Tech Talk: McLaren MP4-29 wishbone wings analysed and explained 7 February, 2014 The McLaren MP4-29 with wishbone wings circled There were some interesting bits and pieces in the Jerez pitlane during the opening four days of Formula 1 testing in Spain late last month, but arguably the biggest talking point were the wishbone wings on the McLaren MP4-29. Matthew Somerfield gives us the lowdown on the canny devices. McLaren had already made it clear before the launch of the MP4-29 that they had a ‘revolutionary rear suspension’ to test before the season commenced. Laying down the marker the team introduced their ‘Wishbone Wings’ for all to see in Jerez. But just like their F-Duct in 2010, have they gone too early? Having shown their hand early during testing in 2010 the F-Duct was rapidly copied by the rest of the field and in certain instances even with chassis integration issues some of their rivals out developed their initial concept. The suspension elements now doglegged rearward from their usual straight on alignment – photo shows the elements from above The suspension layout utilised by McLaren is another great interpretation of the regulations with the rear suspension elements made to replicate the outgoing beam wing in terms of the way the airflow operates in that region. The idea is to simulate the same flow pattern that allowed the beam wing to interact with the airflow structures generated by both the Diffuser and upper rear wing elements. In order to do this McLaren have had to make several design concessions; The suspension elements are now doglegged rearward from their usual straight on alignment. Narrower forward edge suspension elements In order to recreate the height of the beam wing the forward section of the suspension elements have been shaped with a narrower forward edge. This means that the elements are shaped like a parachute, which is all well and good in terms of creating additional downforce, as this creates an area of low pressure behind the suspension elements and therefore encourages interaction from the diffuser. However, it means that there will be a net increase in drag from the components too. McLaren has tried to mitigate this by not only carefully managing the shaping of the components in a 3 dimensional sense, but also reducing their width and height at the outer edges (either side of the rear wings endplates). Furthermore, the team is looking to usher the pressure gradient towards the central section of the car/crash structure where it is met by a ‘Butterfly’ Upwash Device. Butterfly Upwash Device on the McLaren MP4-29 This not only relieves the pressure and therefore drag being induced by the oversized suspension elements, but also helps in the interaction with the exhaust plume. It remains to be seen if this is a significant performance differentiator and just how difficult it would be for teams to integrate their own version (Likely requiring a whole new crash structure along with several other components). It’s therefore likely that the other teams will not only be analyzing its merits in their CFD/Wind Tunnel before Australia but they may also request clarification, or protest it’s use at the race too. (Analysis by Matthew Somerfield). Subbed by AJN.