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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).[2] Allied intelligence initially believed Ki-61s were Messerschmitt Bf 109s and later an Italian Macchi C.202, which led to the Allied reporting name of "Tony", assigned by the United States War Department.[3] The design originated as a variant of the Kawasaki Ki-60, which never entered production. The Ki-61 became the only mass-produced Japanese fighter of the war to use a liquid-cooled inverted V engine. Over 3,000 Ki-61s were produced. Initial prototypes saw action over Yokohama during the Doolittle Raid on 18 April 1942, and continued to fly combat missions throughout the war.[4][5]

Ki-61 Hien
Role Fighter aircraft
Manufacturer Kawasaki Kōkūki Kōgyō K.K.
First flight December 1941
Introduction 1942
Retired 1945
Primary users Imperial Japanese Army Air Service
Number built 3,078[1]
Developed from Kawasaki Ki-60
Developed into Kawasaki Ki-100
Kawasaki Ki-61 Hien with drop tank

Design and development edit

The Ki-61 was designed by Takeo Doi and his deputy Shin Owada in response to a late 1939 tender by the Koku Hombu[N 1] for two fighters, each to be built around the Daimler-Benz DB 601Aa. Production aircraft would use a Kawasaki licensed DB 601, known as the Ha-40, which was to be manufactured at its Akashi plant. The Ki-60 was to be a heavily armed specialised interceptor, with a high wing loading; [N 2] the Ki-61 was to be a more lightly loaded and armed general-purpose fighter, intended to be used mainly in an offensive, air superiority role at low to medium altitudes.[N 3]

Both single-seat, single-engine fighters used the same basic construction: all-metal alloys with semi-monocoque fuselages and three-spar wings, with alloy-framed, fabric-covered ailerons, elevators and rudders. Priority was given to the Ki-60, which first flew in April 1941, while design work on the Ki-61 did not begin until December 1940. Although the Ki-61 was broadly similar to the Ki-60, it featured several refinements exploiting lessons learned from the disappointing flight characteristics of the earlier design.[6]

The all-metal, semi-monocoque fuselage was basically oval in cross-section, changing to a tapered, semi-triangular oval behind the cockpit canopy, with a maximum depth of 1.35 m (4 ft 5 in). An unusual feature of the Ki-61 was that the engine bearers were constructed as an integral part of the forward fuselage, with the cowling side panels being fixed. For servicing or replacement, only the top and bottom cowling panels could be removed. A tapered, rectangular supercharger air intake was located on the port-side cowling. Behind the engine bulkhead were the ammunition boxes feeding a pair of synchronized 12.7 mm (.50 in) Ho-103 machine guns which were set in a "staggered" configuration (the port weapon slightly further forward than that to starboard) in a bay just above and behind the engine. The breeches partly projected into the cockpit, above the instrument panel. The Ho-103 was a light weapon for its caliber (around 23 kg/51 lb) and fired a light shell, but this was compensated for by its rapid rate of fire. The ammunition capacity was limited, having only around 250 rounds for each weapon. A self-sealing fuel tank with a capacity of 165 L (44 US gal) was located behind the pilot's seat. The windshield was armored and there was a 13 mm (.51 in) armor plate behind the pilot. The radiator and oil cooler for the liquid-cooled engine were in a ventral location below the fuselage and wing trailing edge, covered by a rectangular section fairing with a large, adjustable exit flap.[6]

The evenly-tapered wings had an aspect ratio of 7.2 with a gross area of 20 m2 (215.28 ft2) and featured three spars; a Warren truss main spar and two auxiliary spars. The rear spar carried the split flaps and long, narrow-chord ailerons, while the front spar incorporated the undercarriage pivot points. The undercarriage track was relatively wide at 4 m (13 ft 1.5 in). Each wing had a partially self-sealing 190 L (50 US gal) fuel tank behind the main spar, just outboard of the fuselage. A single weapon (initially a 7.7 mm/0.303 in Type 89 machine gun) was able to be carried in a weapons bay located behind the main spar.[6]

The first prototype of the San-shiki-Sentohki ichi gata ("Type 3 Fighter, Model 1", the official IJAAF designation) first flew in December 1941 at Kagamigahara Airfield.[7] Although test pilots were enthusiastic about its self-sealing fuel tanks, upgraded armament, and good dive performance, the wing loading of 146.3 kg/m2 (30 lb/ft2) at an all-up weight of 2,950 kg (6,500 lb) was viewed with scepticism by many of the senior officers of the Koku Hombu, who still believed in the light, highly manoeuvrable, lightly armed fighter epitomised by the then new Nakajima Ki-43-I-Hei which had a wing loading of 92.6 kg/m2 (19 lb/ft2) (and even that was considered borderline compared to the earlier Ki-27).[8]

To address these concerns, Kawasaki staged a fly-off between two Ki-61 prototypes and the Nakajima Ki-43-I, a pre-production Nakajima Ki-44-I, a defector-flown Lavochkin-Gorbunov-Goudkov LaGG-3, a Messerschmitt Bf 109E-7, and a captured Curtiss P-40E Warhawk. The Ki-61 proved the fastest of all the aircraft and was inferior only to the Ki-43 in manoeuvrability.[8][9][10][11]

The Ki-61 was the last of the fighters powered by the DB-601 or its foreign derivatives, and it was soon overshadowed by fighters with more powerful engines. By the time it first flew in December 1941, one year after the Macchi C.202's first flight and three years after the first Bf 109E, the engine was already underpowered compared to the new 1,120 kW (1,500 hp) inline or 1,491 kW (2,000 hp) radial engines being developed (and already nearing the mass-production stage) to power the next generation of combat aircraft such as the Republic P-47 Thunderbolt. Moreover, the inline Ha-40 engine proved to be an unreliable powerplant,[12][13] exacerbated in the South Pacific campaign, where high temperatures caused problems with the fuel pumps.[14]

The DB-601 engine required precise and sophisticated manufacturing; the Ha-40 was lighter by roughly 30 kg (70 lb) and required even higher manufacturing standards. Reaching these standards proved difficult for Japanese manufacturers, an issue further complicated by the variable quality of materials, fuel, and the lubricants needed to run a sensitive, high-performance engine. The Japanese equivalent of the more powerful DB-605 engine was the Kawasaki Ha-140, which was fitted onto the Type 3 to produce the Ki-61-II high-altitude interceptor.[12][15]

Compared to the Ki-61-I, the Ki-61-II had 10% greater wing area, used more armour and was powered by the Kawasaki Ha-140 engine generating 1,120 kW (1,500 hp). After overcoming initial fuselage and wing stability problems, the new interceptor reverted to the original wing and was put into service as the Ki-61-II-KAI. However, the Ha-140 engine had severe reliability problems that were never fully resolved, and around half of the first batch of engines delivered were returned to the factory to be re-built. A US bombing raid on 19 January 1945 destroyed the engine factory in Akashi, Hyōgo, and 275 Ki-61-II-KAI airframes without engines were converted to use the Mitsubishi Ha-112-II radial engine, resulting in the Ki-100. While the Ha-112 solved the problems encountered with the Ha-140, the new engine still had a major weakness: a lack of power at altitude, which diminished its ability to intercept high-flying B-29 Superfortresses relative to the Ki-61-II.[12][16]

During testing, the Hien proved capable,[17] but several shortcomings were subsequently revealed in operational service,[citation needed] namely the armor protection that was insufficient against larger guns and a sub-standard engine that eventually led to a new engine being considered.[citation needed]

Operational history edit

 
A captured Kawasaki Ki-61 fighter tested by the U.S. Navy Naval Air Test Center Patuxent River, Maryland (USA), in June 1945

The Ki-61 looked so different from the usual radial-engined Japanese fighters that the Allies at first believed it to be of German or Italian origin, possibly a license-built Messerschmitt Bf 109. The first Ki-61 seen by Allied aircrew had been misidentified as a Bf 109 by USAAF Capt. C. Ross Greening during the Doolittle Raid. In early reports, when it was thought to have been a German fighter, the Ki-61 had been code-named "Mike".[4][5] The final, and better known code name adopted was "Tony", because the Ki-61 looked like an Italian aircraft.[18][19]

The new Ki-61 Hien fighters entered service with a special training unit, the 23rd Chutai, and entered combat for the first time in early 1943, during the New Guinea campaign.[20] The first Sentai (Air Group/Wing) fully equipped with the Hien was the 68th in Wewak, New Guinea,[20] followed by the 78th Sentai stationed at Rabaul. Both units were sent into a difficult theatre where jungles and adverse weather conditions, coupled with a lack of spares, quickly undermined the efficiency of both men and machines. Because the Ki-61 was so new, and had been rushed into service, it inevitably suffered from teething problems. Almost all of the modern Japanese aircraft engines, especially the Ki-61's liquid-cooled engines, suffered a disastrous series of failures and ongoing problems,[13] which resulted in the obsolescent Ki-43 still forming the bulk of the JAAF's fighter capability.

