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Hien 
Read the corresponding
Ki-61/Ki-100 story
by Scott Hoffman
 
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  Hien
The Army Type 3 Fighter Hien (swallow), also known as the Kawasaki Ki-61 or "Tony", is either admired for its clean, aggressive appearance or disliked as unorthodox and un japanese. It will, however, hardly leave any aviation enthusiast unaffected. It was one of the first airplanes to meet the enemy over Japan when a lone Hien encountered with Doolittle's raiders in 1942 and one of the last in helpless efforts to shield the country from the ever present B-sans.
        This is not an attempt to completely cover all the features and history of this aircraft, only an opportunity to present a few highlights and share some high resolution drawings and colour profiles with fellow enthusiasts. If you'd like to comment on any of the content or suggest any improvements to this page please mail to me at mark@marksindex.com
 
  Brief story
Kawasaki Ki-5
Kawasaki Ki-5 from 1933 (8K)

Kawasaki Ki-28
Kawasaki Ki-28 from 1937 (11K)

Kawasaki Ki-60
3-view drawing of Kawasaki Ki-60, first prototype (47K)

Ki-61-I-Otsu (165K)
Ki-61-I-Otsu, 50 Sentai, 2 Chutai, Heho airfield, Burma, Apr.44 (165K)

Ki-61-I-Hei (241K)
Ki-61-I-Hei flown by 1st.Lt. Mitsuyo Oyake, 6th Shinten spec. attack unit of the 18 Sentai, Japan, Jan.45 (241K)

Ki-61-I-Tei (381K)
Ki-61-I-Tei flown by 1st.Lt. Naoto Fukunaga, 18 Sentai, Java, Dec.44. The hiragana on the front reads "tsurugi" (sword)(381K)
(All three profiles above by Shigeru Nohara)
In 1937 Kawasaki Kokuki Kogyo K.K. lost its position as the prime supplier of fighters for the JAAF when, in the competition for the replacement of the Ki-10, the Army favoured Nakajima and its lighter, nimbler Ki-27. Kawasaki's entry, the Ki-28 with a V-12 liquid-cooled engine, proved fast but too heavy to handle for the pilots. It was based on the experiences from the Ki-5, a low-wing all-metal monoplane, way ahead of it's time. It failed to meet Army expectations in 1933, but eventually led to the more traditional Ki-10 contract in 1934. The Ki-5s father was Dr. Richard Vogt, a German designer leading Kawasaki between 1923-33, later to become head engineer for Blohm & Voss. He left for his pupil and successor Takeo Doi a strong faith in the potential of the in-line aero engine.
        During 1938 Kawasaki acquired the licence rights for the Daimler Benz DB601A engine and successfully adapted it for production in November 1940 as the Army Ha-40. Influenced by this, and not without Kawasaki's persistence and some political pressure, the Army contracted Kawasaki for the development of the new line of aircraft: the Ki-60 heavy interceptor and the Ki-61 all-purpose fighter. The three Ki-60 prototypes made, lacked the expected speed and with a wing loading of 182kg/m2 (as opposed to 96kg/m2 for the Ki-27) were immediately rejected by the still conservative test pilots, terminating the project.
        Instead, Takeo Doi and his deputy Shin Owada gave now full attention to the refinements of the Ki-61, concentrating on weight reduction, maneuverability and speed. In December 1941 the first prototype took to the air, the serial production started in autumn of 1942 and the aircraft entered service as the Army Type 3 Fighter Hien. It undergone a series of modifications affecting the armament, engine and airframe (For the external evolution see the profiles in the drawings section below. Read Scott Hoffman's corresponding Ki-61/Ki-100 story) Hien was generally successful and liked by its pilots, but the complex engine proved too much for the tropical field conditions the aircraft had to face during 1943 and for the inadequate maintenance and supply situation within the JAAF. It's career was crippled by fate when its main adversary, the B-29s, raided and completely destroyed the Akashi engine plant in January 1945.
        Necessity is the mother of invention, so fate rather than design forced the engineers to adapt the Ha-112 14-cylinder radial engine to the 275 headless Ki-61-II bodies left after the raid, resulting in one of the finest fighters of the war, the Army Type 5 / Ki-100. It began entering service already in March 1945, but by then the disadvantage in experience and numbers was all that counted and the war was soon to be lost.
 
