was a Japanese

aircraft designer Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is si ...

. He designed many World War II fighter aircraft used by the

Imperial Japanese Army Air Force The Imperial Japanese Army Air Service (IJAAS) or Imperial Japanese Army Air Force (IJAAF; ja, 大日本帝國陸軍航空部隊, Dainippon Teikoku Rikugun Kōkūbutai, lit=Greater Japan Empire Army Air Corps) was the aviation force of the Im ...

. His most important work was the , aka

Kawasaki Ki-61 The Kawasaki Ki-61 ''Hien'' (飛燕, "flying swallow") is a Japanese World War II fighter aircraft. Used by the Imperial Japanese Army Air Service, it was designated the "Army Type 3 Fighter" (三式戦闘機). Allied intelligence initially b ...

("flying swallow") or "''Tony''". Also he was one of the chief designers of the

Nihon Aircraft Manufacturing Corporation The Nihon Aircraft Manufacturing Corporation ( ja, 日本航空機製造株式会社 ''Nihon Kōkūki Seizō Kabushiki-gaisha''), or NAMC, was the manufacturer of Japan's only successful civilian airliner, the YS-11. Rather than an individual ...

(NAMC)

YS-11 The NAMC YS-11 is a turboprop airliner designed and built by the Nihon Aircraft Manufacturing Corporation (NAMC), a Japanese consortium. It was the only post-war airliner to be wholly designed and manufactured in Japan until the development of ...

Biography

Takeo Doi was born in Yamagata city,

Yamagata prefecture is a prefecture of Japan located in the Tōhoku region of Honshu. Yamagata Prefecture has a population of 1,079,950 (1 June 2019) and has a geographic area of 9,325 km² (3,600 sq mi). Yamagata Prefecture borders Akita Prefecture to the north ...

, Japan in 1904. He graduated from the Yamagata Higher School in 1924, and from the Department of

Aeronautics Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies ...

, Faculty of

Engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...

Tokyo Imperial University , abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project b ...

in 1927 .

Jiro Horikoshi was the chief engineer of many Japanese fighter designs of World War II, including the Mitsubishi A6M Zero fighter. Early life Jiro Horikoshi was born near the city of Fujioka, Gunma Prefecture, Japan, in 1903. Horikoshi graduated from the ne ...

and

Hidemasa Kimura Hidemasa (written: 秀政, 秀匡 , 秀征 or 英正) is a masculine Japanese given name. Notable people with the name include: *, Japanese sumo wrestler *, Japanese samurai *, Japanese golfer *, Japanese footballer *, Japanese samurai *, Japanese ...

, who designed the

Mitsubishi A6M The Mitsubishi A6M "Zero" is a long-range carrier-based fighter aircraft formerly manufactured by Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and was operated by the Imperial Japanese Navy from 1940 to 1945. The A6M was ...

''Zero fighter'' and the ''Koken'' (Tokyo Imperial University Aeronautical Research Institute) Long-range Research-plane, respectively, were his classmates at the department in the university. In 1927 Doi started his career at the Aircraft Department of Kawasaki Dockyard Company Limited (

Kobe Kobe ( , ; officially , ) is the capital city of Hyōgo Prefecture Japan. With a population around 1.5 million, Kobe is Japan's seventh-largest city and the third-largest port city after Tokyo and Yokohama. It is located in Kansai region, whic ...

, Japan), which later became Kawasaki Aircraft Company Limited in 1937. These are the predecessors of present

Kawasaki Heavy Industries Aerospace Company is the aerospace division of Kawasaki Heavy Industries (KHI). It produces aircraft, space systems, simulators, jet engines, missiles, and electronic equipment. During the 1930s and 1940s, Kawasaki Aircraft Industries developed numerous types ...

reorganized in 1969. At that time, Dr. Richard Vogt was also working for the Kawasaki Dockyard Company Limited. The company invited Vogt from Germany as a technical advisor to teach its engineers in the construction techniques of Dornier aircraft which Kawasaki was building under license. As a chief designer, Vogt trained Doi to be his successor. They worked jointly on several aircraft projects, including the (KDA-5 Army Type 92 biplane fighter, KDA-2 Army Type 88

reconnaissance In military operations, reconnaissance or scouting is the exploration of an area by military forces to obtain information about enemy forces, terrain, and other activities. Examples of reconnaissance include patrolling by troops (skirmishers ...

