Mercedes AMG: Engine Build Challenge


During my visit to Mercedes AMG before Christmas, the company set us a challenge that’s been put to other more notable visitors. In the engine build area, two engines were arranged in each bay, but without the coil pack, heat shield and exhausts fitted. Our task was to fit these parts to one side of the engine, along with tightening each fastener to the correct torque setting. A dozen journalists attended the day, the challenge being made even greater as the two current Mercedes AMG drivers had also previously completed the challenge.

The coil pack is handed over and the challenge starts...

The first job was to fit the coil pack. The four-pronged carbonfibre cased unit is a press fit atop each spark plug, then the we needed to connect CAN electronics interface near the front of the airbox.

Next the heatshield goes on... (eventual challenge winner watching intently behind)

A small reflective coated carbonfibre heatshield goes over the coil pack, attached with three small bolts, one of which is smaller and requires a different torque setting.

Access to the 24 exhaust studs under the engine was surprisingly good

Then onto the exhaust system, weighing about 3kg each exhaust is hand made from thin sections of inconnel welded together. Although the 4-into-1 exhaust is one assembly, there is some play in the primary pipes joints with the collector, so fitting the four exhaust pipes to the studs on the engine requires a little fiddling. Each exhaust pipe bolts to the exhaust port with three nuts, two above and to the side of the exhaust pipe, and one centrally below.

A blur of hand movement gets each nut threaded on...

Each of these 24 nuts being tightened to the same torque setting. With the engine up on the stand and being able to kneel below the engine, getting access to each fastener was surprisingly easy, none of the exhaust pipes being particularly obstructive. I’m sure doing the same job with the engine in the car and the floor fitted is a very different story.

A quick check that each nut is torqued correctly and the job's done.

I completed the challenge in 4m 30s and I was satisfied I’d done a good job. However ex Racecar Engineering magazine editor, Charles Armstrong Wilson completed the challenge in an impressive 3m 30s! Even though one (un-named) journalist took as long a 7m 57s, as group us journalists were confident we’d done a good job. But the teams Drivers had soundly beaten us all. Nico Rosberg did the challenge in 3m 15s, while Michael Schumacher did it thee minutes dead!

The job of the F1 engine builder and mechanic is a difficult and skilled one, the skills of the F1 driver are ever impressive and I’ll stick to drawing racecars and not working on them!

Mercedes F-Duct Front wing

Note: Updated 24th Oct

Mercedes GP are rumoured to be running a novel front wing. This has been reported in the three major F1 magazines (AMuS, Auto sprint and Autosport). It seems the front wing uses the nose hole to blow a slot under the wing. Although this is a completely passive system (i.e. no moving parts or driver intervention), the fact that it alters aero performance at speed, has seen it dubbed as an F-duct Front Wing.

This solution was first heard of by Michael Schmidt of German magazine ‘Auto Motor und Sport’ (AMuS). Schmidt passed the tip off to Giorgio Piola who spent hours in the pitlane observing the Mercedes car and how mechanics handled the different wings. A task made additionally difficult, as he could not arouse suspicion by Mercedes and give away the fact he was researching the tip off.
He found only two noses had the nose-hole with the splitter and that these wings were only carried parallel to the ground when moved around the pitlane. The final piece of the jigsaw was when he saw a mechanic inspect the wing with his hand leading to understand the slot placement and this information allowed him to work out the system and draw it for the aforementioned magazines. Its remarkable such a tiny detail can be observed and goes to show the hard work that went into Piola exposing this innovation.

Description
AMuS article

Autosprint article

As described in the illustrations and texts, the wing assembly (including the nose) is as follows. The nose hole is used to pass air down through the front wing pylons into a slot on the underside of the wing. It appears that the slot has a wide span and is very narrow.

