04/07/2013
FEATURE BY MATT SOMERFIELD
Away from the drama that ensued at Silverstone due to the plethora of tyre failures the teams had a number of upgrades available for the race.
After much anticipation throughout 2012, Lotus finally ran its DRD (Drag Reduction Device) in anger, with Raikkonen using it in qualifying and the race at Silverstone. The passive device has been tested by Lotus since Germany last season, with Mercedes, Sauber and Red Bull having invested time and money investigating its merits since then also. The Lotus variant has the inlets bonded to the airbox and so when these were shown on the launch version of the E21 it was plain to see the team intended to continue its evaluation.
 |
The problem with DRD is it requires preparation time at each GP to tune it to the requirements of the circuit. As the switching process is passive (ie requires no interaction from the driver) the system must be tuned to switch at a specific speed.
The system works by taking airflow in through the outlets either side of the airbox, this flows through the pipework in the engine cover and exits out of the outlet through the specifically shaped ‘monkey seat’. As the speed of the car increases it becomes unsustainable for the airflow to extract through this outlet and begins to climb up the periscope. The periscope, now placed under the rear wing’s mainplane blows this airflow onto it, disturbing the natural airflow regime and sending the wing into a stall, reducing downforce and in turn drag.
 |
The problem teams have encountered is inconsistency in the way the stall occurs due to temperature, fuel load, etc. Lotus' latest iteration of DRD however featured some changes to the previous variants with a new outlet at the base of the periscope, which serves the purpose of bleeding off the airflow as it progresses up the periscope, whilst the periscope itself now falls short of the mainplane where before it connected with it.
 |
These changes were made in order to affect the way in which the stall occurs and moreover perhaps the way in which the team utilises the device itself. Previously the team seemed to be using DRD in a similar way to which we saw the F-duct used to increase straight line speed. However, as indicated by Raikkonen and Grosjean attaining the same top speed in the speed traps, it would appear they've now decided to try and leverage more downforce from it. This is done by increasing the rear wing’s angle of attack (AoA) which increases the downforce generated but will also come with a raised increase in drag. The DRD is used to nullify the drag element by stalling the wing at higher speeds thus giving a best of both worlds scenario.
The problem with this however is 're-attachment'. For a wing to operate efficiently the airflow has to stay attached to the surface of the airfoil. Drivers often complain of poor balance and this in part can be caused by airflow not re-attaching to the wing(s) quickly enough as the driver slows the car down. The introduction of another airflow regime (DRD) whilst braking could be enough to cause a delay in the airflow re-attaching to the rear wing and cause an imbalance at the crucial stage of turn in. Raikkonen was visually struggling with this throughout qualifying, not helped, in part, by the strong cross wind blowing across Silverstone on Saturday.
With costs and development time escalating I'm sure Lotus will be looking to maximise its use of this device over the next few races, it was just unfortunate the weather didn't permit much running through FP1 last weekend in order to better tune and assess it.
Whilst Raikkonen donned the DRD setup for Silverstone his team mate Grosjean also had new parts to test with a new engine cover that slimmed at the rear and features a ‘shark fin’.
 |
Red Bull arrived at Silverstone with an exhaust coated with reflective heat treatment. With bodywork in such close proximity to the exhausts it can not only have an effect on damaging the bodywork but also the internal and external aerodynamics around the exhaust.
 |
Ferrari seemingly took a couple of backward steps at Silverstone with the curve over sidepod airflow conditioners abandoned for the earlier specification. The Maranello outfit also went back to an older specification front wing with the more conventional cascades. The team did however test a front wing during free practice that featured inboard 'r' cascades.
 |
Its step forward however came at the rear of the car as, like most other teams have already done, it added a leading edge slot on their rear wing endplates (yellow arrows). These slots aid in controlling the airflow spilling off the tyres. Controlling this airflow is ever more important this season with the way the tyres deform vertically under load. The slot allows some of the airflow to move inside of the endplate reducing the pressure and distributing the airflow more effectively. Furthermore the team continued to cut away the section of endplate behind the wings looking to further reduce drag (blue arrows).
 |
The team also made changes to the design of its beam wing with a more shapely iteration adorning the F138 at Silverstone. (Seen below with flo-viz applied).
 |
Silverstone was a strange one for the Scuderia with the team suddenly having an issue with balance during the braking and turn-in phase. It goes to show the importance of aerodynamic balance and moreover the effects of cross wind on an F1 car.
Mercedes arrived at Silverstone with a new front wing. Having already made strides in this area this season moving to a four tier wing, the team went a stage further adding a tier and detaching the top flap from the inner joint. This will undoubtedly create a vortex off the wing tip and aid in the flow toward the sidepod.
 |
Force India arrived at Silverstone with a new front wing, the change was minimal, but just like Red Bull in Montreal the team has added small guide vanes on the top of the wing in order to guide the airflow to the strakes at the rear.
 |
Williams, one of the true strugglers of 2013, continues to bring developments with the team back-to-back testing components from 2012 also. For Silverstone the team once again had a different nose to try, returning to the higher shaped tip but this time with a chin underneath to mirror the effects of the lower nose for the flow between the front wing pillars, whilst the front wing design mirrors that used on its predecessor the FW34. As we can see in the image below the team also split strategies with the use of the 'boomerang wing' in the foreground and a more conventionally designed wing in the background.
 |
Marussia briefly tested what appeared to be a blown front axle during free practice. Using the same theory as Williams, the hollow axle receives airflow from the brake cooling duct and passes out the end of the axle which is unencumbered by an enclosed wheel nut.
 |
Note: All pictures can be found in higher resolution here.
To learn more about Matt and check out his previous features, click here