Connect with us


Details of F-Duct system



The McLaren have found a intelligent loop hole in the 2010 policy permission them to stall the rear wing at high speed, Racecar looks at how they may have get this, and why it offer an advantage

At what time McLaren’s F-Duct system first introduce in pre-season testing it was hailed by many a a true stroke of genius, a classic illustration of out-thinking the regulations. With the basic idea being that the driver is able to alter the airflow over the rear wing, without infringing regulation 1.1 (below), and in doing so gain a speed benefit on straights.

1.1 Aerodynamic influence : With the exception of the cover

described in Article 6.5.2 (when used in the pit lane), the driver

adjustable bodywork described in Article 3.18 and the ducts described in

Article 11.4, any specific part of the car influencing its aerodynamic

performance :

* Must comply with the rules relating to


* Must be rigidly secured to the entirely sprung part of

the car (rigidly secured means not having any degree of freedom) ;

* Must

remain immobile in relation to the sprung part of the car.

This speed plus appears to have given the team the upper hand at the Shanghai circuit, Racecar decided to examine the theory behind the new system.

Why is the F-Duct helpful?

Basic wing theory

First we need to look at some basic aerodynamic theory regarding wing profiles and lift/drag ratios. At the simplest level a wing generates downforce due to its profile accelerating airflow on its lower surface in relation to the flow over the top surface. If flow is accelerated pressure drops, with the result being a pressure differential between the upper and lower surface of the wing and thus a net downward force, as illustrated below.

Flaps and slot gaps

If the angle of attack of a wing is increased it can ultimately ‘stall’ due to flow separation along the trailing edge, with a resultant loss in downforce and consequently aerodynamic grip.

The above video shows a lift generating wing stalling, however the basic theory is the same for a downforce generating racecar wing.

To get around this problem, dual element or slot-gap wings are used, these allow for some of the high pressure flow from the top surface of the wing to bleed to the lower surface of the wing. This increases the speed of the flow under the wing, increasing downforce and reducing the boundary flow separation. (See below)

If you look at a modern F1 rear wing you can see this concept taken to the extreme, with multi-element wings creating huge amounts of downforce, the downside being a significant drag penalty. However if the flow over the ‘flap’ section of the wing can be stalled, the lift/drag ratio worsens, but the overall result is a massive drop in the coefficient of lift, resulting in a net reduction in drag, hence the benefits in relation to top speed. It should however be noted that it is only stalling the trailing edge flow that is beneficial as opposed to stalling the entire wing.

Early solutions

Previously teams had contrived to create flexible wing sections the allowed the ‘slot gap’ to close up under high aerodynamic loads, once this became evident to the governing bodies it was rapidly outlawed. Wings are now subject to static load tests to ensure that they cannot flex. So if a team were able to achieve a similar effect within the regulations, considerable straight-line performance gains could be made. Racecarcar spoke to a source in F1 to find out exactly how significant these gains could be.

‘If you stall the flap on an F1-wing (in the wind tunnel) then the drag drops enough to calculate that the top-speed of the car could be 3-5kph faster (we did this ten years ago) but the trick is doing it in a way that’s legal (well, not illegal). Wind tunnel engineers can do this by altering the slot-gap geometry and/or changing parts to simulate flexing-on-the-track. It’s very easy to demonstrate in a wind tunnel – just very difficult to engineer it so that it’s not illegal.”

McLaren’s solution

McLaren appear to have found a very neat solution for redirecting the airflow over the rear wing and consequently allowing the flap to stall. Whilst they have been very tight lipped about the system, it is most likely that the conduit from the front to rear of the car has a vent in the cockpit that can be blocked by the drivers left leg, which is not in use on long straights. Blocking the vent could direct enough airflow through the conduit to disrupt the flow over the rear flap and induce a stall. This approach is ingenious for two key reasons:

:By using the drivers leg to direct the flow, the regulations are not contravened regarding movable areodynamic devices.

:By incorporating the design into the monocoque it becomes very difficult for other teams to copy the device, due to the fact monocoques have to be homologated and changes are very expensive to make.

Below are some images of the most probable routing for the system:

(Illustrations by Craig Scarborough)

Additional pair of slot gaps in the upper rear wing element are fed by airflow from the duct that exits from the ‘Shark Fin’ enigne cover.

Photographs of the Mclaren cockpit show a clear channel running alongside the driver.

Illustration of the most likely routing for the duct.

Tags:Sky Broadband & Talk, Sky Broadband and Talk services, Sky Broadband products,Switching to Sky, Sky Talk Line Rental

Latest Results

Latest F1 News

2018 F115 hours ago

Raikkonen move means ‘Sauber is now Ferrari’ – Ecclestone

  Bernie Ecclestone has applauded Kimi Raikkonen’s move to Sauber. Raikkonen, 39, surprised the F1 world by signing up with...

2018 F11 day ago

McLaren split boost Honda progress – Verstappen

Max Verstappen admits he is getting excited about 2019. Recently highly critical of Renault, the Dutchman finished second behind Ferrari’s...

2018 F11 day ago

I’m “very happy” to join Sauber F1 for 2019 – Raikkonen

Kimi Raikkonen says he is “very happy” to join Sauber for 2019, even though he finally ended his winning drought...

2018 F11 day ago

F1 chequered flag rules changed for 2019

F1 has changed a long-standing rule about the iconic chequered flag. In Montreal this year, the end of the Canadian...

2018 F12 days ago

Max made brilliant P2, what a drive from P18 – Red Bull

Max Verstappen took a remarkable drive to second from 18th place on the grid at the United States Grand Prix,...

2018 F12 days ago

Magnussen facing disqualification from US Grand Prix

Kevin Magnussen is facing disqualification from United States Grand Prix after it was detected that the Haas speedy exceeded the...

2018 F12 days ago

Raikkonen troll Hamilton after US Grand Prix win?

Race winner Kimi Raikkonen and second podium finisher Max Verstappen, both asked Lewis Hamilton whether he had still become the...

2018 F12 days ago

Raikkonen wins his first race in 2044 days by claiming US GP

Ferrari speedy Kimi Raikkonen wins US Grand Prix. Its ends his 113-race wait for a top podium. Lewis Hamilton finish...

2018 F12 days ago

How can Lewis Hamilton win the fifth F1 title at the US Grand Prix

Mercedes speedy Lewis Hamilton took a big step near to sealing his fifth F1 world title after securing his Mercedes...

2018 F12 days ago

Verstappen quiet over female-only series

Max Verstappen is keeping his mouth shut about the new female-only open wheeler category. When the ‘W Series’ concept was...

Most Popular is not affiliated with Formula 1, Formula One Management, Formula One Administration, Formula One Licensing BV, Formula One World Championship Ltd or any other organization or entity associated with the official Formula One governing organizations or their shareholders. Copyrighted material used under Fair Use/Fair Comment.

We could use the following leading F1 news sources for stories: SkyF1, BBC F1, Autosport, ESPN F1, FIA Media Center, MotorSport, JamesAllen and others leading authors blog.

All Rights Reserved © 2017 Prime Sport Media