The nose hole feeds air through a duct into a slot under the front wing

This design is somewhat similar to Mercedes early 2010 F-duct rear wing, which was passive. The driver didn’t have a control duct, as with the McLaren system. Instead the ductwork would only blow with enough force to stall the rear wing at a certain airspeed. Tricky to design and tune, this system worked well for Mercedes last year. Its not improbably that just such a system could be made to work on the front wing.

Aiding downforce or stalling the wing?
Typically slots in the wing are for two purposes; aiding or stalling the flow over the wings surface. How the slot creates these two very different effects depends on the slots angle to the wings surface.

To aid the airflow, you need a slot blowing nearly inline with the surface and airflow. Known as Tangential flow, this flat entry angle creates a relatively wide slot when viewed externally.

To stall the airflow, you need a slot blowing at near right angles to the surface. This creates a narrow slot when viewed externally.

Looking at what you need to aid or stall the airflow also requires different placement of the slot.

To aid the airflow, you would inject the flow from the slot in an area downstream on the wings surface where the boundary has slowed and thickened. On a front wing this would arguably be somewhere on the flap towards its trailing edge.

To stall a wing, you want to upset the airflow where it’s moving quite fast, for a front wing it would be placed towards the leading edge of the wing. Last year with F-ducts we saw the stalling slots initially placed on the flap, until Renault placed theirs on the main plane for a better stalling effect.

This analysis suggests the narrow slot towards the leading of the front wing is for stalling not aiding the airflow.

Why stall the wing?
However, while we have got this far in reverse engineering the Mercedes front wing. We now need to work out what the benefit of stalling the front wing is. When stalling aerodynamics there are two possible benefits. Reducing drag for more top speed or reducing downforce.

Drag Reduction
For a front wing the drag loss wouldn’t be that beneficial on top speed. Sitting within the frontal area of the cars silhouette the front wing has very little form drag. However, induced drag from vortices produce particularly at the outboard ends is a factor, but far less than with rear wings. With teams increasingly bending their wings down at speed to gain greater downforce, they are creating most of the load towards the wing tips. By making the wing more aggressive at its outer ends, means that more vortices will be produced and sent around the front tyre. This flow structure creates drag and stalling the wing, especially near the tips would reduce this drag and boost top speed. Martin Whitmarsh was quoted in the AMuS article as suggesting a 5/8kph gain from stalling the front wing.

Drag is induced by the vortices created at the wing tips

With the front wing stalled, some of the energy it robs the airflow can pass towards the underfloor, increasing the pressure at its leading edge, forcing more flow under the floor for more downforce. With more downforce from the underbody, a smaller rear wing can be raced, which also creates less drag for more top speed.

Aero Balance
But that may not be the greater goal of stalling the front wing. Instead the aim may be managing the balance of the car through out its speed range. This would be done by the loss of downforce altering the cars Centre of Pressure.

Firstly, let’s review what the front wing does for the cars dynamics at different speeds. An f1 cars downforce is produced largely by the front wing, rear wing and the floor. With the front and rear wings being the main tuning elements. By tuning the front and rear downforce you alter the cars Centre of Pressure.
Centre of Pressure (CofP) is the balance of downforce at the front and rear axles. As such it’s analogous to being the aerodynamic equivalent of Longitudinal CofG (balance of mass between the axles). CofP is also known as termed as aero balance.
Typically the CofP position closely matches that the CofG. Starting from around 1-2% behind the CofG, then as the car gains speed the car gets lower making the front wing and diffuser work better. Fairly soon the stepped bottomplank choke flow into part of the diffuser, this robs the diffuser of some downforce. While as the front wing gets closer to the track, it works in ground effect to create even more downforce. The combined effect of the loss of some rear downforce and gain in front downforce is that the CofP moves further forwards.

