BMW-SAUBER F1.09

   After a triumphant 2008, in which BMW-Sauber fought for the championship and secured its first and only victory with Robert Kubica in Canada, expectations for 2009 were extremely high. The team halted development of the 2008 car early to focus entirely on the new F1.09, convinced they could dominate under the new technical regulations. Instead, for the German team as well, 2009 marked a transition from fighting for the title to battling for minor placings. The new regulations, which introduced a drastic aerodynamic simplification (eliminating almost all appendages, revolutionizing wing dimensions, reintroducing slick tires, and especially bringing in the Kinetic Energy Recovery System—KERS), also led BMW-Sauber down the wrong path.

BMW-SAUBER F1.09, Robert Kubica
Interlagos, Brazilian GP 2009

   The radical rule changes unsettled even the most organized teams. The F1.09 stood out for its extremely high, flat, and wide nose, contrary to other teams that pursued more slender and flowing shapes. The goal of this squared nose design was to maximize airflow under the chassis to feed the floor and diffuser, but it made the car highly sensitive to pitch and ride-height variations, resulting in nervous handling. The Swiss-Bavarian car was one of the first to feature a full-width front wing (200 cm), with a straight main profile and electrically adjustable flaps (a 2009 novelty drivers could activate twice per lap). However, BMW’s aerodynamicists struggled to manage the vortices generated at the nose extremities, which disrupted airflow to the rest of the car. A partial solution came through the sidepod design, very tall and long, with a less pronounced undercut than competitors, to push turbulent air away from the rear wheels. The biggest flaw of the F1.09, however, was its very conventional diffuser, which generated too little downforce. Due to the performance deficit, the car was completely overhauled from the Spanish Grand Prix onward, featuring a slimmer nose, a new diffuser profile (attempting to replicate the double diffuser), and even cleaner sidepods. Despite these efforts, the car remained aerodynamically unbalanced and chronically unable to bring the tires into the correct operating window.

BMW-SAUBER F1.09, Robert Kubica
Suzuka, Japanese GP 2009

   The team’s technical staff consisted of around 700 people and cutting-edge facilities. In Munich, Mario Theissen (BMW Motorsport Director) was the main advocate of KERS and responsible for halting development of the strong 2008 car to focus on the new technology. In Hinwil, Switzerland, Willy Rampf (Technical Director) acted as the link between the German and Swiss groups. A pragmatic and highly respected engineer, Rampf oversaw the design of the F1.09. Under his leadership, the team had consistently produced reliable cars, but in 2009 his engineers were caught off guard by the aerodynamic revolution driven by Theissen. He would leave his role the following year, marking the end of an era for the team. Christoph Zimmermann (Chief Designer) and Thomas Knodel (Deputy Chief Designer) were directly responsible for the car’s design, working closely with the aerodynamic department led by Willem Toet (Head of Aerodynamics) and Seamus Mullarkey (Chief Aerodynamicist), who managed the Hinwil wind tunnel, then considered the most advanced in the world (equipped with the “Albert” supercomputer). Loïc Serra (Chief Vehicle Dynamicist) collaborated with Christian Ebner (KERS Project Leader) and Markus Duesmann (Engine Director) on integrating the new energy recovery system into the car.

BMW-SAUBER F1.09, Nick Heidfeld
Hungaroring, Hungarian GP 2009

   The standout feature of the F1.09 was once again the BMW P89/9 V8 engine, both powerful and efficient. The Bavarian V8 was designed to work in conjunction with KERS and to act as a structural element of the chassis, with extremely rigid mounting points for the rear suspension. With the return of slick tires, suspension mechanics became crucial for generating mechanical grip, as aerodynamic grip had decreased. The F1.09 used a push-rod suspension layout both front and rear, with double wishbones. The car suffered from chronic understeer, and mechanics worked frantically on anti-roll bars and dampers to improve rotation. However, weight distribution, affected by the KERS batteries located under the fuel tank, made the setup window extremely narrow. Temperature management was a major challenge in 2009: KERS generated significant internal heat, forcing frequent modifications to the sidepod radiators and complicating airflow management. The hybrid system itself proved to be a double-edged sword, weighing about 25–30 kg. At a time when the minimum combined weight of car and driver was just 605 kg, this extra mass prevented engineers from using ballast to balance the car. Robert Kubica, being about 10 kg heavier than teammate Heidfeld, was forced to run without KERS for much of the season because the car exceeded the weight limit. In summary, the F1.09’s mechanical complexity, and the attempt to pioneer KERS, compromised the flexibility needed to adapt to slick tires and aerodynamic shortcomings.

BMW-SAUBER F1.09, Nick Heidfeld
Suzuka, Japanese GP 2009

   Unsurprisingly, performance suffered. After the illusion of the opening races (in Melbourne, Kubica delivered a masterful drive and was fighting for victory thanks to perfect tire management before colliding with Vettel’s Red Bull, eliminating both; in Sepang, Heidfeld finished second in a race stopped on lap 31 due to torrential rain), the F1.09 fell into a deep crisis from the third race onward. The cars were often eliminated in Q1 and rarely scored points, managing only two seventh-place finishes. From mid-season, the technical staff decided to abandon KERS and overhaul the aerodynamics. The “cleaned-up” car finally began to work, producing a series of positive results, including Kubica’s second place in Brazil. The bitterest realization for BMW engineers was that the F1.09 ended the season as one of the fastest cars on track, just as the board of directors had already decided to withdraw from Formula 1. Thus ended BMW’s four-year stint as a constructor in the top series, with only one victory to its name: Kubica’s win in Canada in 2008.