Toro Rosso STR8

Whilst James Key is the technical director at Toro Rosso the Chief Designer is Luca Furbatto, at the launch of the STR7 he reviewed the cars design.

“In pre-season testing last year, we were able to get a first look at the strengths and limitations of the STR7. It was clear from the start that we had some issues with the weight distribution of the car and we were not able to effectively cover the entire weight distribution range, as controlled by the FIA regulations. This therefore became a point we wanted to rectify with STR8. Another fact to emerge from initial testing, was that the car appeared to be more compliant in terms of laptime sensitive compliances, when compared to other cars I have worked on and that was another point we wanted to rectify with this year’s car. A further key point was that I wanted to create a platform for aerodynamic development of the car. The rear end of the STR7 was effectively derived from the previous model, the STR6 and I felt the rear could be made much slimmer and more compact and that was another area we focussed on in designing STR8. We sought to give a mechanical infrastructure to the aerodynamic department which would be a good platform for their development work.

The project began in March 2012 and we started with the rear end of the car- gearbox, hydraulics and rear suspension – because the production time and the testing required for these components is very extensive. We were able to issue the drawings for the gearbox parts in July and, as we prepare for our first track test, our dyno testing suggests we have a strong and reliable gearbox. The second phase was to integrate within the gearbox design a revised rear suspension, with the emphasis on making it more aerodynamic, in order to generate more downforce. When designing the chassis, again, providing a platform for aerodynamic development was an important consideration.

In terms of suspension layout, kinematics and internals those are again brand new. The STR7 was very limited in terms of set-up possibilities and with STR8 we opened up this aspect substantially, adding devices and features not present on previous STR cars. This should allow race engineers and drivers to perfect the handling and ride behaviour of the new car.

As for the aerodynamic concept of the car, this too has changed fundamentally from the previous year. Development was rather limited in 2012 and this was because the STR7’s distinctive sidepod design, although initially looking quite good, later proved difficult to develop, so that we reached a plateau during the season. We therefore decided in early August to go down another route and at the same time took the opportunity to change the cooling layout of the car and so, on STR8 the radiators are much lower. This also allows us to drop the deck of the sidepods more aggressively. These changes mean the car actually looks quite conventional, while still retaining some of the features of STR7, because even if it is a new concept, it is an evolution based on the current regulations. We are also planning an aggressive development programme for the first part of the season, based around a very narrow rear end and low exhausts.

From a weight distribution point of view, we believe that thanks to the architectural shape of STR8, we should be able to explore all the opportunities within the weight distribution range allowed in the rules. Initial indications on suspension compliance are encouraging and in terms of aero development, we are in better shape than at the end of last season and another positive step is that the rate of development is increasing, indicating there is further potential to move forward in terms of downforce.

Operationally, we continue to work with a wind tunnel and part of our aerodynamic staff based in Bicester in the UK. Over the past 12 months there has been a big improvement in communication between the various departments and we have invested in new technologies on this front, so even though we are operating on different sites, effectively it is as though we are working next door to one another. This step up in communication means the new car is better integrated than in the past. I can sum it up by saying that, twelve months ago, when work came through from Bicester, engineers in Faenza felt on the receiving end of something that was designed elsewhere, now it really feels like a co-design from different departments within the same team, which is encouraging for the future, both short and long term.”

At the front of the car it is instantly apparent that the STR8 utilises the optional vanity panel, but unlike on other cars seen so far the panel gap can be seen on the side of the car clearly showing where it runs (above).

