With a lot of expectation around McLarens new car, the newly unveiled MP4-26 did indeed surprise with its sidepods. Termed “U” shaped by Technical Director Paddy Lowe, as the two “L” shaped individual inlets together form a “U”. As with other design elements on the McLaren these are almost directly opposite to what the rest of the grid is doing.
What the team have done is to shift the inlet for the radiators at the front of the sidepod as far outboard as possible, to allow a freer flow of air to the rear beam wing (the lower element between the tail lamp and the top rear wing). Typically teams place the inlet for the radiators as close inboard a possible, as this airflow is the cleanest and with the most energy. This allows the sidepods to cool efficiently and hence have smaller inlets for less drag. By placing them outboard the vertical inlet catches the turbulent airflow from the front wheel wakes. Its this messy airflow teams try to keep away from the car with the pod fins. While McLaren may have to have a slightly larger inlet to cope with the poorer airflow, the benefit is that the better airflow closer the centre of the car can now be directed at the beam wing. With the double diffuser banned, a larger proportion of rear downforce will have to come the from the rear wing.
Also by creating this shape inlet it means McLaren cannot have the deep undercuts in the sidepods, which other teams use to direct the airflow around the sidepod and over the diffuser. McLaren have still managed to keep an undercut, but this is much smaller and lower, at about the same as the bottom of the raised nose.
Packaging radiators and ducting into this shape is far more complex than a simple inlet. The radiators themselves have a stepped upper edge, the protruding section reaching up inside the higher “L” shape section of sidepod. This makes the duct that directs air from the inlet to the radiator much simpler.
It remains to be seen if this set up works better than conventional undercut sidepods for creating rear downforce. Others team would be able to recreate the McLaren “L” shaped sidepod inlets. Although it would require a significant change the radiators and bodywork, making it a major package upgrade and not a quick test. For those teams that have not already tried this idea in the past, they will certainly being giving it some simulation time over the next few weeks.