Sebastian Vettel's fuel problem
When Sebastian Vettel was asked to "stop the car" on his in-lap after qualifying, it was clear that his weekend was going to get a lot more complicated.
It transpires that on his slowing-down lap, the telemetry showed low fuel pressure in the fuel collector.
This, the risk that the high-pressure fuel pump could be damaged by running dry rather than the simple implication that the engine was about to be starved of fuel, was what prompted the call.
It then emerged that the car did not appear to have the mandatory one-litre fuel sample within its tank. What goes on inside the tank suggests that the reasons for this could be more complex than simply not having enough fuel.
When in the pits between runs, Formula 1 cars are routinely drained of fuel and then refilled. This ensures the car goes out with the correct amount of juice.
The mobile fuel trolley dispenses fuel very accurately and records the fuel transferred for later checks.
It's possible that the fuel rig did not dispense the correct of fuel for the remaining runs, although this does not appear to be the case with Vettel's car on Saturday.
Inside the fuel tank, its volume is broken up into different chambers. Each chamber drains into another, with their locations progressively lower and more rearward.
Once the fuel is in the final chamber - where the fuel pump is located - it is prevented from passing back into the previous ones by a series of one-way valves.
In the last chamber there will be 3-4 low-pressure fuel pumps. These devices draw the fuel into a carbon fibre bottle, known as the fuel collector. This holds 1-2 litres of fuel and, in theory, should never run dry if there is fuel in the tank.
Fuel from this tank is then pumped into the engine by a high-pressure fuel pump, an expensive and precise component driven mechanically from the engine.
It's this part that will fail if it runs dry, hence the call to stop the car when low pressure was detected from the pump. In this part of the tank, there is also the pipework that the FIA uses to drain the sample of fuel from the tank.
As with when Lewis Hamilton's McLaren ran dry in qualifying in Spain, insufficient fuel for a sample leads to the driver being excluded from the qualifying session.
Now, the collector would run low on fuel if there was no fuel in the final fuel tank chamber to feed it. This could be either because of not enough fuel in the tank, or the fuel that was in other areas of the tank could not make to the last chamber. Red Bull may not have had enough fuel to start with.
Perhaps there was fuel in the tank but it had not drained into correct place to be picked up by both the fuel pumps and the FIA sampling pipework. This could be because of a fault on one of the trap doors between chambers in the tank. The rules state that the FIA one-litre sample must be taken from the sampling pipework and not with any interventions from the team.
With the car back in the garage and the team able to inspect the inside of the tank, the actual explanation become clear. It is possible that repairs could be made to correct any faulty mechanisms inside the fuel tank, such that the fuel will drain correctly during the race and the team not have to overfill the tank, adding weight in what is already going to be a difficult race for Vettel.
Ferrari has run a series of upgrades this weekend
Reactive brake cooling
The FIA issued a technical clarification on Friday morning following a question from Red Bull about a brake cooling system that adjusts according to temperature. It requested a clarification on the use of a heat-sensitive mechanism, for example a bimetallic strip, to alter brake duct openings to provide the appropriate cooling level for the brake temperatures.
In this instance, Red Bull did not want to use such a system, but as is often the case used this method to highlight something that it thinks a rival team might be doing. It's a far less confrontational approach than a direct protest.
The FIA declared that such methods of altering the brake systems are illegal. It's hard to understand how these would have been allowed in the first place for movable bodywork is strictly banned in the regulations. That said, brake ducts do not fall into the bodywork regulations, leaving space for different interpretations of what's allowed.
McLaren has been known to have brake ducts that can be adjusted, but the adjustment is achieved by a mechanic with a tool during pitstops, so this is not the system that being questioned by Red Bull. Perhaps Red Bull thinks that technique has been superseded by an automatic system, but so far there's no evidence to back up these claims.Red Bull
Ran with flo-vis paint on the front wing, in an effort to monitor the airflow under the nose and around the turning vanes.
Nothing visibly new, but is believed to be running small tweaks.
"It's the normal Friday mystery," said McLaren technical director Paddy Lowe when asked about why the car was so fast in FP1. "We just go out and do our normal thing and do our best and see where we are.
"We have some new stuff on the car, but don't know what the others are doing. I would not have thought that what we have got on the car would explain any particular gap we have seen."
In Friday practice Jenson Button tried the older Spa version of the sidepod wings. These are the 'r' shaped wings that wrap around the front of the sidepods. They were updated few races ago to create a more equal gap between the wing and the sidepod. These sidepod wings help direct the airflow down to the exhausts. This downwash redirects the exhaust towards the diffuser for more downforce. Button subsequently resorted to the later design of pod wings.
