Here is the first thread of this kind
Mc Laren introduced in 2005 the famous NO KEEL chassis and the VIKING HORNS
In 2005 the FIA once again raised the front wings outer tips and again the emphasis on the obstruction behind the wing was a higher priority. McLaren were having already run very drooped front wishbones were able to devise a better layout for the front of the car.The team managed to mate the wishbones directly to the chassis . This is a stiffer lighter set up and also creates the free space under the nose so as to improve the nature and speed of the airflow under the body of the car .
Since then many teams copied the no keel design and in 2007 all the team's chassis ( except Renault) and in 2008 are keel-less .
Their purpose are to divert and guide airflow towards the rear wing to increase downforce
Since then only BMW F1.06 – 2006 season , F1.07 – 2007 season and F1.08 – 2008 winter testing and Honda RA108 – 2008 winter testing copied them . Mc Laren dropped them since mid 2007 season .