Every Formula 1 team has arrived at the last race of the 2016 season without new developments for their current cars, the focus instead being on completing the last grand prix of the year with minimal fuss against a backdrop of high-mileage components, as well as preparing for the major rules shake-up in 2017.
As first practice for the Abu Dhabi GP was run in the day time, and not in conditions comparable to either the race or qualifying, teams devoted a lot of the session to 2017 preparations, many cars fitted with '17 development parts and extra sensors to perform some final experiments ahead of the winter test ban.
F1 2017 has started already
It's still important for teams to run sensors on the current cars even if new parts aren't fitted. All this work focuses on establishing baselines, and ensuring the data gathered from a known solution matches the simulation data they have.
The teams will have already designed much of their new cars - the big structural decisions were made many months ago. As the power unit, monocoque and gearbox are the longest lead time items, the basic decisions of wheelbase and general layout had to be decided early.
With the new rules come new areas of the car to exploit, so the relative lengths of these parts along the wheelbase can open space for new solutions. For example, it's likely the tub may be longer, as the space freed up for larger bargeboards is relative to the cockpit opening and the front axle line.
With these big decisions already taken, and production of these major parts underway, the work now is in designing the details, and settling on initial aero specifications.
In comparison to the big structures, these areas are quicker to design and manufacture, so the final car specification is agreed very late. This is why understanding that current details on the 2016 cars are working as they should is vital to ensure the whole programme doesn't slip off course.
Correlation between what the designers think is happening on the car and reality is critical, as any false assumptions will hurt the design of the new car.
Some teams are already trying out 2017 concepts on their 2016 cars. McLaren and Williams have run 2017 front wing solutions at races this year. This ensures there is data to back up the early thinking of the design teams back at headquarters.
Mercedes can't stand the (brake) heat
Mercedes has been on the limit with its brakes all season long, and having to push the 28mm discs hard creates a lot of heat, leading to premature wear.
Even though brake disc thickness will increase to 32mm next year, this problem will still be present, thanks to heavier cars and more downforce, so Mercedes has been evaluating options for controlling the temperature of the brakes.
Carbon brakes must operate above 400C, but if kept above 900C for prolonged periods the surface of the disc oxidises, which increases wear.
Teams are reticent to overcool the discs through the brake ducts, firstly as this can cause the disc temperature to drop below the 400C threshold, and secondly because the larger brake duct scoop adds drag to the car, slowing it on the straight.
Over the past few races, Mercedes has tested secondary carbon plates spaced slightly away from the brake disc face.
These plates are fixed to the upright so that they do not spin with the wheel, and are roughly the same shape as the exposed portion of the disc, so effectively round with a cutout for the brake caliper.
They appear to be similar carbon material to the brake disc, and feature radial holes much like the brake disc.
The exact purpose for these carbon plates is not clear. One possibility is they are heat sinks for the disc's side faces.
When the actual brake disc heats up from the friction of the braking event, the heat will pass into side plates and help reduce the peak temperature of the disc. Air will pass through the side plate's drillings to help prevent them from overheating.
After the braking event, the side plates will retain some heat and help the brake disc retain some heat for the next braking event.
With this the team can prevent premature wear from hard braking and still have the brake in its operating temperature window when it reaches the next corner.
Ferrari gets all vane
As the sole team to run any significant upgrades over the past two races, Ferrari tried new rear brake ducts in Abu Dhabi.
These featured a larger forward protruding vane, plus a new hot air outlet created behind the duct.
Rules allow the brake duct to extend as far forwards as the front perimeter of the tyre, so on the front and rear ducts the duct bodywork forms a vane that reaches forwards around the tyre's sidewall.
At the rear Ferrari has run a very small vane until now, but the new specification features a vane as large as the rules allow, and the greater depth directs the air better towards the cooling inlets and 'wings' mounted to the duct.
Looking behind the brake ducts, a stack of 'wings' usually fill the 120mm wide space allowed for brake duct bodywork.
