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ADV-WF-F1-210x297-feb2017.indd 1 20/02/2017 10:15:11 CONTENTS/COMMENT Racing improves the breed

one, it seems, are the days when is a danger that the skill will be lost if the cars engineering excellence delivered continue down this current path. CONTENTS an outstanding result. Decisions Maybe I don’t need to worry. F1’s in good 4 THE DANGER FACTOR Gtoday seem to be based on hands, and I hope that the technical regulations Peter Wright assesses the analysis of fairness and equality. Racing is no longer simply are opened up suffi ciently under the new risk in modern Formula 1 racing about winning; today’s decisions are based on management to allow technical innovation. Ross encouraging more competitors, and therefore Brawn’s most recent title was thanks to a clever 6 F1 TEST UPDATE more money. The new Formula 1 regulations for double diff user, and throughout the history of F1, The Barcelona tests showed the cars 2017 appear to bear this out. In an interview with engineers have been free to experiment. to be as quick as expected, but also Racecar Engineering (October 2016, V26N10), Max One thing that is clearly lacking in F1 at very sensitive to set-up changes Mosley admitted that the reason for hybridisation the moment is the need for the drivers to look 10 CFD ANALYSIS of F1 was to give the manufacturers more after the car during a race. The tyres are harder, F1 has piled on more downforce, corporate responsibility for their racing. It has and Pirelli expects there to be fewer pit stops. but does this mean less overtaking? nothing to do with improving the competition. Arguably this puts more emphasis on overtaking 18 MERCEDES POWER UNIT Today’s new regulations similarly have on the track, but we have seen that these facts The rumour is that the Merc PU nothing to do with improving the racing; the don’t necessarily go hand-in-hand. A return to now runs with over 50 per cent wider, more aggressive stance was designed to steel brakes would be better, or a reduction in effi ciency. Peter Wright investigates increase the audience wow factor, while also brake cooling would help to increase the braking requiring more of the driver. However, it seems distances, the latter also encouraging a little bit 24 NEW ENGINE RULES to be that the Formula 1 cars, and incidentally of mechanical sympathy. At least there is the Do the 2017 Formula 1 power unit the WEC cars, are more about safe and effi cient issue at some circuits of needing to conserve fuel, regulations really allow for technical delivery of power than cornering. although this has already been compensated for innovation and closer competition? The drivers are actually less relevant now in the new regulations with a larger fuel tank. 30 F1 FUELS than they were in the past, when there was no I hope that the new season goes well in We take a look at the hi-tech blends downforce and a need to be able to execute more F1, that the issues highlighted in this edition, that power modern Formula 1 cars racecraft. That is not to say that the current crop brought together from our coverage in previous 37 TECH DISCUSSION of drivers don’t have that racecraft, but there magazines, don’t hold completely true, and that Is Formula 1’s aero approach the competition will be as fi erce as ever. This is based on fl awed thinking? the start of a new era, with new ownership, a new helmsman, and a wealth of opportunities. 40 PETER WRIGHT Racecar’s technical consultant ANDREW COTTON considers the best way to fi x F1’s Editor, Racecar Engineering problem of a lack of overtaking

Cars have bulked up for the 2017 Formula 1 season, but will that improve the racing, or just lead to drivers needing to do the same?

FORMULA 1 2017 www.racecar-engineering.com 3 WRITE LINE – PETER WRIGHT Calculating risk Is Formula 1 forgetting the fundamentals when it comes to risk management?

otorsport is dangerous – it says so on the pressures, and the nature of the competition. At any licence requires it. To try and unify risk in all forms ticket. It always has been and always will time they combine to form a set of rules that define of motorsport would result in closed-wheel, closed- Mbe, just as descending stairs is dangerous. and limit the risks. Those who participate in the cockpit cars on circuits, and would eliminate karting, It’s an activity which is right up there as a cause of sport, as opposed to watching it, know what these rallying, and single-seaters. Nobody wants that. accidental death with pedestrian road accidents, risks are and accept them. They volunteer to expose drugs and alcohol. Or, to put it another way, themselves to these risks and can always walk away Acceptable risks motorsport is remarkably safe; if you are going to if they believe they are unacceptable. What is an acceptable risk has changed with time. have a high-speed crash in a car, make sure it is in a Experience and technology have been applied If we take the highest class of racing, initially road- racing car. But this was not always the case. by the motorsport industry to steadily reduce the racing, then grands prix, and now F1, in the early The early races, city-to-city contests, had only risks, but occasionally social pressures intervene days the driver and his unfortunate mechanic sat on been going a few years before nine fatalities during and demand a further reduction in risk. Examples top of the car with little protection. In an accident the Paris-Madrid caused the French government include: 1907 Paris-Madrid; 1955 Le Mans, and 1994 they were usually thrown clear and hoped the car to halt the race in Bordeaux and ban all open road Senna and Ratzenberger at Imola. didn’t land on top of them. Even after the occupants racing. Governments do not want to have to control were lowered and surrounded by bodywork in any sport, let alone motorsport, and will only step in Risk factors the interests of performance, being thrown clear if sporting fairness or safety is compromised; instead Influencing this steady evolution of risk is the nature was the preferred option. Anything that inhibited they look for sanctioning bodies capable of doing of the competition. Leaving bikes aside, the four the driver escaping from a car that was on fire was the job properly. In international motorsport, that main categories of wheeled motorsport are: Karts; rejected. In the late ’60s, aided and abetted by organisation is the FIA, with its affiliated member open-wheel, open-cockpit, single-seaters; closed- Jackie Stewart, F1 drivers started to not accept the clubs acting as the national sanctioning bodies. wheel, closed-cockpit circuit cars, and closed-wheel, unnecessary risks involved. Over the next decade, closed-cockpit rally and cross-country cars. standards were established to completely change Explosive issue They do not have identical safety risks, so why the philosophy of protecting a driver in an accident. High on the agenda of anybody responsible for is that tolerated? Neither do they have the same This resulted in the cockpit becoming a survival any form of motorsport is safety. The sport is still risk as racing motorbikes, downhill skiing, base space, particularly by the installation of a roll over inherently dangerous, because of the level of energy jumping, cross-country horse eventing, scuba hoop. Also, the driver was restrained in this survival embodied in a high-speed car, the use of flammable diving, or flying home-built aircraft. space using a full harness, he wore fire protection fuels, high voltages in electrical energy stores, and They are all different, they all involve different clothing, and fuel tanks were fitted with bladders. the number of people involved in the running of risks, and participants understand and accept the Alongside these fundamental changes to the sport. The nature of the contest requires this risks, or at least they should do so, as their racing driver protection, changes to the race circuits, the concentrated energy to be conducted by a human at the limit of control – the kinetic energy of an The kinetic energy of an LMP1 racecar at LMP1 car at maximum speed is equivalent to over 1kg of TNT; while the full fuel tank is over 0.5 tonnes maximum speed is equivalent to 1kg of TNT of TNT. And accidents will happen. The job of the sanctioning body is to keep any sudden release of this energy away from humans. Track workers and spectators must be protected by the circuit layout and design, but officials, teams, marshals, and drivers are inevitably likely to be exposed. This is where the management of risk becomes necessary. Motorsport cannot be 100 per cent safe; there are always risks and they need to be understood and managed. The instruments by which these risks are managed are the Sporting and Technical Regulations. The way the drivers, officials, marshals, teams and all engineers involved conduct themselves are laid down here. Also set out are how they will be policed and the sanctions for non-compliance. These regulations have been developed over more than 100 years, with variations for all the different forms of motorsport from bikes, to trucks, to dragsters, to rally cars, and to F1.

Four forces have shaped the evolution of XPB these regulations: experience, technology, social While F1 is nowhere near as dangerous as it once was it still has its moments. This was at last year’s Russian GP

4 www.racecar-engineering.com FORMULA 1 2017 emergency intervention, and the medical facilities at the tracks were also taking place. Once the driver was strapped into the cockpit, he was subjected to the deceleration of the car if it impacted a solid object. These were steadily removed from the edges of tracks and replaced by impact attenuating barriers. Standards for the strength of the car chassis were developed and thought given to impact attenuating structures on the cars themselves. Unfortunately, at that time the sides of the car structure were mainly fuel tanks. However, the spaceframe and aluminium chassis of cars in the 1960s and 1970s would not hold up well in an accident and intrusion injuries became prevalent, for example with Clay Regazzoni and Ronnie Peterson. And so the driver was moved back to put his feet out of harms way and fuel was stored in a single, central fuel tank. Driving change Drivers drove these changes, new technologies

enabled them, and there was little pushback against XPB the changes, as they did not infringe on the F1, Halo looks set to come in to Formula 1 in 2018 and is sure to be used on other single seaters too. But have the open-wheel, open-cockpit concept. The advent risk factors been properly assessed and is it worth diluting the essence of open cockpit racing if they have not? of CFRP monocoque chassis then led to the concept of the strong survival cell for the driver, a statistical science, with development normally then there’s the lawyers (‘it is too complex to define; surrounded by impact attenuating structures of being based on experiments rather than theory. depends on which territories are involved in any regulation-prescribed performance. Any safety feature introduced into an activity resulting action’). The risks reduced dramatically as intrusion can only be assessed in a limited number of Any proposed reduction in risk that also injuries became rare and deceleration injuries were experiments, which will never cover all eventualities. changes the nature or perception of the activity is addressed with better harnesses, helmets, cockpit Once sufficient confidence in the benefits has bound to cause controversy. Safety doesn’t work surrounds, and HANS developments. been established it can be introduced and the with clear, irrefutable numbers, and this is why the The cars were still open-wheel and open- actual benefits, measured against the downsides, Additional Frontal Protection proposed for F1, is cockpit, and fans could just about see and identify assessed statistically. In motorsport there is usually creating so much discussion; how much does the with the drivers. Drivers started to take more risks a competitive benefit from taking risk, which must Halo reduce risk? How much does it increase it? as the consequences of a mistake were reduced. be balanced. Unfortunately motorsport safety Would a screen reduce it further? Or increase the Circuit design, run-off areas and barriers, race statistics are very hard to establish reliably. With one risk? Is there an alternative? How much would it direction, and intervention protocols applied fatality in Formula 1 every 20 years the data is not cost to apply to GP2, F3, and F4 etc.? How many throughout motorsport meant that a new statistically significant. Head strikes by loose objects people would it put off watching F1? generation of drivers arrived in Formula 1 who occur about once a decade. However, drivers Risk management is possible when clear had never experienced a fatality at a motor themselves are expert at assessing risk, they do it numbers exist, although the unintended racing event. Until Imola 1994. every time they brake into a corner at racing speeds: consequence can still rear its head. Without firm Three accidents involving two fatalities occurred ‘If I leave my braking later and enter the corner numbers it is just a battle of opinions. It should be where the injuries incurred could be attributed in faster I will take pole. If I brake too late, I shall not resolved by the drivers (the risk takers), and by the part to the lack of head protection in an open- get pole and may damage the car or myself, which guardians of motorsport, the sanctioning body (the cockpit. Measures were put in place to reduce will affect my chances in the race.’ sport) and the CRH (commercial rights holder), but the risks, but none impinged significantly on the It is the drivers who accept the risk. No one can in a world dominated by social media, everyone concept of the open-wheel, open-cockpit single- do that for them. The problem comes when they believes they have a right to have their views heard. seater formula. The risks became acceptable again. collectively say the risk is unacceptable; something From risk management to democratic government, We are now in a new era following a number of has changed. At this point they can walk away, it is becoming harder and more complex to find accidents where loose objects have hit the driver’s as Niki Lauda did on occasion, or lobby for a risk- the right path in such an environment. head, and the risks are being reassessed once again. reduction technical or procedural solution. This time there is a difference, as the only potential solutions affect the open-cockpit concept of motor Dangerous liaisons racing’s premier formula, and inevitably, all the Enter the other stakeholders; the fans (‘something rungs of the single-seater ladder up which the must be done’ or ‘I shan’t watch F1 if there is no The race drivers young drivers climb to Formula 1. danger involved,’); the sponsors (Mercedes after Karl Wendlinger’s accident at Monaco in 1994 themselves are experts Risky business ‘We are not in this for a driver to be so injured in at assessing risk, they How are the risks assessed for acceptability in a car with a three-pointed star on it.’); the a volunteer activity? How are the sanctity of a sanctioning body (must regulate safety to a do this every time they concept and the image of a sporting activity level such that governments do not step in); the determined? Who decides these issues? Risk is Commercial Rights Holder (against anything that brake in to a corner at usually analysed statistically as it relates to the puts fans off watching); the teams (‘tell us what probability of uncertain future events. Safety is the rules are in time to implement them.’ And racing speeds

