Analysis: 2013 F1 Rules and Trends

SF1_2013

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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In Detail: F1 Cockpit Head Rests

A feature of every F1 car since 1996, the cockpit headrest padding has evolved to become a critical safety feature.  Introduced as part of the response to the incidents of 1994 and in particular the Wendlinger Monaco accident, the regulations are now very specific in regards to the shape and material of the padding.  Although outwards these are simple pads, their design is tightly governed by the regulation the final detail is balanced between the drivers and the aerodynamicists.

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RenaultSport: Torque Maps & Drivability

As RenaultSport consitently provide such detailed technical explanations, I have posted their Pre-Korea Technical Feature in its entirety below

The torque map is probably the single most important reference map used in Formula 1 engine management.  It is the fingerprint of an engine and of critical importance for engine engineers to help optimise the on track engine performance.

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F1 Jack Technology

For years the F1 quick lift jack was a simple humble tool used around the garage and at pit stops. Since pit stops have become an ever greater part of the team’s performance during the race, the jack has come in for increasing levels of development. As powered jacks are no longer allowed, teams rely on a hefty pull from a mechanic to lift the car and gravity to return the car to the ground. Improving this process has lead to most teams adopting a similar quick-release swivel jack. At first a complicated looking piece of kit, the jack is still a simple device when reduced to its component parts.

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Analysis: F1 Fuel System


One of the great pieces of unseen technology in the F1 car is the fuel system. Comprised of complicated fuel tank and an array of pumps, the system is taken for granted. The super safe and highly efficient fuel system delivers the F1 cars 160kg of fuel during a race with barely any reliability issues.
Historically fuel tanks were simply metal tanks formed to fit in wherever they could be fitted. Often prone to puncturing during accidents and impacts, the fuel could easily spill and cause a huge fire. Major fires in F1 car are now thankfully rare. It’s fair to say the biggest leap in F1 safety has probably been the advent of the flexible fuel cell. Flexible bags to house the fuel have been part of the regulations for decades, There’s been no major fuel tank fire at an F1 race since Berger Imola crash in 1989 and no fire related deaths since Ricardo Palletti in Canada in 1982, or in testing with Elio De Angelis in 1986.

Anatomy

Fuel systems in F1 are split into two areas; the fuel tank itself and the fuel pump system that delivers fuel to the engine.

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InDetail: Caterham Front Upright

Not everything in F1 is aggressive, extreme, radical or innovative. In fact in many areas the car’s are very close in general design terms. Some times it’s enough just to soak up the detail engineering and explain what all the little bits and pieces do on the car. In this series of short articles, we’ll do just that, thanks to these amazing photographs from MichaelD. Following on from the details of the Force India front corner, with these photos of the Caterham in Melbourne, we can now see more of the upright design.

Upright


Caterham’s upright is fairly typical of most contemporary F1 designs. By regulation all F1 cars have to use Aluminum for their uprights. This one appears to be a fully machined or perhaps a cast part. Before the restriction to aluminum, investment cast Ti or MMC were common.
In format the upright is tightly fitted between the upper and lower ball joints and the two bearing for the hub. This design has been common in the past ten years, before that the upright tended to be a larger item with a large vaned housing for the bearing that would be the route for cooling air to reach the brake disc. Now teams route the cooling around the upright rather than through it. One exception of this design practice was Honda who routed the cooling air internally through an oversize hub. This design was dropped in 2010, as the design prevented the lower wishbone mount being as high the aerodynamicists wanted.
The upright creates part of the suspension geometry, with the distance between the upper and lower ball joints and the angle between them and the steering axis.
The first observation of a current F1 upright compared to any other racecar is the distance between the upper and lower wishbone joints. The upper joint is probably as high as the 13” wheel will allow, and then the lower wishbone is raised to near the wheels centerline. Having the mounts close together creates more loads in the wishbones and restricts space for a track rod to be mounted high up, with enough of a steering arm length to be efficient. This is a compromise forced by the aerodynamicists, who require the wishbones to be placed in the most beneficial position relative to the front wing upwash.


Due to the offset of the bulk of the upright from the steering axis, the design at first appears to offer a lot of King Pin Inclination (KPI), but closer examination of the ball joints shows them to be relatively normal for an F1 car. An increased KPI angle creates more camber change through steering.
We can see the upper ball joint (UBJ) that links the upright to the wishbone is created with a clevis bolted the upright. The wishbones outer end holds the spherical bearing. Shims between the clevis and the upright adjust the static camber. The lower ball joint (LBJ) is a fixed mounting and is not adjustable. We can see in the case of the Caterham that the lower end of the pushrod is mounted to the wishbone and the not upright. It joins near the spherical bearing in order to keep the bending load in the wishbone end to a minimum.

Adjustments


The steering rack is mounted low down on the front bulkhead and the track rod passes in line with the lower wishbone and attached to its own clevis on the upright. Adjusting camber also adjust steering toe angle, so any change in the camber shims will require a shim altered on the track rod arm. As the clevis is formed by the upright, the track rod arm is split, with the metal end fitting bolting to the carbon fibre arm, a shim in between this joint creates the difference I track rod length.
In between the track rod and lower wishbone is one of the two tethers to hold the wheel on in an accident; there appear to be plastic clips to hold the tether in place between the two parts.

