Tech: McLaren's wing, engine war and tyre tricks

New development parts are thin on the ground at the Austrian Grand Prix, but the engine upgrade race is hotting up and Pirelli's tyre pressure demands are back in the spotlight as the FIA has stepped in to prevent a trick that's become common this season.

DEVELOPMENT PATHS

The shape of in-season development for 2016 is becoming clear. With the drastically different rules coming in for 2017, teams are cutting back on upgrades and merely refining finer details.

The reward for investing in chassis development for 2016 is now limited, as the development curve has flattened off for the current rules, whereas the unknowns of 2017 make it a much more fertile ground for deploying factory resources.

But engine development, which has been quite muted since the new rules were introduced in 2014, has suddenly become much more aggressive.

Manufacturers are spending tokens on upgrades and bringing new fuels every few races.

It's clear the development curve for the petrol engine element of the power unit has now become much more fruitful as teams develop their lean-burn combustion technologies.

This is underlined by the reliability issues many teams are having as the push for more efficient power units gets more aggressive.

While the chassis rules are being largely torn up at the end of 2016, engine regulations will be mostly unchanged for the new era. Money spent on chassis upgrades right now only brings benefits for a few more races. Development spend on engines can be recouped over several seasons.

McLAREN'S REAR WING CATCHES THE EYE

The most notable development on the chassis side this weekend has been McLaren's slotted rear wing endplate.

This is the most extreme version of this trend we have seen, with the panel bisected by several large vertical slots.

These slots feed in higher pressure from outside the wing to pass through the duct formed by the wing and endplates.

This may seem counterintuitive to creating low pressure below the wing, but more air passing under the wing speeds the flow and lowers the pressure. The net result is more downforce.

This means the wing is more efficient, therefore the team can lessen the drag penalty for adjusting the angle of the top rear wing.

This is likely to be a development used at subsequent races and copied by other teams.

FERRARI'S ENGINE PUSH CONTINUES

Ferrari remains the big spender on engine development tokens and a further token has been used this weekend for its latest performance update.

Furthermore, there's a new Shell fuel that will boost the V6 engine's performance.

Increasingly the regulatory freedom for fuel development is where huge effort is being spent to boost efficiency.

TYRE PRESSURE BACK IN THE HEADLINES

The practice of heating the cars' brakes and wheel hubs to gain a tyre pressure advantage has been brought into focus this week, and the FIA has finally acted to properly enforce starting tyre pressures.

Since the spate of tyre failures two seasons ago, Pirelli has been enforcing increasingly high tyre pressures to ensure the tyre's structural integrity while under load at high cornering speeds.

This pressure increase has a negative effect on the cars' handling. Drivers don't like the feel of high-pressure tyres and the engineers can find faster lap times with lower pressures.

Since Monza last year starting tyre pressures have been checked by the FIA to enforce the minimum pressure limit. Therefore a cat and mouse game has started with the teams trying to run lower pressures and the FIA trying to still enforce the mandatory limits.

This season it seems some teams have been heating the brakes and wheel hubs on the grid, before the starting tyres are fitted to the cars.

While this was initially explained as brake heating for the start of the race, after the Chinese GP rumours began to float that teams were able to run under the minimum tyre pressure after their out-laps.

By the time of the Russian GP the hub warming was explained as a means to boost or at least maintain tyre temperature once the tyres were fitted to the cars.

Overheating the tyres by nature of gas laws means that the pressure also rises. If the tyre can be kept at this elevated temperature and pressure for the FIA inspection when the tyres are fitted to the cars on the grid, they will be passed as legal.

The tyres can then cool once the cars get going on the formation lap, ready to race at lower temperature and pressure.

Sure enough I witnessed what I believe to be hub heating on the grid at the Spanish GP, with small noisy heaters being blown into ducts around the entire brake and upright assembly.

Several more teams have since adopted the practice, even using the same Leister mini heater hardware!

Now the FIA has effectively made this practice redundant as the tyres will be checked in their tyre warmers before being fitted to the car on the grid.

If we continue to see teams running these heaters then perhaps the practice can be explained as having been for another purpose after all. But I suspect these noisy heaters will now disappear from the grid.