Kawanishi N1K Kyōfū "Rex" / N1K-J Shiden "George"

Experimental model of the N1K2-J featuring a cleaner, redesigned engine cowling.

The Kawanishi N1K is an Imperial Japanese Navy fighter aircraft, developed in two forms: the N1K Kyōfū ("Strong Wind", Allied reporting name "Rex"), a floatplane designed to support forward offensive operations where no airstrips were available, and the N1K-J Shiden ("Violet Lightning", reporting name "George"), a land-based version of the N1K. The N1K-J was considered by both its pilots and opponents to be one of the finest land-based fighters flown by the Japanese during World War II.

An improved variant, the N1K2-J "Shiden-Kai" first flew on 1 January 1944. The Shiden Kai possessed heavy armament, as well as surprisingly good maneuverability, due to a mercury switch that automatically extended the flaps during turns. These "combat" flaps created more lift, thereby allowing tighter turns. Unlike the Mitsubishi A6M Zero, the Shiden Kai could compete against the best late-war Allied fighters, such as the F6F Hellcat, F4U Corsair, and P-51 Mustang. 

Kawanishi's N1K was originally built as a single pontoon floatplane fighter to support forward offensive operations where no airstrips were available, but by 1943 when the aircraft entered service, Japan was firmly on the defensive, and there was no longer a need for a fighter to fulfill this role. The Navy's requirements for this fighter were nearly impossible to achieve for a float plane, and the expected protracted development period led Nakajima to develop an interim float plane fighter based on the Zero, the Nakajima A6M2-N. In the end, the Kyofu only saw limited service, mostly in Southeast Asia. A number were flown out of Ambon and the Aru Islands in the Moluccas, while some were stationed at Penang Island, off the Malayan peninsula. They were also used in the Battle of Okinawa. Towards the end of the war, Kyofus were also used in the homeland defense role, operating from Lake Biwa by the Sasebo Air Corps and the Ōtsu Air Corps.

The N1K was powered by the Mitsubishi MK4C Kasei 13 14-cylinder radial engine. Top speed was 489 km/h (304 mph); considerably less than the unrealistic Navy 310 kn (574 km/h; 357 mph) requirement. 

The requirement to carry a bulky, heavy float essentially crippled the N1K against contemporary American fighters. However, Kawanishi engineers had proposed in late 1941 that the N1K would also be the basis of a formidable land-based fighter, and a land-based version was produced as a private venture by the company. This version flew on 27 December 1942, powered by a Nakajima NK9A Homare 11 18-cylinder radial engine, replacing the less powerful MK4C Kasei 13 of the N1K-1. The aircraft retained the mid-mounted wing of the floatplane; combined with the large propeller, this necessitated a long, stalky main landing gear. A unique feature was the aircraft's combat flaps that automatically adjusted in response to acceleration, freeing up the pilot's concentration and reducing the chance of stalling in combat. The N1K did have temperamental flight characteristics, however, that required an experienced touch at the controls.

The Nakajima Homare was powerful, but had been rushed into production before it was sufficiently developed, and proved troublesome. Another problem was landing gear failure due to poor heat treatment of the wheels. Apart from engine problems and the landing gear, the flight test program showed that the aircraft was promising. Prototypes were evaluated by the Navy, and since the aircraft was faster than the Zero and had a much longer range than the Mitsubishi J2M Raiden, it was ordered into production as the N1K1-J, the -J indicating a land-based fighter modification of the original floatplane fighter.

Only four days after the Shiden's first test flight, a complete redesign began. The N1K2-J addressed the N1K1-J's major defects, primarily the mid-mounted wing and long landing gear. The wings were moved to a low position, which permitted the use of a shorter, conventional undercarriage. The fuselage was lengthened and the tail redesigned. The production of the entire aircraft was simplified: over a third of the parts used in the previous Shiden could still be used in its successor, while construction used fewer critical materials. The N1K1 redesign was approximately 250 kg (550 lb) lighter, while faster and more reliable than its predecessor. The Homare engine was retained, even though reliability problems persisted, as no alternative was available. A prototype of the new version flew on 1 January 1944. After completing Navy trials in April, the N1K2-J was rushed into production. This variant was named the "Shiden-Kai", with Kai meaning modified. 

The N1K1-J Shiden entered service in early 1944. The N1K1-J and the N1K2 Shiden-Kai released later that year were among the rare Japanese aircraft that offered pilots an even chance against late-war American designs, such as the F6F Hellcat and the F4U Corsair, and could be a formidable weapon in the hands of an ace. In February 1945, Ensign Kaneyoshi Muto, flying an N1K2-J as part of a mixed formation of at least 10 Japanese aircraft, faced seven U.S. Navy Hellcat pilots from squadron VF-82 in the sky over Japan; the formation shot down four Hellcats with no loss to themselves. After the action, Japanese propagandists fabricated a story in which Muto was the sole airman facing 12 enemy aircraft. (A leading Japanese ace, Saburō Sakai, later asserted in his autobiography that Muto had done this feat at an earlier stage of the war – albeit at the controls of a Zero fighter.)

