Formula One car development blog
McLaren's car updates have pushed the car back up in between the front runners, and unsurprisingly, the improvement came once again from exhaust modifications. McLaren redesigned the sidepod to have the exhaust exit lower above the ground and further back, creating a more consistent flow onto the outer extremities of the diffuser.
In essence, McLaren's update appears to be influenced by Ferrari's famous acer ducts, something which the MP4-27 now features as well. The ducts are sloping down and feature an undercut of the sidepod, allowing air to flow underneath the tail of the duct and towards the centre of the car. The resemblance is striking, and particularly interesting because it was Ferrari that initially copied McLaren's downwash exhaust exit.
In addition to the sidepod, the fins at the bottom of the rear wing endplate have been modified as well. Again, these work in combination with the diffuser to generate downforce at the rear end of the car.
Since their major car update at the European GP in Valencia, Ferrari have been testing a new version of its front wing. Since then, the wing has appeared in every free practice session on Friday and Saturday, on both cars, but at no occasion has it been used to race. While the visual changes do not seem to be major, the new wing certainly has an interesting influence on the car's balance given that the team prefer to test it a little bit longer. Of course, the rain in Silverstone and Hockenheim have not helped the Scuderia in this respect.
Either way, the new wing has a smoother curve on the trailing edge of the upper flap. The stacked element was reduced in size slightly, but it seems that the changes around the endplate are most important for this update. The new iteration features much larger apertures that allow air flowing outward of the endplates to be sucked into the low pressure area underneat the front wing's flaps. There, is is flowing faster and upward, generating downforce.
Along with the angled front wing adjuster, air getting underneath the outer extremities of the wing is used for downforce and at the same time directed as much as possible around the front wheels. This should help reduce drag a little bit but can also greatly influence the car's balance as it will change the flow field in the wake of the front wheels.
Further proof of the importance of this area is the cut in the flap of the stacked element where it joins the endplate - aside of the Shell logo, as marked with an arrow. This cut is specifically designed to reduce the strenght of the vortex that comes off of the front wing at the arrow's location. While this reduces somewhat the downforce generation of the stacked winglet, it reduces the amount of air that is spilled over the top of the endplate. This, again, would have an - apparently unwanted - influence on the flow around the front wheel.
Pictures taken at Silverstone this weekend have uncovered that Red Bull have adopted or are at least testing an exhaust chamber. Also known as a Helmholz exhaust, the regular exhaust pipe features a blind additional branch which can accumulate exhaust gases when pressure is high in the exhaust pipe. It can then release those gases again when the driver gets off the throttle, hence evening out the pressure differences that occur in the exhaust pipe.
Apart from the evening out in an attempt to gain a more constant exhaust flow - and hence a more constant rear downforce at the diffuser - a Helmholz resonance chamber can also help the "Kadenacy Effect" in a specific RPM range of the engine.
The Kadenacy effect is an effect that forms from pressure-waves in gases. In essence, careful design of the dimensions and position of the exhaust changer can assist scavenging of exhaust gases out of the cylinders and therefore increase the pressure drop across the intake and exhaust valve area within a specific RPM range. As such it could be used to increase engine performance in the engines' most used RPM range.
To make room for the exhaust chamber that Ferrari debuted in F1 through 2011, RBR redesigned the entire exhaust of the RB8. While it previously ran close to the car's engine heat cover and then curved downward with a 180° turn, the final turn is now curved upwards, similar to Williams' exhaust layout.
Also note, as marked with yellow, the upward direction of the final 10cm of the exhaust pipe. The regulations specify that this must be a straight, circular section pointing up between 10° and 30°.
Just two weeks after introducing a major rear end upgrade on the RB8, Red Bull have fitted their car with yet another exhaust tweak at Silverstone. This time around the change is small but may have a big effect nonetheless.
The sides of the exhaust channel have been raised to have two small bulges on each side of the channel, trying to keep the exhaust flow from spilling over the sides. Remember that the actual exhaust exit is point 10° upwards, as defined by the regulations. Ever since the team's first version of their exhaust ramp, introduced at Barcelona pre-season testing, the team is trying to channel the exhaust gases downward over the sidepod slope, rather than spilling over the sides of the sidepod.