Such is the potential of the front wing and the near equal tyre sizes front to rear; an F1 car is largely limited on corner entry by the rear grip available. In low to mid speed turns the car needs a slight rear bias to the CofP, this prevents the car suffering corner entry oversteer. Where the car wants to spin as it approaches the apex. Too much front wing in these corners will make the car too pointy and hinder laptimes.
In faster turns the front wing can lead the car. The drivers turn in gentler to fast turns, which creates less lateral acceleration at the rear axle. So it’s rare for the rear to step out on turn-in to fast corners. Thus, at higher speeds you can have a CofP biased towards neutral or the front. Last year with the adjustable front flap, (rather than used for the overtaking balance adjustment for which it was designed) teams would use alter the front flap angle into a fast turn.

So typically you wouldn’t want to shed front downforce for fast turns, by stalling the front wing. Stalling the front wing will reduce front downforce and drive the CofP rearwards, robbing the driver of front axle load just when he needs it.

But, the move towards a rear biased high speed set up could be a response to other problems with the chassis. We knew the 2010 Mercedes W01 suffered understeer and Michael Schumacher didn’t like that facet of its handling, even though Nico Rosberg could cope with it. Perhaps Schumacher’s style of being aggressive on initial turn in, helps the car to rotate into turns more to gain speed through slowmedium speed corners. This tendency corner entry oversteer wasn’t present in the 2010 chassis.
The 2011 W02 is shorter and designed to rotate better, it certainly isn’t a natural understeer. We can suggest this forwards bias, as a possible reason for the car being hard on its rear tyres.
So if the W02 has a forward biased aero balance, this would move the car closer towards corner entry oversteer. We’ve also seen the mid season wing upgrade displays some flexibility, as with many teams front wings. This would have the effect of moving the front wing in yet closer proximity to the track and create even more front downforce at higher speeds.
So with the W02, as speed increases and the CofP moves forwards. Now the corner entry oversteer create a danger of high speed spins, the team need to calm the chassis down a little. So when the wing stalls, the CofP moves rearwards and gives the drivers more confidence with a little understeer. In Michaels case his naturally aggressive turn in is tolerated and as we’ve seen Rosberg can cope with understeer. So both drivers benefit. This might also save the tyres from slip in high speed turns, which could be detrimental to the tyres grip.

Front Ride Height

Another possibility with the stalling front wing is that it’s allowing 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.

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 heightspeed 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.

Summary
Looking at the options listed above, I would definitely say the cars wing is stalling.  with little to be gained from drag reduction the stalline is most likley to create another effect on the chassis.
In comparison to the manipulation of the CofP to resolve handling problems, the speed sensitive ride height control 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.

Legality
So if we now accept that this theory is how the might wing work, we need to look at the legality and construction of the set up. Firstly a passive system that involves no moving parts or driver intervention is legal. Secondly the rules on the closed sections forming the front wing are much freer than those applied to the rear wing. So slots can be legally made across the side spans of the front wing. Clearly it would be legal in both of these respects, that the stalling slot can be made to blow at certain speeds.
The biggest issue is with the nose hole itself. This is covered in the rules and is allowed for the purposes of driver cooling. This being worded into the nose cone regulations for 2009 to prevent Ferrari style slotted noses. We know the nose hole is used to blow the front wing for several reasons. Firstly Mercedes do have the nose hole, but rarely use it, instead the duct moulded into the access panels atop the chassis are normally used for driver cooling. Most of the time the nose hole is sealed up with clear tape.
But one crucial picture in the AMuS gallery accompanying their article, was of the car with the nose removed, showing a black carbon fibre cover going over the front bulkhead. This would seal the nosecone, such that air entering the nose hole would not pass into the cockpit and instead pass down the wings support pylons. With this panel in place the nose hole cannot function as driver cooling and goes against the rules. Perhaps this set up using the nose hole was just at Suzuka for testing, as Teams are unable to do much full scale testing away from the circuit. It could be legally run in a Friday practice session, as teams are given some leeway to test parts which might otherwise be unacceptable to the scrutineers. As long as the parts aren’t run for qualifying, then apparently illegal parts can get limited Friday running.
So for 2012 the wing might gain its inlet from another position. At Suzuka, the use of the nose hole might have been a good way to disguise the system when it was tested.