biplane, KDA-3 single-seat fighter, and KDA-5 Army Type 92-I biplane fighter). During this period, Doi was dispatched to Europe, where he worked for one and a half years. In Europe he studied aircraft engineering. While Doi was in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Nor ...

he paid attention to the technology of

George Dowty Sir George Herbert Dowty (27 March 1901 – 2 December 1975) was an English inventor and businessman. He founded Dowty Aviation in the 1930s producing aircraft components such as hydraulic systems, undercarriage units, and warning devices. Ear ...

, founder of Dowty Aviation. As Dowty's technology in aviation

hydraulic system Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...

s was state-of-the-art and met the requirement of the Japanese military, Doi chose Dowty equipment for the

landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...

of the Army Type 92-I Fighter. This decision helped Dowty to develop his company, Dowty Aviation, and became a milestone for the expansion of the Dowty Equipment group thereafter. By strange coincidence,

Dowty Rotol Dowty Propellers is a British engineering company based in Brockworth, Gloucestershire that specialises in the manufacture, repair and overhaul of propellers and propeller components for customers around the world. It is owned by General Elec ...

, descendant of the company, was the supplier of the propellers used on the

NAMC YS-11 The NAMC YS-11 is a turboprop airliner designed and built by the Nihon Aircraft Manufacturing Corporation (NAMC), a Japanese consortium. It was the only post-war airliner to be wholly designed and manufactured in Japan until the development of ...

airliner. After Vogt returned to Germany, Doi became the key person in the design bureau of Kawasaki Aircraft until the company ceased operations at the end of World War II. His most important and outstanding work was the design of Army Type 3 Fighter

"''Hien''". Ki-61 ''Hien'' demonstrated surprising performance that surpassed the famous

Mitsubishi A6M Zero The Mitsubishi A6M "Zero" is a long-range carrier-based fighter aircraft formerly manufactured by Mitsubishi Aircraft Company, a part of Mitsubishi Heavy Industries, and was operated by the Imperial Japanese Navy from 1940 to 1945. The A6M was ...

. A total of 3,159 Ki-61 ''Hien'' and its variants were built. After WWII, Doi was forced to interrupt work on aircraft design until the

Treaty of San Francisco The , also called the , re-established peaceful relations between Japan and the Allied Powers on behalf of the United Nations by ending the legal state of war and providing for redress for hostile actions up to and including World War II. It ...

came into force in 1952. During this period, he worked as a day laborer, while continuing to have faith that he would eventually return to aviation field. He continued to study the latest technology with Kimura who was the professor fired from the

University of Tokyo , abbreviated as or UTokyo, is a public research university located in Bunkyō, Tokyo, Japan. Established in 1877, the university was the first Imperial University and is currently a Top Type university of the Top Global University Project by ...

.Swords into plowshares: Civilian application of wartime military technology in modern Japan, 1945-1964 (PDF)
/ref> Kimura was Doi's best friend. When the treaty lifted the ban on designing and operating aircraft, Doi returned to his original work. In 1956 the

Ministry of International Trade and Industry The was a ministry of the Government of Japan from 1949 to 2001. The MITI was one of the most powerful government agencies in Japan and, at the height of its influence, effectively ran much of Japanese industrial policy, funding research and d ...

of Japan announced a domestic production plan of middle-sized commercial aircraft, i.e. the YS-11. The consortium of companies, the

(NAMC), was established. NAMC included

Mitsubishi Heavy Industries is a Japanese multinational engineering, electrical equipment and electronics corporation headquartered in Tokyo, Japan. MHI is one of the core companies of the Mitsubishi Group and its automobile division is the predecessor of Mitsubishi Motors ...

, and

Fuji Heavy Industries is a Japanese multinational corporation and conglomerate primarily involved in both terrestrial and aerospace transportation manufacturing. It is best known for its line of Subaru automobiles. Founded in 1953, the company was formerly named ( ...

