Following a technical directive from the FIA in Monaco which was to come into force for the Canadian Grand Prix, wing flexing became the topic of conversation yet again. But, what actually is wing flexing and why is it so important in Formula One?
To state the obvious, wing flexing is initially quite self explanatory. As a Formula One car accelerates and its speed is increasing, so too does the aero load which the front wing especially is always in contact with. Moveable aerodynamics are banned in Formula One but it does not stop teams from finding any loopholes around such a rule.
In a similar way to how DRS works, a teams desire is to make their car as slippery (less drag) as possible in a straight line to aid rate of acceleration and top speed. DRS is a legal moveable aerodynamic device that, when activated, opens up the upper element of the rear wing in order to reduce drag, hence the name Drag Reduction System. If it were possible and legal, teams up and down the grid would exploit this system on nearly every piece of drag inducing rear body work. This is strictly illegal however so, instead, a common loophole has been used by teams in ordered to achieve a similar desired effect. This is where wing flexing has its part to play.
The original test for wing flexing was a very simple test, of loading the endplates (farthest end of the wing from the tip of the nose), with none of the front wing flaps explicitly highlighted in the rules stated in article 3.17.1 of the 2015 F1 Technical Regulations.
“Bodywork may deflect no more than 10mm vertically when a 1000N load is applied vertically to it at points 675mm and 975mm forward of the front wheel centre line and 720mm from the car centre line…”
This test only covers the main plane of the front wing which has a much weaker effect aerodynamically in terms of flexing, in comparison to the multiple elements of flaps we see the teams running on 2015 cars front wings. This has meant teams have been able to exploit the lack of load testing on the front wing flap elements.
The best way to put the concept into layman’s terms is if you’ve put your hand outside of a car window when travelling at 50/60 mph If you put your hand in position where your palm faces the direction you’re travelling in, you’d be creating a substantial amount of drag compared to placing your hand flat (palm facing the road surface). The same is directly true with front wing elements, except for the fact when in a drag inducing position, these wing elements are shaped in such a way to produce downforce which drag is an inherent by product of. However, little downforce is required – most commonly on straights at high speeds- in order to produce faster acceleration and a higher top speed, however downforce is required initially to provide traction at the rear otherwise there’d be no grip when power is applied. To overcome this, the wing elements are designed and built to flex (effectively pushed down by the aero loading) and have a less steep angle, making them produce less downforce and therefore drag. Once a car is in deceleration, the aero loading becomes weaker and so the flap elements close to their original position as overall speed decreases.
This does however place such elements into a grey area, as to whether or not they are indeed moveable aerodynamic devices, which are of course illegal. In order to clear this up and provide a clearer ruling whilst clamping down on the clever work around, the FIA issued a technical directive. The directive says:
“The FIA intends to introduce a further load/deflection test on parts of the bodywork forward of the front wheels.
“A 60N point load will be applied to any part of the trailing edge of any front wing flap, the load will be applied normal to the flap at the relevant point.
“Under the load, the deflection may not exceed 3mm when measured vertically at the trailing edge.”
This means the test will simulate the loads the wing flap would be exposed to when travelling at a considerable rate, and therefore restrict how much the trailing edge of any flap could “flex”, which in turn limits how much drag could be saved when front wing flap elements flex. To better understand this, when watching a Grand Prix, keep an eye out for when pictures from the nose mounted cameras are broadcast and you should have a clear view of the front wing flaps flexing as speed and aero loading increases, and then start to return to their original position when under braking (reducing speed and aero loading).