Publications: F1 Race Technology Report

Every year High Power Media, who publish ‘Race Engine Technology’ (RET) Magazine, produce a number of magazine format Race Technology Reports. Covering F1, Moto-GP, Nascar, Drag racing and 24-hour racing.

Just out is the current F1 Race Technology issue, covering Technical subjects from 2011 and 2012.

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McLaren MP4-26 2011 – Fan Tail (Octopus) Exhaust

McLaren went into 2011 with an aggressive design strategy, this was a response to the poor initial form in 2010 and resulted in the dramatic “U” sidepods and a mysterious exhaust system.


It was this exhaust system that stole most of the column inches in the F1 press and the fan forums during pre season testing. One particular column fed the interest around the exhaust and christened it the “Octopus”. The article suggested the exhaust was ducted to several exits and used high temperature Glass Ceramic Carbonfibre (GCC). It went on to explain the unreliability of the exhaust solution was due to the heat making it fail.
It was true McLaren’s first tests, even from the first private shakedown runs before the public testing had started, demonstrated a problem with the initial exhaust design. But this exhaust solution was not the “Octopus” as described; in fact McLaren Technical Director Paddy Lowe explained to me at the 2012 cars launch, that “it didn’t look anything like an Octopus”. Adding “The exhaust we had was a slot, we called it a fantail”, which was a simpler, albeit still innovative solution.

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Mercedes AMG: KERS development

One of Max Mosley’s lasting legacies in F1 was the introduction of his vision of a green initiative in F1. As a result KERS (Kinetic Energy Recovery System) was introduced 2009, as part of a greater package of rule changes to change the face of F1.
KERS is a system which harvests energy under braking and stores it to provide the driver with an extra power boost each lap. A simple technical summary of KERS is here (https://scarbsf1.wordpress.com/2010/10/20/kers-anatomy/ ).
During the 2009 season McLaren were applauded for running Mercedes KERS at every race and it was widely reported as the best KERS in use that year. Along with a few other journalists, I was invited along to Mercedes AMG Powertrains in Brixworth, UK to hear about KERS development since 2009. With Managing Director Thomas Fuhr and Engineering Director Andy Cowell giving a presentation on the range of work Mercedes AMG does with its F1 teams.

Mercedes AMG Powertrains reside on the site that was previously Mercedes Benz High Performance Engines (MBHPE). Now renamed to reflect the wider application of the groups knowledge, both to uses outside F1 and to areas other than engines. Powertrain is a catch all term covering; engine, transmission, electronics and of course KERS Hybrid systems.
The company have built a purpose designed Technology Centre on the site, which historically was the Ilmor engine plant and positioned just a few miles from Cosworth in Northampton. Clearly this area has a rich seam of Engine knowledge.
Formed around three buildings the entire F1 engine and KERS development is carried out on site, only specialist functions such as the casting of the crankcases is carried out off site. Additionally other Mercedes AMG work is carried out here, such as the AMG E-cell car.

KERS 2009
Mercedes AMG (MBHPE as it was known then) developed their first KERS for 2009 in house. At the time McLaren were the primary customer for the system, although Force India and at the last minute Brawn GP were also customer teams that year.  Force India had a chassis prepared to run KERS, but chose not to during the season.  Brawn had a chassis designed before their switch to Mercedes engines, so their car was not designed to accept the Mercedes KERS.

Mercedes AMG: 2009 Battery pack and water cooling radiator

In designing the system, Mercedes AMG had a specific requirement from McLaren. As the effectiveness of KERS was unknown, McLaren didn’t want to compromise the car if KERS was removed. So the system was packaged to fit into a largely conventional car. Whereas other KERS suppliers went for a battery position under the fuel tank, McLaren and Mercedes AMG placed theirs in the right hand sidepod. Low down and far forward, on the floor between the radiator and the side impact structures. The battery pack contains not only the array of individual cells, but also the pump and pipe work for its water cooling circuit. As well as the electronic interfaces for its control and monitoring. The assembly is around 7cm high, 12cm wide and 40cm long. The KBP is probably the single heaviest KERS component. In 2009 this sidepod package was acceptable as the teams were still on Bridgestone tyres and seeking an extremely forward weight distribution. Thus the 5cm higher mounting in the sidepod was offset by its forward placement.