  St.Sgt. Matsumi Nakano
Nakano's Hien 1
Nakano's Hien 2
Nakano's Hien 2
Corporal Nakano's Hien on display outside Tokyo's Matsuya Dept. Store, Christmas 1944 (428K, 207K, 242K)

Nakano's Ki-61-I-Otsu
Colour profile of Corporal Nakano's Ki-61-I-Otsu. The hiragana on the rudder reads "na" (by Shigeru Nohara, 100K)
Click to view large photo of Matsumi Nakano & some other 244 Sentai Shinten-pilots (193K)Click to see larger photo of Matsumi Nakano (42K)
Click the thumbnails to view larger photos of Matsumi Nakano and some other Shinten-pilots of 244 Sentai
On December 3, 1944, Corporal Matsumi Nakano of 244 Sentai's special Shinten (body attack) detachment, flying from Chofu airfield near Tokyo, caught up with a box-formation of twelve B-29s. After two failures to approach, he made a third dive on an aircraft in the centre of the box. He missed and ended up just under the bomber's fuselage. After a few seconds of level flight he zoomed in at full throttle and tore into one of the horizontal stabilizers with his propeller. He then ascended, as if his Hien was fixed to the B-29. After a while the bomber began to fall down and a moment later Nakano somehow managed to disengage and belly-landed safely.
        His plane was displayed outside of Tokyo's Matsuya Department Store during Christmas, together with a full scale mock-up of the B-29 and some parts of the bombers wreck. (See photographs. The moderate damage to the lower parts of the Hien seems to indicate Nakano possibly landed gear-down!).
        On January 27, 1945, Nakano, now promoted to St.Sergeant, was flying together with Sgt. Masao Itagaki (who had also succeeded in two ramming attacks!). They found a formation of ten B-29s flying slightly below. Nakano dove, missed again, tore off the bombers tail, just like on the first occasion, and made another safe belly-landing.
        The a/c used the first time was a Ki-61-I-Otsu, probably with armament removed (see colour profile). Some sources claim the "33's" on the gear doors were red. The markings of the second a/c are not known. (Thanks to Ryusuke Ishiguro for research!)
 
  "Blue 24" of Maj. Kobayashi
Ki-61-I-Tei of Maj. Kobayashi
Two Ki-61-I-Tei machines flown by CO 244 Sentai Maj. Teruhiko Kobayashi in February (blue "24") and April (red "87"), 1945 (128K)


Kobayashi's Ki-61-I-Otsu in which he scored his 6th victory (64K)


Kobayashi's "Blue 24" Ki-61-I-Tei as commonly illustrated (I.Hasegawa, 98K). See also below

"Blue 24" by K. Hashimoto
Another profile of "Blue 24", by K. Hashimoto, FAOW #98/1978 (114K)
Maj. Kobayashi in one of his early Ki-61-I-OtsuMaj. Kobayashi in front of one of his fighters (74K)
Maj. Kobayashi with his Bukosho Medal of Honour (55K)Maj. Kobayashi in front of his Ki-100-I-Otsu, Spring 1945
Click the four thumbnails to view larger photos of Maj. Kobayashi
Maj. Teruhiko Kobayashi started his career in the JAAF as a light bomber pilot over China. He rose to fame as a CO of the 244 Sentai defending the skies over Tokyo in 1944/45. Kobayashi's final credit is 14 (20?) kills, most of them B-29s, and although formally not a "shinten" pilot, he scored his 6th victory on January 27, 1945, by ramming a Superfortress. For this merit he received the Bukosho Medal of Honour (see photograph). He flew several different Hien and the very fact that the many markings of his aircraft are well documented is a confirmation of his popularity.
        There's a controversy about his most famous mount, the "Blue 24", illustrated in at least two different versions, the first when freshly received after his ramming attack, in natural metal finish, the second camouflaged in drab blotches with 8 additional kill marks added. Careful study of photographs (particularly in Watanabe's "Air War Over Japan") reveal that Mr. Hashimoto was probably right in 1978 when he illustrated the plane with blue wing bands, parallel to the fuselage and located midway between the end of the ID-band and the Hinomaru (see illustrations). Please also note the obvious dark band on the starboard wing of the a/c on the photograph of the 244 Sentai Shinten pilots. The correct colour of the "24" on the gear door is blue. The tail inscription on the second "Blue 24" says "I win everytime". Ususally in the JAAF, the numbers on the gear doors were the last digits of the serial number, but there's a possibility that the blue (red?) "24" flown by Kobayashi in November -44 was in fact a different airframe.
 
