Section 5. Wartime Research and Production
Item 9. Aircraft Development and Production
Helicopter prototype production
While devoting efforts to the automobile business, Kiichiro Toyoda also retained a strong interest in the aircraft business. In 1936, he bought the French-made ultra-compact aircraft 'Pou Du Ciel' ('sky louse') and brought it to the Tokyo Shibaura Laboratory for study by Eiji Toyoda and the aviator Bunzaburo Kataoka. As an evolution of the 'Pou' with its short takeoff distance, research was conducted into an autogyro with rotor blades. The goal was set of developing an aircraft that flew on the aerodynamic force provided by motor-driven rotor blades-in other words, a helicopter.1
In 1937, aircraft research operations were relocated to Kariya. Here, along with aircraft engine research, prototype wooden propellers were created in a woodwork shop, and flight performance and other qualities were investigated with the propellers actually fixed to an aircraft.
In November 1938, with the start of operations at the Koromo Plant, work began immediately on the construction of the Aircraft Research Department. In spring of the next year, 1939, the laboratory was completed on a site close to the east gate of the Koromo Plant (close to the current site of the north wing of Office Building No.2), and in May, Kataoka-who was on a special short-term contract-officially joined the company and proceeded with research as a special research deputy chief responsible for aircraft research.2
The prototype aircraft parts produced were fixed to a decommissioned naval K1Y training aircraft for performance tests, which were performed at the Koromogahara Airfield close to the Koromo Plant (close to the present site of the Motomachi Plant completed vehicle yards). Next, using a rotor designed by Professor Shiro Nukiyama of the Tohoku Imperial University Engineering Department, Takeaki Shirai carried out experimental measurements of buoyant force at the Aircraft Research Department using an actual engine to drive the rotor. Additionally, in 1941, a Beechcraft passenger biplane was acquired and its fuselage investigated. Lessons were learned from the fuselage design, which protected passengers from the wind pressure caused by the rotor.
The circular single flow motor that Sakichi Toyoda invented was passed on to Kiichiro in the form of rotary engine development. In a document entitled “Rotary Engine Production and Testing” written in the autumn of 1944, Kiichiro stated that “Sakichi Toyoda produced a steam engine known as a circular engine at the company’s current Sako-cho Plant 35 years before now”, but “making a rotary engine in the form of an internal combustion engine is extremely difficult”. When the rotary engine was designed, Toyota Motor Co., Ltd. also participated in the development of a gas turbine engine for aircraft and was responsible for manufacture of the combustion chamber.
The research by Sakichi and Kiichiro on the circular loom and circular single flow motor (rotary engine) was not brought to practical application, but the spirit of the research was passed on to many Toyota group companies such as Toyota Motor Co., Ltd.4