Bite Size Tech: McLaren MP4-30 Diffuser - Silverstone

Fernando Alonso at the wheel of his McLaren MP4-30 prior to the incident with Kimi

In Austria the team only had the updated parts available for one driver, which it was Fernando Alonso's turn to go first.  I covered the bulk of these updates for Grand Prix Times but a good rearward shot of the MP4-30 eluded me in order to show the changes the team had made to their diffuser.  With both drivers sporting the updates at Silverstone it was easier to get some quality shots of the diffuser to make comparisons

Comparison of the new and old diffuser gurneys and Y150 winglet that sits under crash structure (please remember you can click to see a hi-res version of this image)

The diffuser and detached gurney trim have been revised on the MP4-30 with the gurney split into two, retaining a similar overall height but the additional detachment helps with separation, which is part of the reason why teams started to use perforated gurneys rather than blunt ones in the first place.  This means the Y150 section, under the crash structure, has also been split into two too.

With the exposed starter motor hole banned with the 2014 regulations several workarounds sprung up, but most simply used a hinged flap in the central diffuser transition.  Mercedes, then latterly McLaren used a U shape section in the middle of the diffuser, allowing both access to the starter and improving centralised flow attachment by allowing flow from the floor to intersect with the diffuser, much like had been done prior to the 2014 rule change.

For 2015 McLaren's U was significantly smaller (highlighted in green, top right inset), more or less now just an access point for the starter, but still providing some attachment assistance.  The design first run in Austria by Fernando see's a hinged flap added to the two sections of the Y150 gurney trim under the crash structure (highlighted in green, upper left inset)

The outer section of the diffuser and gurney have also been revised, as the team look to manage how the diffuser and rear wheel wake structures interact.  Marked in green you can see how the outer wall of the diffuser has been elongated and curved backward on itself to get closer to the tyre.  Allied to this, the gurney which is now split into two extends further backward around the corner (yellow) whilst the upper gurney (blue) stops shorter.

It must be said that the angles in these two images are slightly adrift and so the changes are exagerated, however the geometry of the diffuser wall and gurneys have clearly changed.