RED BULL RB6
eplaced by DRS for 2011 one innovation was present on the Red Bull RB6, which is discussed in the new ‘owner’s manual’ from Haynes Publishing. The following is an extract from it. The f-duct was an innovation
R
for 2010, first developed by McLaren. The system appeared on the RB6 for the first time at the Turkish Grand Prix in May. Adrian Newey explains the system’s origins: ‘Really it was experimentation. The f-duct technology actually stems from the Cold War in the 1950s, when the Americans were worried the Russians would develop ways of jamming the electronics on their fighter aircraft, and so they developed, effectively, a pneumatic version of electronics.
A schematic showing the key components of the RB6 f-duct
So an f-duct is actually a transistor, but using air rather than electricity.’ Although a high level of
rear downforce is desirable under certain circumstances (on slower, low-grip circuits and when cornering), on a high- speed straight ultimate speed is compromised by a high level of downforce, as a high downforce wing produces a high level of drag. The idea behind the f-duct
was to provide the car with a straight line speed boost by temporarily reducing the drag created by the rear wing. Two elements are used on the rear wing to prevent the wing from stalling, by creating a slot to allow high-pressure air to bleed through. So, if this effect can be
reversed, and the wing can be deliberately stalled, drag (and downforce) will be reduced and straight-line speed increased. Of course, this is only desirable in a situation when downforce is not so important – such as on a long straight – so the effect needs to be temporary, or ‘switchable’.
a rear wing design that stalled under the influence of the f-duct, but did not compromise downforce when the system was not in operation. The RB6’s system took time to develop, and initially the air from the f-duct was blown over the wing upper element. A reasonable
the f-duct technology
actually stems from the Cold War in the 1950s
An attempt to achieve this
effect was first made during the 2004 season, when several teams used ‘flexible’ rear wings, which allowed the slot between the two elements to close up under high load (for instance, on a high-speed straight), stalling the wing. From the 2006 Canadian Grand Prix, by regulation rigid separators had to be fitted between the wing elements to prevent them
from flexing. The f-duct achieved the same
The driver operates the f-duct by placing his left hand over the snorkel in the cockpit
effect as closing up the slot between the wing elements, by temporarily allowing extra air to flow over one of the elements, causing the airflow to separate from it (flow separation) and hence stall it. It was found that this system could create a top speed increase of up to 4mph. The key to optimising the f-duct system was to develop
stall was achieved, but at the expense of a small reduction in rear wing performance when the system was not being operated. The system was developed and improved during the season and, at the Japanese Grand Prix, a major revision appeared, with the air from the f-duct being blown over the main wing element rather than the upper element. The switching of the airflow
from the lower to the upper duct in the engine cover is being achieved by using a ‘fluid switch’ operated by the driver. The basic method of operation is as follows:
• ‘Control’ air flows into the system ducting through an intake in the right-hand sidepod. In the ‘default’ position, this air flows out through the ‘snorkel’ on the left-hand side of the cockpit. • ‘Stall’ air flows into the ducting from an intake in the bodywork above the driver’s head, above the main engine air intake. In the default position, this air flows out through the outlet in the rear bodywork below the rear wing lower element. • The driver places his hand over the snorkel to activate the system. • The ‘control’ airflow is diverted along the ducting inside the engine cover, where it deflects the ‘stall’ airflow upwards so that it exits through the void in the rear wing upper element (early season) or over the main wing element (late season). The stall airflow creates turbulence at the rear of the wing element, stalling the airflow.
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www.racecar-engineering.com • September 2011
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