2009 KERS and the batteries sidepod location relative to the engine

Conversely the smaller Power Control Unit (PCU) was placed in a similar location in the other sidepod, ironically the PCU is around the size and shape of road car battery. This left the monocoque uncompromised, aside from the smaller cut out for the MGU in the rear bulkhead.

The 2009 Zytek developed MGU

Then the Motor Generator Unit (MGU) is mounted to the front of the engine.  This device generates and creates the power for the KERS. Its driven from a small set of gears mounted to the front of the crankshaft.  the unit remains with the engien when the car is dismantled and is oil cooled along with the engine.

All of the components are linked both to the SECUs CAN bus and to each other by High Current Cable. The latter taking the DC current between the Batteries and MGU. With this packaging Mercedes AMG quotes the total system weight as 27kg.
Designed and developed by Mercedes AMG, but other partners were involved; the unique battery cells were supplied via A123 and the MGU was partnered with Zytek. Although the power control electronics were solely a Mercedes AMG in house development.
Through the 2009 season both McLaren drivers had a safe and reliable KERS at each race. The system was safe even after crashes and was fault free despite rain soaked races. Safety was designed in from the outset, all electrics were double insulated. Teams can also measure damage to the unit via accelerometers and insulation sensors, so any impact or incidental damage can be monitored and the car retired if the need arises. Additionally each cell in the battery has its temperature monitored. KERS batteries are sensitive to high and low temperatures, each cell needing to operate in a specific thermal window. Too low and the unit is inefficient and too hot and there’s the danger of explosion.
Perhaps the only criticism was the sidepod battery mounting, despite several incidents, this never put any one in danger, so this never proved to be an unsafe installation.

KERS 2011

2011_Mercedes_AMG_engine

For a variety of non technical reasons KERS was agreed not to be raced from 2010 until the planned 2013 rules. However this plan changed, but not before Mercedes AMG had made new strategic plans around KERS.
Mercedes AMG set out a longer term strategy to work on research for KERS in preparation for 2013, as well as working with AMG to develop the road car based E-cell technology.
(Link Mercedes AMG E-Cell chassis  )
This changed when the plans for the 2013 engine were pushed back to 2014 and KERS was agreed to be reintroduced for 2011. Thus the 2013 development plans had to rebased and deliver a refined version of the 2009 KERS for 2011. Moreover there were now three teams to be supplied with KERS. There was no Christmas for Mercedes AMG staff 2010!
As a result of the research work carried out after 2009, Mercedes AMG now solely design, develop and produce the entire KERS package, aside from the Battery cells. So now the MGU is a wholly Mercedes AMG part.

The MGU fits to the front of the engine and driven from a small set of gears

With KERS effectiveness proven in 2009, it was possible to have the cars designed around it, rather than it be an optional fitment. So the packaging was revised and the entire system integrated into just two units. The MGU remains attached to the front of the engine, still driven off a spur gear on the nose of the crankshaft. While the KBP and PCU are now integrated into a much smaller single package and fitted under the fuel tank. The unit bolts up inside a moulded recess under the monocoque, the unit being attached using four vibration mounts, and then a closing panel and the cars floor\plank are fitted under it.

The 2009 battery pack (yellow) is now integrated with the power electronics (not shown) in a single unit under the fuel tank (red).

It’s this integration of the batteries and power electronics that has has really slimmed the 2011 system down. Mercedes AMG now quote 24kg the entire KERS, much of the 3kg weight loss being down to the reduction in the heavy power cabling between these units.
Not only is the packaging better, but the systems life and efficiency is too. Round trip efficiency stands at a stated 80%, which is the amount of power reapplied to the engine via the MGU after it has been harvested and stored. Improvements in efficiency being in both the charge and discharge phases.
Battery pack life was extended to as much as 10,000km, several times the 2009 predictions that batteries would need replacing every two races (2,400km). Over this period, the cells do not tend to degrade, as the team manage the unit’s condition (‘State of Charge’ & temperature) throughout the GP weekend to maintain their operational efficiency.
The 80hp boost KERS provides, stresses the engine. This was well known back in 2009, but for 2011 along with DRS the car can be several hundred revs higher than the usual EOS (end of straight) revs. Mercedes AMG quoted 15-25% more stress for a KERS and DRS aided lap, this needing to be taken into account when the team monitor the engines duty cycle, thus deciding when to replace it. Mercedes conducted additional dyno development of the engine being kept on the rev limiter to fully understand and counter this problem. This work paid benefits; Hamilton ran many laps at Monza bouncing off the rev limiter along the main straight, while chasing Vettel.