Initially, this campaign went successfully for the Japanese Army Air Force (JAAF), but when the Allies re-organized and enhanced the combat capabilities of their air forces, they gained the upper hand against the JAAF.[13] High non-combat losses were also experienced by the Japanese during this campaign. For example, while in transit between Truk and Rabaul, the 78th lost 18 of its 30 Ki-61s.[21][22] The finicky Ha-40 engine could not be overhauled in the theatre, instead they had to be shipped to the nearest service depot in Halmahera, in eastern Indonesia.[14]

Even with these problems, there was some concern in Allied aviation circles regarding the Hien. The new Japanese fighter caused some pain and consternation among Allied pilots, particularly when they found out the hard way that they could no longer go into a dive and escape as they had from lighter Japanese fighters. General George Kenney, the Allied air forces commander in the Southwest Pacific, found his Curtiss P-40s completely outclassed, and begged for more Lockheed P-38 Lightnings to counter the threat of the new enemy fighter.[citation needed]

However, the increasing numerical strength of Allied bomber units, along with inadequate anti-aircraft systems, imposed crippling losses on Japanese units. Approximately 174 out of 200 Japanese aircraft based in the Wewak area were lost during the attacks of August 17–21 1943.[23] By the end of the campaign, nearly 2,000 Japanese aircraft had been lost in air attacks from up to 200 Allied aircraft at a time, around half of which were Consolidated B-24 Liberators and North American B-25 Mitchells armed with fragmentation bombs.[13] After the Japanese retreat, over 340 aircraft wrecks were later found at Hollandia.[13]

 
Capt. Teruhiko Kobayashi's Ki-61 of the 244th Sentai

The Ki-61 was also utilised in Southeast Asia, Okinawa, China and as an interceptor during US bombing raids over the Japanese home islands, including against Boeing B-29 Superfortresses. The Ki-61 was notable for many reasons: initially identified as of either German or Italian origin, these aircraft were capable of matching Allied aircraft such as the P-40 in speed, and as evaluation had already shown, were superior in almost every respect. However, the armament of the early Hien was lighter, but still sufficient for most purposes. Some authors claim that the Lockheed P-38 Lightning was measurably superior.[24] The Ki-61 carried a great deal of fuel, but due to having self-sealing fuel tanks it was not considered readily flammable, as many other Japanese aircraft were.[12]

Owing to the additional weight, the Ki-61's performance and agility suffered when its armament was increased, but it still remained capable with a 580 km/h (313 kn) maximum speed. The cannon armament was needed to counter the Allied bombers, which proved to be difficult to shoot down with only 12.7 mm (.50 in) machine guns. The empty and maximum weights for the Ki-61 prototype (2 × 12.7 mm/0.50 in + 2 × 7.7 mm/0.303 in) were 2,238 kg (4,934 lb) and 2,950 kg (6,504 lb), respectively; for the Ki-61-I basic (4 × 12.7 mm/.50 in) 3,130 kg (6,900 lb); and for the Ki-61-KAI (2 × 12.7 mm/0.50 in + 2 × 20 mm), 2,630 kg (5,798 lb) and 3,470 kg (6,750 lb).[12]

A number of Ki-61s were also used in Tokkotai (kamikaze) missions launched toward the end of the war. The Ki-61 was delivered to 15th Sentai (group/wing), as well as some individual Chutaicho (Squadron Leaders) in other Sentai, and even to operational training units in the JAAF. The aircraft was largely trouble-free in service except for the liquid-cooled engine which tended to overheat when idling on the ground and suffered from oil circulation and bearing problems.[25]

Ki-61 Special Attack Unit edit

 
An ex-23rd Sentai, 2nd Chutai Ki-61 found and photographed at Inba airbase by USAAF personnel in 1946.

The tactic of using aircraft to ram American Boeing B-29 Superfortresses was first recorded in late August 1944, when B-29s from Chinese airfields attempted to bomb the steel factories at Yawata. Sergeant Shigeo Nobe of the 4th Sentai intentionally flew his Kawasaki Ki-45 into a B-29; debris from the explosion severely damaged another B-29, which also went down.[N 4][26] Other attacks of this nature followed, as a result of which individual pilots determined it was a practicable way of destroying B-29s.[27]

On 7 November 1944, the officer commanding the 10th Hiko Shidan (Air division) made ramming attacks a matter of policy by forming ramming attack flights specifically to oppose the B-29s at high altitude. The aircraft were stripped of their fuselage armament and protective systems in order to attain the required altitudes. Although the term "kamikaze" is often used to refer to the pilots undertaking these attacks, the word was not used by the Japanese military.

The units assigned to the 10th Hiko Shidan included the 244th Hiko Sentai (Fighter group), then commanded by Captain Takashi Fujita, who organised a ramming flight called "Hagakure-Tai" ("Special Attack Unit"), which was composed out of volunteers from the three Chutai (squadrons) of the 244th: the 1st Chutai "Soyokaze", 2nd Chutai "Toppu", and the 3rd Chutai known as "Mikazuki".

First Lieutenant Toru Shinomiya was selected to lead the Hagakure-Tai. On 3 December 1944, Shinomiya – along with Sergeant Masao Itagaki and Sergeant Matsumi Nakano – intercepted a B-29 raid; Shinomaya rammed one B-29, but was able to land his damaged Ki-61, which had lost most of the port outer wing, back at base. After attacking another B-29 Itagaki had to parachute from his damaged fighter, while Nakano rammed and damaged Long Distance of the 498th BG and crash-landed his stripped-down Ki-61 in a field. Shinomaya's damaged Ki-61 was later displayed inside Tokyo's Matsuya department store while Nakano's Ki-61 was displayed outside, alongside of a life-size cut-away drawing of the forward fuselage of a B-29.[28][N 5] These three pilots were the first recipients of the Bukosho, Japan's equivalent to the Victoria Cross or Medal of Honor, which had been inaugurated on 7 December 1944 as an Imperial Edict by Emperor Hirohito (there are 89 known recipients, most of whom fought and scored against B-29s).[29][30] The existence of the ramming unit had been kept confidential until then, but it was officially disclosed in the combat results announcement and officially named "Shinten Seiku Tai" ("Body Attack Detachment") by the Defense GHQ. On 27 January 1945, Itakagi survived another ramming attack on a B-29, again parachuting to safety, and received a second Bukosho; he survived the war as only one of two known double-Bukosho recipients.[31] Sergeant Shigeru Kuroishikawa was another distinguished member of the unit.

 
A Ki-61 of the 149th shumbutai, taken in Ashiya after the war. The tail markings indicate it formerly came from the Akeno Kyodo Hikoshidan and the 59th sentai before being allocated to the 149th.

Despite their successful attacks, these pilots gained no reprieve, and were obliged to continue these deadly and dangerous ramming tactics until they were killed, or else wounded so badly that they could no longer fly. They were regarded as doomed men and were celebrated among the ranks of those who were going to certain death as Tokkotai (kamikaze) pilots.[32]

Some other Ki-61 pilots also achieved renown, among them Major Teruhiko Kobayashi of the 244th Sentai, who was credited by some with a dozen victories mostly due to conventional attacks against B-29s.[33]

Variants edit

Note: Ko, Otsu, Hei and Tei are the Japanese equivalents to a, b, c, d. Kai ('modified' or 'improved') was also used for some models of the Ki-61.

Ki-61-Hien
  • Ki-61 Prototypes: 12 built
  • Ki-61-I-Ko First production version: fully retractable tailwheel, two 7.7 mm (0.303 in) Type 89 machine guns in the wings and two synchronized 12.7 mm (0.50 in) Ho-103 machine guns in the forward decking. Capable of carrying one 151 L (40 gal) drop tank or a light bomb.[12]
  • Ki-61-I-Otsu Second production fighter variant: Tailwheel retraction mechanism was unreliable, the aircraft was modified accordingly. Two 12.7 mm (.50 in) Ho-103 machine guns replaced the wing 7.7 mm (.303 in) machine guns.[12]
  • Ki-61-I-Hei: The Hei was built in conjunction with the Otsu variant, the wing machine guns were replaced by Mauser MG 151/20 cannons.
  • Ki-61-I-Tei Fighter variant with two fuselage mounted Japanese 20 mm Ho-5 cannon and two 12.7 mm (.50 in) wing mounted Ho-103 machine guns.
  • Ki-61-I-KAId: Interceptor variant with 2 × 12.7 mm (.50 in) machine guns and 2 × 30 mm (1.18 in) Ho-155 wing cannon.
  • Ki-61-I- w.c.e.s: Experimental aircraft with evaporation system, as used on the Heinkel He 100. It was the fastest Ki-61 built, achieving 630 km/h (395 mph).
  • Ki-61-II Prototype with 1,500 PS (1,103 kW) Ha-140 engine and first flown in December 1943.
  • Ki-61-II-KAI: Pre-production version which reverted to the Ki-61-I-Tei wing, a 220 mm (8.7 in) fuselage stretch, enlarged rudder, and Ha-140 engine; 30 built.
  • Ki-61-II-KAIa: Armed with 2 x 12.7 mm (.50 in) machine guns in the wings and 2 x 20 mm cannon in the fuselage.
  • Ki-61-II-KAIb: Armed with 4 x 20 mm cannon.
  • Ki-61-III Prototype: This version had a cut-down rear fuselage and a canopy design which was later used by the Ki-100-I-Otsu

Production edit

Ki-61-I Production: Kawasaki Kokuki K.K[34]
Year
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
1942 1 3 5 10 15 34
1943 22 32 31 37 44 40 53 60 70 87 104 130 710
1944 150 156 145 142 118 236 254 198 164 174 101 53 1,891
1945 19 19
Total 2,654

Not included:

  • Pre-production started with the first prototype completed in July 1941,[35] and with further eleven builds in early 1942.[36]
Ki-61-II Production: Kawasaki Kokuki K.K[34]
Year
Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Annual
1944 1 3 26 0 0 0 0 1 26 41 71 70 239
1945 68 56 15 19 7 165
Total 404

Note:

  • Out of 374 Ki-61-II builds, 275 were completed as Ki-100 Ia.[1]

Not included:

  • Pre-production started with eight prototypes completed during Aug. 1943 to Jan. 1944.[1]
Total production:
According to USSBS Report: 3,058 [34] Figure includes: 2,654 Ki-61-I and 404 Ki-61-II builds
According to Francillon: 3,078 [1] Figure includes: 2,666 Ki-61-I and 412 Ki-61-II builds

Operators edit

  Japan

Post War

  China
  China
  Indonesia
  • In 1945, Indonesian Air Force –then Indonesian People's Security Force (IPSF) (Indonesian pro-independence guerrillas)– captured six such aircraft at numerous Japanese air bases, including Bugis Air Base in Malang (repatriated 18 September 1945). At least one was restored.[37] Most aircraft were destroyed in military conflicts between the Netherlands and the newly proclaimed-Republic of Indonesia during the Indonesian National Revolution of 1945–1949.[37]

Ki-61 units edit

 
Derelict Ki-61s in 1945 after the surrender. A Kawasaki Ki-45 heavy fighter is in the background.

