Lotus are set to give 'the device' its race debut at Silverstone. The ducting system, more commonly known as DRD (Drag reduction device) is fitted on Kimi Raikkonen's car. At a time when other teams have seemingly given up all hope of racing it, despite Mercedes, Red Bull and Sauber testing similar designs during winter testing, Lotus is pushing ahead.
The system contains two separate inlet channels, one from the airbox itself, and one other. In Lotus case, this is indeed the airbox, while the ears on each side of the main inlet provide the second inlet channel. Lotus have moulded the ear into the chassis, making them a structural part of the monocoque, explaining why the ears are present on the car, even when DRD is not used - in which case the ducting specific for DRD is not present and the holes are covered. Having one each side of the main airbox make them less sensitive to yaw.
There are also two outlets. One is neutral and exits just above the beam wing. Lotus have put together a cleverly shaped monkey seat to work as some sort of a diffuser on that neutral channel to help extract air from that channel and get some downforce from that. An upward scope is also present, blowing air underneath the middle of the rear wing.
The entire system is most likely based on differing air pressures between the ear inlets and the airbox, along with changing pressure underneath the rear wing. It's effectively a very complex fluid switch that requires tuning race to race, mainly by varying the sections of the different ducts. When done properly, the system directs air through the upper duct to stall the rear wing at higher speeds when downforce is less important and drag reduction is beneficial.
Several members of the teams who were working on similar developments during the winter have noted the main problem with the system is getting the switchover right, and it is here that one must look when searching for reasons as to why the system didn't become a great success so far. Lotus have however recently done a straight line aerodynamic test and are believed to understand the system better now.
The most recent developments on the Lotus system are particularly noticeable in the modified monkey seat which is now more circular. The upper duct is also no longer connected to the rear wing, but rather leaves a little space between the wing element and the duct itself, following the designs from Mercedes AMG and Sauber as seen at Barcelona winter testing in March.
Racing the device will provide the team with a lot of additional data, especially because Romain Grosjean's E21 is fitted with a new, slim engine cover without DRD. If the Great Britain GP would prove to Lotus that DRD is not effective, it may well mean the end of the DRD altogether. We're however not yet at that point, and Lotus have obviously put in some more effort into the system to tune it it work as it should.