on - the batteries and connections were flooded.

We try to make electrical systems that are good for water ingress.

Yes, there are little holes where water can get in and out, so it doesn't fill up and drown the driver.

But we deliberately don't drill holes in the bottom because the airflow under the car is so important.