The Hiko Sentai, usually referred to as Sentai, was the basic operational unit of the Imperial Japanese Army Air Force, composed of three or more Chutai (companies or squadrons). A Sentai had 27 to 49 aircraft, with each Chutai having 16 aircraft and pilots plus a maintenance and repair unit. Several sentai had other units under their operational control, most notably the Hagakure-Tai ("Special Attack Units") of the 244th Sentai. By 1944, with the depredations of Allied attacks on supply lines and airfields, as well as the loss of pilots and aircraft through combat attrition and accidents, few sentai were able to operate at full strength.[citation needed]

Units operating the Ki-61 "Hien"[38][39]
Sentai Established Aircraft type(s) Area of operations Disbanded Notes
17th 10 February 1944 at Kagamigahara, Gifu Prefecture[N 6] Ki-61, Ki-100 Philippines, Formosa, Japan End of war One of Kawasaki's main factories was located at Kagamigahara which, in 1944 was not yet a city.
18th 10 February 1944 at Chōfu from the 244th Sentai Ki-61, Ki-100 Philippines, Japan End of War Lt Mitsuo Oyake won Bukosho for shooting down three B-29s (one by ramming) 7 April 1945 and damaging three others.
19th 10 February 1944 at Akeno Fighter School Ki-61 Indonesia, Philippines, Formosa, Okinawa End of War (Formosa)
23rd 11 October 1944 at Inba, Chiba Prefecture Ki-43, Ki-44, Ki-61 Iwo Jima, Formosa, Japan End of war (Inba)
26th Late 1944 Ki-51, Ki-43, Ki-61 Formosa End of war (Formosa)
28th June 1939 in Manchuria Ki-46, Ki-61, Ki-102 Manchuria, Japan July 1945
31st July 1938 in China Ki-10, Ki-43, Ki-61 Manchuria, Philippines 30 May 1945 at Singapore
33rd Summer 1937 in China Ki-10, Ki-27, Ki-43, Ki-61 New Guinea, Manchuria (Manchoukuo), East Indies End of war, Medan, Dutch East Indies (currently Indonesia)
53rd 23 March 1944 at Tokorozawa, Saitama Ki-61, Ki-45 Japan, Eastern Defence Sector flew Ki-61 for a short time in Home Island Defence
55th 30 May 1944 at Taishō, Osaka Prefecture Ki-61 Philippines, Japan End of war at Sana, Nara Prefecture
56th August 1944 at Taishō Osaka Prefecture Ki-61 Japan End of war at Itami, Hyōgo Prefecture Unit claimed 11 B-29s for 30 pilots lost. Warrant Officer Tadao Sumi (five B-29s plus one P-51 Mustang destroyed, four B-29s damaged) Bukosho recipient.
59th 1 July 1938 at Kagamigahara, Gifu Prefecture Ki-10, Ki-27, Ki-43, Ki-61, Ki-100 China, Manchuria (Nomonhan), Indochina, East Indies, New Guinea, Okinawa, Japan End of War at Ashiya, Fukuoka Prefecture 1st Lieutenant Naoyuki Ogata Bukosho recipient. Warrant Officer Kazuo Shimizu flew with unit from February 1942 right through to August 1945; 18 victories, including nine bombers.
65th presumably 1938-1939 Ki-32, Ki-51, Ki-43, Ki-61, Ki-45 Philippines, Formosa, Okinawa, Japan End of war, Metabaru, Saga Unit used Ki-61 from the summer of 1944
68th March 1942 at Harbin, Manchuria Ki-27, Ki-61 Rabaul (New Britain), New Guinea, Halmahera 25 July 1944 First unit to convert to the Ki-61. Unit was destroyed by Allied air forces in New Guinea. Most surviving ground and aircrew were used as infantry, with few survivors. A Ki-61-1-Otsu, manufacturer's No. 640 is one of the best preserved aircraft wrecks in New Guinea.[40] Captain Shogo Takeuchi transferred from 64th Sentai, April 1942. KIA 15 December 1943 30+ victories.

Sgt. Susumu Kaijinami officially credited with eight victories plus 16 unofficially.

78th 31 March 1942 in China Ki-27, Ki-61 Manchuria, Rabaul, New Guinea 25 July 1944 Second unit to convert to the Ki-61. Unit was destroyed by Allied air forces in New Guinea. Most surviving ground and aircrew were used as infantry, with few survivors.
105th August 1944, Taichung, Formosa Ki-61 Okinawa, Formosa End of war (Formosa)
244th April 1942, reorganised from 144th Sentai Ki-27, Ki-61, Ki-100 Okinawa, Formosa End of war (Yokaichi, Shiga Prefecture) Nine Bukosho recipients. Major Teruhiko Kobayashi JAAF's youngest Sentai commander. Also had an air-to-air B-29 ramming unit. Sentai claimed 73 B-29s shot down plus 92 damaged. Most famous of the Home Defence Sentais. Captain Nagao Shirai considered the ranking ace of 244 Sentai and possibly leading B-29 "killer" of JAAF (11 B-29s) plus two Grumman F6F Hellcats destroyed, six other aircraft damaged using Ki-61 and Ki-100. Captain Chuichi Ichikawa nine B-29s plus one F6F destroyed, six B-29s damaged. Major Teruhiko Kobayashi, three B-29s plus two F6Fs destroyed.
Training units
23rd Dokuritsu Dai Shijugo (Independent Chutai) Chōfu, 1941 Ki-61 Japan Became basis of 23rd Sentai Evaluation and conversion unit for Ki-61.
Akeno Kyodo Hikoshidan (Akeno Flight School) Akeno, Mie Prefecture, 1935 Ki-10, Ki-27, Ki-43, Ki-44, Ki-45, Ki-61, Ki-84, Ki-100 Japan End of war Main flight training school for Army fighter pilots. Many of the instructors participated in missions in defence of Japan 1944–1945. Akeno Airbase still in operational use.
37th Kyoiku Hikōtai (Flight Training Company) Matsuyama airfield, Formosa, 1943[41] Ki-43, Ki-44, Ki-45, Ki-61, Ki-84 Formosa End of war Flight training school for Army fighter pilots. Many of the instructors participated in missions in defence of Japan 1944-1945

Surviving aircraft edit

Specifications (Ki-61-I-KAIc) edit

 
3-view drawing of Kawasaki Ki-61

Data from Japanese Aircraft of the Pacific War[49]

General characteristics

  • Crew: 1
  • Length: 8.94 m (29 ft 4 in)
  • Wingspan: 12 m (39 ft 4 in)
  • Height: 3.7 m (12 ft 2 in)
  • Wing area: 20 m2 (220 sq ft)
  • Airfoil: NACA 2R 16 wing root, NACA 24009 tip
  • Empty weight: 2,630 kg (5,798 lb)
  • Gross weight: 3,470 kg (7,650 lb)
  • Fuel capacity:
  • Internal 550 L (150 US gal; 120 imp gal)
  • External 2x 200 L (53 US gal; 44 imp gal)
  • Powerplant: 1 × Kawasaki Ha40 inverted liquid-cooled V-12 piston engine, 864 kW (1,159 hp)
  • Propellers: 3-bladed variable pitch propeller

Performance

  • Maximum speed: 580 km/h (360 mph, 310 kn) at 5,000 m (16,000 ft)
  • Range: 580 km (360 mi, 310 nmi)
  • Service ceiling: 11,600 m (38,100 ft)
  • Rate of climb: 15.2 m/s (2,990 ft/min)
  • Time to altitude: 7.0 min to 5,000 m (16,000 ft)
  • Wing loading: 173.5 kg/m2 (35.5 lb/sq ft)
  • Power/mass: 0.25 kW/kg (0.15 hp/lb)

Armament

See also edit

Related development

Aircraft of comparable role, configuration, and era

Related lists

References edit

Notes edit

  1. ^ Koku Hombu was the Technical Branch of the Imperial Army Air Headquarters.
  2. ^ The Nakajima Ki-44 was selected as the standard IJAAF interceptor fighter and followed broadly similar specifications to the Ki-60.
  3. ^ Nakajima designed a similar fighter, the Ki-62, also powered by an Ha-40. This design later became the basis for the Nakajima Ki-84.
  4. ^ The B-29s were Colonel Robert Clinksale's B-29-BW 42-6334 Gertrude C and Captain Ornell Stauffer's B-29-BW 42-6368 Calamity Sue, both from the 468th BG.
  5. ^ Shinomaya eventually lost his life as a Tokkotai pilot in the battle for Okinawa.
  6. ^ There is an inconsistency in the locations given; Kagamigahara is (wrongly) listed by Sakaida as being in the Saitama Prefecture, which is north of Gifu

