The tech behind MotoGP's controversial 'swinglets'

In the wake of Ducati's controversial 'tyre cooler' winglet - or 'swinglet', as it's become affectionately known - being given the thumbs-up by MotoGP technical director Danny Aldridge, the floodgates have cracked open ever-so-slightly. Other manufacturers are creeping in with their own swingarm appendages.

And as Aldridge has been reassured, the important thing to note is that they're definitely not there to create downforce - not at all. There might be an inadvertent by-product of a few Newtons of downforce here and there, but they're actually there to cool tyres, or improve the stiffness of the swingarm. Apparently.

Honda got its own design homologated during the Argentinian Grand Prix weekend before it made its first on-track appearance in the United States, while Yamaha and Aprilia brought winglets last weekend's Spanish GP - where Suzuki also tried its own design in the post-race test. KTM also tried one out in practice at the US GP, which means that all manufacturer operations have at least dabbled with this year's most contentious piece of kit.

Ducati's design derived some inspiration from Yamaha's rain deflector used last season in wet conditions, and consists of three winglets of seemingly equal chord lengths. At its simplest, this scoops the airflow upwards and into the space behind the bottom fairing of the bike. There, Ducati has managed to argue that cooler airflow is able to be brought into the face of the tyre and help reduce the overall temperatures.

Realistically, the shape of the winglets is also able to produce more downforce on the swingarm, which is ultimately going to improve traction under acceleration. If the teams can derive some performance from that effect, all the while convincing the MotoGP technical team that its primary purpose is for something else, then surely it's a worthwhile pursuit.

Ducati rocked the aero formula with its own brand of front fairing-mounted spoilers and has done so again

Aprilia was unhappy following the Qatar season opener, having had a request to run something similar to Ducati turned down by Aldridge before the season began. It eventually brought something to the party at Jerez, working along a similar ethos but with a different configuration.

This too features three elements, but the first features a much longer chord to more deliberately scoop up airflow from underneath the bike and press the swingarm down onto the road. The two further elements have short chords to limit any separation in this area.

Honda and Yamaha elected not to run their respective designs in the race at Jerez, although they tested them out in practice in Spain. Yamaha's looks significantly more anteater-like compared to the others - tapering in dramatically at the leading edge. It seems as though the 'intended' purpose is much different, more closely resembling the rain deflector in its shape.

There's also a small semi-circular cut-out at the trailing edge of the first element, perhaps looking to give the low-pressure air passing underneath a bit more opportunity to expand. The shape also seems to be conducive to developing that low pressure zone underneath, forcing the airflow underneath into a nozzle - which then diffuses into a larger area.

Yamaha's interpretation is a bit of a halfway-house design, taking the benefits of last year's deflector but also generating more downforce at the swingarm axis. It's not as overt as the other designs, especially as the short-span leading edge will limit the amount of downforce produced, but it should offer more options if there are wet track conditions.

Although the Honda winglet has hit the circuit very briefly, its fleeting appearance in Argentina was fraught with controversy - as if to prove a point to Dorna and the FIM over the fickleness of the regulations' intent.

Submitted for homologation with the express purpose of producing downforce, the design was not permitted. Honda then tried again, this time with supporting documentation that the design's primary purpose lay elsewhere - namely, stiffening the swingarm. This was given approval, and was later bolted onto the bike to run.

Ducati's opposition are falling over themselves to swing the pendulum back in their favour

It returned in practice at Jerez, with Jorge Lorenzo giving it some mileage as Honda needed to understand its effect on the bike. It's far more pragmatic than the other designs out there; a single-element piece drops down in front of the rear tyre, and will undoubtedly generate a lot less downforce as a result.

Clearly, it's not something Honda has prioritised as much as its rivals; the RC213V is probably the bike with the best mechanical grip out there - especially in the hands of Marc Marquez - and as such doesn't rely so much on smaller aerodynamic appendages. This applies either during turn-in, lean or in getting the power down.

Meanwhile Ducati, with its more powerful desmodromic-valve V4 engine, has more grunt to channel through its rear wheel, and stability under acceleration on the exit of the corners is vital. So, there's a greater benefit for the squad, which can then make use of its bombastic potential on the straights.

Having finally delivered a bike with race win potential for the first time since 2016, Suzuki has now joined the 'swinglet' movement - and, surely, this design may create some legal consternation.

While the other winglets are somewhat subtle, Suzuki has brought a scoop that's lower and further forward - with a flat first element with a long chord. Running this close to the ground means the wing will undoubtedly derive some degree of ground effect - creating some suction to pull the swingarm closer to the track surface. The following elements are of decreasing chord length, and the slot gap between them and the main element suggest a level of incongruence here.

Those two smaller elements develop a strong upwash structure, shunting any flow from the bottom of the lower fairing upwards and squeezing out some more downforce - and also protects the tyre from churning that airflow into a mass of turbulence.

Though the device made its debut in Monday's test, Alex Rins only got a smidgen of running with the concept - before it unceremoniously fell off during an off-track excursion.

Suzuki's design seems like a far more obvious attempt at drawing on the aerodynamic gains on offer, rather than tempering its concept with the smokescreen of tyre cooling.

On the other hand, the lesser-spotted KTM interpretation (below) is almost a carbon copy of Yamaha's rain deflector, with no slots or wing structures to 'double up' as a tyre cooler. It featured in practice at Austin, and there will be some certain downforce-producing properties. But as proven at the Red Bull Ring last year, the tyre is far less susceptible to the rain spray emerging from the stern.

Although some of the 'swinglet' designs are yet to hit the circuit in race trim, a can of worms has been well and truly opened within MotoGP.

Just as Ducati rocked the aero formula with its own brand of front fairing-mounted spoilers, it has done so again. Through a clever circumvention of the rules, it has kickstarted another aero war - and its opposition are falling over themselves to swing the pendulum back in their favour.