“When I started designing the Cube, it was me, a colleague who was in charge of the gearbox part, while engineer Claudio Lombardi kept relations with Cosworth regarding the engine. The person in charge of the Cube project was Emanuele Borsetto, who is retired today.”
When he was assigned the task of designing the chassis for Aprilia’s first home-grown MotoGP bike, Germano Bergamo immediately realized that he had to design something different: the engine concept was totally unusual for a racing bike, since it came from cars.
“The company entrusted us with the design of the Cube in late 2000, and in March 2002 we debuted it on the track. That is, right on the eve of the championship. We had our first track test in November 2001, and we really put a prototype on the track. In fact, when we took the finished bike to the Motor Show in December, we hadn’t even started it yet-the engine had only run on the dyno.”
Everything took place with a very rushed timeline.
“In January Marcellino Lucchi tested in Jerez, then in early March at Mugello Regis Laconi rode. And that’s where I saw the bike fully functional. We did winter testing in Europe, or at Mugello. We did not go to Malaysia, like the other Japanese manufacturers who debuted in MotoGP in April 2002.”
The shapes, like the aerodynamic part, are clearly derived from studies done on the two-stroke GPs. But the chassis was designed from scratch.
“It was a new design, in the sense that the Cube frame is the first, for Aprilia, built by getting 80 percent of the parts completely machined with machine tools. So no aluminum stampings, or the extruded technology that we in Aprilia used on the 125 and 250 two-strokes; was a technology we were familiar with, but for the Cube, all the parts were made from billet, so using milling machines. And it was the first experience, for us, with that type of frame.”
What is the difference?
“The starting material, from which the parts are made, is better than a casting, or a stamped sheet metal, which has slightly lower basic characteristics in order to be stamped, otherwise it would crack when it goes under the press. With machined parts from solid we were able to get better results, including ease of assembly-that frame was kind of a puzzle of mechanical pieces to put together and weld together.”
Why should this system be considered an innovation?
“When you weld molds you have larger tolerances, you have to make a much more complex set of jig equipment that is very difficult to manage. We had made that choice because we were producing few parts — that is, frames for only two bikes, plus the test team’s one — so with six to eight parts we were managing a season. We spent on the production of the parts, without having to invest in other equipment; that way it is also easier to modify the frame, because you change the pieces without having to disperse too much money in case everything has to be redone. So there has also been an optimization of resources.”
Were the goals compactness and manageability?
“More than anything, we followed the basic idea behind the Cube’s engine concept: to try to make the most of the technology that was available. Because an engine was chosen that was designed to focus on F1-derived technology-such as the combustion part, the pistons, etc.-we directed everything around it, i.e., the vehicle, down that path. We focused on handling, because. In the beginning, the regulations required the 3-in-line to have a 10-pound weight advantage, and that is no small thing.”
That they wanted an F1-inspired engine was a sticking point, then?
“Yes, in fact at first we also had a discussion with Sauber. Then we decided to link up with Cosworth. The idea was to borrow a technological concept from F1, which is why we were the first to use pneumatic valves, Ride by wire, carbon clutch. Let’s say that our concept was particular: it was chosen to make, for a motorcycle, an engine that was a fractionation of a Formula 1 powerplant: the 3-cylinder – making a slight stroke modification, keeping the bore fixed – was the one that came closest to reaching the 990cc maximum cubic capacity required by MotoGP regulations at that time.”
Is the carbon clutch also derived from that concept?
“Yes. Because an F1-derived layout had encumbrances that didn’t fit well on the bike, to optimize everything we chose the carbon clutch because it was much smaller than the traditional steel clutch. And we evolved it to 2004.”
The frame, which is gorgeous, has a number of facets, from the frame to the swingarm. Where did that idea come from?
“The first chassis, that of the “2,” came to us that way because of the technology we used. We were not yet masters, as well as our suppliers, of everything that could be done with CNC processing especially on complex, very curvy surfaces; so the first chassis, mounted on the “2” and the “3,” came with those facets also to simplify certain machining.
When we, together with our suppliers, became a little better and more experienced, we decided to move on to those shapes applied on the “4,” and slowly we arrived at the chassis concept for the “5”: where we finally found much more sinuous shapes, which were much more integrated to the external appearance as well, so also on the level of aerodynamics.”
Does the 2005 have a completely new frame?
“We redesigned the chassis because we redesigned the engine.”
So it is the whole project completely new.
“Yes, because the second generation engine has many differences from the first type. On the 2005 engine we kept only the bore and head measurements, otherwise we redid the whole crankcase. So at the chassis level, the frame, swingarm, rear suspension, steering head area, air box were redesigned… In short, it was a completely new bike.”
Even from the first glance it is apparent that this is a new “thing.”
“But what’s new is that the 2005 engine-which we didn’t do together with Cosworth, as it had been from 2002 to 2004, but we did it all ourselves-is integrated into a concept that wasn’t all that dissimilar to an inline-4 of the time.”
Can we explain this concept of “integration”?
“The new engine has become one thing, one unit, integrating multiple parts that until the 2004 version were on the outside.”
But shouldn’t this be a normal thing, an engine “as one”?
“For motorcycles yes, in the car world no.”
Ah, that’s it.