Citations edit

  1. ^ a b c d Francillon, 1979, p. 120
  2. ^ Mondey 2006, p. 144.
  3. ^ Ethell 1995, p. 82.
  4. ^ a b Bueschel 1971, p. 7.
  5. ^ a b Bueschel 1971, p. 6.
  6. ^ a b c Green & Swanborough 1976, pp. 18–23.
  7. ^ Tanimura 1967, p. 12.
  8. ^ a b Green & Swanborough 1976, p. 23.
  9. ^ Francillon 1966, p. 319.
  10. ^ Green 1975, p. 78.
  11. ^ Francillon 1979, p. 114.
  12. ^ a b c d e f g Gibertini 1998, pp. 6–13.
  13. ^ a b c d e Vaccari 2000, pp. 82–90.
  14. ^ a b Claringbould, Michael John (2020), Japanese Army Fighters: New Guinea & the Solomons 1942-1944, Pacific Profiles, vol. 1, Kent Town, Australia: Avonmore Books, p. 66, ISBN 978-0648665915
  15. ^ Tanimura 1967, p. 17.
  16. ^ Januszewski & Jarski 1992, p. 38.
  17. ^ DeMoss, R.W.; Duncan, R.L. (26 January 1945). "Final Report on Comparative Combat Evaluation Trials of Japanese Tony 1 Type 3 Fighter". Project Ted (PDF) (Technical report). Vol. No. PTR-115. United States Navy. Retrieved 23 March 2010 – via WWIIaircraftperformance.org.
  18. ^ Francillon 1966, p. 316.
  19. ^ Crosby 2002, p. 94.
  20. ^ a b Januszewski & Jarski 1992, p. 25.
  21. ^ Bueschel 1971, pp. 7–9.
  22. ^ Tanimura 1967, p. 13.
  23. ^ Boyer, Allen D. "Shooting up Wewak". America in WWII. Retrieved 1 April 2021.
  24. ^ Green & Swanborough 1976, p. 29.
  25. ^ Green & Swanborough 1976, pp. 27–28.
  26. ^ "Pacific War Chronology: August 1944." 2 April 2010 at the Wayback Machine att.net. Retrieved: 12 June 2008.
  27. ^ Takaki & Sakaida 2001, p. ?.
  28. ^ Photo of Nakano's Ki-61 14 July 2011 at the Wayback Machine Retrieved: 26 October 2010.
  29. ^ Sakaida 1997, pp. 67–70.
  30. ^ Bukosho described xavierb.net. Retrieved: 3 June 2008.
  31. ^ Sakaida 1997, pp. 70, 94.
  32. ^ "Japanese website dedicated to the Tokkotai JAAF and JNAF." tokkotai.or.jp. Retrieved: 7 June 2008.
  33. ^ Sakaida 1997, pp. 74–75.
  34. ^ a b c USSBS, Appendix E., p. 16
  35. ^ Francillon, 1979, p. 112
  36. ^ Francillon, 1979, p. 114
  37. ^ a b Heyman, Jos (November 2005). (PDF). adf-serials.com. p. 8. Archived from the original (PDF) on 14 December 2005.
  38. ^ Sakaida 1997, pp. 82–87.
  39. ^ Bueschel1971, pp. 47–49.
  40. ^ "Ki-61 No. 640." pacificwrecks.com. Retrieved: 8 June 2008.
  41. ^ "Matsuyama airfield" pacificwrecks.com. Retrieved: 4 June 2011
  42. ^ Taylan, Justin (30 January 2022). "Ki-61-Ia Tony Manufacture Number 299". Pacific Wrecks. Retrieved 25 April 2022.
  43. ^ Taylan, Justin (3 May 2016). "Ki-61-II Tony Manufacture Number 379". Pacific Wrecks. Pacific Wrecks Inc. Retrieved 25 April 2017.
  44. ^ Taylan, Justin (3 May 2016). "Ki-61-II Tony Manufacture Number 640". Pacific Wrecks. Pacific Wrecks Inc. Retrieved 25 April 2017.
  45. ^ Marsh, Don; Long, James I. (2004). "The Many Faces of TONY "5017"". j-aircraft.com. Retrieved 25 April 2017.
  46. ^ Taylan, Justin (3 May 2016). "Ki-61-II Kai Tony Manufacture Number 61217 Tail 17". Pacific Wrecks. Pacific Wrecks Inc. Retrieved 25 April 2017.
  47. ^ Izawa, Tomoyuki (14 October 2016). "Flying swallow WWII fighter restored to glory by Kawasaki". The Asahi Shimbun. The Asahi Shimbun Company. Retrieved 25 April 2017.
  48. ^ . Chiran Peace Museum. Chiran Peace Museum. Archived from the original on 26 February 2016. Retrieved 25 April 2017.
  49. ^ Francillon 1979, pp. 119–120.

Bibliography edit

  • Bílý, Miroslav . Kawasaki Ki-61 a Ki.100 (Profily letadel II. Svetové války no.4) (in Czech with English and German captions). Praha, Czech Republic: Modelpres, 1992. ISBN 80-901328-0-4.
  • Bueschel, Richard M. (1971). Kawasaki Ki. 61/Ki. 100 Hien in Japanese Army Air Force service, Aircam Aviation Series No.21. Reading: Osprey. ISBN 0-85045-026-8. OCLC 678232.
  • Crosby, Francis (2002). Fighter Aircraft. London: Lorenz Books. ISBN 0-7548-0990-0.
  • Ethell, Jeffrey L. Aircraft of World War II. Glasgow: Collins/Jane's, 1995. ISBN 0-00-470849-0.
  • Francillon, René J. (1979). Japanese aircraft of the Pacific War. London: Putnam. ISBN 0-370-30251-6. OCLC 6124909. (new edition 1987 by Putnam Aeronautical Books, ISBN 0-85177-801-1.)
  • Francillon, René J. (1966). The Kawasaki Ki-61 Hien (Aircraft in Profile, Volume 5, No. 118). Windsor, Berkshire, UK: Profile Publications Ltd.
  • Gallagher, James P. Meatballs and Dead Birds: A Photo Gallery Of Destroyed Japanese Aircraft In World War II. Mexhanicsburg, Pennsylvania: Stackpole Books, 2004. ISBN 0-8117-3161-8.
  • Gibertini, Giorgio (August 1998). "Rondini Giapponesi". Aerei Nella Storia N.8 (in Italian). Parma, Italy: West-ward edizioni.
  • Green, William. "An Oriental Swallow." Air International, Vol. 9, no. 2, August 1975.
  • Green, William (1961). War Planes of the Second World War, Volume Three: Fighters. Macdonald & Co. ISBN 0-356-01447-9. OCLC 655407936.
  • Green, William; Swanborough, Gordon (1976). JWW2 Aircraft Fact Files: Japanese Army Fighters, Part 1. London: Macdonald and Jane's. ISBN 0-356-08224-5. OCLC 820486093.* Gunston, Bill. World Encyclopedia of Aircraft Manufacturers: From the Pioneers to the Present Day. Annapolis, Maryland: Naval Institute Press, 1993. ISBN 1-55750-939-5.
  • Hata, Ikuhiko, Yasuho Izawa and Christopher Shores. Japanese Army Air Force Fighter Units and Their Aces, 1931-1945. London: Grub Street Publishing, 2002. ISBN 978-1-9023-0489-2.
  • Huggins, Mark (May–June 1999). "Setting Sun: Japanese Air Defence of the Philippines 1944–1945". Air Enthusiast (81): 28–35. ISSN 0143-5450.
  • Janowicz, Krzysztof. 68 Sentai (in Polish). Lublin, Poland: Kagero, 2003. ISBN 83-89088-01-0.
  • Januszewski, Tadeusz; Jarski, Adam (1992). Kawasaki Ki-61 Hien, Monografie Lotnicze 5 (in Polish). Gdańsk, Poland: AJ-Press. ISSN 0867-7867.
  • Mondey, David. The Hamlyn Concise Guide to Axis Aircraft of World War II. London: Bounty Books, 2006. ISBN 0-7537-1460-4.
  • Sakaida, Henry. Japanese Army Air Force Aces 1937-45. Botley, Oxford, UK: Osprey Publishing, 1997. ISBN 1-85532-529-2.
  • Sakurai, Takashi. Hien Fighter Group: A Pictorial History of the 244th Sentai, Tokyo's Defenders (in Japanese/English). Tokyo: Dai Nippon Kaga, 2004. ISBN unknown.
  • Sakurai, Takashi. Rikugun Hiko Dai 244 Sentai Shi (History of the Army 244 Group) (in Japanese). Tokyo: Soubunsha, 1995. ISBN unknown.
  • Snedden, Robert. World War II Combat Aircraft. Bristol, UK: Parragon Book, 1997. ISBN 0-7525-1684-1.
  • Takaki, Koji; Sakaida, Henry (2001). B-29 Hunters of the JAAF. Botley, Oxford, UK: Osprey Publishing. ISBN 1-84176-161-3.
  • Tanimura, Masami; et al. (1967). Kawasaki Ki-61 (Tony). Blaine, Washington: Paul Gaudette.
  • United States Strategic Bombing Survey Aircraft Division. Kawasaki Aircraft Company, Ltd. Corporation Report IV, Washington, D.C. 1947.
  • Vaccari, Pier Francesco. "Guerra Aerea in Nuova Guinea" (in Italian). Rivista Italiana Difesa, N.8, 2000.

