In Detail: Sauber Rear Suspension Pull Rod Rocker

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As F1 shifted from push rod rear suspension to pull rod, the packaging of the various compliant elements pivoting on it became more complex too.  Here we can analyse in depth the lower section of a Sauber C30-C31 rear pull rod rocker from 2011-2012.  This part pivots in a subframe mounted inside the gearbox, to operate the side springs\dampers, heave spring\dampers and anti roll bar.

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InDetail: Mercedes W06 – Walkaround

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Mercedes AMG’s W06-Hybrid dominated the season this year. I’ve been lucky enough to get close to it and find out lots about its design and details. So I’ve put together a comprehensive ‘walk-around’ the car, from my camera phone pictures taking whilst being in the pit lane over race weekends.

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F1 Upright: Design & Geometry

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This 2014 Caterham front upright shows some of the key design features of F1 uprights, although as you can see it is both a 3D printed mock up part and also part of a pull rod front suspension set up. F1 Uprights are the part that completes the front suspension geometry, connecting the axle to the wishbones, whilst also providing mounting points for the brake caliper, pull rod and steering track rod.

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Toro Rosso Factory Tour – Video & Images

Toro Rosso have released a youtube video of a complete factory tour.  Both informative and in depth, the video shows us some detail of the car we do not usually get to see.

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Analysis – Set up sheet explained

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Whenever an F1 car runs on track, the team will have planned what parts are fitted and the set up of every facet of the car. Now over a year and a half old and with an even older car, this set up sheet appeared on the Lotus Media site. It was from Kimi Raikkonen’s debut test at Jerez for the team in a R30 (from 2011). It shows some of the set up detail that the teams go into. This also gives us some insight into the spring\damper configuration modern F1 cars run.

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Analysis: 2013 F1 Rules and Trends

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With far reaching regulation changes coming onto the sport in 2014, the 2013 season is likely to be a year of consolidation, as few changes have been are written into this year’s rule book. So teams will be expected to optimise their designs from last year, correcting mistakes and adopting some of the better ideas of their rivals.
Some rules will have a small effect of car design and some trends from last year will be more common place. Unusually there have been few leaks or well-founded rumours circulating in the off season. This is probably as teams are expending a huge amount of resources in finding big gains for just one year’s competition, instead focussing on plans for 2014.

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Sauber: Rear Inboard Pull Rod Suspension

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With the shift toward pull rod rear suspension, the teams’ mechanics are faced with a maintenance issue.  As the pull rod reaches down into the gearbox casing, access to the transmission is hindered by the inboard suspension inside the gear casing.  Most teams maintain their transmission by first having to remove parts of the inboard suspension.  However the Ferrari engined teams have each found a neater solution to this problem.  Sauber use the Ferrari gearbox and also follow a similar practice of using a separate module to mount the entire inboard suspension in between the engine and gearbox.

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Launch Analysis: Ferrari F2012

Car: Ferrari F2012
Concept
Having followed a very similar concept since the 2009 F60, Ferrari found in 2011 that the conservative route was not making up the ground to their rivals. The F150 was a fast car, but lacked that final ounce of pace to beat the Red Bulls and McLarens. This was exacerbated by the car being easy on its tyres, to the point where it had tyre warm up issues. This showed itself in qualifying were the car would not make the most of a tyre around a single lap and also in cooler weather, or where the harder Pirelli tyre was used. The team recruited Pat Fry in a major reshuffle of engineering staff. Fry spent the year assessing Ferrari problems and set about a recruitment programme of new staff and a more adventurous design programme. The resulting car is clearly very different from its predecessors.
Externally very little remains the same on the new car, it does perhaps shares Ferraris favour for a long wheelbase and clearly is set up to run a fairly steep rake angle. But only the front wing, which is derived from the late 2011 wing appears to be carried over. Even this detail was a development in preparation for 2012, Fry leading the team to follow Red Bulls format of front wing in both shape and aero elasticity.

Layout
With a similar wheelbase, the revised seating position is perhaps the only change to the cars layout. The seating position was altered for Fernando Alonso last year and has been altered once more for a lower position.

Nose

Of all the 2012 front ends Ferrari has one of the most striking, the nose being very wide and square in cross section. The width is part of philosophy to use the extended wing mounting pylons, as a pair of turning vanes cascaded with the normal undernose turning vanes. By making the nose as wide as possible within the space allowed within the regulations, more undernose surface can be used to accelerate air through the duct formed by the nose and vanes. As a result the edges are tightly radiussed and cannot be rounded as with other teams. The aesthetics of the nose being also worse for the rectangular cross section front bulkhead. Ferrari opting not to make a “V” shape of the bulkhead, in order to make the area under the raised chassis uncluttered to make the vane set up work most effectively.