KERS in use
Although the max 60KW (~80hp) output can be reduced from the steering wheel, its normal for the driver to use the full 80hp boost each time they engage the KERS boost. With a reliable KERS, the driver will use the full 6s boost on every lap. Media reports suggest Red Bulls iteration of the Renault KERS does not use this full 60kw. Instead something like 44kw, providing less of a boost, but allowing smaller batteries to be used. The loss in boost being offset by the overall benefit in car packaging.
The driver engages a KERS boost either via a paddle or button on the steering wheel, or by the throttle pedal. The latter idea being a 2009 BMW Sauber development, where the driver pushes the pedal beyond its usual maximum travel to engage KERS. Nick Heidfeld brought this idea to Renault in 2011 and the over-extended pedal idea has also been used for DRS too.
Once the driver is no longer traction limited out of a turn, they can engage KERS. Usually a few small 1-2s boosts out of critical turns provides the ideal lap time. It’s the driver who has to control the duration of the boost, by whichever control. As with gear shift the drivers can be uncannily accurate in their apportioning of the boost around the lap. It’s suggested that the 2009 Ferrari system apportioned the duration of the KERS boost via a GPS map, the driver simply presses the button and the electronics gives them the predetermined amount of boost. This solution came as surprise to Andy Cowell, so one wonders if this is legal or perhaps if the report is true.
From on board shots, we’ve seen the steering wheel has an array of LEDs or numerical displays to show the driver the boost remaining for that lap. The SECU will have control code written to prevent overuse of KERS around a lap.
Typically the battery will hold more charge than a laps worth of harvesting\discharge. So that any unexpected incidents do not leave the driver without their 6s of boost.
In use KERS can be used in several different ways. When lapping alone KERS typically gains 0.45s per lap, although this varies slightly by track. Along with DRS is can boost top speed by 12kmh. As explained the driver uses a pre-agreed amount of boost, decided from simulation work done at the factory before the race. So the planned strategy of KERS usage will be used in practice, qualifying and in parts of the race. However in the race the driver can use KERS tactically to gain an advantage. Drivers are able to use more a KERS boost to either overtake or defend a position. One feature of 2011 along with the Pirelli tyres being in different condition during the race, was the driver’s freedom to alter their racing line and use their grip and KERS to tackle their rivals.

KERS future
KERS continues in its current guise for another two years, then for 2014 along with all new engine regulations there will be a new format KERS. Energy recovery will be from different sources, so the overriding term for the hybrid technology on the car will simply be ERS (Energy Recovery Systems). However KERS will still exist, harvesting energy from braking, but will have a greater allowance for energy stored and reapplied. But, there will also be TERS (Thermal Energy Recovery), which a MGU harvesting energy from the turbocharger. Overall ERS will provide a third of the engines power for some 30s of the lap. No longer will the driver press a button for their KERS boost, it will be integrated in their demand for power from the throttle pedal. The electronics will be constantly managing the Powertrains energy, harvesting and applying energy based on whether the driver is on or off the throttle. In 2014 Powertrains and ERS is set to become very complicated.

Abu Dhabi Test: Red Bull Aero Rake

Red Bull started the Abu Dhabi Young Drivers test with a mass of aero testing equipment fitted to the RB7. Although the test is supposed to be to assess young drivers, this is the first open test since the season started and teams make use of this time to gather data from the car. In Red Bulls case this was a repeat of tests from last year, where the front wing ride height and wake is being measured by a range of sensors.

Pictures via F1Talks.pl & SuttonImages.com
Airflow around the front tyre is critical with the post-2009 wide front wings. The ever more complex front wing endplates direct the airflow around the tyre. This effect varies greatly with front wing ride height, so that when the wing flexes down under load at speed, the airflow changes. I have learnt from F1 aerodynamicists that the effect of the endplate on flow around the wheel as the wing flexes down, is perhaps more important than downforce gained the wing being closer to the ground. So the Red Bull and also Ferrari tests are critical to understand how the airflow passes around the tyres with varying wing ride height.
Clearly the gains from flexible front wings will be an ever greater performance factor next year. Even though the FIA rules amended for 2011 were even more stringent than in 2010.