As there have been problems with new parts developed in the Maranello windtunnel, Ferrari has resorted to producing parts using the Toyota tunnel in Cologne. The fruits of this labour are the new diffuser and front-wing endplates seen in India, plus the aero parts tested this morning. Among these were a new front wing and turning vanes, which were tested by Alonso before he set about evaluating a new rear wing.
The front wing is an evolution of the recent line of Ferrari front wings, where the outer 30cm of wing span is split up into six elements. Having more elements means the wing can be steeper for more downforce, without being prone to stalling. The new wing also follows the Indian GP design, with the endplate featuring an additional opening to help direct flow outwards around the front wheel.
Ferrari has brought a new rear wing aimed at improving DRS performance
The new rear wing is aimed at improving the car's DRS performance. Ferrari had around half the DRS effect of its rivals in India. This means it needed to run less wing to achieve high top speeds, as the DRS was not giving the same 10km/h boost its rivals have. This is a problem in qualifying when DRS use is free.
If Ferrari's new rear wing can provide the extra DRS boost in qualifying, it will allow Ferrari to fight at the front in the race. As proved in India, it's much closer to Red Bull on race pace. To achieve this, the new rear wing flap is now far smaller, enabling it to be flatter when the DRS is in use, reducing the drag.
Further aiding the DRS's effect in stalling the rear wing, Ferrari ran a new Y75 winglet (monkey seat). This adds some downforce, but also helps to connect the airflow from the diffuser and the beam to the top rear wing. When the DRS stalls the top rear wing, the entire airflow at the back of the car stalls, further reducing drag and boosting top speed. The new wing is now linked to the diffuser by a new series of vanes hanging from the endplates.
The team has been so desperate to incorporate these upgrades into the F2012's design this weekend, that it has broken F1's curfew rules two nights running.
No new developments were visible in FP1, but Nico Rosberg's car again ran with the passive drag reduction device (DRD), which is similar to the Lotus concept. This is an F-duct style system that stalls the rear wing at high speed for even greater top speeds.
Mercedes again ran with its passive drag reduction device © XPB
Unlike the original Mercedes double DRS, this system is entirely passive. It takes airflow from a roll hoop inlet and ducts it either to stall the rear wing or to exit neutrally over the beam wing. It is not banned next year, although Ross Brawn is unsure whether it will be part of the 2013 car. Despite being run in free practice, it is not expected to be used in the race.
Another design under question for 2013 is the Mercedes interlinked suspension system. Rather than springs and dampers to control the suspension, the Mercedes uses hydraulic cylinders linked to each other via a system of valves. This is somewhat like active suspension, but is totally passive.
Tried out new 'chassis wings' on Romain Grosjean's car during FP1. Kimi Raikkonen ran a tweaked version of the Coanda exhaust first raced in Korea in order to mitigate the power loss caused by the design.
After problems in India, Paul di Resta arrived in Abu Dhabi with a new monocoque. Such is the toughness of modern carbon fibre tubs, team may only make five a year and a driver can even complete an entire season with just one chassis. Switching to a new tub suggests that there may have been damage to or degradation of his original tub.
Had a variety of different front wings available as it continued the comparison work it was also doing in India.
Williams's drivers use a tablet device to view their telemetry. We are used to seeing the drivers with a sheet of paper in between runs. Williams finds this quicker than printing them out, enabling the driver to instantly access lap comparisons.
Caterham has reverted to an older brake duct for increased cooling
The Caterham CT01 is heavily revised this weekend, with major updates to the sidepods and exhausts. But not all parts on the car are new. Caterham has reverted to an older design of brake duct for the demands of Yas Marina.
Rather than the sleek, scoopless ducts raced since Silverstone, the car features large scoops for greater cooling.
This will increase drag and hinder top speed, but the brakes are severely tested in Abu Dhabi. Caterham also ran a modified front wing, floor and rear wing endplates in an aim to find four tenths of a second worth of improvements.
No new parts, but spent time working on the modified DRS that it originally tried in Korea.
Max Chilton ran with a revised front wing © XPB
Worked hard on development parts during the first runs in FP1.
Third driver Max Chilton went out with a revised front wing, which featured a large turning vane to guide the airflow around the front tyres.
Timo Glock ran with a large array of aero sensors fitted to the rear of the car. These measured the airflow passing off the sidepods and exhaust and towards the diffuser.