FORMULA 1 2017 www.racecar-engineering.com 5 FORMULA 1 – TESTING UPDATE

A sensitive subject With new higher downforce aero regulations and fatter tyres, quicker F1 cars were a given at the pre-season tests. But Barcelona also provided a surprise or two By SAM COLLINS

6 www.racecar-engineering.com FORMULA 1 2017 ‘It does seem that things are quite n 2017 Formula 1 has a new look, new aerodynamic regulations and much bigger tyres, all designed to improve the show and amplified with these cars, because make the cars more challenging to drive. IIt is those tyres, though, that appear to be the you are going that much quicker’ biggest factor following pre-season testing. ‘It is now clear that this season is a big contest not just of aerodynamics, but also the tyres,’ says Paddy Lowe, chief technical officer at Williams. ‘It’s going to be a lot about how you use those tyres which will give you an advantage. These new wider tyres are going to create a huge challenge and the people who are best at understanding them will profit.’ Following the eight days of winter testing at Barcelona and a few shakedowns and filming runs at Fiorano, Silverstone and Misano much more is now known about the new generation of Formula 1 racecars, and it has emerged that they have one unexpected trait. ‘From our experience they seem to be more sensitive to change,’ Toro Rosso technical director James Key says. ‘We knew the tyres would be more sensitive to tyre parameters, where you change the onset angle of the tyre to the road. So I think that’s proven to be the case, but maybe more sensitive than we expected. I think even things like front flap angle changes and this sort of thing all seem to be more noticeable than they were last year. It could be that last year’s cars were quite mature so the teams and the drivers understood the diminishing returns, they were maybe a bit more benign than these cars are, but it does seem that things are quite amplified with these cars, because you are going that much quicker.’ Early days During testing some teams were clearly working hard on understanding the new rubber, though the general feeling in the paddock was that there is still much work to be done. ‘Some of the parameters we expected to be sensitive are sensitive and some of the compounds characteristics are not that far away,’ Key says. ‘But I’d say the majority of it is a learning process. However well you try and model a tyre, until you hit Barcelona in the morning or the afternoon, or with a different fuel load or whatever, you don’t know exactly how it’s going to respond. I think every run we’ve learnt something new about how the tyre responds to changes and how the driver needs to drive his out-lap and this kind of thing. I think in terms of modelling and prediction there’s no nasty surprises, but certainly a few differences in how sensitive they are to certain things’. Pirelli, too, is investigating the performance of not only the tyres but also the cars and how they work on its product. It had not been able to test the new rubber at any time before the new cars were launched in February and has been outspoken about its concerns about that lack of running, though following the tests in

FORMULA 1 2017 www.racecar-engineering.com 7 FORMULA 1 – TESTING UPDATE

Rookie Lance Stroll was caught out by snap oversteer three times, his final spin resulting in this crash and a damaged monocoque. New breed of cars seem much more prone to sudden oversteer than the 2016 racecars

clear that these cars are very, very sensitive. Any suggested was right. Now we are receiving data small change has a big effect on balance and from the teams from testing and it is generally the performance of the cars, so of course the in line with the simulations. In 10 to 12 races tyres are a key factor in that.’ time, with the cars getting much faster, we will Perhaps making car set-ups somewhat have to increase the minimum pressures as the easier are the limitations on tyre pressure and stress on the tyres will be higher.’ camber angle which have been in force in Formula 1 for some time. ‘The original set-up we Hard drive Pirelli was unable to test new rubber before the Barcelona tests, set in testing was 3.5 degrees maximum camber Throughout the test a number drivers where most of the cars were launched. Despite concerns over lack on the front with a pressure of 22psi, but we noticeably struggled with the handling of their of running it was broadly happy with performance of its product then gave the option of going to four degrees cars, some suffering high speed spins and a few of camber but at a minimum of 23psi. The hitting the wall as a result of them. Catalunya its spokespeople all seemed broadly pressures and camber will again be restricted ‘I think in terms of tyres, from my feeling, it is positive about how things were going. during the season, the pressure will be checked not a massive difference in terms of how sudden ‘The degradation level is lower than last year, as the tyres go on to the car, the camber is the loss of grip is, only in the case if the tyre that’s what we expected and that is what we policed by the FIA,’ Isola says. is not hot enough, especially with the harder saw in testing,’ Pirelli’s head of Car Racing Mario compounds, sometimes it can be quite tricky Isola claimed during his test review. ‘When you Under pressure to get them to work,’ Mercedes driver Valtteri overstress the tyres they come back quickly, that In 2016 Pirelli was criticised by some, including Bottas says. ‘The cars are quite snappy if you was a key objective for us. I think the cars will drivers, who thought that the tyre pressures have oversteer, it’s very sudden. But with the have a huge amount of development during the were too high, but as Isola explains, if anything softer compounds, once you get them to do the season so the rate of degradation will probably the minimum pressures are going to increase. temperature, it felt like very much the same rate increase as they gain downforce and power ‘The restrictions will be fairly similar even with of sliding or losing the grip as last year.’ through the year, as you might expect.’ the new tyres. Last year the minimum pressure Once the car has lost the rear it seems that However, the Pirelli engineers also noticed limit was 21.5psi on the front. At the rear it is drivers are struggling to bring it back under the increased sensitivity of this generation of 18psi and I think it was 19.5psi last year, so control. This was very apparent watching them grand prix car. ‘They are more sensitive to any the minimum pressure is higher at the front and tackle some sections of the circuit in testing, and change in set-up, talking with the teams it is lower at the rear as that is what our simulations it could lead to more crashes during races. ‘To

8 www.racecar-engineering.com FORMULA 1 2017 Pirelli’s wet woes

ight large tankers slowly toured around the Circuit de Catalunya during the second pre season test. EThey deposited a quarter of a million litres of water around the whole track; twice. Pirelli had demanded this slightly odd-looking activity as a way to get some running on its new wet and intermediate tyres before the season got underway. Unfortunately, not everything was as the Italian tyre maker had hoped, not least because the Catalan sunshine saw the track dry rapidly. ‘With the new wet tyres we focussed on two things; firstly a tyre which could work in cooler conditions and switch on easily,’ Mario Isola says. ‘We have the new regulations about standing starts in the wet, where you can see the cars driving around behind the safety car for a few laps and then they have to stop and make a standing start, so we need the tyres to work right away. Aquaplaning was another big area, with the bigger tyres the risk of aquaplaning is higher, so we designed the tyres with more Front camber and the tyre pressures are to be limited, which has been the case for the last few seasons. grooves, different sized grooves and different angles, but The pressures will be checked as the tyres go on to the racecars, while camber is to be policed by the FIA we have to test them. At Barcelona the track is not flat and the water just ran off, so there were no rivers or pools, so we could not really test that unfortunately.’ Global warming Paul Hembery, Pirelli’s former head of motorsport says: ‘We have some work to do on switching on the compound, we are working on that. We could see there was an issue warming up the tyres. We found that the intermediate was not switching on how we wanted it to, so we know that there is a bit of an issue and we are working on it. We already suspected that it would be an issue and the test confirmed it, but work is already well advanced. There is probably a case for having two types of wet tyre, one for the warmer wet races and one for the Silverstone or Spa type of wetness, where it is a lot cooler. If we confirm what we are working on we could introduce a wet tyre compound change for the Chinese Grand Prix.’

Tyre degradation will be low in 2017 if the tests are anything to go by. But Pirelli expects the rate of deg’ to increase throughout the year as the teams find more power and downforce through in-season development catch the car is much harder, so you can go off, working to make the cars a lot more predictable, whereas before, you had a slide and you could working on set-ups that are more driveable. It’s catch it. This year it is harder to catch it,’ Esteban clear that when you have more grip and more Ocon, now a Force India driver says. ‘You go at downforce that when the grip is lost the car such a speed in the corners, it is already hard to becomes snappy,’ Isola explains. find the limit and when you start to lose the car, Temperature and the working window of the car is heavier, obviously. The tyres especially the cars, as well as keeping them drivable yet are wider, so when you start to lose the car, the fast, is likely to be the deciding factor in many snap you get is much bigger than [in] previous races this season, and with the cars so sensitive years. That has caught out some of the drivers to any changes it is likely that almost every in winter testing.’ Formula 1 team will get it wrong at some point and that could lead to unpredictable results. The track was soaked to evaluate Pirellis’s wet rubber, but the Snappy days It will be fascinating to watch. Spanish sunshine and the circuit drainage spoilt the exercise This snap oversteer tendency is, according to Isola, really a consequence of the aerodynamic regulations allied to the increased tyre grip. It is highly likely that almost every one of the ‘Snap oversteer is possible as the cars have increased grip, so I know a lot of the teams are Formula 1 teams will get it wrong at some point

FORMULA 1 2017 www.racecar-engineering.com 9 TECHNOLOGY – F1 AERODYNAMICS Follow the leader Downforce levels have increased in F1 for 2017 but will the new regulations improve or reduce the ability of cars to run close together or overtake? By SIMON McBEATH

2017 F1 car models in tandem-running simulation. There’s the usual messy spaghetti, but will it be easier for the following car to stay close or overtake?

ith official F1 testing package designed to achieve the best influence on a driver’s ability to work that MA has performed on scheduled to take lap time, and one which will form the get close to the car in front. And the new 2017 car model to bring place at the end of basis for ongoing developments. being able to get close is the its balance and downforce closer to February, time is now However, with designs and CFD essential preliminary to being able expected levels so that he had a shortW for the teams to complete the services provided by Miqdad Ali (MA) to overtake, which definition here good basis on which to conduct build of their initial aerodynamic at Dynamic Flow Solutions, Racecar excludes artificially assisted passing the line astern simulations. packages to the new regulations Engineering can show the results not manoeuvres that use DRS, or ‘push that come into force for 2017. And only of optimisation work on the to pass’ engine modes, or the release Improvements with limits on the amount of wind 2017 rules model introduced in our of stored energy. The FIA’s passing The 2017 rules model introduced tunnel testing and CFD that the December issue (V26N12,) but of reference (pun intended) to the topic in last month’s issue did not quite teams are permitted to do under the running that car in two-car line- of overtaking was seemingly just to achieve the desired aerodynamic Resource Restriction Agreement, it astern drafting scenarios that we can request that the new rules should not balance or the expected total is improbable that any of them have compare to the similar trials we have make the current situation any worse. downforce level in initial simulations. indulged in the relative luxury of conducted in the past 18 months. Now we can demonstrate what the With the statutory weight distribution running their new designs in multi-car The rationale behind our line initial ‘following car’ simulations on in F1 requiring around 45 per cent scenarios to see how they will perform astern two-car simulations has been our 2017 rules model have indicated, of the weight on the front axle, the in traffic. Their focus will inevitably that the effect on the aerodynamics and our findings are surprising indeed. aerodynamic balance target was have been on hitting the track with a of a following car has an enormous But first, let’s look at the optimisation also to have 45 per cent of the total Now we can demonstrate what the initial following car simulations on our 2017 model have indicated, and our findings are surprising indeed