The N1K1-J aircraft were used very effectively over Formosa (Taiwan), the Philippines, and, later, Okinawa. Before production was switched to the improved N1K2-J, 1,007 aircraft, including prototypes, were produced. Because of production difficulties and damage done by B-29 raids on factories, only 415 of the superior N1K2-J fighters were produced.

The N1K2-J Shiden-Kai proved to be one of the best dogfighting aircraft produced by either side. Along with high speed, the Shiden-Kai offered pilots an agile aircraft with a roll rate of 82°/sec at 386 km/h (240 mph), backing four powerful 20 mm cannons in the wings. As a bomber interceptor, the N1K2-J fared less well, hampered by a poor rate of climb and a reduced engine performance at high altitude.

343 Kōkūtai

The N1K2-J Shiden-Kai offered a formidable, if demanding, aircraft in limited quantities. As a result, the planes were distributed to elite naval fighter units such as 343 Kōkūtai ("343rd Naval Air Group"), constituted on 25 December 1944 and commanded by Minoru Genda. The new Kōkūtai included some of Japan's most experienced fighter pilots, such as Naoshi Kanno and Saburo Sakai. The unit received the best available naval equipment, such as the Nakajima C6N Saiun, codenamed "Myrt" long-range reconnaissance aircraft.

On 18 March 1945, one of the "Myrts" spotted U.S. carriers en route to Japan. The following morning, Shiden aircraft flown by 343 Kōkūtai intercepted 300 American aircraft. Many of the Shiden forces were N1K2s. When the Shidens encountered Grumman F6F Hellcats from USN Fighter Bomber Squadron 17 (VBF-17), three aircraft were lost on both sides in the initial attack: one Hellcat and two Shidens were shot down by enemy ground fire, two fighters collided in mid-air, and one Hellcat crashed while trying to land. Another Shiden dived on a Hellcat group and downed another one. Ultimately, the Hikōtai lost six fighters versus eight VBF-17 fighters on the other side. 

Another noted encounter pitted the N1K against the Vought F4U Corsair; two Corsairs from VBF-10, accidentally separated from their main formations, were attacked by Shidens from the 343rd. Four N1K2s were shot down. The Corsairs returned to their carrier, USS Bunker Hill. A second encounter took place when pilots flying Shidens initially mistook Corsairs from Marine Fighter Squadron 123 (VMF-123) for Hellcats and attacked. A 30-minute aerial duel ensued, in which three Corsairs were shot down, and another five were damaged. Three other F4Us returned to their carriers and were so heavily damaged that the planes were scrapped. No Shidens were lost to Corsairs in that aerial battle. Losses for the Japanese N1K pilots occurred in a related action. However, two Shidens were shot down upon return for landing by Hellcats of Fighting Squadron 9 (VF-9). At the same time, many more Shidens were destroyed by American fighters over another airfield where low on fuel, their pilots tried to land. The 343rd claimed 52 kills, and the U.S. squadrons 63. The losses were 15 Shidens and 13 pilots, a "Myrt", its three-person crew, and nine other Japanese fighters. The U.S. also took heavy losses: 14 fighters and seven pilots, plus 11 attack aircraft. Five days later, an unofficial award was sent to 343rd Kōkūtai for the bravery shown on 19 March.

On 12 April 1945, another fierce battle involved the 343rd during the mass kamikaze attack on Kikusui N.2. The Japanese recorded several kills but suffered 12 losses out of 34 aircraft. On 4 May, another 24 Shidens were sent to Kikusui N.5.

In every encounter with enemy fighters, the Shiden, especially the Kai version, proved to be a capable dogfighter with a potent combination of firepower, agility, and rugged structure. The premier unit flying the Shiden, 343rd Kōkūtai, remained operational until overwhelming unit losses obliged the group to stand down. The 343rd was disbanded on 14 August 1945 when the Emperor ordered surrender.

Variants

N1K1 Kyofu

• N1K1: Standard type as floatplane, which was used from early 1943, with Mitsubishi MK4C Kasei 13 engine.
• N1K2: Reserved name for an intended model with larger engine, not built.

N1K1-J Shiden

• N1K1-J Prototypes: development of fighter hydroplane N1K1 Kyofu, with 1,820 hp Homare 11 engine.
• N1K1-J Shiden Model 11: Navy Land Based Interceptor, first production model with 1,990 hp Homare 21 engine and revised cover, armed with two 7.7 mm Type 97 machine guns and two 20 mm Type 99 cannons. Modified total-vision cockpit.
• N1K1-Ja Shiden Model 11A: without frontal 7.7 mm Type 97s, with only four 20 mm Type 99s in wings.
• N1K1-Jb Shiden Model 11B: similar to Model 11A amongst load two 250 kg bombs, revised wing weapons.
• N1K1-Jc Shiden Model 11C: definitive fighter-bomber version, derived from Model 11B. Four bomb racks under wings.
• N1K1-J Kai a: Experimental version with auxiliary rocket. One Model 11 conversion.
• N1K1-J Kai b: Conversion for dive bombing. One 250 kg bomb under belly and six rockets under wings.

