Vol.04 F450A
CHALLENGERS OF MONOZUKURI
Story of New Model Development
CHALLENGERS OF
MONOZUKURI
Story of New Model Development
Vol.04 F450A
EXTRA ATTENTION PAID TO PERCEIVABLE PERFORMANCES
The flagship model F450A, which boasts the highest horsepower among Yamaha outboard engines, has made its debut in the North American market.
We interviewed the development team members about the developmental background and the path to the release.
Marine outboard engines are one of Yamaha’s products that hold a large share in the global market. They have a long history and Yamaha has been leading the world for more than half a century since the release of the first outboard engine P-7 in 1960. Their flagship model is an offshore outboard with a V8 5.6-liter engine as its power source. In 2018, the F425A and FL425A (“L” stands for a counter-rotating outboard engine with its propeller rotating counterclockwise) were released. These engines were further powered up without increasing the engine displacement and newly added to the product line this year as the F450A and FL450A (hereinafter collectively referred to as F450A). The number in the product name stands for its horsepower. As you can see, the new engine with the highest horsepower among Yamaha outboard engines has been rolled out.
This time we interviewed the five team members engaged in the development and production of the F450A. The four members from Marine Business Operations are: project leader KUROKI Youhei from Project Promotion Group, Advanced Development Division, Development Section;
test engineer KATO Yosuke from Engine Group, Engine Development Division, Development Section;
product planner MOUE Takayuki from Product Strategy Group, Strategy Planning Division, Planning Section;
and WADA Shunki in charge of project promotion from PJ Promote Group, Production Promotion Division, Manufacturing Section;
and one member from the Manufacturing Center is HAYASHI Takao from LP Casting Engineering Team, 3rd Manufacturing Engineering Group, PT Aluminum Components Engineering Division, Manufacturing Engineering Section.
FOCUS ON THE RANGE OF LARGE HORSEPOWER AT AN EARLY STAGE AND START MASS PRODUCTION BASED ON HIGH RELIABILITY
Outboard engines do not just provide propulsion power, but also offer steering control. Due to their relatively small size, lightweight construction and easy maintainability, they have been used for small boats. For this reason, large size inboard engines have been commonly used for large ocean-going boats that require higher output. High-horsepower outboard engines were previously limited to special use such as for racing, but Yamaha had already focused on the range of large horsepower at an early stage.
“Boating is a very popular activity in North America, especially in the southeastern region of the U.S. such as Florida. In recent years, as boats have become larger, there has been a demand for higher engine performance.
Thus, outboard engines are now very popular because they are highly flexible in boat designing and interior layout and easily maintained,” says Moue.
Against such a background, Yamaha made a start on the mass production of large outboard engines based on its accumulated knowledge and technology, and then released the F425A in 2018. Adding two more cylinders to the V6 base model engine F300B, which had already earned high acclaim in the market, Yamaha newly developed a V8 5.6-liter engine. This new model was brought to the market with all Yamaha technologies incorporated, such as direct injection, which was used for a 4-stroke outboard engine for the first time, and plasma spray coating, which contributed to weight reduction and higher durability. As the team hoped, this new model became a major hit product, winning numerous awards.
HIGH POWER AND QUALITY DESIRED IN THE SUPERCAR-LIKE MARKET
Immediately after the release of the F425A, the development team started to draft the concept of the F450A. It was in 2019 that the full-scale development began. The top category of outboard engines has a huge impact on the market in terms of corporate brand as well as product sales. It is said that North American users usually install two or three outboard engines to one boat, and some install as many as five units. “Rather than using the full power of the engine, most users enjoy their boat with the attitude of ‘Speed is Pride,’” says Kuroki, who had once worked in the U.S. as an expatriate employee. There exists a market not just for enjoying the vast ocean to the full extent, but also for requiring overwhelming power as a symbol of higher status. It goes without saying that sophisticated exterior appearance is required in addition to high-quality power feel since outboard engines are seen as a part of a hull.
It’s like a market for luxurious cars or supercars.
“To further extend our lead and expand our market share in this top category, our development team aimed not just for higher horsepower, but also for further improvement of quality such as usability,” says Moue. Under the slogan of “Let’s do what we couldn’t finish in the development of the F425A,” all the team members worked together under Kuroki’s leadership to move forward with the project. They put the most importance on the “voice of the market.” Most users demanded the enhancement in engine output, power feel, and especially quietness. While focusing on these points, the team worked on creating a new model that deserves to be the highest grade.
However, the development started under many restrictions. As the base model F425A itself was an engine that had been tuned to an extremely high level, it was not easy to increase engine output drastically without compromising reliability. Also, it was almost impossible to change the size and shape of the engine. Furthermore, the conflicting relationship between improving quietness and output hindered the development. “The exhaust noise was not that much of concern because the exhaust gas was discharged into water, but the intake noise at high speeds was unpleasant. If we prioritized quietness over power, we had to restrict air intake, making it difficult to enhance engine output,” says Kuroki.