10 www.racecar-engineering.com FORMULA 1 2017 Table 1: The basic aerodynamic parameters on our baseline 2017 FIA rules F1 model at 50 per cent front balance level CD -CL -L/D 2013 1.17 3.94 3.36 2016 0.87 2.84 3.27 Follow the leader 2017 1.20 3.91 3.26

Figure 2: The effects of our optimisation work on the 2017 Formula 1 racecar model. Gains in downforce were made from the underbody and the rear wing areas of the car

Figure 1: Areas optimised on our 2017 model are highlighted in red. The front wing, Figure 3: Comparing downforce contributions with our 2013 model. It’s clear here that bargeboard, rear wing flap and rear wheel brake duct cascade were all re-designed the underbody of the car has become even more important with the 2017 configuration

downforce on the front axle. In its 2017 car to see how it performed the front wing terminates, 250mm downforce by the required amount. first design iteration our model when following. This would give us from the centreline] of the 2013 front The strength of the y-250 vortex generated a 50/50 per cent split in an idea of how it compared to the wing worked well with a raised nose was increased through the use of downforce, so clearly more work was 2013 racecar at various line astern where the resulting y-250 vortex smaller flap elements at higher AoA. required to generate some more rear separations and whether the 2017 interacted well with the vane-vortex Moreover, the y-250 vortex was downforce, and/or to reduce front rules had made things any better.’ coming from the under-nose turning moved outboard (to y-320) (through end downforce. At the same time MA MA continued: ‘To improve both vane. The lowered nose on the 2017 reduced span of the flap elements) was also looking to achieve greater balance and increase downforce car changed the flow in that area and worked better with the bigger total downforce, as he explained: ‘In there were several things on the considerably. We were not getting the bargeboard in deflecting the front the previous feature we compared baseline 2017 car which obviously flow conditions needed for producing tyre wake away from the underfloor. three cars at equivalent balance levels needed work straight away. One efficient downforce. There is also the All these produced a more favourable of roughly 50 per cent front and that would expect this anyway when presence of the bigger bargeboard, flow condition behind the front gave us an idea of where things were, you make simple changes to a car which would need careful placing wing which helped the underfloor as shown in Table 1. The next target which works well under one set of in the context of all the other flow produce more downforce and shifted was to optimise our 2017 car both regulations to meet a different set of structures around the area. Also, the the balance to the rear. for balance and downforce. We also regulations. The first thing to address baseline front wing produced more ‘To improve the underfloor further, wanted to compare the optimised on the 2017 baseline model was the downforce than required. several vertical slots were added 2017 car with our earlier optimised size of the front tyre wake. The results ‘A new front wing was designed to the bargeboard, which kept the 2013 car (at 45 per cent front), against and visualisations showed that the to address the above issues. The flow attached to the inner face of which our following-car simulations baseline front wing and its endplate outboard section diverted the flow the bargeboard; this in turn kept the on various design configurations have did not do a good enough job of around the front tyres a lot better, pressure low and improved mass been compared in previous articles, diverting the airflow outboard of the resulting in a smaller front tyre wake. flow in that area. It also increased the and run the optimised 2017 car at wider front tyres. Secondly, the ‘y-250’ A reduction in chord length of the strength of the bargeboard vortex various separations behind a leading area [where the neutral section of main element reduced front wing (which added downforce in the The visualisations showed that the baseline front wing did not do a good enough job of diverting the airflow outboard of the wider front tyres

FORMULA 1 2017 www.racecar-engineering.com 11 TECHNOLOGY – F1 AERODYNAMICS

Figure 4: This delta-Cp plot shows where pressure reductions were achieved with Figure 5: Turning the airflow more effectively outboard around the tyre also produced optimised 2017 model, leading to downforce gains, especially in the rear underbody reductions in front tyre drag, as shown by the pressure reductions (blue) on front of tyres

Figure 6: A total pressure slice taken 200mm above ground level clearly shows Figure 7: A total pressure slice 900mm behind the front axle line shows how the flow the reduced front tyre wake on our optimised 2017 Formula 1 racecar model structures were modified by the optimisations; note the front wheel wake reduction

Table 2: The basic aerodynamic parameters on our insiders of up to 25 per cent more understeer when closing on the optimised 2017 FIA rules Formula 1 model compared downforce in 2017 than in 2016. car in front, and our simulations on with our earlier 2013 Formula 1 model racecar models to recent rule sets have shown CD -CL %front -L/D Tough act to follow this rearwards shift in aerodynamic 2017 optimised 1.20 4.31 45.0% 3.59 So, coupled with increases in balance at ever closer line astern 2013 optimised 1.17 3.89 45.0% 3.32 mechanical grip from the bigger tyres separations too, which has made it being imposed for 2017, Formula 1 manifestly difficult for following cars lap times will certainly decrease for to close up on the car in front. forward underbody) due to a bigger Table 2 shows the basic aerodynamic cars running in isolation. But how will It was felt that minimising or pressure difference across the two data for this optimised 2017 model following cars in line astern formation eradicating this rearwards shift faces of the bargeboard. and compares it to our earlier fare? We have seen in our various in downforce balance was key to ‘Moving to the rear of the car, optimised 2013 rules model. The studies over the past 18 months mitigating the problem of being able minor changes were made to the 2017 model now generated over 10 that the car’s basic aerodynamic to follow closely, and we saw in V26N2 rear wing flap profile, reducing per cent more downforce than the configuration can alter the total (February 2016) how increasing the its camber to fix some trailing 2013 model. Given that the 2014 to downforce and aerodynamic balance influence of underbody aerodynamics edge flow separation. The slot gap 2016 regulations caused a marked that a following car can generate. MA was one of the important factors between the main element and decrease in downforce compared created one configuration, among in minimising balance shift on the flap was reduced from 12mm to the to the pre-2014 rules, it looks as others, that saw zero balance shift on following car. The 2017 rules enable minimum permitted 10mm. And though our optimised 2017 model the following car across the range of a greater downforce contribution gills were added to the rear wing was producing significantly more longitudinal separations from eight from the underbody, so could we be endplate leading edge to deal with downforce than our 2016 model car lengths to half a car’s length, and optimistic of change for the better? flow separation there. Rear wheel/ would have done at the same balance another that saw much reduced total The data from our 2017 rules tyre assembly lift was reduced via the level, had it too been optimised. downforce losses when following, model in two-car line astern is use of brake duct cascades. All these From this we might conclude although achieving both certainly outlined below, and Figure 8 changes increased overall downforce that, following the optimisation work looked like the search for the Holy illustrates the changes to the usual by over 10 per cent over the baseline MA carried out, our model may not Grail. Meanwhile, out on track in all aerodynamic parameters across 2017 car, with a desired downforce be too far from expected Formula 1 the recent rule-defined aerodynamic the range of horizontal separations balance of 45 per cent front and 55 aerodynamic performance levels configurations we have seen how from half a car’s length to eight car per cent rear,’ [Figures 1 to 7] amid the reported predictions by F1 cars have suffered from aerodynamic lengths. It is immediately obvious It was felt that minimising this rearwards shift in downforce balance was key to mitigating the problem of being able to follow a car closely

12 www.racecar-engineering.com FORMULA 1 2017 Figure 8: Changes to the principal aero numbers on optimised 2017 car when following Figure 9: Changes to front wing downforce on our optimised 2017 car when following

Figure 10: Changes to rear wing downforce on our optimised 2017 car when following Fig 11: Changes to underfloor, diffuser downforce for optimised 2017 car when following that there are some major and very The plot lines in Figure 8 showing the following car might initially be downforce as cars closed up on the surprising differences with this 2017 the front and rear downforce changes able to get closer more comfortably one in front was the dominant cause configuration. The most obvious with car separation confirm the than in previous configurations but of rearwards balance shift and aero difference is in how the aerodynamic forwards balance shift, with front then, as it closed more, become prone understeer when following through balance on the following car changes and rear downforce declining to aerodynamic oversteer. This may a corner. But our 2017 rules model across the separation range. similarly and modestly from eight simply manifest itself as just that, did not suffer this to anything like Initially there was zero balance to four car lengths separations, but oversteer. But could it be that drivers the same extent as we had seen on shift at eight and four car lengths at closer separations both ends will risk spinning off if they get too earlier models, and had this been separation, which does indeed give declined further, but rear downforce close to the car in front? the whole story then we might be ground for optimism that cars could declined much more. contemplating – indeed celebrating – run closer. This minimal balance Translating the relative data in the The detail a scenario in which balance shift when shift at these separations, combined graph to absolute numbers, what we Figures 9, 10 and 11 isolate the following closely was minimal. with just a modest initial decline in saw on our model was the balance downforce changes of the front It was unfortunate, then that, total downforce, and the increased figure change to about 50 per cent and rear wings and the underbody after the initial modest downforce mechanical grip of the 2017 cars, front at two cars’ separation, 55 per across the range of longitudinal losses at eight and four car lengths should make things easier for the cent front at one car’s separation separations to help understand why the rear wing then lost considerably following driver as he first starts to and about 61 per cent front at half a our 2017 rules model responded the more downforce as the car got closer close on the car in front. car’s separation, compared to the 45 way it did. In contrast to previous car to the one in front. A not dissimilar However, the subsequent forwards per cent front figure on our model configurations, with our 2013 rules pattern affected the underbody, and balance shift at closer separations in isolation and at eight and four model shown here for comparison, the rear wing’s losses will have been is the complete opposite of what car lengths’ separation. If this were the 2017 model’s front wing directly related to the underbody we have become used to and is an to transfer out on to the track, what maintained a good proportion of its losses because of the interaction intriguing and – if it translates to we could see in 2017 when cars try downforce at all separations. This in between the two; once the rear reality on track – a slightly worrying to run close together in line astern isolation was quite a step forwards; wing lost downforce, so too did the response for the closer separations. through ‘aero speed’ corners is that previously the loss of front wing underbody. Thus we appear to have a This may simply manifest itself as just that, oversteer. But could it be that drivers will risk spinning off if they get too close to the car in front?

