F1 2014 tech: Aero controversy

Formula 1's aerodynamic regulations for 2014 are far simpler than the powertrain rules, but are inciting just as much controversy.

A few simple dimensional changes are all that have been regulated: a lower nose, a narrower front wing and a single exhaust pipe.

But, at a stroke, these few adjustments have completely changed the flow structure around the car and have set the designers a huge challenge to regain the lost downforce.

And there's also, as fans have loudly noted, a major aesthetic implication...

FRONT AERO

Although not a major performance factor, the changes around the front of the cars will draw most comment.

Firstly the nose tip is to be lowered, from a maximum height of 55cm down to just 18.5cm above the car's floor.

This change, allied to a cross section of the nose tip, was introduced to prevent a flip-over accident where the nose of a following car hits the rear tyre of a leading car, such as we saw with Mark Webber when he vaulted Heikki Kovalainen in Valencia in 2010.

Additionally, the front bulkhead, where the nosecone mounts to the chassis, has also been lowered from its maximum height of 62.5cm to 52.5cm.

Lastly, the front wing has been narrowed from 180cm down to 165cm to reduce its effectiveness. The neutral middle 50cm section of wing is still being enforced.

Collectively, these regulations should have reintroduced the low swept noses of the early 2000s, but the regulations are strewn with loopholes and dispensations.

Teams didn't want the front end of the monocoque lowered too far, as it would enforce an all new suspension set-up, so the bulk of the raised section of monocoque can still be as high as under the previous rules (62.5cm) and only the front face has to be lowered to the new height.

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The nose-tip rules, while well-meaning, were loosely worded and the mismatch of a nose tip being just some 10 per cent of the cross section of the front of the chassis meant teams would want to make the most of the airflow under the raised chassis.

What we have ended up with is a compromise design where teams are meeting the wording of the rules, but contorting the nose structure for aerodynamic benefit, with unattractive results.

There will be alternatives, but the new rules will result in these odd 'finger' shaped noses. These designs meet the minimum nose-tip dimensions with a finger-like extension from the wedge-shaped upper nose.

The finger presents the minimal possible obstruction to the airflow, while the larger upper nose will help direct airflow under the chassis to feed the underfloor for more downforce.

Within this finger-shaped concept there will be variables, some teams will mount the wing to the finger extension and part of the upper shape will simply be a vanity panel used to create the aerodynamic shape. Caterham has been seen to crash-test just such a design.

Other teams will make the upper shape structural and mount the wing to it on larger pylons. This may end up being a heavier nose, but it will give some aero benefits by using the wing mounts as turning vanes, which has been a trend for the past few years using oversize pylons.

As the rules are vague around the shape of the structure, it's possible some teams will push the limits of legality with some extreme shaped structures. Ideas like McLaren's pre-2012 snow plough or exaggerated versions of last year's under-nose chins could be exploited to meet the nose-tip requirement and still be legal.

It will be a compromise to see how slim the inner structure of the nose and finger can be, as the crash test needs to be met.

The slimmer the structure arguably the heavier it will need to be to meet the impact tests. With teams struggling to meet the new 690kg minimum weight, less aerodynamic but lighter noses may be needed.

It's entirely possible teams may race several different nose designs tailored to the development path and/or the circuit's demands.

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Where the nose meets the chassis, what is known as the front or A-A bulkhead, can also be exploited in a way the rules didn't initially consider.

As mentioned, this needs to be lower at just 52.5cm in height, but the teams want as much space as possible under the raised chassis to funnel the front-wing wake and airflow towards the floor.

What we will end up with is a stepped monocoque, where the bulkhead sits at the correct height, but steps up like last year's noses to 62.5cm all the way back to the cockpit opening.

The resulting step in the top of the nose can be smoothed with a vanity panel, which is still allowed in 2014, while the step under the chassis can be managed partly with the nose shape and the turning vanes that teams tend to fit in this area.

Next year this stepped chassis loophole will be removed by a slope from the bulkhead back to the cockpit being at a mandatory angle.

Meanwhile, the narrower front wing introduces some aerodynamic opportunities. Being some 7.5cm narrower each side, the wing profile itself now ends nearer the inside face of the wheel rather than the outer face as before.

Teams may return to in-wash endplate designs as used prior to 2009 © XPB

Therefore the shape of the endplates could either be a continuation of the out-wash design as adopted post-2009 or a return to the in-wash design that directed the wing wake in between the front wheels, as used before '09.

Both designs have their merits. The reduced downforce at the back of the car created by the lack of exhaust blowing and smaller rear wing do not require so much downforce from the front wing to balance the car.

So a narrower front wing and in-wash design makes some sense, as it will keep the front wing's wake inboard, passing between the front wheels.

But the front wing's function is only partly for directly creating downforce. The endplate shape and the cascade winglets above the front wing are all positioned to offset the turbulence created by the front wheel.

By managing the tyres' wake, drag can be reduced and also kept away from the car's rear end, where it would wreck the diffuser and rear performance.

It's likely that teams would rather aggressively turn the airflow outboard of the front wheel to keep this turbulence under control, than turn the flow in between the front wheels.

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SIDEPODS

Moving further along to the mid-section of the car, the impact on aerodynamic design is more influenced by the engine, although new side-impact protection is also now mandated.

Firstly the turbocharger on the engine needs a supply of air. The rules allow for up to two forward facing inlets mounted a minimum of 20cm above the floor.

The 1980s-style snorkels feeding through the sidepods would not be suited to the current sidepod regulations, nor the single centrally mounted turbo. There could be aerodynamic benefit in moving the inlets away from the conventional rollhoop area, but it seems that most teams will retain a rounded rollhoop inlet and perhaps leave more extreme ideas for another year.

