Development leader Hiroshi Unuki
Engine development engineer Michio Izumi
I expect the previous section got you keen for a detailed look inside? We were too, but unfortunately as soon as we started setting up the camera, Hiroshi Unuki, the development leader, smilingly told us we'd only be able to shoot from certain, very restricted angles. "I understand you want to show the fans everything, but it would be a big problem if your photos revealed too much." We could only shoot from the angles he allowed, and we weren't allowed to take photos that would allow anyone to estimate the dimensions of the parts.
First, the camshaft – you get just a tantalizing glimpse of it in the photo. It has been extensively machined to remove every last bit of excess weight, of course, but what really interested us was the cam profile – its shape viewed from the side. This is radically different to any camshaft we've seen before. Instead of the normal metal springs for closing the valves, it uses pneumatic valves. The valves are closed by compressed air. That part is fascinating and it's a great shame we can't show it to you.
Both the intake and the exhaust valves are made of titanium. This material is vastly lighter than steel, but it requires surface treatment or it quickly wears. And not only that, each part of the valve – stem end, stem and disk – must be given a different type of treatment. Because of this, each valve is sent to two different countries for processing in specialist facilities. Photos were strictly forbidden, to avoid revealing important details such as stem thickness, or the shape of the stem end where it contacts the valve lifter.
For the piston, we were only allowed to look at its dome.
We also realized that a part we were sure everyone would really want to hear about was missing – where was the connecting rod? But no, it seemed that there were just too many secrets about the connecting rod, and any kind of photo at all might reveal too much. They did tell us it is made of titanium, but there's nothing novel about that since titanium connecting rods have been around for 30 years or so.
We knew there would be a certain amount of secrecy, but the engineers were far more guarded than we had expected. Unuki explained their reasons.
"It's because the technology today is so good at analyzing photos – just from the shapes and dimensions of certain parts, rival teams would be able to get a good idea of the engine's capabilities. We'd really be doing them a favor if we revealed the shape of some of these components. We would have liked to show you much more, but I'm sorry that simply isn't possible."
It is now over 120 years since the gasoline engine became a practical mobility power source. Such a time having elapsed, we thought that the development technology would have greatly advanced, but we never imagined that it would now be possible to derive the performance of an engine merely from the dimensions of photographed components.
We've all heard how laborious the process of developing race engines is, how many versions must be built, broken down, tested and rebuilt until the result is satisfactory.
Back in the days when the GP500 was the top class and the bikes were two-stroke, they would open the engines at the end of each race to look at how the pistons were fitting the cylinder. Trial and error was the method then – you kept making small adjustments and checking the results until performance improved. When we asked if this was how they developed the RC212V, the engineers smiled. The old methods were abandoned years ago, and now simulation is used to fine tune performance.
So that means much of the difficulty in engine design has gone? This question brought a wry smile to the faces of engine development engineers Michio Izumi and Yosuke Hoi. "That would be nice..."
Engine development engineer Yosuke Hoi
We then talked with engine development engineer Hoi.
"After preparing an engine design on the computer, we bench test the actual engine to measure its performance. Most of the time, the measurements agree with our computer simulation, and we developers feel sure we have a winner. But in fact the real test starts from there. It's no use just producing the horsepower we want if our riders don't give the design their nod of approval after actually trying it out on the track."
Can you give us an idea of some of the comments riders made?
"Dani Pedrosa was especially concerned about the feeling of the engine. He would talk about feeling the power coming in waves, and that he sensed some kind of friction."
These sensations would probably be caused by irregularity in the power output and by something dragging or resisting inside the engine, respectively.
The engine was delivering the required power, but this particular configuration was not smooth enough for the rider to be able to forget it and ride his best. For these top level riders, where fractions of a second determine victory and defeat, this is a major problem.
"Of course, we engineers aren't able to go on the track and feel the bike in action like a MotoGP rider can, but based on our accumulated data and experience we have a good idea of what they are telling us, and this allows us to set about fixing the problem. A lot of the time the test analysis measurement data doesn't give us a full picture of what is happening. In these cases we have to rely on the sensitivity and insight of our riders."
Holding up the crankshaft, Izumi discussed its development.
"For example, we still really haven't determined whether it's better to make this part heavier or lighter." Normally, for a racing bike, it's best to make the camshaft, valves, pistons and other parts as light as possible. But the rule isn't so settled for crankshaft design. Instead this is largely determined by whether the riders feel it makes the bike easier or harder for them to ride.
"Naturally, it affects how the engine behaves at high revs, and also different weights affect handling in corners. Changing the crankshaft weight also alters the output performance. In the extreme conditions of the racetrack where we're trying everything possible to make the bike handle the way the rider wants, just as we think we've maybe solved one mystery, the engine confronts us with another."
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