Caterham F1 have updated their CT01 with a major new aerodynamic package focusing on the rear end of the car. It is quite obvious the team have found inspiration at McLaren and Sauber as the team have now (finally) also implemented a downwash exhaust that aims to extract more downforce out of the diffuser.
First and foremost, the exhaust is now in a hub similar to what is seen on the McLaren. The exhaust exit is now more rearward and more outboard than it was before. As the hub aims to direct exhaust flow down towards the diffuser, the team also removed any airflow obstacles low above the car's floor. An air outlet previously located below the upper front wishbone has been removed for better airflow right above the diffuser.
To ensure there is still enough cooling capacity for the sidepod internals, the Caterham now also features a larger central cooling funnel a la Red Bull (at Canada the team only had a very narrow central cooling funnel).
To top off the updates, the CT01 also features new sidepod panels, now featuring two elements, rather than a single solid structure as was previously the case.
Amidst a large number of updates brought to Valencia, Ferrari changed the mirror supports to gain an aerodynamic effect from those as well. In the image, Massa is pictures on Friday with the old supports which is a neutral element with its length as short as possible to keep drag low.
The new version, as in the upper part of the image shows how Ferrari modified the supports to be aligned with the vortex generators at each side of the cockpit.
By introducing yet another new sidepod version, Red Bull is the only team that can compete with Ferrari when you consider the number of changes made to the rear end of the sidepods since the beginning of the season.
The team has now changed the tunnel that goes underneath the exhaust ramp, making the inlet much larger than it was in the previous version. Aerodynamic tests on track had shown that the tunnel was not acting as the team expected because airflow through the tunnel was much less than anticipated. This caused problems to generate a consistent airflow into the diffuser, and hence created a changing car balance. The problem was this difficult that the team even tested an entirely closed tunnel, only to make sure that drivers could gain a consistent feeling with the car.
With the airflow through the duct now much bigger than it was before, its impact on the diffuser is also a lot more important. Pictures from the rear end of the car appear to reveal that most of the air from the duct is exiting close to the car's centre, aiming to increase the flow-rate over the top of the diffuser. This flow will also increase the flow-rate from underneath the diffuser and the floor, creating an overall positive effect on the efficiency of the diffuser.
The Spanish HRT team came up with a special rear wing aimed to achieve better top speeds at the end of the straights of Circuit Gilles Villeneuve. While that in itself is not special, the actual design is, because it's been a while since we saw such a tiny rear wing on an F1 car. The wing is especially impressive with DRS open, where it generated very little downforce, but also a little drag as possible.
The wing did pay off, as HRT was among the fastest cars on the straight, but unfortunately that came at a cost in the corners. Brake problems for both cars after only 25 laps of racing meant it didn't matter much anyway, as both cars were forced to retire before the halfway mark.
Williams designed a new one-off low downforce rear wing for the Canadian GP, which unfortunately for the team didn't pay off. In fact the special rear wing did not offer a big top speed improvement, at least not compared to what other teams came up with. During qualifying for instance - which is of course always with DRS open at the speed trap, the drivers posted 318.8 and 317.8 km/h, good for 19th and 20th positions on the top speed rankings.
Interesting as well is how this is a competely different rear wing to Williams' unraced 2011 Canada spec wing. Last year, the team opted for a design with raised outer edges, while this year's wing obviously features a raised central part.
Red Bull Racing fitted Vettel's RB8 with an interesting aerodynamic evaluation system. While a grid of pressure sensors is not quite new as many teams have been using that during tests since a few years, it is however interesting to see how Red Bull made a custom grid that perfectly fits the shape of the sidepod, allowing to measure the flow speed in the boundary layer around the sidepod as well as further above the car's body. The grid features 34 individual sensors, each connected to a hub, in this case mounted into a bulge fitted on the left side of the air box, where data is gathered.
However, as if this was not enough, the left part of the rear wing, including the lower beam as well as the upper elements have flowviz applied to visualize the airflow onto and over the rear wing elements.