External links edit

  • KI-61 article on vectorsite (public domain)
  • USN report on captured Ki-61 (pdf file)
  • Japanese website dedicated to the Tokkotai JAAF and JNAF
  • virtual page about performance of Ki-61Kai 30 June 2008 at the Wayback Machine
  • Profile drawings and artwork on the Ki-61
  • The Many Faces of Tony "5017" - Article on Ki-61-II-Kai production No. 5017, still in existence
  • Ki-61-II Tony Manufacture Number 640 - Covers the discovery, recovery and restoration in some detail

kawasaki, hien, 飛燕, flying, swallow, japanese, world, fighter, aircraft, used, imperial, japanese, army, service, designated, army, type, fighter, 三式戦闘機, allied, intelligence, initially, believed, were, messerschmitt, 109s, later, italian, macchi, which, allie. 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 2 Allied intelligence initially believed Ki 61s were Messerschmitt Bf 109s and later an Italian Macchi C 202 which led to the Allied reporting name of Tony assigned by the United States War Department 3 The design originated as a variant of the Kawasaki Ki 60 which never entered production The Ki 61 became the only mass produced Japanese fighter of the war to use a liquid cooled inverted V engine Over 3 000 Ki 61s were produced Initial prototypes saw action over Yokohama during the Doolittle Raid on 18 April 1942 and continued to fly combat missions throughout the war 4 5 Ki 61 HienRole Fighter aircraftManufacturer Kawasaki Kōkuki Kōgyō K K First flight December 1941Introduction 1942Retired 1945Primary users Imperial Japanese Army Air ServiceChinese Nationalist Air ForceIndonesian Air Force IPSF People s Liberation Army Air ForceNumber built 3 078 1 Developed from Kawasaki Ki 60Developed into Kawasaki Ki 100Kawasaki Ki 61 Hien with drop tank Contents 1 Design and development 2 Operational history 2 1 Ki 61 Special Attack Unit 3 Variants 3 1 Production 4 Operators 4 1 Ki 61 units 5 Surviving aircraft 6 Specifications Ki 61 I KAIc 7 See also 8 References 8 1 Notes 8 2 Citations 8 3 Bibliography 9 External linksDesign and development editThe Ki 61 was designed by Takeo Doi and his deputy Shin Owada in response to a late 1939 tender by the Koku Hombu N 1 for two fighters each to be built around the Daimler Benz DB 601Aa Production aircraft would use a Kawasaki licensed DB 601 known as the Ha 40 which was to be manufactured at its Akashi plant The Ki 60 was to be a heavily armed specialised interceptor with a high wing loading N 2 the Ki 61 was to be a more lightly loaded and armed general purpose fighter intended to be used mainly in an offensive air superiority role at low to medium altitudes N 3 Both single seat single engine fighters used the same basic construction all metal alloys with semi monocoque fuselages and three spar wings with alloy framed fabric covered ailerons elevators and rudders Priority was given to the Ki 60 which first flew in April 1941 while design work on the Ki 61 did not begin until December 1940 Although the Ki 61 was broadly similar to the Ki 60 it featured several refinements exploiting lessons learned from the disappointing flight characteristics of the earlier design 6 The all metal semi monocoque fuselage was basically oval in cross section changing to a tapered semi triangular oval behind the cockpit canopy with a maximum depth of 1 35 m 4 ft 5 in An unusual feature of the Ki 61 was that the engine bearers were constructed as an integral part of the forward fuselage with the cowling side panels being fixed For servicing or replacement only the top and bottom cowling panels could be removed A tapered rectangular supercharger air intake was located on the port side cowling Behind the engine bulkhead were the ammunition boxes feeding a pair of synchronized 12 7 mm 50 in Ho 103 machine guns which were set in a staggered configuration the port weapon slightly further forward than that to starboard in a bay just above and behind the engine The breeches partly projected into the cockpit above the instrument panel The Ho 103 was a light weapon for its caliber around 23 kg 51 lb and fired a light shell but this was compensated for by its rapid rate of fire The ammunition capacity was limited having only around 250 rounds for each weapon A self sealing fuel tank with a capacity of 165 L 44 US gal was located behind the pilot s seat The windshield was armored and there was a 13 mm 51 in armor plate behind the pilot The radiator and oil cooler for the liquid cooled engine were in a ventral location below the fuselage and wing trailing edge covered by a rectangular section fairing with a large adjustable exit flap 6 The evenly tapered wings had an aspect ratio of 7 2 with a gross area of 20 m2 215 28 ft2 and featured three spars a Warren truss main spar and two auxiliary spars The rear spar carried the split flaps and long narrow chord ailerons while the front spar incorporated the undercarriage pivot points The undercarriage track was relatively wide at 4 m 13 ft 1 5 in Each wing had a partially self sealing 190 L 50 US gal fuel tank behind the main spar just outboard of the fuselage A single weapon initially a 7 7 mm 0 303 in Type 89 machine gun was able to be carried in a weapons bay located behind the main spar 6 The first prototype of the San shiki Sentohki ichi gata Type 3 Fighter Model 1 the official IJAAF designation first flew in December 1941 at Kagamigahara Airfield 7 Although test pilots were enthusiastic about its self sealing fuel tanks upgraded armament and good dive performance the wing loading of 146 3 kg m2 30 lb ft2 at an all up weight of 2 950 kg 6 500 lb was viewed with scepticism by many of the senior officers of the Koku Hombu who still believed in the light highly manoeuvrable lightly armed fighter epitomised by the then new Nakajima Ki 43 I Hei which had a wing loading of 92 6 kg m2 19 lb ft2 and even that was considered borderline compared to the earlier Ki 27 8 To address these concerns Kawasaki staged a fly off between two Ki 61 prototypes and the Nakajima Ki 43 I a pre production Nakajima Ki 44 I a defector flown Lavochkin Gorbunov Goudkov LaGG 3 a Messerschmitt Bf 109E 7 and a captured Curtiss P 40E Warhawk The Ki 61 proved the fastest of all the aircraft and was inferior only to the Ki 43 in manoeuvrability 8 9 10 11 The Ki 61 was the last of the fighters powered by the DB 601 or its foreign derivatives and it was soon overshadowed by fighters with more powerful engines By the time it first flew in December 1941 one year after the Macchi C 202 s first flight and three years after the first Bf 109E the engine was already underpowered compared to the new 1 120 kW 1 500 hp inline or 1 491 kW 2 000 hp radial engines being developed and already nearing the mass production stage to power the next generation of combat aircraft such as the Republic P 47 Thunderbolt Moreover the inline Ha 40 engine proved to be an unreliable powerplant 12 13 exacerbated in the South Pacific campaign where high temperatures caused problems with the fuel pumps 14 The DB 601 engine required precise and sophisticated manufacturing the Ha 40 was lighter by roughly 30 kg 70 lb and required even higher manufacturing standards Reaching these standards proved difficult for Japanese manufacturers an issue further complicated by the variable quality of materials fuel and the lubricants needed to run a sensitive high performance engine The Japanese equivalent of the more powerful DB 605 engine was the Kawasaki Ha 140 which was fitted onto the Type 3 to produce the Ki 61 II high altitude interceptor 12 15 Compared to the Ki 61 I the Ki 61 II had 10 greater wing area used more armour and was powered by the Kawasaki Ha 140 engine generating 1 120 kW 1 500 hp After overcoming initial fuselage and wing stability problems the new interceptor reverted to the original wing and was put into service as the Ki 61 II KAI However the Ha 140 engine had severe reliability problems that were never fully resolved and around half of the first batch of engines delivered were returned to the factory to be re built A US bombing raid on 19 January 1945 destroyed the engine factory in Akashi Hyōgo and 275 Ki 61 II KAI airframes without engines were converted to use the Mitsubishi Ha 112 II radial engine resulting in the Ki 100 While the Ha 112 solved the problems encountered with the Ha 140 the new engine still had a major weakness a lack of power at altitude which diminished its ability to intercept high flying B 29 Superfortresses relative to the Ki 61 II 12 16 During testing the Hien proved capable 17 but several shortcomings were subsequently revealed in operational service citation needed namely the armor protection that was insufficient against larger guns and a sub standard engine that eventually led to a new engine being considered citation needed Operational history edit nbsp A captured Kawasaki Ki 61 fighter tested by the U S Navy Naval Air Test