  Drawings
Profiles Ki-60 to Ki-61-I-Tei
Profiles: Ki-60 to Ki-61-I-Tei
Profiles Ki-61-II to Ki-100-II
Profiles: Ki-61-II to Ki-100-II

Ki-61-I-Ko marking scheme, port & front (67K)
Ki-61-I-Ko marking scheme, port & front (67K)
Ki-61-I-Ko marking scheme, top & bottom (105K)
Ki-61-I-Ko marking scheme, top & bottom (105K)
Ki-61-I-Tei drawing, port side view (51K)
Ki-61-I-Tei drawing, port side view (51K)
Ki-61-I-Tei drawing, starboard side view (49K)
Ki-61-I-Tei drawing, starboard side view (49K)
Ki-61-I-Tei drawing, top view (94K)
Ki-61-I-Tei drawing, top view (94K)
Ki-61-I-Tei drawing, bottom view (93K)
Ki-61-I-Tei drawing, bottom view (93K)
Ki-61-I-Tei drawing, front view (36K)
Ki-61-I-Tei drawing, front view (36K)
To the right: profile drawings of all important model versions of the Hien, including the Ki-60 and the Ki-100, originally rendered by Tadeusz Januszewski for the "Monografie Lotnicze" #5, complemented and adjusted by me. Beneath: two scans of the marking scheme of the Ki-61-I-Ko and five scans of detailed drawings of the Ki-61-I-Tei.
        Drawings, as well as most other illustrations on this page, are large, larger than what fits onto an average computer screen. They may take a while to download on a slow connection and may be difficult to print on an office printer. I've made every effort possible to compress the files as much as possible without loosing too much quality. To reduce the sizes any further would mean to loose important detail and render the whole exercise pointless.
        There may be some controversy about the designations of the different versions of the Hien. It is not certain that the 388 Ki-61-I's equipped with the Mauser MG 151 20mm guns ever received the official designation "Hei". Consequently, some sources refer to the later, longer version as the "Ki-61-Ic" instead of "d". (The Japanese "Ko", "Otsu", "Hei" and "Tei" are equivalent to a, b, c, and d) Others add the expression "Kai" (modified) to various models, although it was probably not officially assigned, except for the Ki-61-II. Others dignify the Ki-61-I experimentally fitted with two wing-mounted 30mm cannons (and not included in this page's gallery) as the I-Tei. I've tried to assign the designations so as to best correspond with what's most frequently found in recent sources. The important thing, after all, is to recognize the models and their place in the chain of development.
        Notes: Ki-61-I w.c.e.s. (see the profiles) refers to an experimental a/c with a wing cooling evaporation system. It was the fastest Hien ever made achieving 630km/hr (395 m.p.h.), and the last with a retractable tail wheel.
The shape of the wing of the Hien remained virtually unchanged throughout, except for the eight Ki-61-II pre-production aircraft, where the area was increased from 20 to 22m2.
The MG 151 20mm cannon equipped aircraft had the guns mounted lying on the side, turned 90o clockwise, if looking from behind, and received a small blister on top of the wing to accomodate the mechanism. The large blisters underneath the wing, visible on some photographs, are for spent cartridges during practise.
 
  Literature
Encyclopedia of Japanese Aircraft 1900-1945. Vol.4. Kawasaki Aircraft Nozawa,T. (Shuppan-kyodo 1960)
Kawasaki Ki-61/Ki-100 Bily,M. (Modelpress, Praha 1992)
Monografie Lotnicze #5: Kawasaki Ki-61 Hien Januszewski, T. & Jarski, A. (AJ-Press, Gdansk 1992)
Kawasaki Ki-61 Tony Koku-fan authors (Paul Gaudette, ?)
Asahi Journal Vol.2 No.1: Ki-61 / Ki-100 (JII publ. 1994)
Asahi Journal Vol.2 No.3. / Ki-61(cont.) (JII publ. 1994)
JAS Jottings Vol.3 No.2 & 3: JAAF single engine fighters (Jap. Av. SIG, IPMS/UK 1997)
Maru Mechanic No.45: Ki-43 / Ki-61 (1984)
Mechanic of World Aircraft No.2: Ki-61 / Ki-48 (Maru Mechanic reissue, 1993)
Aircam No.21: Kawasaki Ki-61 / Ki-100 Hien Richard M. Bueschel (Osprey, 1971)
Profile No.118: Kawasaki Ki-61 Hien Rene J. Francillon (1966)
Famous Airplanes Of The World No.98: Army Type 3 Fighter Hien (1978)
Famous Airplanes Of The World No.17: Army Type 3 Fighter Hien (7/1989)
Famous Airplanes Of The World No.23: Army Type 5 Fighter (7/1990)
Model Art Spec. No.416: Medaled Pilots of JAAF in WWII (1993)
Model Art Spec. No.428: I.J.A. Kawasaki Type 3 & 5 Fighters Ki-61 / Ki-100 (1994)
Model Art Spec. No.451: IJA Air Force Suicide Attack Units (1995)
For more litterature on Japanese military subjects see my reference list
 

 
  Disclaimer
Most illustrations are copyright of the publications where they first appeared (Maru, Bunrin-do, Model Art, AJ-Press), and are submitted here only for the purpose of sharing them with fellow enthusiasts. They may not be duplicated, printed or used commercially in any way. Should anyone feel the appearance of any of the illustrations on this site violates the copyrights, please mail to me at mark@marksindex.com
 
Mark Kaiser, 1999