The Yokosho K2Y Navy Type 3 Land-based Primary Trainer was the Japanese Navy's main primary trainer during the 1930s and remained in service at the start of the Pacific War.
The Type 3 was designed to replace the Avro 504, which had been in use since 1921. Work on the design began in 1928, the last year in which the Navy used reign years to identify its aircraft. This was the third year of the Showa era, thus the Type 3 designation, although this wasn't officially allocated until January 1930, by which time the Navy was using calendar years instead. The potential for confusion in the older system is demonstrated by the K1Y and K2Y trainers, both Yokosho designs. The K1Y was the Navy Type 13 Trainer, dating it to 1925, or year 13 of the Taisho Era. The more modern K2Y was the Navy Type 3 Trainer, there having been a change of Emperor between the two designs.
The new aircraft was an improved version of the Avro 504. It was a two-bay biplane, with a wooden framework for the fuselage and wings and a fabric covering. The crew of two sat in open cockpits.
The first version of the aircraft was powered by a licence-built 130hp Armstrong Siddeley Mongoose radial engine, manufactured by Mitsubishi. This gave a 20hp increase in power over the Le Rhône engine of the Avro 504. This version entered production at Kawanishi and the first production aircraft was completed in June 1930. The Mongoose powered version was the Type 3 Land-based Primary Trainer K2Y1. It was produced by Kawanishi, Watanabe and Mitsubishi.
In February 1930 Yokosho installed a 130-160hp Gasuden Jimpu engine in the Type 3. This proved to be a more successful engine and was adopted for production. The prototype was designated as the Type 3 Land-based Trainer Kai-1, while production aircraft with the Jimpu engine became the Type 3-2 Land-based Trainer K2Y2. The K2Y2 was produced by by Kawanishi, Watanabe, Mitsubishi, Nippi and Showa.
A total of 360 Type 3s were produced. The first six were built by the Yokosuka Arsenal in 1929-30. Kawanishi built 66 in 1930-32. In 1931 Watanabe began production, eventually building 114 between then and 1937. Mitsubishi was involved in 1934, building 45. Showa produced three in 1938-39. Finally Nippi took over production in 1939-40, and produced 126 aircraft, the biggest batch of any manufacturer.
The Type 3 was a good stable primary trainer, and remained in use from 1930 until the start of the Pacific War. After their military career ended many were sold into civilian use, with the biggest batch going to the Student's Aviation League. The K2Y was eventually replaced by the Kyushu K9W.
Engine: Gasuden Jimpu 2 seven-cylinder air-cooled radial engine
Span: 35ft 9in
Length: 28ft 2.5in
Height: 10ft 3in
Empty weight: 1,448lb
Maximum take-off weight: 1,962lb
Max speed: 100.4mph
Climb Rate: 21min 10sec to 9,843ft
Service ceiling: 15,091ft
Endurance: 4.2 hours