The flow through this vane set up starts with the wing mounting pylons, these are wide spaced at their leading edges and they then converge to end inboard of the main turning vanes. The main turning vanes then pick up the flow accelerating between the pylons and sweep out to direct the flow towards the lower leading edge of the underfloor.
Curiously Ferrari has yet to fit a driver cooling vent into the nose. This hole is not mandatory and clearly not a requirement for a chilly Spanish pre season test.

Front wing
As previously mentioned, the front wing is a derivative of the late 2011 wing. This was extensively detailed in a previous post. The wing is a three element set up, the main plane being slotted to create the leading two elements, and then the flap trails this. An extra slot in the down-turned corner of the flap helps keep flow attached in the steepest section of wing. The footplate is formed by the wing curving down on itself, while the upper section of endplate is a separate vane, albeit joined along a lot of its length to the foot plate. Front wings are now subject to a doubling of the deflection test used by the FIA 2011. So far the Ferrari wing has not exhibited the flutter seen last year, which is not to say it is not flexing.

Front Suspension

A mention of front suspension in the cars launch analysis will be unique to Ferrari this year, as they have revisited an old direction with its layout. Every other car for well over ten years has had pushrod front suspension, but Ferrari has revived the pullrod set up for the front of the car.


This effectively turns the pushrod set up upside down, now the rod passes down from the upper wishbone and connects with the rocker, which is now mounted at the bottom of the chassis. According to Fry, this set up is a little lighter and has a slightly lower Centre of Gravity. These gains alone will not pay for the systems inclusion on the car, so the team claim to have found an aero benefit. The pullrod can be thinner, but the real gain is the pullrod is mounted near horizontal across the front suspension. This places it in line with the upwash from the front wing. Just as with the wishbones, its profile can be subtly altered within the rules to help control the wake from the wing and improve the airflow over the rear of the car. Despite appearances the pullrod is as effective in moving the rocker for a given wheel travel as a pushrod. The important factor is the angle between the rod and the wishbone is connected to, rather than the rods angle to the chassis. I’ll explain a lot more pull rod suspension in a subsequent article.


Roll hoop

Although not a performance differentiator, the new roll hoop is very different concept to that seen in previous Ferraris. A far curvier pair of inlets are formed by the structure, this shaping being at odds with the ungainly nose. It is strange Ferrari have not undercut this area and exposed the structure supporting the roll hoop, which is the common practice to achieve more airflow to the rear wing. The main inlet feeds the engines airbox, while the smaller inlet piggy-backed behind it, most likely feeds the gearbox and hydraulic oil coolers mounted above the gearbox. The lifting point for the trackside cranes is formed by beneath the main inlet and enclosed by a simple bar connecting it to the top of the chassis.

SidepodsCooling

It’s perhaps the sidepods that are the big performance area for the car this year.
Starting at their leading edge, the car sports a new format Side Impact Spar (SIPS) design inside the bodywork. Since 2009 Ferrari had a staggered SIPS arrangement, with a narrower spar sat ahead of a wider spar, creating the distinctive peaked sidepod inlet. Now it spears a single spar spans the sidepod and protrudes through to form the mount for the sidepod vane. This allows the spar to be wider, which creates an easier job to absorb the impact. Viewed from above the sidepod inlet lean inwards. This makes them more efficient at meeting the diverging flow that passes around chassis to enter the sidepod.


Much smaller and far more undercut, the sidepods now feature radiators mounted upright and splaying outwards from the rear of the car. Their new placement allows the flow through the cores to be directed outboard, rather than in towards the central tail funnel. This heated flow from the radiators passes out through the downswept chimney-fairings that differentiate the car from its rivals. This design keeps the centre of the car as slim as possible, with there being no tail funnel to obstruct the rear wing. Airflow passing through the undercut in the sidepod, still enters a coke bottle shape below the chimney-fairings and is passed over the diffuser. But these chimney-fairings also have a more important secondary use, for housing the exhaust outlets.


Additional cooling outlet area is provided in the tail of the sidepods, in between the rounded end of the chimney-fairings and the gearbox fairing. This gearbox fairing is nearly round in cross section also forms an outlet for hot air to exit from the engine bay.