Hub & Bearings


Rotating inside the upright is the front hub, or stub axle. This is a machined titanium part and sits on two bearings. Typically two sets of bearings are used one larger set outboard and a smaller set inboard. From the diameter of the upright you can see the differential in size is quite large. Bearing design is quite secretive, but commonly angular contact ceramic bearing are used. I was told that Honda, who used NTN bearings at the time, would have the bearing last two races and cost several thousand pounds each. Albeit this was at the time they used particularly large bearings to hold the oversize hub. The bearings are located in the upright and the hub and preloaded by the large castle nut visible inboard of the upright.
The hub is hollow and will have openings and pockets machined into it to reduce weight where stiffness isn’t required. The hub also forms part of the brake disc mounting system the wire eroded splined on the flange outboard of the upright mate to matching splines on the brake disc mounting bell. There are also drive pegs to locate the wheel. At the threaded outer part of the hub, the wheel retention system is removed. This is a sprung clip that flicks inout as the wheel nut passes over it during wheel changes. The clip will retain the nut as required by the regulation, should the wheel nut not be tightened sufficiently. It will however not replace the function of the wheel nut in holding the wheel on securely. Drivers leaving the pits will seefeel the wheel wobble slightly, driving for too long will see the retention mechanism fail and the wheel fall off. Typically the hub and wheel nut threaded are handed left of right, to help keep the nut secured.

InDetail: Force India Front Corner

Not everything in F1 is aggressive, extreme, radical or innovative. In fact in many areas the car’s are very close in general design terms. Some time it’s enough just to soak up the detail engineering and explain what all the little bits and pieces do on the car. In this series of short articles, we’ll do just that, thanks to these amazing photographs from MichaelD.
This is the front left corner of the VJM05, seen without the wheel to expose the brakes, suspension mounts, hub and electronics. Details vary from team to team, but what we see here is typical of most F1 cars, indeed some of the components are standard (electronics) or lightly modified by the supplier (brakes).

Brake Caliper

Dominating the picture is the brake caliper. This is supplied by AP Racing and will be designed around Force India requirements, albeit based on their current iteration of an F1 Caliper.
F1 Bake calipers must have no more than six pistons, two pads and two mounting points. The material is restricted by an 80Gpa stiffness requirement; aluminum lithium is most commonly used.
AP have a unique design of caliper for many Formulii, with their RadiCal (Radical Caliper) design. This being the way the inner and outer sections join via the complex bridge structure, to make it as stiff as possible. We can see the caliper is bridged in two places and a radial brace is also used. Keeping his area open is important for cooling the brake disc.
Cooling is also behind the structure around the pistons, the cylinders the six pistons within are nearly completely exposed, with just some links to the calipers structure and internal passageway to route the brake fluid. This allows the most airflow around the cylinderpiston to keep them cool. The pistons themselves are made in titanium and have a series of radial holes machined into them to also keep heat from getting into the brake fluid.
We can see the brake line entering the caliper at the bottom, having been routed through the lower wishbone. At the top of the caliper are the two bleed nipples, these allow bubbles trapped within the system to float up and be removed for better brake feel.
The carbon panel on the outer section of the caliper is either an aero piece or some protection for the caliper when the wheels are slammed back on during pitstops.

Discs and Pads

F1 moved to Carbon discs and pads in the eighties, having moved straight from Cast iron discs. Strangely ceramic discs have not been a development seen at races. Rules limit the diameter and thickness of discs, but no other regulatory restrictions are placed on these parts.
Disc and pad material varies according to their manufacturer (Carbon Industrie & Hitco). It is also tuned for each race and even for each driver. Additionally cooling patterns will vary from track to track, For Force India in Melbourne we can see the high density drillings, with three small drillings across the disc. With Melbourne being heavy on braking the pads are also drilled in attempt to keep the brake system cool. Brakes and pads wear at an equal rate, so the few millimeters gap in between disc surface and drillings is all the wear these parts will see, before catastrophic failure. As wear increases with temperature there are sensors measuring the disc surface temperature and also wear sensors for both the inner and outer pads.

Electronics
To monitor all the functions on the front corner, there will be an array of sensors fitted to the parts. These are all linked back to the main SECU, rather than cabling for each sensor passing through the wishbones to the cars main wiring loom, there is a hub fitted to the upright that collects all he signals and passes them back via a single cable. This Hub Interface Unit (HIU) is a common part supplied by MES to all the teams. It has inputs from the aforementioned Pad wear and disc temperatures sensors, as well as two wheel speed sensor (two in case one fails), also a load cell for measuring pushrod (or pullrod) loads.

Wishbone mounting


Although the aluminum upright can barely be seen beneath the brake ducts, the key function of the upright is joins the hub to the suspension. F1 does not use adjustable suspension in the same way as many racecars. That is with threaded adjusters, but instead solid suspension links are mounted the hard points with shims. These shims are used to alter the camber, ride height, pushrod offset and castor.
Teams are no longer aligning the track rod for steering with the FTWB. So often the track rod needs a separate lower mounting point on the upright. When adjusting camber, a different FTWB shim will alter the steering toe angle, so an additional shim needs to be fitted to the track rod clevis t maintain toe angle.
In this picture, we can see the upper clevis that mounts the front top wishbone (FTWB) and track rod. Force India have done this with the VJM05, but have still been able to join the FTWB and track rod to the same clevis assembly. This way camber can be adjusted with a single shim, rather than separate but matched shims for separate clevises.
We can also see the extremely high front lower wishbone position (FLWB); it’s nearly at the front axle height. Having wishbones spaced further apart is better for reducing the loads fed through them, but aerodynamics demand a higher position. We can’t see the outboard joint with the upright; neither can we see the outer pushrod joint. It’s probably that FIF1 mount these mount to the upright in a set up called ‘pushrod on upright’ (POU), this helps eight transfer with steering angle in slow corners.