, Shinmeiwa Manufacturing,

Japan Aircraft Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, Showa Aircraft, and

Kawasaki Heavy Industries (or simply Kawasaki) is a Japanese public multinational corporation manufacturer of motorcycles, engines, heavy equipment, aerospace and defense equipment, rolling stock and ships, headquartered in Chūō, Kobe and Minato, Tokyo, Japan. I ...

(Kawasaki Aircraft). Doi was nominated the chief designer of equipment team. Doi became a professor at

Meijo University is a private university in Japan. Its main campus is in Tempaku-ku, Nagoya, Aichi Prefecture, and it has two other campuses in Nagoya, Aichi Prefecture. It had two faculty members who were Nobel laureates as of 2021. History The name Mei ...

after he retired Kawasaki Heavy Industries. He also served as a councilor of the Japan Society for Aeronautical Science, a trustee of Japan Aeronautic Association, and an advisor emeritus of Kawasaki Heavy Industries. Details of his philosophy on aircraft design were written in his memoirs, regarding the designing policy, developmental history of the aviation technology, and his friends, published in Japan in 1989.

Aircraft of his design

Kawasaki Ki-10 The was the last biplane fighter used by the Imperial Japanese Army, entering service in 1935. Built by Kawasaki Kōkūki Kōgyō K.K. for the Imperial Japanese Army, it saw combat service in Manchukuo and in North China during the early stage ...

(Army Type 95 Fighter) *

Kawasaki Ki-45 The Kawasaki Ki-45 ''Toryu'' (屠龍, "Dragonslayer") was a two-seat, twin-engine heavy fighter used by the Imperial Japanese Army in World War II. The army gave it the designation "Type 2 Two-Seat Fighter"; the Allied reporting name was "Nic ...

"''Toryu''" (Army Type 2 Two-seat Fighter) *

Kawasaki Ki-48 The Kawasaki Ki-48 ( ja, 九九式雙發輕爆擊機, shiki-souhatu-keibaku, shortened to 'Sokei', Army Type 99 Twin-engined Light Bomber), was a Japanese twin-engine light bomber that was used during World War II. Its Allied reporting name wa ...

(Army Type 99 Bomber) *

Kawasaki Ki-56 The Kawasaki Ki-56 ( ja, 一式貨物輸送機, Type 1 Freight Transport) was a Japanese two-engine light transport aircraft used during World War II. It was known to the Allies by the reporting name "Thalia". 121 were built between 1940 and 19 ...

(Army Type 1 Transport Aircraft) *

"''Hien''" (Army Type 3 Fighter) *

Kawasaki Ki-100 The Kawasaki Ki-100 (''キ100'') is a single-seat single-engine monoplane fighter aircraft used by the Imperial Japanese Army Air Service during World War II. The Japanese Army designation was . It was not assigned an Allied code name. 275 Ki ...

(Army Type 5 Fighter) *

Kawasaki P-2J The Kawasaki P-2J (originally P2V-Kai) is a maritime patrol and ASW aircraft developed for the Japan Maritime Self-Defense Force. A turboprop-powered version of the radial-engined P-2 Neptune, the P-2J was developed as an alternative to buying ...

(customized Lockheed

P-2 Neptune The Lockheed P-2 Neptune (designated P2V by the United States Navy prior to September 1962) is a maritime patrol and anti-submarine warfare (ASW) aircraft. It was developed for the US Navy by Lockheed to replace the Lockheed PV-1 Ventura and P ...

anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typi ...

aircraft) * and more

Writings

* 航空機設計50年の回想 ("''Fifty Years Recollections on Aircraft Design''") by Takeo Doi (Kantosha, October 1989), * 軍用機開発物語 ("''Story of Warplane Development''") by Takeo Doi (Kojinsha, August 2007),

References

External links

Kawasaki Heavy Industries, Ltd.

(in Japanese) * ttp://www.aero.or.jp/web-koku-to-bunka/part2sakaidraft.html "Fifth Alumni of Department of Aeronautics, Tokyo Imperial University (Part 2)"in Airforum(in Japanese) {{DEFAULTSORT:Doi, Takeo Aircraft designers Japanese aerospace engineers 1904 births 1996 deaths People from Yamagata Prefecture University of Tokyo alumni