FORMULA 1 2017 www.racecar-engineering.com 13 TECHNOLOGY – F1 AERODYNAMICS

Figure 12: At four car lengths separation the front wing of the following Figure 13: At four car lengths separation the rear wing of the following racecar received a reasonably energetic and a well aligned airflow racecar also received a reasonably energetic and a well aligned flow

Figure 14: At half a car’s length the front wing of the following car still received Figure 15: However, the rear wing did not fare quite so well at decent airflow; in fact the swept back shape seems to align with the onset airflow closer separations, receiving lower energy and a disturbed airflow

Figure 16: Here the delta Cp plot of the underside at half a racecar’s length Figure 17: At half a racecar’s length separation the rear wing saw pressure separation shows that the front wing incurred relatively minor pressure changes increases on its suction surface that created significant downforce loss configuration that saw this forwards with the ideal. Thus, the wings were wing at half a car’s length we can see with the front wing. In fact, the front balance shift at close quarters. The able to generate a high proportion that most of the flow was high energy wing only lost six per cent of its question is, why did it happen? of what they would have generated coming from outboard of the lead car downforce at half-car length whereas Looking first at streamline images when the car was running on its own. thanks to the in-wash caused by the the rear wing lost around 55 per cent. of the wings at four cars’ length If we now look at Figures 14 highly cambered rear wing, which is When we look at the delta Cp plots in separation, in Figures 12 and 13 we and 15 at half a car’s length apart, a lot closer to the ground [than under Figures 16 and 17 we can clearly can see that both the front and the in the case of the front wing we can 2016 rules] and therefore so was the see that the front wing maintained rear wing of the following car received see that streamlines impinging on it in-washed flow to the front wing. most of its downforce since the flow with reasonably high total were not just reasonably high energy This helped the front wing keep its pressure changes were less, whereas pressure, or energy, as shown here but also had reasonably good flow performance. Furthermore, the swept the rear wing showed significant by the relatively high coefficient of directionality, too. MA picked up the back nature of the 2017 front wing changes in static pressure.’ total pressure. Furthermore, the flow explanation here: ‘When we look at worked well with the in-washed flow Looking at Figure 15 showing the direction was reasonably well aligned the streamlines approaching the front since the flow direction was aligned streamlines impinging on the rear The wings were able to generate a high proportion of what they would have generated when the racecar was running on its own

14 www.racecar-engineering.com FORMULA 1 2017

TECHNOLOGY – F1 AERODYNAMICS

not ideal either.’ Thus, the relatively benign situation at eight and four car lengths’ separation had turned into a significant and intrinsically unstable forwards balance shift at separations of two lengths and less. Total pressure slices in line with the front and rear wing leading edges at four car lengths and half a car’s length separation (Figures 18 and 19) complete the story and show how the energy of the airflow encountering the front wing remained high even at the closest separation, whereas that which impinged on the rear wing had lost significant energy at half of a racecar’s length. Cause for optimism? Could our findings just be a particular Figure 18: Energy of airflow impinging on front wing leading edge didn’t change much from four car lengths to half a car length characteristic of our interpretation of the 2017 rules, or is the forwards balance shift at closer separations likely to be a generic effect? MA commented that ‘our model has the same basic architecture as the cars will have, with the bigger wheels and tyres, and the wings to the sizes and in the locations they have to be, so the main flow structures will be pretty similar. But I’m optimistic that things will be better in 2017, and it looks as though the initial response when closing will be to allow the cars to get closer more easily – I hope so anyway!’ So now we wait to see what happens when the cars hit the track, and in all likelihood it won’t be until the first race of 2017 that we get an idea of how running in traffic has or has not changed. It will be fascinating to see if the new aerodynamics and mechanical layout do provide any Figure 19: Here it can be seen that the energy of the airflow impinging on the rear wing’s leading edge was help to drivers trying to close up on much reduced at half a car’s length separation compared to the situation at four car lengths separation the car in front through a corner. The FIA’s brief to the rule writers was to Dynamic Flow Solutions wing of the following car at half a car’s not make ‘the overtaking problem’ length separation the story was quite any worse. Would the response we different, as MA related: ‘The in-wash have seen here fit that requirement? ynamic Flow Solutions Ltd is an which was beneficial to the front wing In one sense perhaps it would, aerodynamics consultancy led also had to go around the front tyres. although it might simply change the Dby director Miqdad Ali, ex-MIRA The resulting front tyre wake headed reason for the fact that the underlying aerodynamicist, who has performed to the rear wing along with the rear problem, at least in part, remains! design, development, simulation and wing vortex coming from the lead car. But let’s remain optimistic that what test work at all levels of professional The streamlines approaching the rear looks to be at least a partial fix for the motorsport from junior formula cars to wing clearly show this. By the time the aerodynamic reasons for the difficulty World and British touring cars, Le Mans flow reached the rear wing it had lost in following closely, combined with prototypes, up through to Formula 1 a significant amount of energy and an increase in mechanical grip, will and Land Speed Record cars. the direction it approached from was improve the situation overall. Contact: miqdad.ali@dynamic-flow. co.uk web: www.dynamic-flow.co.uk Could our findings just be a particular characteristic of our Ex-MIRA aero man Miqdad Ali (‘MA’), is boss of Dynamic Flow Solutions interpretation of the 2017 rules?

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MSA 2.indd 3 17/03/2017 16:41:00 FORMULA 1 – MERCEDES PU Halfway to impossible One hundred per cent thermal efficiency is simply impossible, but with its 2016 F1 power unit Mercedes HPP was halfway there – Racecar went to its Brixworth base to investigate By PETER WRIGHT

18 www.racecar-engineering.com FORMULA 1 2017 n 2012 the FIA announced new powertrain 100kg/hour of fuel is delivered at a peak regulations with two radical features: firstly From 2012, when HPP rate equivalent to 1240kW or 1686PS. The it determined that power output was to crank power must not include any that derives be a function of thermal efficiency and started work on the its energy from an electrical storage system. Ienergy recovery, and secondly it constrained Cowell then gave some interesting numbers, the configuration of the system – IC engine, current powertrain, starting in 1876, the year that Karl Benz invented and energy recovery and storage – to align the the automobile – see Table 1. technologies with those of the road car industry. efficiency has risen Pressed to be a little bit more specific about For the first time in 64 years of Formula1, the the thermal efficiency achieved today, based on technical objectives of the engineers in both from 29 per cent to the fact that through reverse engineering all his disciplines were very nearly the same. competitors will probably know the figure anyway, Since the first powertrains ran in early 2014, nearly 50 per cent Cowell admitted, ‘not far short of 50 per cent’. half the F1 paddock has been decrying these Halfway to impossible, then … (Table 2). devices on the basis of: ‘not noisy enough’; A one per cent gain in efficiency yields 18ps, ‘too complicated’; ‘too expensive’, and ‘his is so it is easy to see both why HPP is working so more powerful than mine; it’s not fair!’ All to be revved to 10,000rpm, at that time twice the RPM hard on efficiency, and why Cowell is somewhat expected. The other half of the paddock has of a high performance road car engine, such as the cagey about exactly where they have got to. With kept quiet, and this is the extraordinary thing. Jaguar XK. GDI did not return to racing until the additional energy sent to the MGU-K from the Instead of extolling their achievements in radically late 1990s with the Audi R8. The engine for this battery to top it up to its permitted maximum, improving the thermal efficiency of an IC gasoline produced its peak output at 6500rpm, while at the there is at certain times greater than 900PS engine, and the power density of energy storage same time F1 engines, in particular the Mercedes available to the driver at the flywheel. systems, power electronics and machines, they, engine which won the World Championship that being racing engineers, have kept their heads year, turned at up to 18,000rpm, where GDI is Staggering development down looking for the next improvement and not feasible. GDI is one of the technologies that In the 137 years since the inception of the IC competitive advantage. A consequence of this is has had a big influence on road cars, but was not engine, thermal efficiency has been improved that the bath water, baby and all, very nearly got possible to use in F1 until now, when it has been from 17 per cent to 29 per cent, that is 0.00875 per thrown out, with a reversion proposed to return to made central to the current F1 regulations. cent per year. From 2012, when HPP started work irrelevant, high-revving, fuel-guzzling powertrains. As a prelude to the 2016 season, with two on the current powertrain, efficiency has risen successive World Championships under the new from 29 per cent to nearly 50 per cent, that is 5.25 Racing’s relevance regulations in the bag, Mercedes HPP decided it per cent per year. This represents a staggering The relevance of motorsport engineering to road was time to tell the world what it had achieved steepening of the development curve. cars has always been a debated topic, and never to date, how it did it, and the relevance of the HPP made a fundamental decision when it more so than with powertrains. The problem is technologies developed to its passenger cars. heard KERS was to be introduced into F1 in 2009; that motorsport requires the maximum output No one is better placed to do this than Andy that it would take on the responsibility for this within the regulatory constraints, regardless Cowell, managing director of Mercedes HPP, technology, starting work on it in 2007 (Table 3). of cost, while road car engineering sets out to and the architect of this success. Cowell stated that the specific power had been provide adequate output for minimum cost. improved by a factor of 12, which would mean With a swept-volume engine regulation Measuring efficiency that the ‘less than 20kg’ might in fact be nearer dominating throughout F1’s history until 2014, Cowell was at pains to ensure that what is meant to18kg, based on the firm figures supplied. This power output has been the quest for RPM. by efficiency is correctly understood, which in an weight not only includes the battery itself, but Pneumatic valves are an example of an expensive era of energy recovery and energy storage, is not also all the control electronics that monitor the F1 technology that removed a development always the case. True thermal efficiency is the ratio Lithium Ion cells, and control the flow of electrical constraint but had no road car relevance. An of the power delivered at the crankshaft to the energy to and from the two MGU’s (H and K) that opposite example is GDI (gasoline direct injection) power delivered to the engine as fuel. And 100 per form part of the powertrain. This latter computer – present on the W196 Mercedes of 1954, which cent is thermodynamically impossible. In F1’s case, performs a mere 43 trillion calculations in the

FORMULA 1 2017 www.racecar-engineering.com 19 FORMULA 1 – MERCEDES PU

The engine from the first the desired torque, then the MGU-K can draw motor car, as invented by energy from the battery and fill in any holes in Karl Benz back in 1876, the IC engine torque curve. Cowell stated that which had a thermal torque feedback from a sensor on the input efficiency of 17 per cent shaft of the gearbox is not employed as ‘that would look too much like traction control’. This mastery of the mammoth torque of these powertrains has given the drivers better control than ever before, and has meant that talented young drivers can step up to F1 with ease. Spectacular it is not, and however much power the powertrains deliver, that era is gone. But does Mercedes ever burn fuel solely to fill the energy store, under braking or mid corner, or for instance when the traction is limited? Cowell says that would be an inefficient use of fuel, to send the energy via the battery, but admitted it would be possible on circuits where the race allocation of fuel (100kg) is not needed, or when there is an extended safety car period and fuel is conserved. Cowell spoke carefully and somewhat Table 1: Thermal efficiency of Mercedes-Benz guardedly about how HPP had achieved automobile engines since its inception these remarkable results starting in 2012, Year Engine configuration Thermal Efficiency when the new regulations became firm. He 1876 1-litre, 1-cylinder, NA 17 per cent gives much of the credit to four key groups within HPP: Performance Simulation, tasked 2013 2.4-litre, V8, NA 29 per cent with combustion, Dr Nigel McKinley, its team 2015 1.6-litre, V6, turbo-compound >45 per cent leader; Turbocharger Design (Pierre Godof, team leader); Hybrid Systems team (led by John Table 2: Performance of recent Mercedes Formula 1 powertrains Stamford); and the Software Development Year Engine Power Fuel flow Thermal Efficiency group, led by John Goodman. 2005 3-litre, V10, NA 900ps @ 18,000rpm 194kg/hr 27.5 per cent 2013 2.4-litre, V8, NA 725ps @ 18,000rpm 148kg/hr 29 per cent Performance simulation The first powertrain, the GB (the 2016 is the 2015 1.6-litre V6, t-c 750-840ps @ 10,500rpm 100kg/hr 45-50 per cent GF), weighed in at 262kg and would never have fitted in to a car. It did not feature the Table 3: Mercedes-Benz HPP’s work on KERS later engines’ split turbo system, but gave the Year Weight (kg) Power (kW) One-way efficiency (%) Power/Weight (kW/kg) engineers the first validation of the combustion simulation work that is the cornerstone of HPP’s 2007 107.0 60 39 0.56 R&D. Using moving-mesh CFD, essential where 2008 36.5 60 54 1.64 there are geometry changes, the Performance 2009 25.3 60 70 2.57 Simulation group ran hundreds of simulations in 2012 <24 120 80 >5.0 order to understand and optimise the synergy 2015 <20 120 95 >6.0 between: GDI; charge motion; compression efficiency; gas exchange; and combustion – course of a two-hour race. This level of number delivery response to the drivers’ desires, both including molecular-level modelling of fuels crunching is needed to manage the recovery on track and in the simulator. When the driver with a knock limit being the critical boundary. and deployment of the energy between the applies the throttle pedal he wants to receive Results are then proven in a single cylinder MGUs and the battery, and to ensure that the the exact torque at the wheels he desires, and it research engine, and transferred to the latest race driver receives exactly, and repeatedly, must be exactly the same as last time. More can spec of the V6 R&D engines. the torque that he demands. lead to loss of control; less to frustration. At the start of the project, HPP found that The first of these is supervised according to In the days of port fuel injection, the there was virtually no turbocharging expertise the strategy in use: Friday practice, Qualifying, fuel droplets ‘made a couple of laps of the in-house at Brixworth. Turning to parent Race, Safety Car, etc. The software learns and trumpets before disappearing down them,’ says company Daimler, it ended up talking to both updates the strategy according to what is Cowell. Mixture distribution was somewhat the truck division of Mercedes-Benz and the actually happening out on the track. haphazard, and the response of the engine helicopter gas turbine division of MTU. The truck The second function reveals an interesting to a given throttle opening was guesswork. business is driven by the costs of fuel, and so insight about the entertainment value of GDI has solved much of this problem with efficiency is paramount. Also, the power rating F1. Many perceive that F1 has become less predictable, repeatable fuelling of each cylinder. of big truck diesel engines is of the same order spectacular, and that this can be corrected The throttle pedal is a torque demand, and as the F1 powertrain, so learning from truck with more power – although why more grip is the computer determines the actual throttle turbos is not as odd as it may seem. also being prescribed is currently beyond me. opening according to engine conditions at the Freeing up the size of the compressor However, Cowell explained how HPP engineers time, compensating for RPM, turbo pressure, air by taking it out of the V, and mounting it at spend a great deal of time tuning the torque temperature etc. If the IC engine cannot deliver the front of the engine, with the MGU-H just

