Lotus E20 DDRS (Double/Super DRS/F-Duct) - (Hockenheim)

Lotus had come to Hockenheim already stating they had 'interesting' upgrades to test. The interesting upgrade centres around a DDRS system. Lotus race pace this season has been amongst the best but due to a lack of raw pace during qualifying and some unfortunate luck they have been found slightly adrift on race day. In an attempt to bring their car closer to the front in qualifying a DDRS system should add more pace throughout qualifying where DRS is unlimited in its usage and maybe add a small increase in performance during the race.

Unlike the complicated Mercedes DDRS system that employs tubes from the Front to Rear wings the Lotus system echoes the original F Duct principles:

The two ducts either side of the airbox inlet feed air down the engine cover toward ayet unspecified source as soon as more information is available I'll post it. However I'd hazard a guess at either the starter hole or due to the central portion of the Diffuser Gurney having a slot the air exits out the bottom section of the engine covers cooling exit. Either of these will effectively help the diffuser and increase rear end downforce. 

As we can see in the picture below a small feed (Periscope) is also present as the exchanger between the bottom wing element and the collector at the beam wing. This acts as the switch and is actuated by the DRS flap above being opened (Much like the Mercedes variant, although again without the necessary close up shots of that area I can't be 100% accurate) When DRS is active the air usually feeding the lower section of the engine cover or starter hole is then drawn upward and exits out of the rear of the engine cover, the addition of a cleverly shaped cover / monkey seat helps to keep the flow managed without disrupting the flow as it exits from the rear of the car.

To break it down here is a couple of quick pictures I mocked up in MSPaint in order to show the flow pattern when DRS is active and inactive

Above: DRS is inactive and so the air being scavenged by the ducts next to the airbox inlet is sent to the lower exit (Possibly the Starter hole or the lower cooling exit)

Above: With DRS active holes hidden under the Rear Wings Main Plane act use the air to re-divert the air from the airbox inlets and exit it out of the engine cover cooling hole (which is now extended by the addition of the shapely Monkey Seat)

Above: Showing the system from the rear the engine cover now extends close to the appropriately shaped monkey seat which extends the engine covers reach past the beam wing.  On top of the engine cover you can see the periscope tubing which connects the cover to rear wing plane and acts as part of the fluid switch

Above: Slotted Diffuser Gurney as mentioned above the airflow is most likely exiting from the lower portion of the engine cover and having the slot in the Gurney here will intensify the effect of the diffuser in central portion

Above In this image you can see where the lower portion of the engine cover exits (Circled in Red) and does so in the same region of the diffuser gurney slot aft of it

Above: Basic Diagram showing the predicted airflow pattern of the Lotus System: Yellow indicates the airflow entering the ducts next to the airbox which when DRS is inactive exits lower in the cooling exit (light blue) in order to boost the diffusers effectiveness. When DRS is active a hole in the lower rear wing plane is uncovered and air interacts via the periscope duct (Green) and acts much like the old F Duct system moving the airflow to the top exit of the engine cover and through the Monkey Seat (Red)

Other side effects of the Airbox Ear Ducts

The other interesting aspect behind the utilisation of such ducts around the airbox is for 'air spillage', over recent seasons this hasn't been a problem as the engine has been continually consuming air (Off Throttle Diffuser Blowing).  However now the use of off throttle blowing has been curtailed when the driver lifts out of the throttle the required amount of air entering the airbox inlet isn't so large.  This effectively creates a blockage and so the airflow stagnates (builds up) and then cascades over the sides of the engine cover.  This type of airflow is disruptive and effects the bodywork aft of the airbox.  As this occurs during the braking and turning in phase it's quite an undesirable effect as it reduces the effectiveness of the Rear Wing aswell as any residual effect on downforce the exhaust plume may have.  The ducts added to the sides of the airbox inlet act as catchment devices for the airflow during these off throttle moments.  This helps to keep airflow heading toward the rear wing uniform resulting in a downforce gain during braking/cornering.  During normal driving conditions the ducts simply carry additional airflow to the rear of the car.

In summary the Lotus system should boost downforce performance whilst the DRS is inactive and lift the effect when DRS is in use.  Ideal for Lotus' quest for a better qualifying performance and will help with additional downforce during the race


03/08/12 I have added a new article in regard to Lotus using the system for drag reduction via a passive duct system: http://somersf1.blogspot.co.uk/2012/08/lotus-e20-passive-f-duct-system.html

Images Copyright Sutton Images