I have to thank the many people who aided me in my countless questions on this design. Thanks for your patience.

Septembers Technical updates

I’ll compress this months work into one post for simplicity. For updates on F1 technology have a look at the following outlets: Automoto365.com, Motorsport Magazine and Race Engine Technology magazine.

Automoto365.com – Singapore Tech Desk
All the technical devleopments from singapores night race.
- McLarens front wing and nose cone (thanks to bosyber comments on this blog)
- Red Bulls updates
- Mercedes Bargeboards
- Williams Frotn wing
- plus more from Renault and Toro Rosso

http://f1.automoto365.com/news/controller.php?lang=en&theme=default&month=10&seasonid=21&nextMode=ExclusiveNewsForm&news_id=42469

Motorsport Magazine – F1′s Aero Tricks

I’ve illustrated this article on this years must have developments: F-ducts, Exhaust Blown Diffusers and deflecting splitters.

http://www.motorsportmagazine.co.uk/2010/09/30/latest-issue-%E2%80%93-november-2010/

Race Engine Technology


What lies inside a contemporary Formula One engine? Toyota have given Race Engine Technology full access to their current RXV-08 F1 engine. This issue contains the most detailed technical article ever published on a current F1 engine. A 16 page article covering all aspects of the Toyota Formula One engine in a level of detail you will have never experienced before. RET have been given unprecedented access to the engine with the full co-operation of the entire technical team.

http://www.highpowermedia.com/mall/productpage.cfm/RET/2050/352560

Germany Tech Review now on Automoto365.com

My Technical review from Hockenheim is now on Automoto365.com.  With the update on McLarens Blown diffuser, Mercedes and Williams exciting ‘open-fronted’ exhaust blown diffusers, as well as updates from Virgin and Toro Rosso.

http://bit.ly/aviB74

or

http://f1.automoto365.com/news/controller.php?lang=en&theme=default&month=7&seasonid=21&nextMode=ExclusiveNewsForm&news_id=41729

Valencia: Technical review now Automoto365.com

 

My Technical review is now online at Automoto365.com.  With the latest updates across the grid.

http://bit.ly/aGG7yC
or
http://f1.automoto365.com/news/controller.php?lang=en&theme=default&team_id=0&month=07&seasonid=21&nextMode=ExclusiveNewsForm&news_id=41314

Valencia: Technical Review now on Racecar-Engineering.com

My Technical review is now Racecar Engineering Magazines Website. With News on the Ferrari, Renault and Mercedes blown diffusers, Red Bulls and williams Vaned double diffusers, Everyones f-ducts and all the new bits on the cars including Ferrari, McLaren, Renault and Williams.

http://bit.ly/cy1Q3H
or
http://www.racecar-engineering.com/articles/f1/475053/f1-2010-european-gp-technical-updates.html

My work also gets published along with other technical motorsport articles in each months Racecar Engineering Magazine…

Subscribe to the paper edition: Racecar Engineering Subscription
Subscribe to the digital edition: Racecar Engineering digital Subscription

 Follow ScarbsF1 on Twitter

BAR Experimental Carbon Fibre Reinforced Upright?

 

Update:I asked at Mercedes GP (Nee BAR Honda), who had little information, but were able to confirm “It was a development carbon fibre upright we manufactured many years ago but it never ran on the car”

I often trawl around E-Bay to find bits of F1 cars for my collection.  This week I found a seller offering a BAR front upright, although it doesn’t appear to be just any old upright.  Externally it looks like the team may have been experimenting with a carbon fibre upright.  Something I have never heard of a team getting near race ready. Although John Barnard had talked about doing one via his B3 consultancy.  The design certainly doesn’t tally with images I have of the BAR cars from that era. 

The seller doesn’t appear to have any inside info and appearances can be deceptive, but from what I can see the upright is formed of a central metal (probably Ti) core, with the carbon fibre producing a stiffening structure around the wishbone and brake mountings.  We can see even back then BAR used a hollow hub to feed cooling air to the brake disc, a practice only just dropped for this year.

