How Force India is tackling its tough start to the 2018 F1 season

One of the problems it has admitted to is a lack of correlation between the windtunnel/CFD and the racetrack, with technical director Andy Green saying "the tunnel and CFD match, but unfortunately they don't match reality".

This problem was only detected after pre-season testing was completed, meaning the first three race weekends have been all about trying to understand and fix the issue.

This is always very difficult to achieve, as anything running near the ground will always suffer from different airflow separation characteristics to what the research tools predict.

Sometimes you can live with it, but sometimes it masks the car's true performance.

In Bahrain and China, Force India introduced a few variations on the diffuser, with this drawing showing the latest version.

Every team's diffuser will stall to some degree when the rear of the car is close to the ground, which reduces the drag and allows higher top speeds.

But with that it reduces the downforce, and it is vitally important that this airflow reattaches the moment the rear of the car starts to rise. Otherwise, the braking area becomes a bit of a nightmare for the driver.

The upper rear wing and how the wing's airflow reattaches when the DRS is closed will also affect the diffuser airflow reattachment, as will some of the other aerodynamic components further upstream.

So when you have a problem, it is not easy to identify what area is instigating it.

And with any problem, it is vitally important to rectify it at source otherwise it is just a temporary bandage with the issue still waiting to bite you.