The new duct specification has a tall, narrow outlet, which takes up a little of the space for the wings.
This duct vents hot air from the brakes from the inside of the wheel.
This is a common trick used by many teams. The aim isn't brake cooling per se, but as the hot air passes back out from inside the wheel via a shorter route, less heat from the brakes passes into the wheel, heating up the rear tyre less.
This option becomes a set-up aid. If the rear tyres are running too hot, the open duct is fitted and this reduces heat transfer into the tyre. It is taken out again if and when the rear tyre temperatures are too low.
By its own admission, Ferrari has struggled with hot rear tyre temperatures. This duct may be a good way of managing this problem.
McLaren in drag
Like Ferrari, McLaren was playing with brake ducts, but in its case the front ducts, and for very different reasons.
McLaren runs open front axles, an aerodynamic trick whereby the brake ducts blow air out through the axle.
This creates a combined effect with the front wing to push the spinning tyres' turbulence away from the car.
Both the larger brake duct to feed the axle and the blown effect create a little drag themselves.
This loss is recovered by the more beneficial effect on the rear aerodynamics, reducing drag overall.
In Brazil McLaren tested closed front axles and downsized brake ducts, to reflect the reduced airflow through the axle.
While this might be a Brazil specific solution, it's likely that the test was a further part of McLaren's 2017 preparations.
As the tyres will be wider next season, the drag they create will also be larger, so teams will need to reduce drag elsewhere on the car.
Currently the blown axle solution reduces total drag, as its effect can allow the rear wing to be smaller.
However, in 2017 the rear wing will be less important, as the larger diffuser will be creating a lot more downforce.
This means the blown axle will be less effective, so the drag it creates starts to become a potential penalty.
Along with the simpler front wing endplate tested in previous races, McLaren may be testing a very low drag concept for its 2017 car, something other teams are also likely to be pursuing.
Eyes in the back of your head
While not a performance development, the teams have been running 360-degree cameras in free practice, as part of an evaluation of a future virtual reality broadcast.
A small, tennis ball-sized pod has been fitted to several cars at the last two GPs. This unit is made by Fly360, and features a small camera that records video in a 360-degree hemisphere.
Although the raw output is more like an extreme fish eye lens, when watched with the matching software and a VR headset, the viewer can look around to see a more normal view of that section of the footage.
In theory, with the car racing and the camera recording, it's as if your head was sticking out of the chassis, and you can look around as cars and scenery go by.
It's expected this will be an app or service F1 fans can subscribe to in future.
I can feel your halo
As part of preparations for 2018, and assisting the FIA in finalising which cockpit head protection will be used for that season, teams are continuing to run the halo in free practice sessions.
Now in its third iteration, the metal hoop and its carbon attachment points have been temporarily fitted to cars during brief runs in free practice.
The work testing the device is twofold; firstly, for the driver to acclimatise to driving with the structure over them, and secondly for the team to assess its aerodynamic impact.
Drivers' comments are split. There are those who see the safety benefit and think it's a fair compromise to get cockpit safety improved; other drivers are more critical of the impact on visibility.
Part of the change in the halo design over its three iterations has been to place the upper halo hoop in the right position to give the best visibility.
For the teams, the hoop is detrimental to the airflow into the roll hoop. The current cars were designed to have uninterrupted airflow, so the fitment of the halo was sure to upset things.
While there is a downstream effect on the rear wing, the biggest issue has been cooling airflow.
When it first tested the halo, Red Bull was only able to run single laps due to overheating, as the multiple power unit coolers fed from the roll hoop were robbed of airflow.
This weekend Ferrari and Toro Rosso ran the halo. The STR11 was set up with a stack of air pressure sensors to measure the difference in airflow with and without the device fitted.
Teams will continue to test the halo throughout 2017 in readiness for the following year, although the rule makers are yet to decide if the halo or another device will be the chosen safety option for that season.