Many teams have complained about the late decision to Halo. Was the problem maybe smaller for Toro Rosso, because you had to change everything anyway?
James Key: [laughs] To a certain extent, yes. When we had the final confirmation of the Honda plan, we had to reschedule anyway. That helped a little. Of course you can argue that you can do it in any case by just pushing the deadlines backwards, but it costs money and you have less time to optimize. You always have a schedule that expects the fastest car with the best optimization time and the best cost. Everything has changed, but that allowed us to easily integrate the Halo into the later chassis deadline. Of course, Halo was also a challenge, but not as big as changing the engine.
You mentioned that the collaboration came too late to be able to bear fruitful factory team results. But are there any details on the engine that they could influence?
James Key: There are a few small things that Honda has been able to change for us, but also some things we've changed for them. We have already talked about developmental steps that work for both sides. They have already been able to do some work and more over the course of the season. Our approach with them is to give them the flexibility they need to focus on engine development. We do not want to give them too many restrictions through the chassis. As a result, there were no late changes for her, which was very important. We'd better make some compromises, but then benefit from a better engine. That's an important balance to find.
What was the main reason for the new design of the rear axle: aerodynamics or kinematics?
James Key: Slightly more aerodynamics. But we realized last year that we were not too far away with our philosophy. Of course, the suspension has to be adapted to the tires and this is a little guessing game despite the Abu Dhabi test. Nevertheless, we did not feel that we had a problem on the kinematics side. So the redesign was more about the inner components, dampers, springs and so on. There were also some clarifications from the FIA. The system had to become simpler. Still, we were dissatisfied with some systems we had last year and wanted a reset. So it's pretty much different than last year.
One notable change this year is the nose design. Has this only aerodynamic reasons or have the tighter crash requirements changed something?
James Key: That has purely aerodynamic reasons. It is always difficult to pass a crash test, because the requirements for it are very different than for an aerodynamic part - and that's actually the nose rather. It's always a balancing act to get that done. The shape of the nose is mainly dominated by the aerodynamic requirements.
The old nose design was only one season. Did you find that it was the wrong way?
James Key: That's part of the natural evolution. We were satisfied with the nose last year. During development, however, the shapes change slightly and the way the front works changes a bit. This form seems to deliver the best overall performance in our development. The nose is a combination of things. Even she does not do that much, she just has to be there. Front wings and pylons are more the sensitive areas. The nose design is more about how to solve these things.
With the narrow nose came in the past year, a new concept in the front suspension. In combination, it almost looked like a copy of Mercedes. At a nose it has not decreased, at a suspension. Are not the parts hanging together?
James Key: No, not at all. The narrow nose philosophy we have seen in the years before. A few parts of the aerodynamics that we had did not make it to the new car, but their philosophy has remained. Some areas on the fron wing are very influential, especially inside, near the pylons. That was also in the last year. It was a little different, but similar in principle. We looked at all the options and agreed that the narrow nose gave us characteristics that we liked last year. But it had nothing to do with the front suspension. Nose and pylons are more responsible for how the inner part of the front wing works, the suspension has more to do with how the outer part of the front wing works. We changed our nose this year, but the suspension is still very similar.
Another, not so obvious topic is wheelbase and tilt. What have you changed here?
James Key: The wheelbase is longer. The wheelbase is changed for various reasons. One reason is the aerodynamics, but it is also related to the layout of the car. Likewise, the natural weight distribution is related to the wheelbase. It is a combination of various factors that determines a wheelbase, the main reason being the aerodynamics. We had a shorter wheelbase last year and now we're probably in midfield. Weight distribution, architecture and aerodynamics were the reasons for us. Most cars got longer, so we followed the trend. At the inclination we were already relatively high, but with us the inclination was not highest. That too is a trend and we followed him a bit further. I think we will see more and more.
How big was the advantage of being used to late engine changes in the past?
James Key: The advantage was big [laughs]. It was not easy even at V8 times. But with these power units, it's incredibly complicated. There is an awful lot to consider. The physical design of being able to put everything in the right place plays an important role. But there are many other structural elements, such as the entire control units and cooling circuits, of which there are quite a few in these hybrid engines. Technically, this makes it very complicated. We had worse than a decision in September. Since we had experience as a team here, we were able to handle it efficiently. It was not a big problem for us.
The biggest difference between Renault and Honda in architecture is certainly the turbo concept. At Honda sits the compressor - as with Mercedes - at the front of the engine and the turbocharger behind it, at Renault turbo and supercharger are one unit. McLaren's chief technology officer Tim Goss says he prefers Renault packaging. You probably think differently now ...
James Key: That's very diplomatic of him [laughs]. What else should one say? We have also experienced both variants. There are both advantages and disadvantages. The supercharged packaging in front of the engine is a bit simpler than with both parts in the back. With more space in front, it is easier to find gas volumes and to lay certain lines. The oil tank is also less restricted. At the rear, it is more difficult, because there jams all the heat. You also have to keep in mind that the turbo is closer to the gearbox. The exhaust is further back, which additionally increases the temperature at the transmission. On the chassis side, there is pros and cons, but our backside is much cleaner now.
We now have more space and freedom behind the engine for suspension parts and so on. It's a bit narrower at the front, but Honda has found a fantastic arrangement where the parts are housed very well in the little space they have. It was not the compromise we feared. The downside we had was that we could not do that from the outset for 2018 with Honda. But we can do that for 2019 and we are looking for ways to further optimize it. I prefer the Honda approach. Not only because we have Honda now, but because they have some great features around this engine philosophy. It is a tidy approach.
You mentioned that the collaboration came too late to be able to bear fruitful factory team results. But are there any details on the engine that they could influence?
James Key: There are a few small things that Honda has been able to change for us, but also some things we've changed for them. We have already talked about developmental steps that work for both sides. They have already been able to do some work and more over the course of the season. Our approach with them is to give them the flexibility they need to focus on engine development. We do not want to give them too many restrictions through the chassis. As a result, there were no late changes for her, which was very important. We'd better make some compromises, but then benefit from a better engine. That's an important balance to find.
They have already mentioned the transmission. The transmission is not only gearbox, but also houses suspension components of the rear axle and the articulation points of control arms and pull lever. Toro Rosso builds the gearbox itself and uses the innards of Red Bull. How big is the advantage of being able to design the rear axle yourself?
James Key: In any case, it's an advantage. The entire transmission has been redesigned for the Honda Split Turbo installation and other things. It allowed us to revise the entire architecture at the rear, which was not bad. The rear suspension was a new development anyway. The result is a completely new gearbox. It may have been even more critical from a time ago than the chassis, but the guys did a great job getting it together so quickly. This helps if you are suddenly in such a situation because you have a late engine decision. Then you have to be in control of these things around it. This control we have with the gearbox now. That's why we were able to adjust that so quickly. The gearbox we had was quite flexible, so it was not a fundamental redesign. We could adapt it to the principles we already had.
The side boxes look very similar to last year, the airbox has become much larger. Does that mean the Honda engine needs more cooling than the Renault?
James Key: No, I would rather say that the cooling requirements are different because there are different ways of cooling certain circuits in the engine. The side boxes have even become a bit smaller, but they have kept their shape. We wanted to see how the air flow changes as we cool more about the airbox and less about the side boxes. But here, too, we are following a trend of the past years. The 2015 coolers (with Ferrari engine) were quite large, but it also depends a lot on how the engine looks like, whether the space above the engine is a good place to arrange cooling systems. We have managed to stay as much as possible with the shape of the Honda engine. The layout is not dissimilar to the solution we had planned for the Renault engine.
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