The roll hoop of the car is a direct carry over of the STR7 concept, most of the aerodynamic elements of the car need much more development according to Key. “What you see here is just a car, the mechanical elements are pretty much there but there is a huge amount of change to come on the aerodynamic side.” Compare the STR7 (below) with the STR8 and you notice that the extra cooling duct on the ST7 is absent on the 2013 car. This means that the Toro Rosso engineers have found another way to cool key components.
At the rear of the car the pull rod suspension is retained though in revised form, the sidepod undercut is nowhere near as drastic as that of the 2012 car. Note the opening in the floor at the rear of the undercut The front brake ducts are very interesting, they seem to draw air in low on the inner panel below the outer flap of the front wing. Pushrod front suspension is retained.
The diffuser was covered at the launch but the serrated lower part of the endplate was still evident note the vented section the the red coloured portion of the endplate.
The exhaust on the STR8 (below) is very conventional for a 2013 car, though the bodywork ahead of it seems to hold more interest, worth further investigation during the test session at Jerez

TEST 01: JEREZ
Chassis: STR8-01
“We can be satisfied with these first four days of testing. The car showed reasonable potential and reliability was not too bad, which meant we completed a respectable number of laps, first with Daniel and then with Jean-Eric. In contrast to this test last year, when they were rookies, both of them knew what to do and what to expect. However, the two of them had to get used to working with new race engineers and that part of the test also progressed well. There is absolutely no point in talking about car performance at this stage. The most important task we face now is to analyse everything we have done over the past four days in Jerez, so as to decide what our priorities will be in Barcelona in eleven days’ time, when we start the second test session.” – Franz Tots

That aero work partly used flow vis on the floor of the car which is significantly different to the design of the STR7 which had a much larger undercut (below)

Luca Furbatto explains why the change was made “using the big undercut or double floor made the car very difficult to develop aerodynamically and even though we had lots of upgrades the car did not respond. We felt that the concept had reached a plateau of aerodynamic performance so it was time for a change.”

One of the biggest areas of change for Toro Rosso is at the back of the car where an all new transmission is fitted as the result of the adoption of a new suspension concept.
“The gearbox is still built by us, it has a carbon bell housing and and an aluminium main case at the back its very narrow and the rear end of the car is very tiny. Its a totally different gearbox to the STR7, it has new internals, because of the suspension concept we have gone for we could not use last years main case” Furbatto reveals.

“In terms of suspension the STR7 was very limited in terms of the number of systems you could use, so when we decided to redesign the car we decided to reintroduce back some of those systems. For example the STR7 did not have anti roll bars this car does as well as a number of other systems common in modern F1 cars, and we have looked at Interlinked suspension. Because the suspension was very limited in terms of tuning the car was very peaky which made it hard for the drivers. This year they have much more chance to change the balance of the car which should give them more confidence.”

TEST 02: BARCELONA
Chassis: STR8-01

A nice look at the rear of the STR8 with liberal application of flow vis dye. Also note the number of diffuser strakes.

TEST 03: BARCELONA
Chassis: STR8-03

The third and final test in Barcelona began the same way that the previous one ended, which is to say, in the rain, which meant that slick tyres were only viable in the final hour of today’s track time.
Therefore the STR8 spent most of the first day on rain tyres and intermediates, a useful exercise as Pirelli has made changes to its wet weather tyres for this year. However, in between the showers, the team did manage some aerodynamic work, including the evaluation of a few new components. The day ended with two satisfactory runs on dry tyres.

The car was fitted with a revised rear wing featuring a vented rear wing end plate. Following the lead set by Williams.  Compare the new wing (above) with the old (below)
A nice look at the aerodynamic detailing inside the sidepod mounted turning vane, also note the small flow conditioners around the wing mirror (below).

RACE 01: ALBERT PARK, MELBOURNE, AUSTRALIA
Car: 18
Chassis: STR8-03
Result: 12th
Car: 19
Chassis: STR8-01
Result: DNF (exhaust)

The STR8 was fitted with a new nose at Melbourne, in testing the noses ‘vanity panel’ was held on with bolts but at the first race it appeared to be bonded on.
A broken exhaust eliminated one car from the race.

RACE 02: SEPANG, SELANGOR, MALAYSIA
Car: 18
Chassis: STR8-03
Result: 10th
Car: 19
Chassis: STR8-01
Result: DNF (exhaust)

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