Launching the YS-11

The YS-11 turboprop was the first airliner made in Japan after WWII. After the war, Japan's Ministry of International Trade and Industry identified the need for a short and middle-haul airliner for the region, spurring on Japanese companies to work together on its development.

The Nihon Aircraft Manufacturing Corporation (NAMC) was thus formed in the late 1950s including the likes of Mitsubishi Heavy Industries and Kawasaki Heavy Industries. By 1962, the first prototype of the YS-11 was ready for its inaugural test flight.

Specific requirements were set out in the development of the YS-11. Alongside space for 60 passengers, the aircraft had to be able to take off and land on a 1,200 metre runway and have a flight range of 600 nautical miles (roughly 1,100 kilometres). At the time, few aero engines could meet these requirements.

In the UK, the Rolls-Royce developed Dart engine was already in service and known for its reliability in powering the Fokker F27 Friendship turboprop airliner but was still short of the power required for the YS-11.

Rolls-Royce modified the water/methanol injection schedule of the Dart 7 to meet the agreed specifications for the YS-11, further boosting thrust at take-off and delivering a more powerful solution and supplied Dart 10.

Mr Norio Yamanouchi joined NAMC as an engineer in 1963 after the first test flight of the YS-11. At the time, test facilities and equipment were lacking the state-of-the-art capabilities we see today and couldn’t accurately reflect a test pilot’s findings.

Frustrated, Mr Yamanouchi decided to become a test pilot himself. He spent a lot of time discussing with Rolls-Royce’s representatives, not only as an engineer but also a test pilot.

“The YS-11 wouldn’t have been a success without Dart,” explains Mr Yamanouchi. “I can’t recall any trouble with the engine. Rolls-Royce was very supportive and taught us a lot throughout the development process. We were happy to thank them for all their efforts and flexibility in meeting our requirements.”