ACHIEVING QUANTITATIVE TARGETS IS NOT OUR GOAL, BUT CREATING WHAT CUSTOMERS CAN FEEL AND TELL IS
In such a situation, the development team focused intensively on the development of the intake and exhaust system. Without making a major change to the lower part of the F425A engine, the cylinder head was newly designed. The compression ratio was raised from 12.2 to 12.3 and the diameter of the exhaust valves was also enlarged. Regarding the intake system, they installed a silencer to reduce intake noise. Their big challenge was how to flow the exhaust gas smoothly to increase horsepower. The key component to solving this problem was the joint exhaust, one of the exhaust system parts. Due to its extremely complicated structure, the team had difficulty designing this part, but eventually completed the new engine with which users can feel not just its overwhelming power and torque, but also massive and sophisticated feeling, as Kuroki says that the team had paid extra attention to creating what customers can feel and tell.
The team’s attention to the engine feeling is also reflected in the exterior and product design, which was undertaken by GK Kyoto Inc. Outboard engines cannot exist without boats.
In addition to considering the design so as not to give any negative impact on the boat, it was a precondition to adopt an external appearance similar to the previous model F425A for the new model. Therefore, the Yamaha Tuning Fork emblem, Y-shaped rear panel and logos of the F450A were made into 3D graphics. As to technological features, the flushing hose and the wiring for the power trim and tilt unit were hidden into the interior, making the exterior simple and beautiful to realize a surprisingly luxurious appearance.
YAMAHA’S FIRST ATTEMPT?!
MASS-PRODUCE PARTS USING A 3D PRINTER
However, when the development team was about to move to a manufacturing stage after finalizing the engine specifications and drawings, the test engine did not generate the power that was supposed to come out. “All the measurements looked okay, but the engine would not produce sufficient power. We wondered if it was because of variation in part accuracy or power loss or difference in specifications. It was challenging to identify individual causes through a series of tests and achieving the target output by optimizing engine settings,” says Kato, who was in charge of engine testing.
One of the problematic parts was the joint exhaust in the exhaust system. “We used sandcast prototypes for the engines at the advanced/leading development stages, but these adversely affected the cast prototype for mass production,” says Kato.
Small structural changes necessary for production processes and variations in part accuracy, or more specifically the roughness and flatness of the exhaust pipe inner surface, had a negative impact on power. The engine was extremely sensitive to subtle changes. It was as if the development team was talking about a racing engine. This sensitivity also led to difficulties in mass production. “Because of a V8 engine, eight exhaust pipes needed to be merged and twisted in some part. It was quite a challenge to mass-produce such complicated geometries by casting, which was a rewarding task, but also an extremely difficult one,” says Hayashi in charge of manufacturing the joint exhaust. To cast the parts with complex shapes, Hayashi made his first attempt to introduce 3D-printed cores into a mass production phase, on which he had already researched.
With the introduction of the 3D-printed cores, the F450A was finally released as a mass-produced model for the industry in the North American market. It received a high evaluation and plenty of attention from many customers including boat builders. Immediately after the release, a flood of orders rushed in. This was a good start. However, although the development team seemed to have the prospect of mass production of the joint exhaust, the production site was facing difficulties in manufacturing the required number of units.
As Hayashi says the manufacturing department stands at the starting line when production begins, and the department normally makes all kinds of improvements and changes in parallel with actual production. This time, however, they had to deal with a considerable number of orders in a short period of time. To respond to such large orders, the manufacturing department started the production with the aid of the development team and also decided to run a parts production system by shell core casting with all their technologies available.
DEVELOPMENT PLAN MODIFIED REPEATEDLY DUE TO THE MODEL’S HIGH DEGREE OF DIFFICULTY
Even while the difficulty in casting was hampering the improvement of productivity, the factory was snowed under the arrangements of the production system. “When we were operating at a reduced scale due to the COVID-19 pandemic, the market recovered unexpectedly. Other outboard engines also became backordered,” says Wada in charge of production management. Just because the F450A parts couldn’t keep up with production, the engine assembly line couldn’t be stopped. Wada was extremely busy managing the production, such as putting in other model’s production while monitoring the progress of the F450A parts production. In addition, he was under pressure from the market. “I frequently received a severe reprimand like ‘What is your department doing?’ from inside and outside YMC. I was always apologizing to them. There was no such model that underwent so many modifications of the production plan.
But the truth was the market was demanding the F450A. That was pleasing news and highly motivated us,” says Wada. Hayashi and Wada are still making efforts for improvements every day to support the production site of the F450A.
INVISIBLE BUT UNCOMPROMISING QUALITIES INCORPORATED IN A CASUAL MANNER
PRIDE AS A LEADING COMPANY
The highest class F450A was quickly accepted by the market. A great number of technologies, such as a powerful charging system that supports various devices including air conditioners, were incorporated to this new model, but unfortunately all of these cannot be introduced here. Among these highlights, there is a minor feature on which the development team didn’t compromise. It was a reduction of a mechanical clunk sound that was generated when shifting into gear. In fact, it was not a necessary requirement for the development, but the team voluntarily tackled it to improve quietness. Such careful attention to detail should have touched customers’ heart. There is no doubt that this outboard engine with exceptional horsepower is contributing to enriching the users’ marine life.