The seller mentions the part is from 2004, 2003-2004 was the era when teams were switching from vaned fabricated uprights towards the more slender Ti designs with airflow passing around them.  Additionally at the time carbon fibre was increasing being adopted as a gearbox material, with the heat and point loads that a gearbox has to accept being similar to that of an upright.

It would be interesting if anyone has any further insight into this part, or even wants to buy it so we can have a closer look!http://cgi.ebay.co.uk/Honda-F1-Front-hub-and-2x-2004-Honda-BBS-front-wheels-/220606901522?cmd=ViewItem&pt=UK_Sports_Memorabilia_ET&hash=item335d322d12

Follow ScarbsF1 on Twitter

Spain: Mercedes W01 Roll Structure

 
It transpires the tip off we were given regardign the updates to the W01′s airbox was accurate, as Mercedes arrived in Barcelona with a radical new roll structure cum airbox.  Even in its launch guise the W01 exhibited a unique pillar shaped roll structure with the non structural airbox wrapped around it.  Now the team have further decoupled the airbox function from crash protection, by making the protection purely blade-like shape, with the airbox now formed totally by the engine cover and the inlet snorkels not touching the blade at all.  This is a dramatic looking solution and probably worth some improved performance from the rear wing due to the decreased disturbance of the airflow.  But in overall terms the change is only likely to be worth a small gain and not as important as the expected layout change or f-duct rear wing.

Mercedes MGP W01 – Spanish update predictions

Even from the cars early days in testing, Mercedes have had problems with the MGP W01 and Ross Brawn himself has been candid with the cars problems.  Fundamentally the car has the wrong weightaero bias, with it being too far to the front.  Last year one of Brawns strengths was its extreme forward weight bias, typified by the large slab of ballast in the front splitter, when the wider front slicks rewarded a +49% bias towards the front.  This year the tyres changed, the front tyres being 25mm narrower with a 20mm narrower tread, the rear tyres were also stiffened to cope with the heavy fuel loads.  Most teams perceived the loss of grip from the rear tyre change would not offset to loss in front end grip from the narrower front tyre.  Perhaps Mercedes (nee Brawn) felt the tyres would still favour a high percentage of weight towards the front, indeed the car still sports a significant slab of ballast in the front splitter.  At the last race the cars inherent weaknesses were exhibited by Michael Schumacher, who had both understeer and a chronic lack of rear grip, leading to poor traction in the wet and overwork rear tyres in the dry.  In Schumacher’s case his driving style tends to favour oversteer, while Rosberg is able to better cope with lack of turn-in and understeer the Bridgestone’s provide.  This trait of the Bridgestone front tyres has been present since the shift to a single tyre supply, which has only worsened with the move to slicks and now narrower slicks. 

Tyres work within a window of ideal vertical load.  This load comes from weight distribution and downforce, simplistically the former affects low speed grip and the latter higher speed grip.  Teams need to balance the static weight distribution and downforce front to rear to suit the tyres.  A graph of load versus grip for a tyre will see significant drops either end of the scale as the tyre fails to work when either over or under loaded.  It seem that Mercedes have too much load on the front tyres which will see them give up grip as the tyres gets too heavily loaded, this induces understeer.  Conversely they have too little load at the rear which will compromise traction off the line and out of slow turns, but also induce oversteer.  Having both ends of the car with incorrectly loaded tyres loads, will produce a car lacking in balance. The team could reduce grip at the rear to balance the car, but will then have a car lacking in grip. 

Although drivers favour certain degrees of understeer or oversteer depending on their driving style, both prefer this to with consistent balance and grip.  The differences in car set up between drivers are very subtle, its unlikely that one driver will have a significantly different weightaero balance front to rear compared to another, certainly not to the level where one driver runs a different layout or wheelbase.  the changes will be in small differences to; suspension, wing angle andor ballast placement.