Center Patuxent River Maryland USA in June 1945The Ki 61 looked so different from the usual radial engined Japanese fighters that the Allies at first believed it to be of German or Italian origin possibly a license built Messerschmitt Bf 109 The first Ki 61 seen by Allied aircrew had been misidentified as a Bf 109 by USAAF Capt C Ross Greening during the Doolittle Raid In early reports when it was thought to have been a German fighter the Ki 61 had been code named Mike 4 5 The final and better known code name adopted was Tony because the Ki 61 looked like an Italian aircraft 18 19 The new Ki 61 Hien fighters entered service with a special training unit the 23rd Chutai and entered combat for the first time in early 1943 during the New Guinea campaign 20 The first Sentai Air Group Wing fully equipped with the Hien was the 68th in Wewak New Guinea 20 followed by the 78th Sentai stationed at Rabaul Both units were sent into a difficult theatre where jungles and adverse weather conditions coupled with a lack of spares quickly undermined the efficiency of both men and machines Because the Ki 61 was so new and had been rushed into service it inevitably suffered from teething problems Almost all of the modern Japanese aircraft engines especially the Ki 61 s liquid cooled engines suffered a disastrous series of failures and ongoing problems 13 which resulted in the obsolescent Ki 43 still forming the bulk of the JAAF s fighter capability Initially this campaign went successfully for the Japanese Army Air Force JAAF but when the Allies re organized and enhanced the combat capabilities of their air forces they gained the upper hand against the JAAF 13 High non combat losses were also experienced by the Japanese during this campaign For example while in transit between Truk and Rabaul the 78th lost 18 of its 30 Ki 61s 21 22 The finicky Ha 40 engine could not be overhauled in the theatre instead they had to be shipped to the nearest service depot in Halmahera in eastern Indonesia 14 Even with these problems there was some concern in Allied aviation circles regarding the Hien The new Japanese fighter caused some pain and consternation among Allied pilots particularly when they found out the hard way that they could no longer go into a dive and escape as they had from lighter Japanese fighters General George Kenney the Allied air forces commander in the Southwest Pacific found his Curtiss P 40s completely outclassed and begged for more Lockheed P 38 Lightnings to counter the threat of the new enemy fighter citation needed However the increasing numerical strength of Allied bomber units along with inadequate anti aircraft systems imposed crippling losses on Japanese units Approximately 174 out of 200 Japanese aircraft based in the Wewak area were lost during the attacks of August 17 21 1943 23 By the end of the campaign nearly 2 000 Japanese aircraft had been lost in air attacks from up to 200 Allied aircraft at a time around half of which were Consolidated B 24 Liberators and North American B 25 Mitchells armed with fragmentation bombs 13 After the Japanese retreat over 340 aircraft wrecks were later found at Hollandia 13 nbsp Capt Teruhiko Kobayashi s Ki 61 of the 244th SentaiThe Ki 61 was also utilised in Southeast Asia Okinawa China and as an interceptor during US bombing raids over the Japanese home islands including against Boeing B 29 Superfortresses The Ki 61 was notable for many reasons initially identified as of either German or Italian origin these aircraft were capable of matching Allied aircraft such as the P 40 in speed and as evaluation had already shown were superior in almost every respect However the armament of the early Hien was lighter but still sufficient for most purposes Some authors claim that the Lockheed P 38 Lightning was measurably superior 24 The Ki 61 carried a great deal of fuel but due to having self sealing fuel tanks it was not considered readily flammable as many other Japanese aircraft were 12 Owing to the additional weight the Ki 61 s performance and agility suffered when its armament was increased but it still remained capable with a 580 km h 313 kn maximum speed The cannon armament was needed to counter the Allied bombers which proved to be difficult to shoot down with only 12 7 mm 50 in machine guns The empty and maximum weights for the Ki 61 prototype 2 12 7 mm 0 50 in 2 7 7 mm 0 303 in were 2 238 kg 4 934 lb and 2 950 kg 6 504 lb respectively for the Ki 61 I basic 4 12 7 mm 50 in 3 130 kg 6 900 lb and for the Ki 61 KAI 2 12 7 mm 0 50 in 2 20 mm 2 630 kg 5 798 lb and 3 470 kg 6 750 lb 12 A number of Ki 61s were also used in Tokkotai kamikaze missions launched toward the end of the war The Ki 61 was delivered to 15th Sentai group wing as well as some individual Chutaicho Squadron Leaders in other Sentai and even to operational training units in the JAAF The aircraft was largely trouble free in service except for the liquid cooled engine which tended to overheat when idling on the ground and suffered from oil circulation and bearing problems 25 Ki 61 Special Attack Unit edit nbsp An ex 23rd Sentai 2nd Chutai Ki 61 found and photographed at Inba airbase by USAAF personnel in 1946 The tactic of using aircraft to ram American Boeing B 29 Superfortresses was first recorded in late August 1944 when B 29s from Chinese airfields attempted to bomb the steel factories at Yawata Sergeant Shigeo Nobe of the 4th Sentai intentionally flew his Kawasaki Ki 45 into a B 29 debris from the explosion severely damaged another B 29 which also went down N 4 26 Other attacks of this nature followed as a result of which individual pilots determined it was a practicable way of destroying B 29s 27 On 7 November 1944 the officer commanding the 10th Hiko Shidan Air division made ramming attacks a matter of policy by forming ramming attack flights specifically to oppose the B 29s at high altitude The aircraft were stripped of their fuselage armament and protective systems in order to attain the required altitudes Although the term kamikaze is often used to refer to the pilots undertaking these attacks the word was not used by the Japanese military The units assigned to the 10th Hiko Shidan included the 244th Hiko Sentai Fighter group then commanded by Captain Takashi Fujita who organised a ramming flight called Hagakure Tai Special Attack Unit which was composed out of volunteers from the three Chutai squadrons of the 244th the 1st Chutai Soyokaze 2nd Chutai Toppu and the 3rd Chutai known as Mikazuki First Lieutenant Toru Shinomiya was selected to lead the Hagakure Tai On 3 December 1944 Shinomiya along with Sergeant Masao Itagaki and Sergeant Matsumi Nakano intercepted a B 29 raid Shinomaya rammed one B 29 but was able to land his damaged Ki 61 which had lost most of the port outer wing back at base After attacking another B 29 Itagaki had to parachute from his damaged fighter while Nakano rammed and damaged Long Distance of the 498th BG and crash landed his stripped down Ki 61 in a field Shinomaya s damaged Ki 61 was later displayed inside Tokyo s Matsuya department store while Nakano s Ki 61 was displayed outside alongside of a life size cut away drawing of the forward fuselage of a B 29 28 N 5 These three pilots were the first recipients of the Bukosho Japan s equivalent to the Victoria Cross or Medal of Honor which had been inaugurated on 7 December 1944 as an Imperial Edict by Emperor Hirohito there are 89 known recipients most of whom fought and scored against B 29s 29 30 The existence of the ramming unit had been kept confidential until then but it was officially disclosed in the combat results announcement and officially named Shinten Seiku Tai Body Attack Detachment by the Defense GHQ On 27 January 1945 Itakagi survived another ramming attack on a B 29 again parachuting to safety and received a second Bukosho he survived the war as only one of two known double Bukosho recipients 31 Sergeant Shigeru Kuroishikawa was another distinguished member of the unit nbsp A Ki 61 of the 149th shumbutai taken in Ashiya after the war The tail markings indicate it formerly came from the Akeno Kyodo Hikoshidan and the 59th sentai before being allocated to the 149th Despite their successful attacks these pilots gained no reprieve and were obliged to continue these deadly and dangerous ramming tactics until they were killed or else wounded so badly that they could no longer fly They were regarded as doomed men and were celebrated among the ranks of those who were going to certain death as Tokkotai kamikaze pilots 32 Some other Ki 61 pilots also achieved renown among them Major Teruhiko Kobayashi of the 244th Sentai who was credited by some with a dozen victories mostly due to conventional attacks against B 29s 33 Variants editNote Ko Otsu Hei and Tei are the Japanese equivalents to a b c d Kai modified or improved was also used for some models of the Ki 61 Ki 61 HienKi 