Exhausts
With floor level exhausts no longer allowed, the teams have had to find different ways to make use of the powerful exhaust plume. Most teams have directed it over the sidepods towards the centre of the beam wing, but Ferrari have purposely placed the exits as far outboard as allowed (on the launch spec car at least). When viewed from above its clear these are aimed outboard of the rear wing endplate.


Sat inside the downswept chimney-fairings, the exhaust at first might be thought to be pointing downwards. But the rules state the exhaust outlets have to point upwards by at least ten degrees. Although not visible inside the chimney-fairings, the last 10cm of exhaust do indeed point upwards.


But the cleverly the down sweep of the chimney-fairings creates a downwash effect over the exhaust plume and this directs the combined flow downwards between the rear brake ducts and rear wing endplate. This set up will potentially reach the floor and act to seal the diffuser from the ground as with the 2011 EBD.

In testing the set up has gone through several iterations, firstly the exhausts exits were in line with the end of the chimney-fairings, but soon the exhaust tail pipes were shortened and the chimney-fairings above had to be cut back to maintain legality and also the allow the downwash flow to reach the shorter tailpipe.


At the Barcelona test the exhausts were again altered, this time being brought further inboard, approximately in line with the channel formed between the chimney-fairings and the engine cover. Now the exhausts appear to point inboard of the rear wing endplate. It’s not clear if this is an aerodynamic decision or a request for a less obviously aerodynamic solution from the FIA. Should the exhaust outlet stay in this position the sidepod and the chimney-fairings will need to be altered to optimise the downwashed airflow around the tail pipes.

Rear suspension
Almost unspoken of amidst the talk of the front pullrod set up, Ferrari also switched their rear suspension on its head and gone for pullrod on the rear of the F2012. Last year we saw the Ferrari had a very complex setup around the rear suspension rockers and placing this hardware lower down around the clutch and engine drive shaft, will be a tough task package.


Mounted to the revised gearbox, the rear top wishbone has been repositioned this year. It appears to be nearly horizontal; this places it in line with the beam wing, so the wishbone can act as a flow conditioner ahead of the wing. Even if the new gearbox is not as low as the Williams, the wishbone needs to mount to a vertical extension above the gearbox. This wishbone mounting hard point also forms the mounting for the beam wing. At first this appears to be a duct, but is just the thick swan-neck mounting similar to that used by Marussia for the past two years.

Diffuserrear impact structure
Within the bodywork rules, there is not a lot of scope for a very different diffuser. So Ferrari have now added a full width flap around the diffuser on the new car.
Unusually Ferrari have not fully exposed the underside of the beam wing above the rear crash structure. Looking at the crash structure itself its clear it is shallow enough to allow this. Instead the crash structure has additional bodywork above and below it, which merges it with the beam wing.

Gearbox
As already mentioned the gearbox is a new design. The hybrid carbon and titanium case now has to mount a very different rear suspension system, with the switch to pull rod springdamper operation and the raised upper wishbone.
Last year Ferrari were notable for having a single selector drum for their seamless shift set up. Most teams use two selectors; each one operating alternate gears, so that the phasing from one gear engaging and the other disengaging can be adjusted. Ferrari with a single selector must be confident that their system can always shift with the same aggressive phasing, without the option to go for a longer overlap.

KERS
Ferrari develop their KERS with Marelli, the system retains the same layout as in 2011 with the MGU mounted to the front of the engine and the Batteries placed under the fuel tank. The power electronics reside in the right hand sidepod.

Engine
With the engine freeze, not much can be said of the engine. Ferrari have usefully provided a high resolution image of the 056 engine, complete with integral oil tank, but lacking the KERS MGU.

Launch Analysis: McLaren Mercedes MP4-27

As the first real launch of a 2012 F1 car, McLaren have unveiled their MP4-27. In McLaren parlance this was the cars “technical launch” and was carried out at their Technical Centre in Woking, UK.