In Mercedes case, they have tried to shift weight rearwards; this is limited by the team’s ability to find areas to house the slabs of tungstendensamet within the tight confines of the gearbox.  An area now compromised due to the packaging of the double diffuser.  To shift weight distribution 1% needs a shift of 10Kg from one axle to the other, obviously space at the axle line is limited, and so potential a greater weight within the wheelbase may be needed to achieve the same effect. 

If ballast placement is not going to do the trick, which appears to be the case with the W01.  Then the team are facing a layout change.  Which means the front andor rear axles will need to be shifted forwards relative to the chassis.  Something that could be done either by new front suspension moving the front wheels forward, or the same at the rear.  The rear option could also be achieved with a shorter gearbox.  Gearbox lengths have extended in previous years to push weight forwards, thus there is scope to reduce their length without having to resort to all new gear and internals.

According to the informed rumours, Mercedes will opt for a blend of front suspension changes mated to a shorter gearbox.  In the process extending the wheelbase.  Many in the media have highlighted the changes as a wheelbase change as the solution to the balance problem, but the extended wheel base is largely a function of the shifting the axles. It is not in itself the primary solution to their problems.

Shifting weight also demands a shift in aero balance, for Mercedes this means more rear downforce.  this cannot come purely from more rear wing angle as the drag that produces will slow straight lien speeds.  So ideally greater diffuser development is needed.  the team have been quick to get a passive F-duct running, this will certainly aid the ability to run more rear end downforce, but they must be careful its benefit is not eaten up by the need to run more rear wing or sales they will lose the advantage it gives other teams.

It now transpires that the F-duct rear wing on the W01 in China was passive device.  There remains the development of the ducting towards the cockpit and a tip-off suggests this is tied to a reshape of the roll structure.   How the ducting then reaches the rear wing may be either via a shark fin or up through the rear wing support.  Although Brawn tested a sharkfin briefly in 2009 on the BGP001, the team have yet to race a version of it, making them somewhat behind the times and lacking experience in how the taller bodywork reacts on track.

At least one area not a concern for the team will be their mirrors, which are already cockpit mounted and not subject to the repositioning facing some of their rivals (RBR & Ferrari).

We can expect a very different W01 to appear for the next race, we will cover the developments as soon as the car breaks cover in the days preceding the race.

China: Mercedes new rear wing

Just as Ferrari have joined Sauber in trying to catch up with McLarens F-duct blown rear wing, Mercedes also appear to be in the early stages of testing their own solution.  While not as conclusive in proving there is an f-duct as with Ferraris bodywork, Mercedes do have a duct that links the main plane of the wing to the Flap.   However this may not be the complete solution, as there does not appear to be a duct linking this rear wing fin to the chassis.
 
Mercedes are one of the few teams (and Brawn before them) not to have raced a shark fin engine cover.  It could that either Mercedes are awaiting the shark fin cover to run the fully ducted flap and that this test was just a structural test for the now largely hollow slotted rear wing flap.  Or that their solution will duct the airflow up through a central wing support strut (currently absent on this car) or less likely through the wings endplates.  As this would mean the beam wing would also need to be hollow and some how connected to the F-duct.  As Mercedes run a fully exposed beam wing there is little connection between it and the chassis.
 
It also been noted that the Mercedes ran pipework from the front of the sidepods backwards towards the rear of the car and then up inside the rear wing endplate.  These are more likely to be wiring or pressure for sensors, than the duct itself as they are very narrow in gauge and unlikely to pass enough airflow to alter the rear wings aerodynamics.
 
Mercedes do have one advantage, their monocoque has usefully placed apertures by the side of the pedals, these holes have already sported scoops for driver cooling, these could be modified to be the driver interface with the duct to the rear wing.
 
It is not likely we will see the full Mercedes F-Duct solution until the other major updates arrive at the next race in Spain.
 
Follow me on Twitter http://twitter.com/ScarbsF1