61 Prototypes 12 built Ki 61 I Ko First production version fully retractable tailwheel two 7 7 mm 0 303 in Type 89 machine guns in the wings and two synchronized 12 7 mm 0 50 in Ho 103 machine guns in the forward decking Capable of carrying one 151 L 40 gal drop tank or a light bomb 12 Ki 61 I Otsu Second production fighter variant Tailwheel retraction mechanism was unreliable the aircraft was modified accordingly Two 12 7 mm 50 in Ho 103 machine guns replaced the wing 7 7 mm 303 in machine guns 12 Ki 61 I Hei The Hei was built in conjunction with the Otsu variant the wing machine guns were replaced by Mauser MG 151 20 cannons Ki 61 I Tei Fighter variant with two fuselage mounted Japanese 20 mm Ho 5 cannon and two 12 7 mm 50 in wing mounted Ho 103 machine guns Ki 61 I KAId Interceptor variant with 2 12 7 mm 50 in machine guns and 2 30 mm 1 18 in Ho 155 wing cannon Ki 61 I w c e s Experimental aircraft with evaporation system as used on the Heinkel He 100 It was the fastest Ki 61 built achieving 630 km h 395 mph Ki 61 II Prototype with 1 500 PS 1 103 kW Ha 140 engine and first flown in December 1943 Ki 61 II KAI Pre production version which reverted to the Ki 61 I Tei wing a 220 mm 8 7 in fuselage stretch enlarged rudder and Ha 140 engine 30 built Ki 61 II KAIa Armed with 2 x 12 7 mm 50 in machine guns in the wings and 2 x 20 mm cannon in the fuselage Ki 61 II KAIb Armed with 4 x 20 mm cannon Ki 61 III Prototype This version had a cut down rear fuselage and a canopy design which was later used by the Ki 100 I OtsuProduction edit Ki 61 I Production Kawasaki Kokuki K K 34 YearJan Feb Mar Apr May June July Aug Sept Oct Nov Dec Annual1942 1 3 5 10 15 341943 22 32 31 37 44 40 53 60 70 87 104 130 7101944 150 156 145 142 118 236 254 198 164 174 101 53 1 8911945 19 19Total 2 654Not included Pre production started with the first prototype completed in July 1941 35 and with further eleven builds in early 1942 36 Ki 61 II Production Kawasaki Kokuki K K 34 YearJan Feb Mar Apr May June July Aug Sept Oct Nov Dec Annual1944 1 3 26 0 0 0 0 1 26 41 71 70 2391945 68 56 15 19 7 165Total 404Note Out of 374 Ki 61 II builds 275 were completed as Ki 100 Ia 1 Not included Pre production started with eight prototypes completed during Aug 1943 to Jan 1944 1 Total production According to USSBS Report 3 058 34 Figure includes 2 654 Ki 61 I and 404 Ki 61 II buildsAccording to Francillon 3 078 1 Figure includes 2 666 Ki 61 I and 412 Ki 61 II buildsOperators edit nbsp JapanImperial Japanese Army Air ServicePost War nbsp ChinaChinese Nationalist Air Force Operated some captured aircraft nbsp ChinaPeople s Liberation Army Air Force also operated some captured aircraft nbsp IndonesiaIn 1945 Indonesian Air Force then Indonesian People s Security Force IPSF Indonesian pro independence guerrillas captured six such aircraft at numerous Japanese air bases including Bugis Air Base in Malang repatriated 18 September 1945 At least one was restored 37 Most aircraft were destroyed in military conflicts between the Netherlands and the newly proclaimed Republic of Indonesia during the Indonesian National Revolution of 1945 1949 37 Ki 61 units edit nbsp Derelict Ki 61s in 1945 after the surrender A Kawasaki Ki 45 heavy fighter is in the background The Hiko Sentai usually referred to as Sentai was the basic operational unit of the Imperial Japanese Army Air Force composed of three or more Chutai companies or squadrons A Sentai had 27 to 49 aircraft with each Chutai having 16 aircraft and pilots plus a maintenance and repair unit Several sentai had other units under their operational control most notably the Hagakure Tai Special Attack Units of the 244th Sentai By 1944 with the depredations of Allied attacks on supply lines and airfields as well as the loss of pilots and aircraft through combat attrition and accidents few sentai were able to operate at full strength citation needed Units operating the Ki 61 Hien 38 39 Sentai Established Aircraft type s Area of operations Disbanded Notes17th 10 February 1944 at Kagamigahara Gifu Prefecture N 6 Ki 61 Ki 100 Philippines Formosa Japan End of war One of Kawasaki s main factories was located at Kagamigahara which in 1944 was not yet a city 18th 10 February 1944 at Chōfu from the 244th Sentai Ki 61 Ki 100 Philippines Japan End of War Lt Mitsuo Oyake won Bukosho for shooting down three B 29s one by ramming 7 April 1945 and damaging three others 19th 10 February 1944 at Akeno Fighter School Ki 61 Indonesia Philippines Formosa Okinawa End of War Formosa 23rd 11 October 1944 at Inba Chiba Prefecture Ki 43 Ki 44 Ki 61 Iwo Jima Formosa Japan End of war Inba 26th Late 1944 Ki 51 Ki 43 Ki 61 Formosa End of war Formosa 28th June 1939 in Manchuria Ki 46 Ki 61 Ki 102 Manchuria Japan July 194531st July 1938 in China Ki 10 Ki 43 Ki 61 Manchuria Philippines 30 May 1945 at Singapore33rd Summer 1937 in China Ki 10 Ki 27 Ki 43 Ki 61 New Guinea Manchuria Manchoukuo East Indies End of war Medan Dutch East Indies currently Indonesia 53rd 23 March 1944 at Tokorozawa Saitama Ki 61 Ki 45 Japan Eastern Defence Sector flew Ki 61 for a short time in Home Island Defence55th 30 May 1944 at Taishō Osaka Prefecture Ki 61 Philippines Japan End of war at Sana Nara Prefecture56th August 1944 at Taishō Osaka Prefecture Ki 61 Japan End of war at Itami Hyōgo Prefecture Unit claimed 11 B 29s for 30 pilots lost Warrant Officer Tadao Sumi five B 29s plus one P 51 Mustang destroyed four B 29s damaged Bukosho recipient 59th 1 July 1938 at Kagamigahara Gifu Prefecture Ki 10 Ki 27 Ki 43 Ki 61 Ki 100 China Manchuria Nomonhan Indochina East Indies New Guinea Okinawa Japan End of War at Ashiya Fukuoka Prefecture 1st Lieutenant Naoyuki Ogata Bukosho recipient Warrant Officer Kazuo Shimizu flew with unit from February 1942 right through to August 1945 18 victories including nine bombers 65th presumably 1938 1939 Ki 32 Ki 51 Ki 43 Ki 61 Ki 45 Philippines Formosa Okinawa Japan End of war Metabaru Saga Unit used Ki 61 from the summer of 194468th March 1942 at Harbin Manchuria Ki 27 Ki 61 Rabaul New Britain New Guinea Halmahera 25 July 1944 First unit to convert to the Ki 61 Unit was destroyed by Allied air forces in New Guinea Most surviving ground and aircrew were used as infantry with few survivors A Ki 61 1 Otsu manufacturer s No 640 is one of the best preserved aircraft wrecks in New Guinea 40 Captain Shogo Takeuchi transferred from 64th Sentai April 1942 KIA 15 December 1943 30 victories Sgt Susumu Kaijinami officially credited with eight victories plus 16 unofficially 78th 31 March 1942 in China Ki 27 Ki 61 Manchuria Rabaul New Guinea 25 July 1944 Second unit to convert to the Ki 61 Unit was destroyed by Allied air forces in New Guinea Most surviving ground and aircrew were used as infantry with few survivors 105th August 1944 Taichung Formosa Ki 61 Okinawa Formosa End of war Formosa 244th April 1942 reorganised from 144th Sentai Ki 27 Ki 61 Ki 100 Okinawa Formosa End of war Yokaichi Shiga Prefecture Nine Bukosho recipients Major Teruhiko Kobayashi JAAF s youngest Sentai commander Also had an air to air B 29 ramming unit Sentai claimed 73 B 29s shot down plus 92 damaged Most famous of the Home Defence Sentais Captain Nagao Shirai considered the ranking ace of 244 Sentai and possibly leading B 29 killer of JAAF 11 B 29s plus two Grumman F6F Hellcats destroyed six other aircraft damaged using Ki 61 and Ki 100 Captain Chuichi Ichikawa nine B 29s plus one F6F destroyed six B 29s damaged Major Teruhiko Kobayashi three B 29s plus two F6Fs destroyed Training units23rd Dokuritsu Dai Shijugo Independent Chutai Chōfu 1941 Ki 61 Japan Became basis of 23rd Sentai Evaluation and conversion unit for Ki 61 Akeno Kyodo Hikoshidan Akeno Flight School Akeno Mie Prefecture 1935 Ki 10 Ki 27 Ki 43 Ki 44 Ki 45 Ki 61 Ki 84 Ki 100 Japan End of war Main flight training school for Army fighter pilots Many of the instructors participated in missions in defence of Japan 1944 1945 Akeno Airbase still in operational use 37th Kyoiku Hikōtai Flight Training Company Matsuyama airfield Formosa 1943 41 Ki 43 Ki 44 Ki 45 Ki 61 Ki 84 Formosa End of war Flight training school for Army fighter pilots Many of the instructors participated in missions in defence of Japan 1944 1945Surviving aircraft edit299 Ki 61 Ia under restoration to static display at Ardmore Auckland New Zealand by AvSpecs To be displayed at Papua New Guinea National Museum and Art Gallery once completed 42 379 Ki 61 I in storage at the Fantasy of Flight in Polk City Florida 43 640 Ki 61 I under restoration to airworthy condition at Ardmore Auckland New Zealand by AvSpecs It will become part of the Military Aviation Museum collection in Virginia Beach Virginia 44 6117 Ki 61 II Kai on static display at the Kakamigahara Air and Space Museum in Kakamigahara Gifu Previously on display at the Chiran Peace Museum for Kamikaze Pilots in Chiran Kagoshima it was removed from the museum