In Red Bulls the case the set up consists of three main elements; the aero rake, ride height sensors and the cables holding the front wing.

Wing mounting cables

Wing cables & Nose hump – Picture via F1Talks.pl & SuttonImages.com

Ride Height Sensors

Ride Height Sensor – Picture via F1Talks.pl & SuttonImages.com

Ride height Sensors – Picture via F1Talks.pl & SuttonImages.com

Aero Rake

Rake detail – Picture via F1Talks.pl & SuttonImages.com

My interpretation of how the rig works is: the wing is allowed to deflect at speed to a specific height, this is controlled by the cables from the hump on the nose. By limiting droop, a number of wing ride height settings can be assessed during the runs. Laser ride height sensors both in the centre and at the front and rear of the endplate will confirm the actual ride height and wing angle being tested. Then the rake will take measurements of the airflow. The driver will then run at a fixed speed along the straight, keeping a consistent speed will ensure the data is consistent and the amount of wing flex can be predicted for each run.
This will create an aero map of flow across the wing and with the wing at different attitudes. The data from the tests will be used to confirm CFD\Wind tunnel results and direct the team in deciding how the wing should flex in 2012.

We can now look in detail how the rig is made and how it works.

Cables holding the front wing


During some runs we saw the cables lying loose between the wing and the hump. Which confirms they are cables and not solid rods, as with the rake mountings. Being cables they could not be for measuring wing position, as not being stiff, they would not be accurate enough. With the size of the nose hump and the other equipment to measure ride height, I now believe they are to control the droop of the front wing. Perhaps the test wing is more flexible than the usual race wing in order to achieve more attitudes under load. Its possible the hump contains hydraulics to adjust the droop of the wing to different attitudes during each run. The 2009 Red Bull used hydraulics in the nose to control the then legal adjustable front wing flap, so it’s a proven approach to fit more hydraulics into the nose cone. Being able to alter wing attitude on the move would greatly improve the amount of data gathered from each run. With there being two cables for each wing, one mounted on the main plane and the second on the flap, the wing could be controlled not only in droop but also the angle of attack. So that the wing could reproduce different beam and torsional stiffness of a future wing.

Ride Height sensors


We have seen laser ride height sensors fitted to cars through Friday practices and extra units fitted for testing. For the front wing rig Red Bull ran five ride height sensors on the wing. The central unit is fitted to the neutral centre section of wing. This would measure true wing ride height, as the centre section is relatively stiff and is not part of the deflecting structure of the wing. Then two ride height sensors are fitted to front to the front and rear of the endplate. These would measure the ride height of the wing tips. Using the centre ride height sensor as a base line provides the amount the wing tip is deflecting. Just as with the double cable arrangement supporting the wing, the two endplate ride height sensors would measure any change in angle of attack, the delta between the front and rear sensors showing the wings angle of attack.

Aero Rake


With the wings attitude controlled and measured by the cables and sensors, the wake of the wing is then measured by the aero rake. This is an array of sensors measuring air speed, velocity and perhaps even direction. Two rows of rakes are employed and these are securely mounted to blisters on the nose cone. Just as with the wing mounting cables these struts may be attached to hydraulics to raise the rake over a range of positions, to map a wider area behind the wing. A slightly messy part of the mounting system if the bundle of cables exiting the rake and passing up into the nose cone to be attached to the cars telemetry system.

Analysis: Ferraris Front Wing Flutter

In free practice for the Indian GP, we saw a violent fluttering of Felipe Massa’s front wing. This is a higher frequency movement than the flex we commonly see on front wings – in fact, the movement is enough to cause the endplates to hit the ground, sending up showers of sparks. Bearing in mind that the wing is around 75mm off the ground when the car is at rest, we can appreciate the amount of movement that’s occurring here.
This movement is not an aero benefit in itself, but may be symptomatic of other flexibility in the wing.
Ferrari Flexi Wings 2011 Indian Grand Prix FP1 by Mattzel89