20 www.racecar-engineering.com FORMULA 1 2017 The Mercedes F Cell Roadster concept of 2009 (left) was a tribute to the very first car, the Benz Motorwagen (right). The roadster has an electric motor powered by a fuel cell. Mercedes-Benz HPP has now made concept car-like efficiency gains in the real world of F1

closely related to the piston alloy developed by Rolls Royce for the Schneider Trophy R-engine and the Merlin, 90 years ago. The double entry turbine wheel is a cast, high nickel inconel alloy; ceramics are not permitted. We did not get a chance to look at an exhaust system. Inspection of the other IC engine components revealed parts that look similar to the V8 equivalent parts, although there were obviously many, many detailed differences. Much lower RPM has relieved the inertial loads, but the gas loads are way higher. The small V6 also needs some beefing up to maintain its structural stiffness as an integral part of the chassis, and this is particularly evident as a larger Mercedes HPP has achieved a thermal efficiency of close to 50 per cent with its F1 power unit. True thermal web at the base of the crankcase, and tubular efficiency is the ratio of the power delivered at the crankshaft to the power delivered to the engine as fuel structures above the cylinder heads. behind it and the driveshaft extending back to controlled by the MGU-H. A wastegate, however, Electrification the turbine at the rear, brought a number of is required for safety, for instance when it is It is easy to overlook the development that benefits: ‘When added together, they are worth necessary to unload the turbine suddenly has gone into the two electrical machines that the enormous effort needed to make it work – due to an electrical short, triggering the total are part of the powertrain. By their very nature it was very hard,’ says Cowell. disconnection of the high-voltage power they are densely packed cylinders of copper, Inspecting the assembly indicates that the electrical system. It is also sometimes useful steel laminations, and rare-earth magnets, 125,000rpm rotating parts are monitored by to compensate for sudden load shifts during with the smallest of air gaps and only sufficient a number of sensors to ensure that the bearings downchanges. It took 600 CFD simulations to free space for cooling fluid. Weight reduction and shaft dynamics are always within limits. The arrive at the first design, and many containment only comes from reducing the size for a given ‘cogging’ of the electrical machine, combined burst tests to prove it, at £20,000 a test for the power by increasing RPM. Both MGU-K and with the exhaust pulses the turbine experiences, hardware alone. The large diameter compressor MGU-H seem to be around the same size, but make for a highly ‘excited’ rotating assembly. allows HPP to run the turbocharger below the HPP is neither releasing the power rating of the At the front, the compressor inlet conditions maximum 125,000rpm at sea level, and to speed 125,000rpm MGU-H, nor the RPM of the 120kW are controlled by variable geometry inlet guide it up and continue to use the 100kg/hr fuel flow MGU-K. From the sizes observed, it is unlikely vanes, to maintain the surge margin when the rate at altitude, for example at Mexico City, to that either is much under 10kg. throttle is closed. At the rear, variable geometry maintain design power output. A 16ps/kg figure is, however, impressive is not permitted on the turbine, and in fact is not The compressor wheel employs the same compared to around 10ps/kg of the 900ps of required as the whole system is constant speed, alloy as the pistons, an aluminium alloy still the best V10s. The problem with automotive The 125,000rpm rotating parts are monitored by a number of sensors

FORMULA 1 2017 www.racecar-engineering.com 21 FORMULA 1 – MERCEDES PU

Cowell sees no future for the IC engine as a stand-alone powertrain. However, he did also admit that his vision would require clever production engineers to get the costs out without destroying the efficiency. HPP has a total staff of around 500 at Brixworth, of which Cowell is the managing director. To have an engineer with total management control is unusual in F1, and this, plus the autonomy of Mercedes-Benz HPP, located in a different country to the parent company but close to the racing team, is a major contributor towards its success. A number of other things impressed me as Cowell led a brief tour of the factory, during which he offered a number of insights, for instance: ‘In general we don’t employ F1 people. Instead we simply look for very good engineers.’ In the middle of the engineering office was the materials group. ‘We tend not to believe the material performance as published by suppliers, so we do our own tests,’ he said. ‘Then, when something breaks, the materials engineers carry out a full forensic investigation. We have developed three or four alloys, unique to HPP, for the powertrain,’ Cowell added.

Above: The V6, which is smaller Machine shop than the V8 which preceded it, The machine shop was the next stop. It is needed some beefing up to maintain laid out in such a way that machine tools its structural stiffness as an integral can be removed and replaced easily, as new part of the Mercedes chassis technology comes through. This may be Left: HPP spends a great deal of time machine tools themselves or new powertrain tuning the torque delivery response to technology requiring different processes. The the drivers’ desires, both on track and machine tools are relatively lightly used, as in the simulator, so they always know Formula 1 components generally require light what’s under their right foot cuts, and so they maintain their value; HPP depreciates them over five years. Cowell said: electrification is not the motor; rather it is 120-degree rather than 90-degree, for a sweeter ‘We encourage a spirit of change in the machine the storage of the energy sound. Larger capacity with less RPM would shop, not a production mentality.’ Cowell stressed how hard HPP had worked increase thermal efficiency. The fuel regulations Another point Cowell made related to the on the efficiency of the whole power electrical are okay – a reasonable balance between company’s staff: ‘The key to a happy workforce system. The payoff is not just yielding more energy density and knock.’ is to avoid annoying them with silly little things, power, but less cooling of all elements of like there not being enough parking.‘ But the system, which compromises the car’s Tech transfer the workload is heavy: ‘We are working 24/7 aerodynamics. Every aspect is studied to yield Another hypothetical question: if Cowell was through January, February and March to build crumbs of performance, which add up to suddenly and unexpectedly transferred by and test engines for testing and the early races, something useful. Aircraft wiring and connector Mercedes-Benz to design the next C-class and yet we try to be flexible. We build about 100 systems are utilised. In aircraft power electric powertrain, what would he take from HPP engines a year, but we managed to get away cables, copper is replaced with nickel-plated to incorporate into a middle of the range with using only three engines for one driver last aluminium wires, which are half the weight for powertrain? After some thought, but still just year. That is good, as it means we have a spare!’ a given resistance. Running the system under about off the cuff, these are the features he Perhaps the single thing that struck me full power and inspecting with thermal imaging puts forward: 400cc, 90-degree V-twin, with about how different HPP is from many other F1 cameras guides the engineers to hot areas 200PS; electric turbocharger – but not exhaust outfits was the lack of trophies in the entrance where the losses are occurring. ‘It is like the energy recovery as this requires full throttle; foyer. The trophies, and there are many of water and oil systems, you have to eradicate or an MGU-K integrated into the powertrain, them, are displayed around the factory, even in ease every little restriction,’ Cowell explains. with two energy recovery MGUs for each of among the machine tools. Yet while all’s clearly very good at HPP now, the front wheels, giving 4WD when necessary; HPP is quietly confidant of what it is doing; in an ideal world what would HPP like to do to combustion know-how; lower RPM than the that is, something that is quite remarkable in change the F1 powertrain regulations to yield F1 internal combustion engine. ‘The IC engine automotive engineering, and well worth telling greater efficiency? ‘Maybe two less cylinders,’ would effectively become a range extender with the world about. It is halfway to impossible, says Cowell. ‘If it must be a V6, then 60-degree or around 54 per cent efficiency,’ he adds. and has no intention of stopping there. ‘We’ve developed three or four alloys, unique to HPP, for the powertrain’

22 www.racecar-engineering.com FORMULA 1 2017 Untitled-5 1 25/01/2017 16:13 FORMULA 1 – 2017 ENGINE REGULATIONS

fter over a year of debate, dispute and speculation, last year F1 fi nally settled on a new set of technical regulations for the 2017 and 2018 seasons. As expected the rules have seen Athe cars built to a higher weight limit, with wider bodywork and tyres and more dramatic looking aerodynamic devices. Those changes have largely been detailed elsewhere (see V26N5), but the more recent changes to the regulations relating to the power units have been less widely discussed. In a nutshell, the headlines relating to the design of the units have remained unchanged – a direct injection 1600cc turbo V6 mated to an electro turbo-compound hybrid system – but the details of many sub systems have been adjusted. From the moment that the new regulations were introduced in 2014 there were a number of very vocal fi gures in the sport who felt that the power unit had become too much of a performance diff erentiator, Red Bull team principal Christian Horner among them: ‘I think Formula 1 has the three elements which should have equal weight: the driver, the chassis and the engine. So if one of those elements isn’t quite right, the other two can compensate. I think in today’s Formula we’ve off set that balance, so you’ve probably got, 50 per cent engine, 25 per cent chassis, 25 per cent driver.’ Convergence of power Under pressure from the likes of Red Bull, and notably Bernie Ecclestone, Formula 1’s rule makers have now moved to redress this balance somewhat by adjusting the regulations to allow the performance levels of the four diff erent power units to converge, with the aim of reducing the huge advantage that Mercedes HPP is perceived to have. ‘One our main objectives with the rule changes was to help performance convergence,’ the FIA’s head of powertrain, Fabrice Lom, says. ‘To do that the fi rst big thing that people thought was important is to have stability in the regulations. There was a lot of discussion of changing completely the regulations, going back to normally-aspirated engines, no hybrid. Nobody wanted that because the trend in the world is to go hybrid and low consumption, but also they thought if there’s a big change there will be a redistribution of the cards, and there could be a big diff erence in performance between the power unit manufacturers, so they said that stability of regulations would help a lot.’ To allow for power unit manufacturers to be able to close the gap, the much debated upgrade token system has been dropped entirely, allowing for free performance development during the season; the idea being that the law of diminishing returns will apply and, over time, the performance of the units will converge naturally. Perhaps in an attempt to accelerate this process a number of component weight restrictions have been introduced, as well as some minor changes in the material specifi cations. Both MGUs will now have a minimum weight applied of 7kg for the kinetic and 4kg for the heat. Inside the combustion engine similar minimum weights are being applied, too, with the minimum piston weight set at 300g, and the connecting rod also at a 300g. The piston weight includes the pin, rings and retaining clips, while the rod weight includes the bolts and bearings. The crankshaft will be restricted, too, both in terms of weights and dimensionally, the main bearing journal is limited to a minimum of 43.95mm and the pin bearing journal 37.95mm. A complete crankshaft assembly including all balance weights, bolts and bungs must weigh at least No smoke without fi re: the debate over Formula 1 power units has been heated and divisive over 5.3kg. The total power unit minimum weight remains the past years, but last year the teams and the FIA fi nally agreed a new set of engine rules