in September 2015 and restored by Kawasaki Heavy Industries from 2015 to 2016 45 46 47 48 Specifications Ki 61 I KAIc edit nbsp 3 view drawing of Kawasaki Ki 61Data from Japanese Aircraft of the Pacific War 49 General characteristicsCrew 1 Length 8 94 m 29 ft 4 in Wingspan 12 m 39 ft 4 in Height 3 7 m 12 ft 2 in Wing area 20 m2 220 sq ft Airfoil NACA 2R 16 wing root NACA 24009 tip Empty weight 2 630 kg 5 798 lb Gross weight 3 470 kg 7 650 lb Fuel capacity Internal 550 L 150 US gal 120 imp gal External 2x 200 L 53 US gal 44 imp gal Powerplant 1 Kawasaki Ha40 inverted liquid cooled V 12 piston engine 864 kW 1 159 hp Propellers 3 bladed variable pitch propellerPerformance Maximum speed 580 km h 360 mph 310 kn at 5 000 m 16 000 ft Range 580 km 360 mi 310 nmi Service ceiling 11 600 m 38 100 ft Rate of climb 15 2 m s 2 990 ft min Time to altitude 7 0 min to 5 000 m 16 000 ft Wing loading 173 5 kg m2 35 5 lb sq ft Power mass 0 25 kW kg 0 15 hp lb Armament Guns 2 20 mm 0 79 in Ho 5 cannon 120 rpg 2 12 7 mm 0 50 in Ho 103 machine guns 250 rpg Bombs 2 250 kg 550 lb bombsSee also editRelated development Kawasaki Ki 60 Kawasaki Ki 100Aircraft of comparable role configuration and era Curtiss P 40 Warhawk Dewoitine D 520 Hawker Hurricane Heinkel He 100 Lavochkin LaGG 3 Macchi C 202 Messerschmitt Bf 109 Mikoyan Gurevich MiG 3 North American P 51 Mustang Supermarine Spitfire Weiss Manfred WM 23 Ezust Nyil Yakovlev Yak 1Related lists List of aircraft of World War II List of military aircraft of Japan List of aircraft of Japan World War IIReferences editNotes edit Koku Hombu was the Technical Branch of the Imperial Army Air Headquarters The Nakajima Ki 44 was selected as the standard IJAAF interceptor fighter and followed broadly similar specifications to the Ki 60 Nakajima designed a similar fighter the Ki 62 also powered by an Ha 40 This design later became the basis for the Nakajima Ki 84 The B 29s were Colonel Robert Clinksale s B 29 BW 42 6334 Gertrude C and Captain Ornell Stauffer s B 29 BW 42 6368 Calamity Sue both from the 468th BG Shinomaya eventually lost his life as a Tokkotai pilot in the battle for Okinawa There is an inconsistency in the locations given Kagamigahara is wrongly listed by Sakaida as being in the Saitama Prefecture which is north of Gifu Citations edit a b c d Francillon 1979 p 120 Mondey 2006 p 144 Ethell 1995 p 82 a b Bueschel 1971 p 7 a b Bueschel 1971 p 6 a b c Green amp Swanborough 1976 pp 18 23 Tanimura 1967 p 12 a b Green amp Swanborough 1976 p 23 Francillon 1966 p 319 Green 1975 p 78 Francillon 1979 p 114 a b c d e f g Gibertini 1998 pp 6 13 a b c d e Vaccari 2000 pp 82 90 a b Claringbould Michael John 2020 Japanese Army Fighters New Guinea amp the Solomons 1942 1944 Pacific Profiles vol 1 Kent Town Australia Avonmore Books p 66 ISBN 978 0648665915 Tanimura 1967 p 17 Januszewski amp Jarski 1992 p 38 DeMoss R W Duncan R L 26 January 1945 Final Report on Comparative Combat Evaluation Trials of Japanese Tony 1 Type 3 Fighter Project Ted PDF Technical report Vol No PTR 115 United States Navy Retrieved 23 March 2010 via WWIIaircraftperformance org Francillon 1966 p 316 Crosby 2002 p 94 a b Januszewski amp Jarski 1992 p 25 Bueschel 1971 pp 7 9 Tanimura 1967 p 13 Boyer Allen D Shooting up Wewak America in WWII Retrieved 1 April 2021 Green amp Swanborough 1976 p 29 Green amp Swanborough 1976 pp 27 28 Pacific War Chronology August 1944 Archived 2 April 2010 at the Wayback Machine att net Retrieved 12 June 2008 Takaki amp Sakaida 2001 p Photo of Nakano s Ki 61 Archived 14 July 2011 at the Wayback Machine Retrieved 26 October 2010 Sakaida 1997 pp 67 70 Bukosho described xavierb net Retrieved 3 June 2008 Sakaida 1997 pp 70 94 Japanese website dedicated to the Tokkotai JAAF and JNAF tokkotai or jp Retrieved 7 June 2008 Sakaida 1997 pp 74 75 a b c USSBS Appendix E p 16 Francillon 1979 p 112 Francillon 1979 p 114 a b Heyman Jos November 2005 Indonesian aviation 1945 1950 PDF adf serials com p 8 Archived from the original PDF on 14 December 2005 Sakaida 1997 pp 82 87 Bueschel1971 pp 47 49 Ki 61 No 640 pacificwrecks com Retrieved 8 June 2008 Matsuyama airfield pacificwrecks com Retrieved 4 June 2011 Taylan Justin 30 January 2022 Ki 61 Ia Tony Manufacture Number 299 Pacific Wrecks Retrieved 25 April 2022 Taylan Justin 3 May 2016 Ki 61 II Tony Manufacture Number 379 Pacific Wrecks Pacific Wrecks Inc Retrieved 25 April 2017 Taylan Justin 3 May 2016 Ki 61 II Tony Manufacture Number 640 Pacific Wrecks Pacific Wrecks Inc Retrieved 25 April 2017 Marsh Don Long James I 2004 The Many Faces of TONY 5017 j aircraft com Retrieved 25 April 2017 Taylan Justin 3 May 2016 Ki 61 II Kai Tony Manufacture Number 61217 Tail 17 Pacific Wrecks Pacific Wrecks Inc Retrieved 25 April 2017 Izawa Tomoyuki 14 October 2016 Flying swallow WWII fighter restored to glory by Kawasaki The Asahi Shimbun The Asahi Shimbun Company Retrieved 25 April 2017 Main exhibit room Chiran Peace Museum Chiran Peace Museum Archived from the original on 26 February 2016 Retrieved 25 April 2017 Francillon 1979 pp 119 120 Bibliography edit Bily Miroslav Kawasaki Ki 61 a Ki 100 Profily letadel II Svetove valky no 4 in Czech with English and German captions Praha Czech Republic Modelpres 1992 ISBN 80 901328 0 4 Bueschel Richard M 1971 Kawasaki Ki 61 Ki 100 Hien in Japanese Army Air Force service Aircam Aviation Series No 21 Reading Osprey ISBN 0 85045 026 8 OCLC 678232 Crosby Francis 2002 Fighter Aircraft London Lorenz Books ISBN 0 7548 0990 0 Ethell Jeffrey L Aircraft of World War II Glasgow Collins Jane s 1995 ISBN 0 00 470849 0 Francillon Rene J 1979 Japanese aircraft of the Pacific War London Putnam ISBN 0 370 30251 6 OCLC 6124909 new edition 1987 by Putnam Aeronautical Books ISBN 0 85177 801 1 Francillon Rene J 1966 The Kawasaki Ki 61 Hien Aircraft in Profile Volume 5 No 118 Windsor Berkshire UK Profile Publications Ltd Gallagher James P Meatballs and Dead Birds A Photo Gallery Of Destroyed Japanese Aircraft In World War II Mexhanicsburg Pennsylvania Stackpole Books 2004 ISBN 0 8117 3161 8 Gibertini Giorgio August 1998 Rondini Giapponesi Aerei Nella Storia N 8 in Italian Parma Italy West ward edizioni Green William An Oriental Swallow Air International Vol 9 no 2 August 1975 Green William 1961 War Planes of the Second World War Volume Three Fighters Macdonald amp Co ISBN 0 356 01447 9 OCLC 655407936 Green William Swanborough Gordon 1976 JWW2 Aircraft Fact Files Japanese Army Fighters Part 1 London Macdonald and Jane s ISBN 0 356 08224 5 OCLC 820486093 Gunston Bill World Encyclopedia of Aircraft Manufacturers From the Pioneers to the Present Day Annapolis Maryland Naval Institute Press 1993 ISBN 1 55750 939 5 Hata Ikuhiko Yasuho Izawa and Christopher Shores Japanese Army Air Force Fighter Units and Their Aces 1931 1945 London Grub Street Publishing 2002 ISBN 978 1 9023 0489 2 Huggins Mark May June 1999 Setting Sun Japanese Air Defence of the Philippines 1944 1945 Air Enthusiast 81 28 35 ISSN 0143 5450 Janowicz Krzysztof 68 Sentai in Polish Lublin Poland Kagero 2003 ISBN 83 89088 01 0 Januszewski Tadeusz Jarski Adam 1992 Kawasaki Ki 61 Hien Monografie Lotnicze 5 in Polish Gdansk Poland AJ Press ISSN 0867 7867 Mondey David The Hamlyn Concise Guide to Axis Aircraft of World War II London Bounty Books 2006 ISBN 0 7537 1460 4 Sakaida Henry Japanese Army Air Force Aces 1937 45 Botley Oxford UK Osprey Publishing 1997 ISBN 1 85532 529 2 Sakurai Takashi Hien Fighter Group A Pictorial History of the 244th Sentai Tokyo s Defenders in Japanese English Tokyo Dai Nippon Kaga 2004 ISBN unknown Sakurai Takashi Rikugun Hiko Dai 244 Sentai Shi History of the Army 244 Group in Japanese Tokyo Soubunsha 1995 ISBN unknown Snedden Robert World War II Combat Aircraft Bristol UK Parragon Book 1997 ISBN 0 7525 1684 1 Takaki Koji Sakaida Henry 2001 B 29 Hunters of the JAAF Botley Oxford UK Osprey Publishing ISBN 1 84176 161 3 Tanimura Masami et al 1967 Kawasaki Ki 61 Tony Blaine Washington Paul Gaudette United States Strategic Bombing Survey Aircraft Division Kawasaki Aircraft Company Ltd Corporation Report IV Washington D C 1947 Vaccari Pier Francesco Guerra Aerea in Nuova Guinea in Italian Rivista Italiana Difesa N 8 2000 External links edit nbsp Wikimedia Commons has media related to Kawasaki Ki 61 KI 61 article on vectorsite public domain USN report on captured Ki 61 pdf file Japanese website dedicated to the Tokkotai JAAF and JNAF virtual page about performance of Ki 61Kai Archived 30 June 2008 at the Wayback Machine Profile drawings and artwork on the Ki 61 The Many Faces of Tony 5017 Article on Ki 61 II Kai production No 5017 still in existence Ki 61 II Tony Manufacture Number 640 Covers the discovery recovery and restoration in some detail Retrieved from https en wikipedia org w index php title Kawasaki Ki 61 amp oldid 1207338213, wikipedia, wiki, book, books, library,

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