2011
McLaren had one of the fastest cars in 2011, on its day the MP4-26 was faster than the Red Bull. So the basic approach of the new car did not need to veer too far from direction McLaren had been following. Last year the season was blighted by poor form in pre season testing. Most of the winter tests were interrupted by exhaust problems, as the now near mythical “octopus” exhaust broke after a few laps out on track. This exhaust turned out to be far simpler than the rumours suggested. The exhausts ran sideways across the floor to exit in a longitudinal slit ahead of the rear wheels. This being a complex way to achieve the same sort of fluid skirt that Red Bull achieved with their outer blowing exhaust layout. Once McLaren had followed Red Bulls lead with the exhaust, they were able to catch up. McLaren perhaps even surpassed Red Bull with the exhaust blown diffuser, as the Mercedes Hot Blown engine mappings were superior to the Renault cold blown solutions. Despite the rules trying cap the hot blown benefits as early the Canadian GP, the Silverstone GP weekend showed how much McLaren were lost relative to Red Bull when the restrictions really bit hard.

Philosophy
With a strong car at the end of 2011, the team have learnt about the damage a slow start to the year makes to their championship chances. This year evolution is required, McLaren do not need to find large chunks of time, but do need a car that will perform well at the opening races. Thus we see the refinement of old concepts and little in the way of radical development.
Thus the new car bred from the recent line of McLarens, the family resemblance goes further than the colour scheme. With a low nose and sweeping lines over rounded sidepods are now trademarks of the Woking design team. With the second year of the fixed weight distribution and Pirelli tyres, little needed to be done to the cars basic layout. Running much the same chassis, fuel tank size and gearbox, so the wheelbase is similar to the previous car.
Although the 2012 Pirelli front tyres are a new shape tyre, Paul Hembury from the tyre supplier confirmed to me that the change in the new profile is “not visible to the eye”. So only small optimisations of the front end aero are needed to cope with the change.

The nose-down, tail-up 'Rake' of the car is evident, with as much as 10cm of rear ride height

The studio photos of the car in side profile show off the amount of rake the car is designed to run. This is also a carry over from 2011, as the car could often be seen with a clear 10cm of ride height at the rear axle line. Although managing rake will be harder this year as the greater rear height introduces more leakage into the diffuser from the sides. As yet the teams solution to seal the diffuser are hidden by a simple floor fitted to the launch, although these are removable panels and more complex designs will soon be seen.

With so much to carry over in philosophy and design, what has changed for 2012?

MP4-27 in detail
The stand out points on the MP4-27 are the nose, sidepods and exhaust position.

Firstly the front wing is near identical to the late 2011 wing, so we can expect its general design to carry over, as will the snow plough vane below the nosecone. But the height of the nose at first appears to be at odds with the 2012 rules on a maximum 55cm height for the front of the nose.

Looking closer at McLarens chassis in side profile its clear the family history of low noses has helped here. The dashboard bulkhead is may be just 3cm higher than the cockpit padding (which is 55cm high), the chassis top then curves downwards towards the front wheels. By the point of the front (A-A) bulkhead the top is lower than 55cm, may be as low as 5cm below the maximum height. When compared to the maximum heights (the dotted line on the drawing), its clear this is a very low nose overall.

The snow plough vane under the nose might be part of the secret to a low nose

This creates less space under the raised nose, but the teams snow plough device under the nose works aggressively as a turning vane, so perhaps the team don’t need the higher chassis to get the correct airflow to the sidepods leading edge. McLaren also find the lower nose provides the classic vehicle dynamics benefits of a low CofG and a less extreme front suspension geometry. This trade off works for McLaren and goes to prove not everything in F1 has to be a compromise in search of aero advantage.

Unique drillings between the rim and spokes of the wheel aid brake cooling, the ring fairing is missing on the launch car.

Although details around the front end will change, the wheels are typically a design chosen to last for the whole season. This year the McLaren Enkei wheels sport a novel set of drillings to aid brake cooling. The usual spokes formed into the wheel between the hub and the rim, stop short and a radial set of holes are made near the rim. Although not present of the launch car, there will be a dish shaped fairing added to small pegs formed into the wheel to aid the airflow out of the wheel.

The high rectangular inlet and large undercut set the car apart from the "U" pods of the 2011

In 2011 McLaren were not afraid to try a radical sidepod set up, This was the “U” shaped sidepod, with the angled inlet shape creating channel in the upper section of sidepod (About the MP4-26 “U” shaped sidepods).  This year the team have adopted more typical sidepod format, with highwide sidepod inlets and steep undercut beneath. I got to ask Tim Goss about this:

ScarbsF1: Can you tell us about why the concept’s changed, why you don’t feel that was a benefit this year?
Tim Goss: Last year’s U-shaped side-pod worked very well with what we were trying to achieve last year with the exhaust layout, it was all intended at creating more down wash to the rear end, and it performed particularly well last year. This year at a fairly early stage we set about a different approach to both the external and the internal aerodynamics of the car, and then once the exhaust regulations started to become a little bit clearer then it was quite obvious to us that the U-shaped side-pod no longer fitted in with both the internal aerodynamics and some of the external aerodynamics that we pursued early on. So it works, it worked very well last year, but it’s actually just not suited to what we’re trying to achieve this year.”