“In fact, the 2005 engine is a big step toward a return to ‘motorcycle’ concepts. It is therefore also totally integrated as a gearbox and thermal part; in contrast, on the Cosworth project (which remained on the track until 2004) the gearbox was combined with the thermal part, in the sense that that engine was not born already with the gearbox included. It was not totally integrated.”
Does this mean that the “5,” which began as an integrated project, is more “motorcycle”?
“We have completely redesigned the crankcase extraction pumps, integrating them with the engine; and there is no longer a detached pump body, typical of F1s of the time: on cars there was a need to put the pumps alongside the crankshaft in order to keep the center of gravity of the engine as low as possible. But that was not our goal on a motorcycle: in fact, those pumps gave layout problems at the level of passing the exhaust pipes, or in the positioning of the radiators.”
Which by the way on the Cube are unusual, too.
“The Cube’s radiators are separate, kind of like they’ve been cut off-it was like that until the 2004 version.”
Again, radiators away from the engine are an automobile concept.
“And in fact on the “5,” which was born with a different idea, we had a radiant mass system (the radiators) of the traditional type, completely enclosed and much closer to the engine; so with the exhausts much more compacted on the engine, because the whole layout had been readjusted and evolved for these very aspects. Engineers havemodified the angle of inclination of the cylinder bank, also increasing the inertia of the crankshaft. In short, the engine became like one for MotoGP, not F1. For example, because the engine and gearbox used to be separate units-and this is a car concept, not a motorcycle concept-the engine was longer and consequently affected the Proper design of a motorcycle frame.”
Has the engine-to-frame ratio always been critical, on the Cube?
“We made a step when we changed the exhaust system, going for a cross between the cylinders to have a more gradual and full torque curve; already in 2003 there was something positive, then we evolved it on the 4 and finally in the 5 it is was much improved; then we applied flywheels, that is, a mechanical mass that would somehow smooth out those power peaks that disturbed the driver so much, giving a characteristic of linearity. And working on the crankshaft, on the flywheels, we increased the inertia of the engine. There, that started to give characteristics of the bike such that even the interventions on the chassis level turned out to be tavan appreciated by the pilot.”
It seems to be understood that with “5” you were on the right track to aim for important results.
“Yes, and we still think so today. We had found the right concept of a “vehicle,” in the sense that the chassis had evolved a lot, and the engine was more compact and more manageable. The second-generation engine had also undergone a significant increase in power, which was about 10 hp. We were up to handling 240 hp at 18,000 rpm maximum. For that time, I’m talking about 2005, they were excellent values.”
And you had not even begun development….
“No one knows where we would have been even halfway through the season, or at the end of the championship. It would have been nice to be able to continue, because ideas came out of the 2005 Cube that we then applied to the RSV4. And we started to do a lot of development on the electronics level, designing system me that they really controlled the engine.”
Were the electronic systems on the Cube so primitive?
“So at first we thought: we have electronic throttle control, so we can change the throttle command ramp and we get what we want. But no. That was theory in fact in practice we needed to find a combination of electronic management factors. And I repeat: by studying those problems with the Cube, we found ideas and solutions that we later transferred to the RSV4: the Cube was a hotbed of knowledge, a real laboratory. And some of the ideas that came up for the Cube, we also used in 250. When Simoncelli won the 250 World Championship with us (in 2008) his bike had a traction control system. As primitive as it was, that system took advantage of a lot of our experiences with the Cube, which had forced us to work really hard to find solutions. Those ideas were the basis for putting new things on the 250, and then carrying other evolutions onto the RSV4. So it’s from that Cube project that Aprilia has grown a lot technologically; it’s been an enormously useful laboratory, to raise the level of the racing department.”
The rear suspension of the “5” looks so much like the one that characterized the legendary Honda RC211V, in 2002.
“Yes, that is true. After all, the 2005 was born with the aim of transferring all the studies and experiments done with the three previous versions, and in that study phase we were looking at everything that was invented by others as well. When we designed the “2005” we had thoroughly studied the mounting of the Unit – Pro Link system. So even on the “5,” the monoshock is housed inside the swingarm, and not anchored to the frame. To do this we also lengthened, not just redesigned, the swingarm: this also brought a benefit from the point of view of traction.”
That type of suspension was an interesting innovation, but then the engineers
of Honda no longer adopted it on the others, namely the “212” and the “213.”
“We were not able to verify the effectiveness, because the “5” really did very little riding. We were inspired by that idea (the Unit Pro Link system) because we were trying to reduce the transmission of vibration that came from the rear wheel and was carried over to the whole bike. That is the infamous chattering. The Unit Pro Link scheme seemed effective, we just couldn’t test it thoroughly enough to say that we found satisfactory results. Surely the 2005 season should have given us those answers. Although we did some experimenting anyway, working on the ‘4’.”
How do you mean?
“On the 2004 version we already installed a prototype of swingarm, then of suspension, which was already similar to the Unit Pro Link system. Since the development had gone well, we had decided to transfer it stably to the 2005; in fact, that chassis was born just like that, that is, for that type of suspension.”
So “2004” was also a laboratory.
“Well, the “4” was the laboratory we needed to take the first real step forward. Although then it has to be said that the Cube has always been a kind of unique project, in the sense that the “4” was a continuation of the “2” and the “3.” And, indeed, all the work done on the 2004 had been done to transfer developments to the “5.” But the company decided otherwise.”