Side impact structures have been standardised, altering the sidepod area

Within the sidepods themselves the shape will be dictated by the new side-impact protection, the increased cooling demand from the engine and the lack of Coanda exhaust blowing.

It's clearly going to be the case that the sidepods will be larger. Starting at the front the wider side-impact spars will prevent super-narrow-fronted sidepods as on the 2013 Sauber. Then the sidepods need to house a huge intercooler to cool the air compressed by the turbo before it goes into the engine, as well as larger radiators for the two types of ERS.

Luckily, the engine itself has a reduced heat output, so the natural arrangement will be for one sidepod to be full of turbo intercooler, the other sidepod full of oil and water radiators for the power unit. Although the amount of cooling area will be large, the heat exchangers are likely to extend as far back as the engine.

Once the air has passed through the coolers it needs to be vented out of the back of the car. The usual route through a large central outlet may be obstructed by the turbocharger, so outlets around the gearbox are going to be needed, at least for the first flyaway races, which are in hot climates.

Of course the narrowness of the Coke-bottle shape of the sidepod aids airflow to the diffuser, but this shaping has been masked by the bulged Coanda exhaust outlets for the past two years. As the exhausts now feed from the engine up and around to the turbo, these bulges will be extraneous.

Also, the rules now demand a single central exhaust outlet, exiting behind the rear axle line, so the exhaust can no longer blow the diffuser area.

Since exhaust-blown diffusers were re-introduced by Red Bull in 2010, they have reduced lap times by over a second. Their loss will be deeply felt by the aerodynamic departments.

The new high and rearward exhaust position holds little possibility for usefully blowing the diffuser. An extreme-shaped rear crash structure could just possibly blow the central trailing edge of the diffuser, but the rewards for this may not be great enough.

It's expected the teams will blow the exhaust under a 'monkey seat' winglet to gain some upwash effect from the limited energy the exhaust now has.

Recouping the blown-diffuser effect with just freestream airflow will be limited, though small fences and vortex generators may well appear around the rear-tyre cut outs.

Raised sections towards the rear, like Newey's 2009 Red Bull solution, will aid airflow © XPB

In 2009 Adrian Newey used coved, scoop-like sections either side of the diffuser to set up a sealing airflow. These may well return, but any means to seal the edges of the diffuser are likely to be of limited benefit.

As teams can't blow the edges of the diffuser to seal the gap from leaking, the extreme raked set-ups with high rear rideheights are likely to be lost too.

We should see cars with rather less than the 10cm+ rear rideheights of the 2013 machines.

If teams can't blow the edges of the diffuser, then other means to make the diffuser more effective need to be sought.

One method had been re-purposed for aiding the Coanda exhausts. Vanes and fins on the fronts of the sidepods were used to create a vortex passing down over the sidepods. It was Lotus that first used these before it adopted Coanda. The team found that the vortex formed at the front of the sidepod could be trained down to the diffuser trailing edge and raise pressure above the diffuser for more downforce.

Using this technique, teams are likely to still employ the various devices on the front of the sidepods and create a ramped sidepod top that leads down to the diffuser.

This method may suffer the same problem as the early ramped Coanda sidepods, where the airflow passing around the sidepod can conflict with the vortices.

Red Bull's solution to this issue in 2012 was to direct the flow passing around the sidepod into a tunnel and pass it under the ramped section.

So it's possible some teams might continue to have ramped and tunnelled sidepods despite there being no exhaust flow over the sidepod, but use the set-up to maximise the sidepod-top vortices.

REAR WING

In a similar vein to the changes elsewhere around the car, the rear wing regulations feature small but far-reaching adjustments.

Changes to the rear wing will significantly reduce downforce

The 2014 rear-wing assembly loses the lower rear wing known as the 'beam wing'. Although only a moderately sized, single-element aerofoil, the beam wing worked as much to connect the up-wash from the diffuser to that of the top rear wing as it did to produce downforce.

Thus the loss in rear downforce is compounded by the loss of the airflow control at the back of the car, as well as the loss in downforce from the beam wing.

Making up for the absence of the beam will not be easy. There is limited space ahead of the rear wing to mount new bodywork and the rear wishbones are limited to near-neutral aero profiles.

One solution is to mount a small wing low down ahead of the rear wing in a space that already exists in the regulations and has been exploited before. This would be of some benefit, but not a major gain.

Other options may be enclosing the rear suspension in an aerofoil-profiled shroud, which sits in the small area below the other rear wing and sidepod restrictions.

As the shroud does not move with the suspension, it is counted as bodywork and can be shaped to provide some up-wash, replacing the beam wing. Any such solution is likely to be contentious.

Otherwise changes around the back of the car are limited to the top rear wing being some 5cm shallower. The gap between the rear wing flap and main plane when DRS is open has increased from 5cm to 6.5cm, which means the flap can be larger for more downforce with the same DRS effect.

Wider monkey seats will become commonplace this season © XPB

Below this the central winglet, known as the monkey seat, has been widened from 15cm to 20cm to allow the exhaust to pass beneath it. This winglet usefully serves to create upwash, much as the beam wing did, so with the loss of the beam wing, these winglets are likely to far more commonplace in 2014.

Lastly the loss of the beam wing means the usual means of mounting for the rear wing has gone, too. It is possible to use one or two vertical pillars to the support the top rear wing.

However these have to mount beneath the rear wing and thus the wing loses some of its effectiveness, which is the reason these pillars were dropped a few years ago.

It's possible to reinforce the diffuser and mount the rear wing endplates directly to it. This rids the wing of the obstructive pillars, but will be a heavier solution than the structurally efficient pillars. As with nose designs, teams may choose their option depending on how close to the weight limit they are.