InDetail: Caterham CT01

Caterham have been slowly working their way clear of Marussia and HRT to close-in on Q2 sessions and the Toro Rosso’s in the race. This year the CT-01 is a clean sheet design and exploits a Renault engine with a Red Bull gearbox and KERS.

I’ve been lucky to have been given permission from Ionut Pascut to post these detail pictures taken at Monaco, to allow us to look at the detail of the 2012 Caterham.

Caterham were something of the fall guys for the 2012 regulations, as they unveiled their car first, and the general public became aware of the odd compromise the 2012 nose regulations had created. Having seen the rest of the field, the Caterham design is no worse aesthetically than most of the cars. Clearly the design team went for the highest possible chassis and nose tip, to end up with the stepped nose we see here.
Having this high nose creates more space under the chassis for airflow, which in turns allows the large turning vanes to be hung from under the nose.
Joining the front wing to the nose are two pylons. For Caterham they are a relatively short chord, but as is common practice they mount to the very rear edge of the front wing, this allows them to act somewhat like turning vanes. Even though the pylons are quite narrowly spaced together, the camera pods mounted to the bottom do not quite meet in the middle, as other teams have be able to achieve. Having the camera pods in this position allows them to act like aerofoils and reduce the lift the neutral centre wing section creates.

As Team Lotus in previous years, the front wing has been quite simple design, but this year has seen a revolution in their wing design, which has lead to several subsequent evolutions on the theme.
The wing is a relatively complex contemporary design, although the profile is long and tall across most of its width, creating an evenly spread pressure distribution over its span. Rather than the elliptical loading on the Red Bull style wing, which is wider at the tips and narrower towards the middle.
The unpainted carbon fibre flap is adjustable, the section in-between the silver fences being the movable section. On its inner side we can see the wing adjusters for flap angle adjustment.
Above all of this are the complex cascades. The primary surface is the ‘CNN’ branded winglet; this is joined with a double aerofoil section to the end vane and is supplemented by a small inboard winglet.
Note how the brake duct inside face is formed by the tyre sidewall.

With a reverse view, we get a clearer understanding of the how the front wing endplate works. The flat horizontal section is termed the foot plate, this needs to meet a minimum surface area rule. The footplate helps to both seal the pressure difference above/below the wing and also to shape the airflow trailing behind the wing. Note how the inboard section footplate is curved to create a vortex flow around the outside of the front wheel.
Attached to the footplate is the curved vane (with the “Air Asia” logo), again this is partly there to meet the minimum surface area rule and is also used to mount the cascades and divert flow around the wheel. The vane appears to have quite a thick cross section, especially at its tip where a horizontal lip is created. This lip appears to line up, but not join, the rear part of the endplate formed by the main wing sections.
Under the wing is a small fence to help direct airflow outboard around the front tyre. Like the endplate vane, the fence has an unusually thick cross section.
As seen on the previous image, the silver vertical sections either side of flap show how much adjustment is possible in the front flap angle, again the mechanics of the wing adjuster are evident

Markings on the tyre denote this is Petrov’s car, the barcode (in the six o’clock position) allows Pirelli and the team the track each individual tyre through its life.
Even F1 wheels need balancing; the weights will be applied to both the outer and inner rim. In the middle of the wheel a rounded end to the front hub is created, to ease the wheel nut onto the shaft during rapid pit stops.
What’s most interesting is the unusual suspension geometry, the front top wishbone is extremely angled, and the front leg being near the top of the chassis, as high as the pushrod, hence some 600mm high. Compare this to the rear leg, which is some 10cm lower. This will have an effect on the geometric antidive, created by the plane of the wishbones aligning with the car’s centre of gravity, this should see the car pitch downwards less under braking.

Note how the high chassis (625mm high) merges smoothly with the lower cockpit opening at (550mm.high). Air passing over the top of the nose will flow either side of the cockpit and over the sidepods, reducing the inherent lift they create. No doubt the mirror stalk position will help direct this flow in the right direction.
The lower edge of the raised foot well section of monocoque retains its edge all the way back to the sidepod front; this creates more room under the nose for air to flow into the sidepods undercut. The dash bulkhead must be 45cm deep, so gains in this area are hard to create without compromise, we will see lower edge again, when we look inside the cockpit later.
We can see how the T-Tray splitter ramps up from its leading edge up 5cm to the step plane level; this then merges with the bargeboard’s lower edge and the sidepod floor. The lower leading edge of the floor forms an axe head shape and this area is machined from metal to protect it from debris thrown up from the track.

We can see the seat shell, the area under the drivers thighs are cut out; this is to clear the raised lower edges of the chassis mentioned in the previous section. In the “V” beneath the seat, the team have fitted the triangular shaped SECU; we can see the three large CAN interface connectors exiting under the seat. The McLaren developed ECU was shaped this way specifically to fit in the space created above the T-Tray splitter, although not every team place it in this location. The fire extinguisher will be tucked under the SECU in the tiny space remaining. To fit into these spaces the extinguisher is specially made from carbon fibre to conform to the space available.
On the cockpit side to the right, the umbilical connectors for the pit electronic are visible. Ahead of that is a small connector and switch panel with the on-off switch and fire extinguisher button.
On the left side of the cockpit is the complex multifunction brake bias control. With the silver lever allowing several preset brake bias positions to be selected in between corners, then the red dial control for finer front-to-rear bias control.
The front edge of the cockpit shows the vestigial screen designed to reduce buffeting of the drivers helmet at speed. The gold part is the steering column bearing mounting. Part of the driver’s safety protection is an “M” shaped foam pad, fitted inside the footwell; this protects the driver’s legs from hitting the top and sides of the monocoque in accidents.