This clip shows the Ferrari crest the hill before braking into a turn (4s into the clip). As the car crests the hill at high speed with DRS open, it’s clear that the wing is bowed from the aero load. It’s possible to see the side spans of the wing bend down from the central section. At this point there is some vibration in the wing, but not an excessive amount. As the car starts to go down hill (DRS still open) and passes a shadow across the track, the wing starts a rocking motion (5s into the clip). This rocking soon increases in violence until Massa closes the DRS and starts to brake as usual for the corner (at 9s), so this episode only lasts three seconds. I counted around 20 movements of each endplate, which increase to the point where the endplates’ skid blocks strike the ground.
The cause may be explained as follows: the wing is bowed at speed, but as the car crests the hill the wing is unloaded slightly. Then, as the car starts to move down hill, that load would reverse and the wing (which was already vibrating) is sent into a rocking motion. One endplate moves down, while the centre section and wing mounting pylons appear to be rigidly fixed to the car and are not moving. The load passing from the endplate must have been transferred across the central spar of the wing to the other endplate, which now drops. This movement resonates in a wave from one side of the wing to the other, increasing in frequency and amplitude until the wing actually hits the ground.
I can’t explain why closing the DRS and braking calmed this resonance so quickly, but the wing rapidly returns to the low-amplitude, high-frequency vibration seen elsewhere on track.
Also, I’m no expert on composites but my limited knowledge does suggest that carbon fibre structures are relatively well damped (compared to, say, a metal structure), the rebound effect of flex being relatively well damped and not prone to oscillating.
Ferrari introduced the new front wing in Korea. Alonso ran the wing as it was clear that it displayed the accepted level of flex as used by many other teams. The wing is legal as it meets the more stringent FIA 2010 deflection test. Last year Red Bull set a precedent when its wing, which openly appeared to bow downwards at speed, passed the tests and was declared legal, even when the test loads were increased mid-season.
This bowing effect – where the tips of the wing move downwards at speed – is commonly used as the front wing then sits closer to the ground and can generate more downforce. Despite a lot of theories about mechanisms or heat being responsible for the flex, the answer is much simpler: it is down to the way you want the wing to work i.e. the tips to bend down without the wing twisting and thereby reducing the wing’s angle of attack. This is all done with the lay-up of the composites – I’m told it is a “nightmare“ and have heard of composites technicians spending weeks trying different lay-ups to get this effect, but once worked out it is very effective.
Of course F1’s knowledge of carbon structures has been used to create very stiff parts, but now that we are starting to allow controlled flex, we will start to see resonance becoming an issue. There is a new field of knowledge to be understood and controlled.
It seems the wing was tried again in FP3 and the FIA has taken an interest in the wing. The wing was removed and one would assume that it will not be raced for fear of mechanical failure or a post-race ban, although Ferrari’s Friday press release may suggest that the wing is a development item not planned for use in the race, but as part of the 2012 programme. Pat Fry: “We continued with the now usual parallel programmes: on the one hand looking for the best set-up for the car at this circuit and on the other, working to get a greater understanding of the latest aerodynamic updates, with the new car project in mind.”
We have seen extreme movement of front wings before in super slow motion, such as wing tips fluttering, wings swaying sideways on their mounting pylons and endplate devices flapping. All of these movements, although highly visible, have been accepted by the FIA because the tests have been passed. All of which is to the detriment of the overriding regulation that bodywork should be rigid and immovable.

Thanks to Andrew Biddle (andrewbid@gmail.com) for his assistance as Copy Editor

UPDATE: “See-saw” Splitter, FIA issue a Technical Directive

Before the Korean GP, I published a proposal for a flexible but legal splitter (https://scarbsf1.wordpress.com/2011/10/14/a-legal-but-flexible-t-tray-splitter-the-see-saw-solution/). This so-called See-Saw arrangement of the T-tray splitter was a response to the need for the splitter to deflect to allow a low front wing ride height, but still meet the FIA tests. It’s design was influenced by unusual wear marks seen on cars at previous races. My blog post was provocative, as I did not personally believe it is legal. But, by playing devils advocate, it was clear a case could be made for the See-Saw splitters legality. I had seen no direct evidence such a splitter is in use in F1 and I had no information suggesting that it might have been used in the past.