24 www.racecar-engineering.com FORMULA 1 2017 Power games After much deliberation the F1 power unit regulations for the next two years were put in place last year. But what were the implications for the engine builders and the teams? By SAM COLLINS

The much debated upgrade token system has been dropped entirely allowing for free performance development during the season

FORMULA 1 2017 www.racecar-engineering.com 25 FORMULA 1 – 2017 ENGINE REGULATIONS

There has been no major changes in the basic engineering philosophy of F1 PUs in 2017; they are still 1.6-litre turbocharged V6 hybrids

‘There has never really been as much of a link between an engineer developing a Formula 1 engine and an engineer developing a road car engine as there is now’

unchanged at 145kg. ‘These limits were put unit since 2014. The technology, which was higher the potential efficiency, but it also brings where the best [power unit] is today so that patented relatively recently, relies, according a risk of knock with it,’ Yusuke Hasegawa of people know the target, and also allow us to to its inventor, the Mahle Group, ‘on a special Honda R&D says. ‘So the level set at 18:1 is high stop the best ones developing more, to go surface ignition, which in turn allows for higher enough for us not to care about it for now. HCCI lighter or smaller, so that we put something like engine performance. The ingenious trick here [see page 16] and pre-chamber systems are very a bit of a barrier to development,’ Lom says. is that the air-fuel mixture is pre-ignited in a much in the R&D phase at the moment.’ In 2018, an additional restriction is also pre-chamber around the spark plug.’ This results These sentiments are echoed by being introduced on the temperature of the air in the formation of plasma jets that reach the Renaultsport F1’s technical director (power in the plenum, which will have to be more than piston primarily at the outer edge and ignite unit) Remi Taffin, who says: ‘If you look at 18:1 10degC above the ambient temperature. On top the remainder of the mixture. While ignition and look at the maximum cylinder pressure it’s of that more of the ERS control systems will have normally takes place in the centre of the frightening, but that new regulatory limit is not to be packaged inside the monocoque. cylinder, with Mahle Jet Ignition it essentially a restriction on us. We don’t think we will reach One aspect of power unit development takes place from the outside toward the inside. that any time soon. I know what the constraints which has been at the forefront of Formula 1 This allows significantly better combustion of are, I look at the materials technologies I have research and development work, particularly the fuel mixture. The result is more power with around me and I don’t think there is anything over the last 12 to 18 months, is the combustion considerably less residue. ‘With this lean burn to cope with this for the next five or six years. process, and this is an area where significant combustion process a substantially greater These regulations will not stand for the next 20 innovations are now being applied. But the FIA efficiency can be achieved than with previous years. Look at it in that way, the limit is far away has now moved to restrict performance in ignition concepts,’ Mahle tells us. enough that it is not limiting us.’ this area somewhat, with a maximum In addition to the limit on compression compression ratio of 18:1 being enforced High compression ratio, the FIA will also introduce restrictions from 2017 onwards, again in order to force This is not the only technology under on the number of different fuels used by each performance convergence. development in this area, as the quest for team, with only five fuels allowed per season Part way through the 2015 season, Ferrari efficiency grows the levels of compression have and two per event. Fuel development has been adopted the Mahle Turbulent Jet Ignition risen substantially, to the point where at least a major area of performance gain under the concept on its Formula 1 V6, a technology which partial compression ignition is almost possible. current formula, especially when allied with the is thought to have featured on the Mercedes ‘In theory the higher the compression the combustion developments, and the limits have

26 www.racecar-engineering.com FORMULA 1 2017 Renault’s has struggled to keep pace with its rivals in recent seasons but the dropping of the engine token system could give it more scope to develop its PU for the 2017 season. Early testing proved inconclusive been introduced for similar reasons. ‘It’s all about depends on the parts restricted, and what those how your ICE is working,’ Taffin explains. ‘If you restrictions are. If you restrict everything then look at how the fuel developed, early on we look the sport has no meaning and it has no value to to get the best out of the knock sensitivity, then us anymore. I think the 2017 regulations do not as you develop the combustion chamber you restrict us really, at least not so far.’ F1 cars will feature a sound generator from 2017, but details of its get a bit more freedom to develop the fuel, as design and operation were not yet available. The picture shows an you can be a bit less knock sensitive, but get a R&D relevance earlier attempt to improve the engine noise; waste gate exit pipes bit more energy from the fuel.’ Taffin points out that while some of the Each car will be able to use a little more fuel combustion techniques under development each power unit for each race and each PU in 2017, as the maximum amount used on each have some very real applications to the manufacturer, then we do the average over the car for the duration of the race will increase from mainstream, the way Formula 1 uses its engines three races. This should give a power index of 100kg to 105kg, to deal with the wider, heavier is very different and as a result technology performance for each power unit manufacturer.’ and more draggy cars defined by the chassis transfer is not all that straightforward. ‘We are If one power unit is found to be substantially rules. It is not a change all were in favour of. using engines that are not all that close to what above or below the rest on this Index of Mercedes boss Toto Wolff says: ‘Claire Williams you see in production,’ he says. ‘We are revving Performance (Lom stresses that this is not a [Williams deputy team principal] raised [this] to 11,000rpm or more and we spend a lot of Balance of Performance) then Lom’s team at the in the meeting itself, that the whole world is time at full throttle. If you work out how much FIA will escalate the situation. ‘We will report to looking to reduce emissions, and she asked can time you spend at full throttle in your road car, the Strategy Group, and the action is a decision we possibly vote in favour of an increased fuel you understand that the duty cycle is not in the of the Strategy Group. We will check this in allowance from 100kg to 105kg?’ All Mercedes- same area. But saying that, there has never really the first three races, which is [at a time] that is powered teams voted against the increase, been as much of a link between an engineer before the deadline to make a change at the but they were in the minority. developing a Formula 1 engine and an engineer majority for the following year,’ Lom says. It could be argued (and has been) that the developing a road car engine as there is now, Not all of the changes are directly aimed at new restrictions, especially those impacting and that it is probably the best thing about encouraging convergence. Many changes to fuel development and compression ratio, could these rules. Even if the technology cannot be both the technical and sporting regulations are reduce the relevance of F1 to production car switched directly from race to road.’ aimed at reducing costs and ensuring that every R&D – the very reason the current power units With the changes made to the technical team in F1 has a guaranteed supply of power were introduced in the first place. ‘When we regulations aimed at forcing the varying units, something which was not the case at the started to discuss convergence, there were performance levels of the power units to start of 2016, and could have conceivably seen suggestions of defining a power limit, but we converge, the FIA has decided that it will three teams drop out of the sport as a result. were totally against that,’ Hasegawa says. ‘But monitor very closely if indeed convergence is The first step in this process did not quite it is natural to have some kind of limitation as taking place. ‘We have a process agreed with go as far as a pure cost cap, but is a direct this is a sport, not pure R&D. You cannot have the power unit manufacturers, we don’t look at infinite development, so some kind of restriction lap times, we have tools to simulate everything, is necessary. Technical freedom is a good thing, so we can calculate the performance of the ‘The new regulatory limit that is our philosophy as a company, but we power unit itself on each car and we transform don’t want to make everything ourselves. Why this in a power index,’ Lom says. ‘You have this is not a restriction on us, would we design a coffee cup when we can just hybrid system and an engine and you cannot buy a perfectly good one? only talk about horsepower, so it is translated we don’t think we will ‘I think restrictions can reduce the value of into a power index. We check every car, every F1 R&D to production cars, but it very much lap of the first three races. We take the best of reach that any time soon’

FORMULA 1 2017 www.racecar-engineering.com 27 FORMULA 1 – 2017 ENGINE REGULATIONS

‘One of our main Both MGUs have a minimum weight applied from 2017. objectives with the rule This will be 7kg for the kinetic (K) (pictured) changes was convergence and 4kg for of performance’ the heat (H)

reduction in the price charged to customer suggested that Honda would end up having to teams. This reduction is €1m in 2017, compared subsidise customer teams if it had to. to the price in 2016, and it’s reduced by €4m, In a further effort to reduce the cost of compared to 2016, from 2018 onwards. From the units the FIA has regulated that it will 2018 a cost cap of €12m is applied to teams restrict the sensors used in some areas of the working with new suppliers (that is, if they power unit to a single specification (see box have switched from one supplier to take an out below left). ‘It is a small part of the engine suppy from another). reduction but it is a bit of a reduction,’ Lom In order to get the manufacturers to agree to says. ‘In general terms all pressure and The 2016 Mercedes HPP power unit had a big advantage; this reduction in price the FIA had to take other temperature sensors, apart from in-cylinder which is why the new engine technical regulations have been steps, Lom says: ‘We cannot ask the power unit pressure sensors and sensors embedded in formulated with convergence of performance in mind manufacturers to reduce price without reducing electronic boxes, will be control parts.’ cost. So to reduce the cost, firstly in 2017, we will go down to four power units per driver Power supply per season, instead of five today, whatever the Finally, the last objective of the 2017 changes number of grands prix. In 2018, and this is a big was to ensure that all teams had access to task for them, we will go down to three ICE, plus a power unit supply. If by June 2016 a team turbo, plus MGU-H, and only two energy stores, had yet to be allocated a power unit then control electronics and MGU-K. So it’s nearly 50 the manufacturer with the smallest number per cent fewer parts, so it should reduce the cost of customer teams will be obliged to supply by a nice amount.’ whatever team lacks an engine. Every power While this is a reduction on total price paid unit manufacturer is obliged to have the Honda has been forced to enlarge its power unit manufacturing out per team, it is actually an increase in price capability to supply an equal share of the grid, facilities in England (pictured) and Japan, largely as a response to per power unit with the reduction of number of so with 11 teams in Formula 1 at the moment new F1 engine rules which might oblige it to supply an extra team units allowed per season. Not all of the power each must be able to supply three teams unit manufacturers are entirely happy about the (rounded up from 2.75). This has seen Honda F1 single spec sensors reduction in units, and Lom’s comments came as significantly increase its facilities in both Japan a surprise to some in the paddock. and the UK. A complex set of regulations about ‘It is very tough even now,’ Hasegawa says. the specifics of supply appear in the rulebook Regulation 5.13.1: ‘Any pressure sensor used to ‘Last year we struggled to achieve the (including a rather unnecessary equation), measure pressure of any fluid necessary to ensure the durability. This year it’s much better but we but as things stand if any Ferrari or Mercedes power unit functions correctly at all times (including are still struggling, so longer mileage is pretty powered team loses its supply then by default it but not limited to coolant, oil, fuel and air) must be tough. Bringing in longer mileage, we need will run with a Honda, while if Red Bull loses its manufactured by an FIA designated supplier to a some more time to do that, even just for life supply there will be a coin toss to see if it runs specification determined by the FIA. Cylinder pressure testing. In some ways that actually increases either a Honda or Renault power unit. sensors are excluded from this requirement.’ the cost for us, not reduces it. As the seemingly endless discussions about Regulation 5.13.2: ‘With the exception of exhaust ‘I think it’s true that when you want to make the 2017 and 2018 rules come to a long overdue temperature sensors and temperature sensors something last longer you get it heavier, and as conclusion thoughts now turn to the future of embedded in electronic boxes, any temperature sensor a whole vehicle that is not efficient, so it’s a bit the sport in the years to come. ‘One possibility used to measure temperature of any fluid necessary to controversial. If you want to make a car faster, of is increasing the importance of the electronic ensure the power unit functions correctly at all times course, you would make the power unit lighter, parts,’ says Hasegawa. ‘Right now we have a (including but not limited to coolant, oil, fuel and air) it’s the opposite direction for an endurance car.’ 120kW limitation, and an energy limitation. must be manufactured by an FIA designated supplier Hasegawa went on to hint that he felt that If those limitations are removed then I think to a specification determined by the FIA.’ the 2018 price level was a bit too low and the cars might be a lot more exciting.’

