McLaren MP4/19 Mercedes (2004)
While the new Mac looks different to the rest of the grid, McLaren have in fact merely adopted a number of other practices from around the grid, compressed into one car. The result if it gels should be good, but the original 17 and 18 never gelled as predicted.
The twin keel set up for McLaren has always splayed the keels away from the chassis at angle, this creates less blockage under the nose and puts the mounting points where the bargeboards are placed, making double use of the space. The wavy front wing (W shape) makes the most downforce in the middle of the outer sections, hence the keels are not placed in the main flow but instead direct this flow around the car. The keel only runs down to the suspension mounting, the bodywork ahead, behind and below it is removable and hence changeable through the season.
The McLaren front wing follows the 2003 wavy (or W) format, But the underside of the nose on both the 18 and 19 is unlike any recent f1 car, it is more akin to the early nineties nose\wing shapes. The main plane and first flap element are full width and hang from the drop plates under the nose section, but the second flap is split under the nose. This set up places the underside of the nose in much closer proximity to the wing than the F2001 for example. Splitting the second flap makes for a shorter chord, which will make less downforce and drag and upset flow less under the floor and into the sidepods. The wavy front wing (W shape) makes the most downforce in the middle of the outer sections this reduces the vortices near the endplates and improves flow under the middle of the car. Hence the main flow is directedaround the car (yellow arrow lower picture).
Two main concerns have dictated the shape around the rear of the car, cooling and vortex management. The sidepods are now as waisted as the Ferraris inorder to achive this more cooling outlet area (orange) is required towards the front of the sidepods. Hence the 19 has large openings on the shoulders of the sidepods, large outlets around the exhaust pipes and a slightly smaller outlet on the rear of the sidepods. Lastly a small outlet is created at theof the ducktail at the rear of the gearbox. Vortex management helps reduce drag and unwanted turbulence ahead of the rear wing. Any wing will create a wing tip vortex, High wing angles and endplates make them even stronger. While the perceived wisdom that the trails form rear wings in the damp suggest the wing is efficient, in fact these trails add drag tot he car and upset the flow exiting the diffuser. Mclaren as with many teams make the inner profile of the winglets atop the sidepods much flatter, this reduces the vortex created that would otherwise hit the rear wing. The rear wing itself uses a notched endplate and shorter chords on the outer edges of the flaps, on both the main wing and lower element to reduce the vortex created.
Major structural differences between the 18 and19 are in the chassis. The front portion of the monocoque from the dash bulkhead forward, is still inclined but is now lower, no longer featuring the potentially controversial structural windscreen to create a lower nose and remain within the dimensional regulations. Also the fuel tank is much shorter as teams no longer run heavy fuel loads as a result of the parc ferme qualifying rules.
The sidepods now mimic Ferraris F2002, but not the 2003GAs undercut front face. The radiators are much sculpted to fit into the shape but probably are installed in a vertical axis. The 18s large flip up and fence between the rear wheels is carried over. But the fin on the engine cover is no longer on the car, instead Newey has followed his preferred solution of a long streamlined shape.