It was therefore a great surprise when I was tipped off that the FIA had sent out a Technical Directive (TD) on the matter during the Korean GP weekend. It transpired that a top teams Chief Designer had approached the FIA to propose they wanted to use just such a solution for their 2012 car. In the teams communication to the FIA Technical Delegate Charlie Whiting, the See-Saw concept was drawn and described as a method to ensure the splitter isn’t damaged by contact the ground, thus making the car more reliable and damage prone. The request further explained the reaction force provided by the FIA test rig, allowed the more complaint splitter to still meet the FIA deflection test. This being possible even without a kinematic fixing joint (i.e.not having a moving bearing or pivot as the splitters fulcrum point).
Its not unusual for teams to take this approach in protesting another teams car. Its less confrontational, as they argue the technologies legality, rather directly protesting another team. There have been several instances of this in the past. The team probably weren’t seriously wanting to use the See-Saw splitter, nor did they feel its use was for reliability reasons. More that they were concerned another team were currently gaining an advantage from its use and wanted the design exposed and its legality confirmed.

The FIA’s response was a technical directive, coded TD35.  It’s not surprising that it confirmed such an splitter would not be legal. But, crucially the FIA confirmed that they reserve the right to alter the test to ensure the deflection test procedure isn’t being exploited. Therefore future scrutineering checks, may well include an inspection of the splitters mounting and conducting the deflection test with the cars weight bearing down at different points, rather than sat flat on top of its plank.

Several personnel within F1 teams have since contacted me on this subject. Its been suggested that such a construction is, or has been used in F1. The catalyst for this design was the further restriction on splitters after the Ferrari\McLaren protest in 2007. But with the further restriction on splitter mounting and deflection announced at Monza Last year, the See-Saw solution may have become even more useful in 2011.

As yet the change to the FIA testing procedure has not been detailed. Although the Indian GP weekend will be the first chance for the FIA to act on this technical directive with revised checks. It will be interesting to hear if any teams are asked to alter their splitter construction as a result of this.

UPDATE: Mercedes F-Duct Front Wing

Another possibility with the Mercedes stalling front wing is that it allows an opportunity to play with the linearity of the cars ride height. In particular the proximity of the splitter to the ground at different speeds. Looking at this in comparison to other possible uses, I would suggest this is a more realistic and beneficial solution than those initial proposed (https://scarbsf1.wordpress.com/2011/10/21/mercedes-f-duct-front-wing/).

As has been much discussed, the front wing needs to run as low as possible to create downforce. To achieve this teams run as lower front ride height as possible. The limitation of a low front wing ride height is the front splitter grounding, this becomes an increasing problem as speed increases and the aero load builds up and compresses the front suspension. So at the ‘End of the Straight’ (EOS) at very high speed the car is at its lowest and splitter is grounding. This forces the car to have a higher ride height, to keep the plank from wearing away in the EOS condition. Thus at lower speeds the front ride height is correspondingly higher, compromising the potential of the wing.

If Mercedes stall the front wing as the car reaches top speed, hence above the speed of any corner on the track. Then when the wing stalls, the load on the front axle will suddenly decrease and the front ride height will increase. Effectively the ride height\speed map is no longer linear. Ride height will decrease linearly at lower speeds, then above the speed of the circuit’s fastest corner, the wing stalls and ride height increases.
What this allows the race engineers to do is shift the ‘ride height curve’ down the map for a lower initial (static) ride height. Knowing that the splitter will not ground in the end of straight condition. Therefore with the unstalled wing having a lower ride height, more downforce can be generated. When the wing is stalled the lack of downforce is less consequential as the car is on the straight. Plus there may still be the small boost in top speed from the lack of induced drag from the stalled wing.

One other potential of such a solution is the front wing grounding. We have seen the midseason version of the Mercedes front wing ground quite easily in some turns this year. So as with splitter ride height, endplate ride height at top speed may become the limiting factor in benefiting from the wing flexing at lower speeds. Stalling the wing on the straight will see the load on the wing decrease and the wing will naturally flex upwards. Giving the opportunity to flex more at slow speeds and have the stall prevent grounding on the straight.

In comparison to the manipulation of the CofP to resolve handling problems I initially proposed, this would be a more likely purpose of the stalling wing. Perhaps more importantly this would be a universal solution, one that other teams could legally adopt in preference to flexible splitters or excessive rear ride height to achieve lower front ride heights.