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Not extreme like the "U" pod, but the sidepod tops do incline slightly

In frontal profile the high and wide cooling inlet is obvious.  The team have been able to incline the sidepod tops slightly, this isnt quite a “U”pod shape, but is quite distinctive.  At the rear the team have kept the sidepods narrow and slimmed the coke bottle shape in tightly to make the sidepod join the gearbox fairing creating a continuous line of bodywork to the very tail of the car.

the heated air from the radiators passes up over the engine and out of the central tail funnel

As well as the external airflow considerations, McLaren looked the sidepods internal airflow, they wanted a cooling exit on the cars centreline. This would have been compromised with the “U” sidepod, so the more conventional shape was selected. The cooling arrangement is similar to Red Bulls philosophy, the radiators direct their heated airflow upwards and around the engine, this then exits in a tail funnel. The launch car had quite a modest central outlet, but we can expect to see far larger versions used at hot races.

the front upper section of sidepod is switchable for version with cooling outlets

Aiding the tail funnel there are also cooling panels on the upper leading edge of the sidepod, either side of the cockpit padding and various panels arund the rear of the coke bottle shape. Different panels will be used depending the cooling andor drag demands of the of the track.

Last years more complex roll hoop cooling inlets have been simplified into one below the engine inlet

Other cooling functions are covered by the inlet below the roll hoop. Last years double inlet set up has gone and now a single duct is used. This probably cools both the gearbox and KERS.

Viewed through the rear wing the exhaust bulge is obvious

The other notable aspect of the sidepods are the exhaust bulges. These stick out prominently on the flank of each sidepod. They don’t serve an aerodynamic function themselves, but simply fair-in the final 10cm of exhaust pipe. This final section of exhaust is now strictly controlled by the regulations. Its position must sit within specific area, it must point upwards between 10 – 30 degrees and can point sideways plus or minus ten degrees. McLaren have fixed the exhaust in the lowest most rearwards position possible, the tail pipe then pointing steeply upwards and inwards. From the limited view it would appear to direct the exhaust plume towards the outer span of the rear wing.

This would make a blown rear wing (BRW), the added flow from the exhaust aiding the wing in creating downforce at lower speeds. The exhaust position and fairing also suggests an alternative exhaust tailpipe could be used. Paddy Lowe confirmed that different solutions would be tried in testing. From overhead its clear to see the exhaust could be angled differently to blow over the rear brake ducts fairings to create downforce directly at the wheel.


The gearbox case design is not the shrunken design we saw with Williams in 2011 , the differential is low but not unduly so. The top of the case sitting neatly under the tail funnel. Pull rod suspension remains at the rear of the car, while conventional pushrod is on the front end. Lowe commented that the Lotus brake antidive system was not specifically looked at, but was part ”of a family of solutions” that has been looked at in the past. The engineers feeling that the Lotus system was illegal and hence had not been explored further. They declined to comment of the possibility of an interlinked suspension system.
Behind the gearcase, the rear impact structure is mounted midway between the beam wing and floor, fully exposing both the beam wing and allowing airflow into the central boat tail shape of the diffuser. As the diffuser was covered up, its not clear if there are features to drive airflow into the starter motor hole. A new feature on the beam wing is an upswept centre section, the extra angle of attack in the middle 15cm of the wing having a slot to help keep the airflow attached. The upper rear wing is a new design albeit similar the short chord DRS flap wing, we saw introduced at Suzuka last year. The DRS pod is still mounted atop the rear main plane and its hydraulics fed to it through the rear wing endplates. The flaps junction with the endplates follows recent McLaren practice with a complex set of vents aimed at reducing drag inducing wing tip vortices.
Not much else in terms of structures or mechanical parts were evident at the launch. Lowe did confirm to me that the Mercedes AMG KERS remained packaged under the fuel tank in one assembly. Also adding that there would not be an significant weight loss to the system.  As a significant reduction in weight was made between the 2009 and 2011 season, via the consolidation of the Batteries and Power Electronics into one unit.

Mp3 of the MP4-27 Engine fire up via McLaren