28 www.racecar-engineering.com FORMULA 1 2017 Innovative Damper Technology

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The powertrain suppliers had to change emphasis from ultimate power to efficiency, and the need for close collaboration with fuel partners became ever more important

30 www.racecar-engineering.com FORMULA 1 2017 Pump action When fuel flow was limited in Formula 1’s new-for-2014 regulations those companies that supplied its racing juice had to meet a whole new set of challenges head on. Here’s how they went about it

etween the start of the 1989 season while it is a myth that F1 cars run on pump limitations on the standard fuel properties are and the end of 2013 turbocharged fuel – in other words a product which you can inspired by the European Standard for gasoline: engines were banned in F1, and buy on a forecourt – the fuel used does have EN228. The second section of the rules relates the technical regulations evolved to meet a specification broadly similar to the to the chemical composition and it essentially Bpredominantly to govern and reduce EU regulations on commercially available fuel. forces F1 fuel to contain 99 per cent of the same displacement and maximum revolutions. But in ‘All the fuels we are using in motorsport you types of compounds as fuels for the road. 2014 all of that changed with the introduction could run in your road car,’ Wolfgang Warnecke of the current power unit regulations, which of Shell claims. ‘The aim is to have the science in High Octane saw the reappearance of turbocharging and the fuel make its way to the road. For example, Racing fuels, based on road car specifications, had fuel flow limitation at their core. in the Le Mans diesel fuel we use a very high are a trade-off between octane number and Limiting the fuel flow created a very amount of GTL and that’s the same as we sell flame speed, and energy density. The first different challenge for the fuel suppliers; on the road. But the fuels need to be different requires high RON aromatics, and oxygenates, namely Mobil 1, Shell, Petronas and Total. Under to that which you get at the pump, because the latter high heating value/kilogram paraffins, the flow restrictions the route to performance today’s road cars simply cannot meet the olefins and naphthenes. These two properties became all about considering the maximum efficiency levels that you see in Formula 1 these are in opposition to each other and the range fuel efficiency by mass. The change from high- days. They are close to 50 per cent efficiency. In of molecules the fuel developers are permitted revving, normally aspirated, indirect injection the past that was only possible with very large to work with is tightly restricted. Pre-2014, engines, with a non-regulated fuel load, to marine or energy generating engines.’ octane number was king; post-2014, energy low(er)-revving, turbocharged, direct injection engines with a maximum fuel load per race Petrol head and a fuel flow rate limit as well, caused the The regulations for Formula 1 fuels (which can fuel suppliers to radically change tack, yet still be found in Article 19 of the 2016 technical within the FIA’s fuel specification regulations. regulations) are divided into two parts; firstly The powertrain suppliers had to change the physical properties of the fuel itself – these emphasis from ultimate power to efficiency, and the need for close collaboration with fuel partners became ever more important. In simple terms, the regulation shifted from an air-limited engine to a fuel-limited one. Tank battle Four major racing classes adopted fuel flow limitations as the core of their technical regulations from 2014 onwards, but only one, Formula 1, did not also place harsh restrictions on fuel development. The other three all used single specification fuels. In LMP1 all cars would use identical petrol (or diesel) from the same supply, while in GT500 and Super Formula the cars had to run on whatever was sold from the circuit’s own pumps in the paddock. This has meant that Formula 1 has become the leading racing category in the world in terms of fuels development and, according to some, it also leads the way in road fuel innovation, and even that components found in conventional road fuels are developed in Formula 1 race fuels. Formula 1’s introduction of direct injection engines Shell is a technical partner to Ferrari. Formula 1 is an adventure Unsurprisingly, there is not complete and fuel flow limits changed the fuel requirements. playground for racing fuel developers with fewer restrictions than freedom in the rules for fuels in Formula 1 and Now it’s all about optimising a fuel-limited engine other categories, but F1 gas still has to be similar to road car fuel

FORMULA 1 20176 www.racecar-engineering.com 31 TECHNOLOGY – RACING FUELS

density rules. Exactly where the trade-offs lie are determined in the simulation computer and proven in combustion research engines in laboratories. Hundreds of formulations are evaluated, and just a few are FIA homologated and find their way into an F1 fuel tank. According to Total, its Formula 1 fuel is made up of about 200 different substances from the gasoline refining process. These components are selected like a kit of parts to build the perfect fuel for each iteration of the Renault 1.6-litre V6 turbochraged combustion engine. Or, in other words, the regulations force the Formula 1 fuels to be made using the same set of ingredients, but to a very different recipe. RON speak Today Formula 1 fuels have no upper limit to the RON and MON values, though previously this was the case. A change was introduced in 2010 in preparation for the return of turbocharged engines, to permit optimised fuel formulations to be explored within the road relevant framework of the regulations. Following this common objective that Formula 1 fuel development should embrace new technologies and their transfer to road fuels, the regulations were further amended to permit the use of other bio-components alongside bio-alcohol, and today they play a crucial role and must make up a minimum of 5.75 per cent of the fuel blend. Since the banning of refuelling in Formula 1 the fuel rigs are not so prominent but they are still at the very heart of the action Of course, even putting the rules to one side the switch from absolute power for performance to efficiency based performance had a considerable impact on fuel formulation. Under the previous regulations, fuel predominantly influenced the performance of a Formula 1 car in two aspects, firstly absolute engine power output, with an obvious positive impact on lap time and also fuel mass consumption, with an obvious negative impact on lap time due to the decreased car dynamic when carrying more fuel weight. Absolute power Weighted in relative numbers, the sum of the two factors was clearly in the advantage of the absolute power number, meaning that the engine power was more important than fuel consumption for competitiveness. The ratio was dependent on the race track and some The Formula 1 regulations were recently amended to permit the use of other bio-components alongside bio- low speed tracks could have been in favour of alcohol and today they play a crucial role and must make up a minimum of 5.75 per cent of the fuel blend a slightly lower consumption fuel when other high speed tracks needed the fuel formulation with the maximum absolute power. So at times In terms of engine design all the the fuel suppliers created track specific blends, a heavier fuel which gave more power at Spa and Monza, and a lighter fuel with a lower parameters have been refocused from power output at Monaco, for example. Today, as the fuel mass flow rate (100kg/h) optimal configuration for an air limited and the maximum fuel payload (100kg) is limited, the key factor in ranking fuel engine to optimal for a fuel limited engine performance is the power output of the power unit from this limited quantity of fuel.

32 www.racecar-engineering.com FORMULA 1 2017 In terms of engine design, it means that all the parameters have been refocused from optimal confi guration for an air limited engine (naturally aspirated, limited displacement and revolutions), to optimal for a fuel limited engine. The goal is now to achieve the best power from the given l00kg/h fuel fl ow rate (ie the best effi ciency), thus the lowest Brake Specifi c Fuel Consumption (BSFC, in g/kWh). This has seen compression ratios rise rapidly as the engine designers seek performance through effi ciency and the leanest burn possible. To make this possible the challenge Figure 1: This shows the heating value against RON for a range of gasoline molecules. It can be seen that the racing for the chemists in the fuel development fuel formulator faces a quite substantial challenge as these two properties are antagonist for RON values above 100 laboratories is substantial. There are three main areas of fuel formulation that are now the focus. Anti-knock Firstly, the anti-knock properties of the formulation are crucial. High octane value is a known positive property for spark-iginition engine effi ciency. Thanks to the better anti-knock properties of high octane fuels, the spark advance can be increased, leading to a better combustion phasing and hence engine effi ciency. Secondly, the fuel energy content by mass. As the mass fl ow is fi xed to 100kg/h, it is possible to select compounds with higher energy per mass, i.e. providing more energy with the same given fl ow. Thirdly, combustion speed. The speed and completeness of combustion through higher fl ame speed formulations is a constant target as these items are having a direct impact on the thermodynamic effi ciency of the ICE. So to formulate the best possible fuel, these three factors and the relationships between them must be considered. Based on the table (Figure 1) of heating value against RON for a range of gasoline molecules, it can be seen that the fuel formulator faces a challenge as these two properties are antagonist for RON values above 100; the use of high RON aromatics will always lead to a decreased energy content of the fi nal formulation. So the fuel formulator must fi nd the optimum balance between the three parameters for a given engine specifi cation, and the 2016 regulations allow fi ve diff erent specifi cations a year not including test engines. Different forms of motorsport have different requirements. It’s interesting to see how fuel philosophy differs between series In the same graph, two typical fuel formulations have also been positioned: a typical European maingrade gasoline, located centrally, It is known that a large number of varying fuel showing that the formulation is a balance of all components, paraffi ns, olefi ns, naphthenes specifi cations were being introduced by each and aromatics, and a Formula 1 fuel for the turbocharged F1 engine of the l980s. supplier throughout the 2015 and 2016 seasons Honda’s accord In a paper on the 1.5-litre V6 Honda F1 engine, released some years ago by the Japanese company, the fuel formulation used in 1988 was revealed. The formulation was a mixture of 84 vol% of toluene and 16 vol% of n-heptane. This fuel is obviously positioned close to the

FORMULA 1 20166 www.racecar-engineering.com 33 TECHNOLOGY – RACING FUELS

European Union regulations will see bio-content increase in production car fuel so that is likely to be replicated in any new regulation on fuel

aromatics family in terms of RON and energy By comparison, the BSFC of the current breed of the 2015 and 2016 seasons. That practice content. At that time the RON was limited to downsized and turbocharged Formula 1 power is being restricted for 2017, however, as a 102, but the anti-knock properties were key for units is below 200g/kWh. Therefore, to achieve temporary limit on the number of specifications the engine performance and hence this fuel the same duty, the fuel consumption has been introduced by each manufacturer has been included a substantial amount of toluene with reduced by over 25 per cent and within the brought in in an effort to even up the power n-heptane used to trim the RON of the final context of road relevant regulations. unit performance somewhat. formulation to exactly 102. This fuel cannot be considered as road relevant because of the very New limits Fuel speed ahead high aromatic content, which falls outside the None of the fuel companies will disclose exact Thoughts about the fuels used in Formula 1 are current levels specified within EN228 and thus details of their current fuel formulations for now starting to turn to the future. European falls outside the current F1 fuel regulations. obvious reasons, but it is known that a large Union regulations will see bio-content increase In the same paper, the BSFC of the 1988 number of varying fuels specifications were in production car fuel so that is likely to be Honda F1 engine is revealed to be 272g/kWh. being introduced by each supplier throughout replicated in any new regulation on fuel. A bigger factor in production car legislation is the EU maximum fleet average CO2 emissions of 95g/km and this has seen motorsport begin to consider the impact of emissions for the first time (See RCE V26N8). This is sure to impact the fuels used, too. CO2 is one of the parameters used to evaluate sustainability, and looking to the sustainability of cars it can be seen that there is a reduction already directly due to the increased efficiency of LMP1 and Formula 1 cars since 2014. According to Shell, which supplies the fuel for the Le Mans 24 hours, the CO2 emissions through fuels have reduced from 436 tonnes in 2012 to 320 tonnes in 2015. Although a major contribution on CO2 is based on the production and combustion of the fuels used for the race event, other energy intense sources such as tyre manufacturing will also need be considered. Ensuring that developments within motorsport ultimately make their way to road car fuel applications is a core mindset within the fuels industry and continuing this will – according to many working in this industry – be essential in nurturing and motivating the fuel industry for the future. Fuel’s paradise Allowing multiple fuel development cycles per season, and being open to new types of fuels in some race series, is clearly a motivation for the fuel companies, and is also an attractive proposition for those involved to continue to push the technical boundaries. Next month we will look at what the racing fuel of the future might be like, and also the fuels of the past.