Moving on the top body which forms the sidepods and engine cover, we can see Caterham’s unique cooling\exhaust arrangement. The exhausts exit quite far forward and inboard. The sunken section the exhaust exits through also provides an option for sidepod cooling at hotter races, although for most races the louvers in the sidepod are sufficient outlet area. These louvers are on the edge of the wording of the bodywork rules, they are all joined by the thin slot through their middle, and this way they form a single opening and not four separate louvers. Somewhat like a fishbone, with a spine and ribs.
The effectiveness of the cooling louvers along with the tail funnel exit allows Caterham to sweep the coke bottle shape in very tightly and completely enclose the rear of the car in bodywork. Only a small extra cooling duct is fitted for Monaco, exiting just under the top wishbone.

Further evidence of the clean streamlined rear end is noticeable when viewed from this angle. Also the large expanse of flat floor belies how slim the rear end is. Caterham have a particularly thick floor section, as shown by the tapered step running around its periphery. The small bump in the floor is the rear tyre temperature sensor; these infrared sensors detect the tyres temperate at several points across its contact patch.
By using the Red Bull gearbox, Caterham are obliged to use similar onboard mountings for the wishbones and pullrod suspension.
The beam wing sitting behind the suspension sits exposed atop the tall ridge formed by the top of the gearbox and crash structure, which is a Red Bull trademark. This presents more of the wing area to the airflow for better downforce.
Poking out from the rear wheel is a relatively simple rear brake duct, the duct forms two scoops, the larger top opening feeds the brake disc itself and the smaller lower inlet feeds the brake caliper pistons.

Up close the rear pullrod suspension is clearer to see, and the driveshaft emerging from the gearbox is visible too. The blue item surrounding the driveshaft is a silicone gaiter, to keep dirt from entering the drive shaft’s tripod joint.

The rear wings dimensions are tightly controlled, as is the height of the gurney strip that fixes to the wings trailing edge. Gurney strips are used as a means to fine tune the wings downforce, when a change in wing angle is too great a change.
Caterham like many teams use a small pod above the wing for operating the DRS, the pod solution is used as it keeps the mechanism away from obstructing the underneath of the wing. Inside a small hydraulic actuator will pull the wing open, should the hydraulics fail, the wing should shut closed from the aero pressure being exerted in it. The hydraulic line for the actuator will pass through the wing, down the endplate and inside the beam wing. The spine on top of the gearbox has receptacle moulded into it, for the DRS’s hydraulic line to connect the cars hydraulic system. This connection will have a dry break connector, so the wing can be removed without the hydraulic system being exposed to dirt or leak its fluid.
The small louvers in the endplate are a solution on all F1 cars, they take the higher pressure inside the endplate send a small stream of it towards the outer wing tip, and this reduces the pressure difference at the wing tip and reduces the drag inducing wing tip vortex. As the endplate is a sandwich construction of carbon fibre skins and a foam core, moulding the finely detailed louvers is difficult. So we have seen Caterham in the past (as Team Lotus) create these from Rapid Prototyped resin, bonding this ‘plastic’ part into the endplate allows a far more accurate louver shape to be created.

A close up view of the rear shows how the beam wing is mounted to a very slim spine on top the gearbox\crash structure. Beneath the crash structure the metal jacking point is made easier to spot for the rear jack man by the fluorescent paint.

Many teams are now joining the rear wing endplate to the diffuser, although Caterham have yet to create the additional vanes hanging from the endplate that trail the diffuser.
Diffuser design is now heavily restricted, teams are limited to detail geometry design of the underside and the use of gurneys and flaps above the trailing edge. Caterham use a tall gurney all the way around the perimeter, with just a small opening to allow the flow along the strake on top the diffuser roof to exit, this is a solution similar to that used by Williams last year.
The last detail and an increasingly important one are the rear brake ducts. Earlier we saw the relatively simple inlet scoop for brake cooling. From behind we can see the area allowed for brake ducts is exploited with these four flicks. They take no part in brake cooling, but do aid the aerodynamics by contributing the general up wash flow behind the car and creating downforce directing at the wheel. This was a practice the sport tried to eradicate in the sixties when first wings were also fitted directly to the suspension uprights. But the current do allow a great deal of scope for these vanes to apply load at the wheels.

7 thoughts on “InDetail: Caterham CT01

  1. Scarbs: if the centre of the front wing (which I believe has it’s positions and dimensions set by the FIA) is ‘neutral’ how can if generate lift? Judging from the pictures I’ve seen in the technical regs, it doesn’t look like it should produce and lift/downfore

    • Ground proximity and venturi effect, air is forced to speed up through a small gap (road and underside of wing) which is the cause of the lower pressure underneath even a ‘neutral’ wing.

  2. Well, just in time for the big Silverstone update … the car will look quite different. I trust you will follow up with a detailed comparison?

  3. hello craig, my feeling say’s that the mclaren runs better at normal tempature’s, like we have seen in australia and montreál, what’s youre opinion about it? cause when i saw the race at valencia, and also bahrein i tought, it was very hot (track tempeture around 42°C) and it seems to me that on those conditions they have more problems then others, how come? thnx a lot, a big follower

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