The Toro Rosso is one of a number of cars this season which was designed without certainty about which power unit would be installed in the rear of it. In the end it was decided that a 2015 specification Ferrari would be used after protracted negotiations. This will have had an impact on the design of a number of components including the rear of the monocoque and the design of the transmission (the car uses a bespoke casing fitted with Red Bull/Xtrac internals).
“When it comes to this year’s chassis, we wanted to concentrate on improving the low-speed cornering capability of the car. Last year’s car was a big step forward and particularly good in medium and high speed corners, but we have felt our lower speed performance was not as competitive as we would like” James Key reveals.
“That has been one area which has led to a change in approach for our 2016 car. In other aspects we have an evolution of strong areas of development from 2015, or a completely new direction where better ideas have formed or we need to address other known weaknesses.”
The design continues a number of recent James Key lead STR designs and most notably that includes a large airbox with cooling ducts. It seems that both Mercedes and STR arrived at similar concepts during the development of the cars over the winter.
This sees the main air intake split into three segments (above) with the central segment feeding combustion air to the Ferrari V6 while the segments either side feed cooling air to other components, possibly the charge air cooler (or coolers!)
Unlike the Mercedes it seems that the whole outer shape of the airbox duct is structural with the dividers in the duct acting as roll hoop bracing. Under the main hoop there is a small central support (above).
The nose of the Toro Rosso is particularly interesting, while at first glance it is visually quite similar to the designs found on a number of cars in detail a few interesting features become apparent.
The nose features four NACA style ducts two each side (above). These appear to be development of the ducted noses used by a number of teams for some years. It seems likely that the larger NACA duct feeds an outlet at the trailing edge of the nose itself.
Above the bellcranks for the front dampers there is a small lump on the bodywork, this likely shrouds some suspension parts (possibly the third element), a number of other cars on the grid such as the Haas and Red Bull has similar features.
Although the Toro Rosso uses the 2015 Ferrari engine it still has to comply with the new rules relating to wastegate design. As such the STR features twin wastegate exit pipes either side of the main exhaust exit, Ferrari having reworked the wastegate arrangement specifcically so that Toro Rosso could use the old spec unit this year. The rear wing support passes through the tailpipe as it did on the 2015 car – a concept copied by some other teams in 2016.
The leading edge of the rear wing endplate is noteworthy as the usual vents are open ended.
The rear suspension of the STR remains a pull rod layout with the pull rod passing through the rear bodywork as it did on the 2015 design. Note the blended lower wishbone.
A neat detail on the STR, the sharkfin is attached to the rear wing pylon which in turn has a winglet attached to the rear. Note the rear wing pylon passing through the tailpipe.
On closer inspection the rear wing vents are linked together at the leading edge, but with very small bits of material
The STR features a Mercedes style blended lower wishbone a concept which is not ideal in terms of suspension design but brings an aerodynamic gain.
A look from above at the outlet for the vented nose. Note the bump above the inboard front suspension components.
The rear floor is still a complex and crucial area for all F1 cars, here some of the cut outs and turning vanes on the STR can be seen
Detail of the rear corner of the STR, note the way the pull rod passes through the sidepod.
The STR is fitted with a late 2015 specification Ferrari power unit, the installation of which is apparently not fully optimal.
“Our directions for the STR11 were well established in August last year but when the engine change decision was made we had to put a large part of the project effectively on hold” James Key explains. “This did not stop us developing, but did increasingly constrain the flexibility we had to design-in what was at that stage an unknown Power Unit. When the agreement was finally given the go ahead in late October last year and we were able to discuss details with our partners at Ferrari it was clear that the task ahead was significant, we made life more difficult for ourselves too by specifically setting out a plan to fit the new Power Unit into the existing packaging space we had to minimise any installation performance deficit on the rest of the car as best we could.
Power units form a very large part of current cars architecture as implications go well beyond the space between the chassis and gearbox. There are also the other critical systems – cooling circuits, electrical installation, gearbox internals design, exhaust systems and specification etc which all need to be covered and redesigned, and all of this affects everything from the cockpit to the rear suspension.”
Another look at the NACA ducts on the nose of the STR11. A very neat vented nose solution.
The front bulkhead of the C35 with the nose removed and the steering rack clear to see, note the lack of master cylinders.
A look at the sidepod of the STR11, note how small the main duct is. Also visible are the upper and lower side impact structures.
The front brake setup on the STR11 with the Brembo caliper mounted at the rear of the disc.
The carbon fibre transmission casing on the the STR11 is bespoke but it uses Red Bull/Xtrac internals. With a very late switch to a Ferrari power unit manufacturing this ‘box must have been very difficult to finalise and produce in time.
The Toro Rosso uses last years Ferrari power unit with very few modifications. The turbocharger has been reworked to have a separate wastegate exit. Also in these images it appears that the thermal barrier on the exhaust headers has been revised.
At Sochi the STR ran a revised rear wing end plate with fewer elements on the upper rear wing end plate. The two elements remain largely exposed. The earlier version with more elements reappeared in Spain
The Toro Rosso wheel rims featured a rather rough carbon fibre cover during pit stop practice. This prevents damage to the rather expensive and bespoke wheels used on the cars.
The front brake setup with the disc removed, the Brembo caliper is clear to see mounted at the rear of the (absent) disc.
At Sochi the Toro Rosso sported an asymmetric cooling layout – note how the left hand cooler exit is much larger than the right hand side one. It ran a similar setup in China also. Compare with the layout used in Melbourne.
A look at the underside of the STR11’s front wing and nose, note the ducting.