Shell presented a paper to the 37th International Vienna Motor Symposium, titled ‘Innovation from Track to Road: The Role Fuels can Play in Motorsport’. In it, the history and technical challenges presented by motorsport are described in detail, this article is largely but not entirely based on it. It also draws on interviews The fuel industry is keen to sell the green credentials of the fuel it uses in motorsport. CO2 limits could be the next challenge conducted by Peter Wright and Sam Collins.

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50_RC_0417_.indd 28 23/02/2017 14:14 TECH DISCUSSION – F1 AERODYNAMICS Clear the air A feature in Racecar from last year has led to some radical ideas on what’s really important when it comes to F1 aero By RUDY PYATT

Simon McBeath has addressed the problem of a lack of overtaking in F1 in a series of features for Racecar. One of these has inspired Rudy Pyatt to suggest teams adopt a fresh approach to the issue

imon McBeath’s piece in the February difficult to obtain, at least via F1 teams. The engined layout, allied to light weight and 2016 issue of Racecar (Follow Closely, inertia of received wisdom, standard practice, effective, though not overwhelming, engine V26N2), which was produced in and frankly, ego, prevents the F1 establishment power had sufficient advantages over the collaboration with Miqdad Ali and from assuming that aerodynamic downforce then prevailing practice as to usher in the SDynamic Flow Solutions, refers to the Purnell- creates the fastest car. But the way remains so-called ‘rear engine revolution’. I believe that Wright paper of 2007 and reproduces a graphic open for lesser categories that permit teams we are at a tipping point in F1, much as in the included in that paper (see p38). At minimum, to build their own chassis, such as Formula 3, 1950s, when current practice will give way to a McBeath and Ali have raised questions worthy to put ideas to the test which, if successfully demonstration of the effectiveness of a simpler of additional computer simulation and implemented, can reset the concept of what is approach. The demonstration this time will be experiment, an idea for which I present here. the most effective open-wheeled racecar. success through aerodynamic efficiency. All told, McBeath’s article and the Purnell- Ask most teams and engineers what they Wright graphic present enormous opportunities Time for change? mean by aero efficiency and you’ll probably for a team of sufficient boldness and ingenuity This has happened before of course: then- hear something along the lines of ‘the greatest to exploit. Simulation will be necessary simply lesser teams Cooper and Lotus so effectively amount of downforce for the least amount of because real world empirical data will be demonstrated that the long discredited rear drag’. As proven time and again in the last 20 A car with high RaE is one that is the least sensitive to wake turbulence and other effects and it can follow the racecar ahead of it more closely

FORMULA 1 2017 www.racecar-engineering.com 37 TECH DISCUSSION – F1 AERODYNAMICS

Are there Formula 1 tracks with characteristics such that the RaE versus the LaE balance point can be reached over the course of a lap?

years, whoever gets this combination right, at reverse being true around corners. And therein In other words, where (fc) and (sc) are least if they have an appropriately powerful lies the rub, leading to the following questions approximately equal, Tr will be ‘Balanced’ engine, will have a car that produces the fastest with respect to F1 especially: In what kind of (BTr) and LaE has no advantage over RaE. lap possible in qualifying. Pole position, or corners does a high LaE car excel? Are corners You can take this as a ‘track corollary’ to the at least a spot on the first two rows, usually with such favourable characteristics uniformly Purnell-Wright Continuum. comes with that performance. For the reasons present at all F1 tracks? Are there F1 tracks with So, in theory, we have a continuum of tracks outlined by McBeath, cars outside the first two characteristics such that the RaE v LaE balance and a continuum of cars running – Ad[LaE] – BTr rows often find that lack of qualifying pace to point can be reached over the course of a lap? – Ad[RaE] – and the question becomes: just how be an insurmountable obstacle. They cannot Intuitively, it seems that high LaE works to close do the values of (sc) and (fc) have to get closely follow, let alone overtake, the cars best advantage on tracks with lots of high speed before reaching BTr on a given track? And are ahead of them because of aerodynamic effects. corners. Those conditions allow downforce to there any existing race tracks on the calendar For these reasons, I believe that the correct maximise and maintain speed through corners that allow both RaE and LaE to thrive without measure of aerodynamic efficiency is what I call that would otherwise require deceleration one dominating the other? ‘racing efficiency’ or RaE. So measured, efficient (via lifting or braking) to safely and effectively But let’s go back to the cars, because here’s aerodynamics are those least affected by other negotiate. Conversely, RaE seems best suited to where the simulation comes in. Let’s take a CFD cars. In other words, a car with high RaE is one long straights and slower corners – conditions model of an ordinary non-wing, non-diffuser that is the least sensitive to wake turbulence that allow an advantage gained on the straights Formula Ford, and give it the same 900bhp as and other effects and can follow the car ahead to be sufficiently large to fend off opponents the average F1 car as the stand-in for RaE. of it more closely – closely enough that the despite having to corner slowly. Now let’s take the McBeath Racecar driver can overtake without the racecar’s Let me attempt some maths here (I’m a Engineering 2013 Formula 1 model as LaE and handling deteriorating in bad air. lawyer and former journalist, and members assume the same horsepower. To eliminate of both professions are stereotypically bad the influence of tyres, assume they both have Downforce issues at mathematics. I am not the exception to current F1-spec hard compound tyres. This is why the Purnell-Wright graphic is prove the rule, but bear with me) to the extent so significant. It shows the aerodynamic of defining some fairly obvious terms and Simulated duel continuum from ‘racing efficiency’ to what I’ll equations for present purposes to illustrate. Let Now, pick some set of tracks from the current call ‘lap time efficiency,’ or LaE. Quite plainly, (fc) = fast corner and (sc) = slow corner. Let Ad Formula 1 calendar – let’s say Silverstone, cars optimised for LaE (high downforce) cannot (like I said, I’m being obvious here) = Advantage, Monaco, Dubai and Sepang – and run some follow each other closely and passing is difficult Tr for track. The foregoing intuitive conclusions simulations. Start with simulating a qualifying to impossible. More interesting still, the Purnell- would be expressed as: lap. What lap times do the cars produce when Wright graphic shows the point at which LaE Ad[LaE] @Tr if (fc)>(sc) and Ad[RaE] if (sc)>(fc). alone on each track? What about together, and RaE balance out such that a car with high But, from the Purnell-Wright Continuum, this in a simulated duel for the lead? What about RaE (low downforce) will have an advantage implies that where: expanding the simulation to include a complete down the straights over a high LaE car, with the Tr(sc) = Tr(fc), then Ad[LaE] = 0 and Ad[RaE] = 0. grid using a mix of our two CFD models: does starting grid position correlate closely with finishing position for RaE? Based on every description, the 2017 F1 rules have aimed to increase LaE: the explicit goal was to reduce absolute lap times. This should make for an excellent time trial car; but it seems that making a good racing car – a car that maximizes RaE – is at best a hoped-for by- product of the new rules. On at least some tracks, my fear is that close racing, with genuine (non-DRS) overtaking, will in fact be rare. My hope is that an analysis of the kind I have outlined here will show that a race team can succeed with a radical approach that doesn’t sacrifice all other considerations on the altar of absolute lap time. Of course, these considerations are not confined to Formula 1. It may take successful teams in other categories to show the way forward. After all, Formula 3 doesn’t have to be what amounts to a Dallara spec-series. Perhaps analysis as outlined here will prompt a team to take up Formula 3’s standing invitation to This graphic was included in a paper from 2007 by Peter Wright and Tony Purnell. It suggested that a lack of overtaking in design and build its own car? If that happens, F1 was due to high downforce, a dependence on the front wing, and the drag produced by downforce-generating devices and succeeds? Vive La Revolucion!

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CRCEF103 F1 supp 17.indd 1 24/03/2017 12:16 WRITE LINE – PETER WRIGHT The laps of the gods A view from Olympus on F1’s lack of real racing – and what might be done about it

ormula 1 seems to be in such a state of (yes, really, overtaking was a subject for debate banned, though fought over until 1983 when fl at schizophrenia that everyone and anyone can 18 years ago) he undertook to use this database bottoms were mandated. From that year on the Foff er solutions to what is fundamentally a lack to calculate the number of changes of position in front wing became the dominant aerodynamic of interest in the younger generation. In fact, it is each GP, each year, as noted as the cars cross the feature on Formula 1 cars, and overtaking declined not just the young; Gerhard Berger admitted that start/fi nish line. This data was condensed down to steadily. Plotting average overtaking manoeuvres/ he falls asleep watching Formula 1 once he knows an average number of such manoeuvres per year, race against front wing downforce generates a clear who will win, usually after the fi rst few corners. as can be seen in the chart below. trend, as seen on the chart on the following page. Rather than plunge headlong into this melee, Unfortunately, Jabby’s analysis was never I am going to ask you to momentarily suspend Draft excluders extended to the present day, but we can probably belief and imagine I am the God of Sport, residing Certain features are immediately apparent. First; predict what it would look like up until the time on Mount Olympus. Imagine Zeus has just given when the great slip-streaming circuits ceased to that DRS and Pirelli tyres reinstated overtaking. me instructions to go and sort out F1, as he is sick be used in the early 1970s, overtaking reduced by Most people know that the front wings, of the whinging of mortals. The brief is to take no around 60 per cent from an average of 20 a race. elaborate multi-element devices, are the culprits, account of the politics or commercial self-interests, Second, overtaking reached a minimum in the yet F1 itself is unable to do anything about them. and on no account to form a committee or working mid-1970s, and then nearly doubled again by the Time for a thunderbolt then. Limit front wings group to decide what to do. Having observed mid-1980s. Finally, from then on it fell steadily drastically, controlled by size and number of motor racing over the last 100 or so years, and seen over the next decade to an absolute minimum elements – max one or two at the most. Then we the highest level become the Formula 1 of today, of two to three per race. should limit overall CLA to, say, 50 to 60 per cent of he has become annoyed. Why? In the early 1970s, wing-generated current values, or maybe even less. I do wonder what has become of the ‘racing’ downforce was being steadily developed, with drag The fi rst can be regulated dimensionally, the in ‘motor racing’. Given the brief to sort it out less important, due to the absence of the very fast second requires the measurement of downforce on quickly, I would decide to concentrate on just circuits. Overtaking reduced. track, normalised with pitot pressure, and limited this issue, as overtaking means uncertainty, and In the late 1970s, Average number of overtaking manoeuvres per uncertainty means entertainment (us gods are ground eff ect with skirts Average number of overtaking manoeuvres per race good at broad, sweeping statements). entered the arena and race.

My fi rst port of call would be to go and fi nd front wings shrunk, 25.00 Jabby Crombac, the late editor of Sport Auto, acting mainly as trim who attended all grands prix from 1955 until just tabs. The overtaking 20.00

before he died in 2005. He maintained, by hand, then increased. In 1981, 15.00 a rigorously accurate lap chart of each GP. In 1998 sliding skirts were 10.00 overtaking manoeuvres. Average no. of 5.00

0.00 1955 1965 1975 Year 1985 1995 2005

Many believe F1 is not exciting these days beyond the cut and thrust of the fi rst lap – but might there be a way to improve the racing by changing the aero regulations?

40 www.racecar-engineering.com FORMULA 1 2017