Tech Talk: GP could be won on Friday.

The tight title battle continues at Hockenheim this weekend with Red Bull and McLaren pushing development boundaries hard in different areas - but how will their respective progress affect things this weekend?
Bridgestone will bring their widest tyre gap of the season this weekend to spice things up, but while much of the focus (providing the weather remains dry) will be on how the cars cope with this difference in tyre performance styles perhaps the biggest key to this weekend's battle between Red Bull and McLaren will actually be their respective progress with their f-duct and blown diffuser designs.
The long straights around the 2.84-mile track mean 60 percent of the circuit is spent at full throttle, while the combination of a 190mph straight heading onto a first gear 40mph hairpin will also put an emphasis on top-end power and, more importantly, aerodynamic efficiency and low drag - making the f-duct a key performance tool.
McLaren have had their f-duct working well since the start of the season, with their rivals playing catch-up. The team's managing director Jonathan Neal joked that their rivals call it the "f-ing duct" because of the challenges it is presenting in getting their own designs to work as well as McLaren's well-honed solution.
There is no denying Red Bull have been on the back foot when it comes to top speed, with team boss Christian Horner admitting earlier in the season that their Renault engine was "30hp to 40hp" down on the power produced by the Mercedes unit in the back of the McLaren.
To overcome the additional f-duct advantage enjoyed by McLaren, Red Bull's engineers have been working hard on their solution, but Mark Webber admitted at Silverstone that the system has been "not an easy thing to get on top of" and that this is only one of the team's many design focuses as they push boundaries on every little detail.
Red Bull's hand-operated f-duct is a more difficult (and arguably more dangerous) one to operate than the knee-operated system run by McLaren - some say it was the removal of Webber's hand from the steering wheel to operate the system that caused his crash in Valencia.
They have only used it in three races so far, and in qualifying at the last event at Silverstone, the lead McLaren was still 3.3km/h faster than the lead Red Bull of Vettel through the speed trap and 4.1km/h faster than Webber. In the race, though, Vettel was actually 0.4km/h faster than the fastest McLaren. Earlier in the season, McLaren had up to 8km/h advantage, so it suggests Red Bull may have made their f-duct breakthrough.
McLaren's development focus, meanwhile, has been on the blown diffuser, which Red Bull have had the benefit of all season. Again, this is a challenging system to put onto a car, as McLaren found out to its detriment at Silverstone, but they are continuing to push to find a solution.
An important factor of this weekend's race, however, is that although there are 17 corners around the track, the layout of the circuit and its focus on the low-speed stadium complex means there is a reduced importance on overall downforce compared to Silverstone or Barcelona - and that means the blown diffuser concept could not be as beneficial as at other circuits.
Despite this, McLaren are still focusing on pushing this development forward for this race and since Silverstone they have put in a series of rig tests, dyno running and development in the wind tunnel and will make a final validation of it at the circuit in a major test programme on Friday. The team will run both drivers on back-to-back evaluations with old and new floors, and make a decision whether to run it for the rest of the weekend at the end of the day.
And that could play right into Red Bull's hands.
Bridgestone's decision to bring the softest and hardest tyres to the track will mean teams have some important tyre testing to do to make sure they get don't get caught out by degradation - and most of that would be done on Friday.
"It should provide a challenge for everyone and should be interesting," said Hirohide Hamashima, Bridgestone director of motorsport tyre development. "If it is hot the super soft will be a challenge to manage for stability and durability. If it is cold then ensuring the hard is in its temperature operating window will be a tough task."
If McLaren spends essential set-up time trying to push forward its blown diffuser while Red Bull, who seem to have found the solution to their f-duct development, can benefit from the extra time in learning how their car will work the tyres, that could be where the race is won.