Japanese aircraft engine identification systems

Japanese aero-engines for military aircraft were given a wide variety of designations depending on the customer. This led to much confusion, particularly among the Allied forces, where a single engine type could have up to six different designations. This situation emerged because of the almost total lack of co-operation in weapons procurement between the IJAAS (大日本帝國陸軍航空隊 - Dai-Nippon Teikoku Rikugun Kokutai - Imperial Japanese Army Air Service) and the IJNAS (大日本帝國海軍航空隊 - Dai-Nippon Teikoku Kaigun Koukuu-tai - Imperial Japanese Navy Air Service).

Engines could have designations in any or all of these designation systems:

Army Hatsudoki experimental designation
(Kawasaki Ha40)
Army long designation
(e.g. Army Type 99 900hp Air Cooled Radial)
Navy experimental designation
(Nakajima NK9B)
Navy Name designation
( Nakajima Homare 11)
Manufacturers designation
(Nakajima NBA)
Unified system introduced by the Ministry of Munitions in April 1942
(Kawasaki Ha-60)

Data from:Japanese Aircraft 1910–1941[1] & Japanese Aircraft of the Pacific War[2] & Japanese Aircraft Engines[3]

  1. ^ Mikesh, Robert; Shorzoe Abe (1990). Japanese Aircraft 1910–1941. london: Putnam. ISBN 978-0-85177-840-2.
  2. ^ Francillon, Rene (1979). Japanese Aircraft of the Pacific War. London: Putnam & Company Limited. ISBN 0 370 30251 6.
  3. ^ Mawhinney, Robert. Japanese Aircraft Engines. Washington D.C.: NASM. Archived from the original on 2013-11-03. Retrieved 2013-12-01.