Exterior development engineer Takeshi Inoue
Exterior development engineer Keisuke Nakata
It was near the beginning of 2011, during the furious development rush to prepare the RC212V for the final year of 800cc.
Casey Stoner, who had switched from Ducati to Honda after the end of the previous season, made a special request – he wanted to visit the HRC factory in Asaka City, Saitama.
After talking at length with the engine, electronics and body developers, Casey surprised everyone by using his mobile phone to take a snap of an unpainted cowling, still bare carbon fiber. "I'll use it for my phone's wallpaper" said the top MotoGP racer, obviously still teenage motorbike fan at heart.
After taking a good look at all parts of the 2011 prototype RC212V, Casey had this to say:
"I think it looks great. But could I ask you to add a hole in the upper cowl for when we're racing in strong winds?"
This comment gives an idea of the importance of aerodynamic performance.
Takeshi Inoue and Keisuke Nakata are the engineers responsible for developing the RC212V exterior. This was Nakata's reaction:
"Simply put, aerodynamic performance involves two major things we need in a racing bike. First there's protection, which is an essential factor on the straight. Then there's stability and controllability, vital for cornering. You also have to take engine cooling into account. Without considering all these factors, you can't achieve good aerodynamic performance."
"For the straights, we want to increase speed and acceleration by reducing the bike's air resistance, since this gets stronger the faster you go. This is affected by the bike's front profile. The side profile becomes important when you're laying the bike over for the corners – it determines whether you can bank smoothly or not. When Casey saw our design, he seemed worried that it might not deliver the handling he wanted in strong winds."
As Inoue says, so many conflicting factors contribute to aerodynamic performance that any solution necessarily involves compromise. They couldn't respond to Casey's request simply by adding a hole. Making this change could adversely affect many other things, from the balance between handling and protection to cooling performance, creating new problems to be solved. Nevertheless, the development team swung into action to provide Casey what he wanted.
"It's our job, of course, to give the riders what they need. But we really wanted to do our best for Casey. Here was a rider who had specially made the trip to Japan just to see our work, and on top of that it turned out that he was just as big a bike geek as any of us – we'd be happy to work with this guy to make the bike better. The problem was that we'd already perfected the design using wind tunnel tests to get the performance we wanted, and we could see fresh issues coming up if we added a hole. Anyway, we rethought the side profile and...."
At that point, Inoue was interrupted by a smiling Unuki, his manager:
"I think we'd better keep that part under wraps, don't you?"
Well, I suppose Honda has always been strict about preserving secrecy. Back when I was an HRC works rider, we riders would never have even been allowed into the factory. Looking apologetic, Inoue resumed his comments:
"Anyway, we managed to get it right in time for the opening race. We found a way to alter the side design that kept the light handling Casey wanted even in strong winds."
Obviously, I can't give out any details on how exactly they changed the RC212V exterior to comply with Casey's request, but maybe you can guess if you look closely enough....
The side view certainly reveals a shape designed for a balance of protection and cornering ability.
Just as I was despairing of getting some real meat out of these guys, Unuki spoke up again. Saying "Wait, I've got something to show you that we're really proud of," he opened up the tail cowling.
This revealed the tight coil of the exhaust pipe, indeed a thing of beauty, and a shame that it's always hidden out of sight. Even the stays fixing it inside the seat cowl are specially designed instead of simply made out of aluminum sheet. It vividly reminded me of the old saying "God is in the details."
It may seem strange, but the engine developers don't make the exhaust pipe – this is the job of the body developers.
The engine developers perform bench tests to determine the required specs, like length and diameter. But then it's up to the body designers to figure out how to squeeze this part into the very limited space available.
This is really where the body team get to show off their skills. Engine developer Izumi commented "Sometimes I feel really bad, asking them to do the impossible, but they always manage it."
"To improve engine output, you need to optimize air intake, combustion and exhaust. Obviously an exhaust pipe that's as nearly straight as possible gives the least air resistance, and in the past we tried fitting straight pipes along the lower side. That resulted in an outcry from the riders – they couldn't concentrate because of the incredible noise bouncing off the track every time they leaned the bike. So we needed a pipe with the right length to deliver the required engine performance, and a way to position the end well away from the rider. The best solution we found was to coil the pipe and stow it in the tail cowl."
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