Last updated on .From the section Formula 1

Williams are 10th and last in the constructors' championship and have discovered a major aerodynamic flaw with their car

Williams' head of aerodynamics has left the team after a disappointing start to the Formula 1 season.

The departure of Dirk De Beer, who joined the team from Ferrari early last year, follows that earlier this month of chief designer Ed Wood.

Williams finished fifth last season but have slipped down the grid with an uncompetitive 2018 car and are last in the championship after six races.

Chief engineer Doug McKiernan has been given full design responsibility.

McKiernan, who worked for McLaren from 1999 to 2015, joined Williams in February this year.

Williams have discovered that a major aerodynamic flaw is responsible for the car's lack of pace this year.

When the front wheels turn, they disrupt the intended airflow to the back of the car, and the critical rear floor area suffers an aerodynamic 'stall', robbing the car of downforce and grip on corner entry.

The problem is particularly acute on long corners, which is why the car performed better at Monaco last weekend, where short corners predominate, than at the previous race in Spain, where nearly all the corners are long.

A Williams spokesperson said De Beer, who had previously worked at Sauber, Renault and Lotus, had "stepped down, effective immediately".

Under McKiernan, who reports to chief technical officer Paddy Lowe, Dave Wheater has become head of aerodynamics.