Tech Analysis: Toro Rosso STR9
Unlike previous years, Red Bull’s sister team has gone bolder and braver for 2014. Adopting its bigger sibling’s Renault powertrain and a whole new aerodynamic philosophy, Toro Rosso are looking to project themselves back up the field and give Red Bull junior drivers Jean-Eric Vergne and Daniil Kvyat a worthy car to display their talent in.
Arguably the least attractive of the 2014 bunch, the STR9 adopts the “finger” nose for this coming season. Having already admitted that they explored the Lotus “tusks” nose concept during development, they chose the less aesthetically pleasing solution as a more conservative bet.
Apart from the extruding appendage, the upper part of the nose is ridged slightly where the almost-triangular cross section meets the flat-profiled wedge. Although only a small detail, the ridge should smoothen the transition of the airflow between the two surfaces and keep it attached to the boywork for longer.
Further aiding this process is the declination of the chassis from the cockpit right down to the nose tip itself. Like the McLaren that was launched last week, Toro Rosso have also decided against a stepped chassis. This is also a conservative decision, although the nose design should negate some of the lost performance of a lower chassis.
The tip of the nose, like many of the cars this season, includes a fine mesh grill to provide the driver or electronics systems with a small amount of cooling.
The front wing is currently a launch-spec version so we can expect to see further refinements before we head to Australia. Having said this, the STR9 features the new addition of a slot on the inboard area of the upper flap element. The slots, in conjunction with the main plane below, shed vortices to block the tyre wake from impinging the leading edge of the floor.
The sinuous, yet simplistic, cascade elements give us some indication of what the team are trying to achieve regarding the direction of airflow around the front tyre. Shallower sections are merely to guide airflow onwards whereas the deeper areas shift air towards the upper regions of the tyre.
Having switched to Renault power for 2014, the launch of the STR9 gave us the opportunity to have a first glimpse of the cooling requirements for the French-made power unit.
The intakes are substantially larger than some of its rivals, although they are quite heavily undercut. They then taper dramatically inwards towards the centre of the car, which bare a remarkable resemblance to last year’s Red Bull. These are flanked by some basic vertical airflow conditioners that will no doubt receive some treatment as the testing period goes on.
Ahead of the sidepod intakes, there is little-to-no extra detailing as yet, although the mirrors – like in 2013 – are mounted via a horiztonal turning vane. The team utilised transparent vortex generators on top of the car last year so perhaps they will re-install these after some initial mileage.
Cooling apertures at the back of the car exit before the rear suspension mounts as well as further outlets that open up around the gearbox. Doubling up the outlets reduces drag as there’s less blockage around the central section of the car, although it is worth noting just how much cooling the Renault power unit appears to require.
Further evidence of this statement is confirmed by the design of the STR9′s airbox, although this could just be a unique feature of their car design rather than the Renault power unit’s heat inefficiency.
The top inlet is likely to feed the turbo unit and gearbox oil cooling facility, with the lower, larger inlet providing another entry for general cooling of the engine itself. The driver’s helmet will create a little blockage, although the aerodynamic aids that are plastered above the head and on the front will help air reach this lower inlet.
The reason why this could be a feature unique to Toro Rosso is due to their tightly wrapped sidepods. Now that we have seen the Red Bull RB10 and Caterham CT05, this could well be a case of opting for a different cooling strategy to maximise the potential of a smaller sidepod rather than the Renault power unit producing a heat surplus.
Remaining virtually unchanged, the rear wing received only a few subtle changes to accommodate for this season’s regulations. Once again it was interesting to note that it was attached to the top of the diffuser rather than via a central pylon. It is intriguing that the smaller teams have gone for the aforementioned option and the top teams voting for a pylon.
There for all the preying media eyes to see was the Y100, Monkey Seat winglet. Its curved profile is aimed at aligning itself with the exhaust plume, creating an upwash effect against the rear wing. This is complimented by the small ‘u’ shape made to the rear crash structure, preventing the plume from being disrupted as it exits.
Long endplates attached to the side of the winglet suggest that they want to keep the plume as straight as possible as it exits the pipe, making the upwash effect more efficient.
Images courtesy of Octane Photographic and Toro Rosso