N1K2-J Shiden-Kai

• N1K2-J Prototypes: N1K1-Jb redesigned. Low wings, engine cover and landing gear modified. New fuselage and tail, 8 built.
• N1K2-J Shiden Kai Model 21: Navy Land Based Interceptor, first model of series with a Nakajima Homare 21 engine.
• N1K2-Ja Shiden KAI Model 21A: Fighter Interceptor version: 2,000 hp Homare 21-18 engine with a low wing and larger prop design with four 250 kg ground bombs. Fixed problem with teething pains of N1K2 J at high altitude.
• N1K2-K Shiden Kai Rensen 1, Model A: Fighter Trainer, modified from N1K-J Series with two seats, operative or factory conversions.

Further Variants

• N1K3-J Shiden Kai 1, Model 31: Prototypes: Engines displaced to ahead, two 13.2 mm Type 3 machine guns in front, 2 built.
• N1K3-A Shiden Kai 2, Model 41: Prototypes: Carrier-based version of N1K3-J, 2 built.
• N1K4-J Shiden Kai 3, Model 32: Prototypes: 2,000 hp Homare 23 engine, 2 built.
• N1K4-A Shiden Kai 4, Model 42: Prototype: Experimental conversion of N1K4-J example with equipment for use in carriers, 1 built.
• N1K5-J Shiden Kai 5, Model 25: High-Altitude Interceptor version with Mitsubishi HA-43 (MK9A) with 2,200 takeoff hp, project only. 

Surviving Aircraft

All four surviving Shiden Kai aircraft are now displayed in American and Japanese museums, while all three surviving Kyofu aircraft are displayed/stored in American museums.

One N1K2-J (s/n 5128, tail code A343-19) is at the National Naval Aviation Museum at Naval Air Station Pensacola, Florida.

The second N1K2-Ja (s/n 5312), a fighter-bomber variant equipped with wing mounts to carry bombs, is on display in the Air Power gallery at the National Museum of the United States Air Force, at Wright-Patterson Air Force Base near Dayton, Ohio. This aircraft was displayed outside for many years in a children's playground in San Diego, suffering considerable corrosion, and had become seriously deteriorated. In 1959 it was donated to the Museum through the cooperation of the San Diego Squadron of the Air Force Association. In October 2008 the aircraft was returned to display following an extensive eight year restoration. Many parts had to be reverse engineered by the Museum's restoration staff. Four different aircraft serial numbers were found on parts throughout the airframe, indicating reassembly from three different wrecks brought back to the U.S. for examination, or wartime assembly or repair from parts obtained from three different aircraft. Serial number 5312 was found in the most locations, and is the number now cited. This N1K2-Ja is painted as an aircraft in the Yokosuka Kōkūtai, an evaluation and test unit. This is indicated by the tail code (Yo)ヨ-105.

The third example (s/n 5341, tail code A343-35) is owned by the National Air and Space Museum but was restored by the Champlin Fighter Museum at Falcon Field, Mesa, Arizona, in return for the right to display the aircraft at Falcon Field for 10 years after restoration. It currently is on display at the National Air and Space Museum's Steven F. Udvar-Hazy Center.

The fourth authentic Shiden-Kai is displayed in a local museum at Nanreku Misho Koen in Ehime Prefecture, Shikoku, Japan. This aircraft is known to be from the 343rd Kōkūtai, as the unit flew sorties in the area, but the tail code is unknown as it was partially restored from a corroded wreck recovered from the sea. After an aerial battle on July 24, 1945, its pilot ditched the aircraft in the waters of the Bungo Channel, but he was never found; by the time of the aircraft's recovery from the seabed on July 14, 1979, he could be identified only as one of six pilots from the 343rd squadron who disappeared that day. Photographs of the six—including Takashi Oshibuchi, commander of the 701 Hikōtai, and Kaneyoshi Muto—are displayed under the aircraft engine. In 2019, the aircraft was restored to non-flying condition.

N1K1 Kyōfū (s/n 514) is in storage at the National Air and Space Museum's Paul E. Garber Preservation, Restoration, and Storage Facility in Suitland, Maryland.

N1K1 Kyōfū (s/n 562) is located on display at the National Museum of the Pacific War in Fredricksburg, Texas.

N1K1 Kyōfū (s/n 565), formerly displayed at Naval Air Station Joint Reserve Base Willow Grove, Horsham Township, Montgomery County, Pennsylvania, stored at the National Naval Aviation Museum in Pensacola, Florida. Now being restored by American Aero Services, New Smyrna Beach, Florida, for the American Heritage Museum in Stow, Massachusetts. 

N1K2-J Shiden-Kai (George 21).

N1K2-J.

N1K1-J.

N1K2-J destroyed by the Japanese on the ground to prevent its capture.

 A Kawanishi N1K2-Ja Shiden Kai ("George") prior to restoration at the National Museum of the United States Air Force.

Kawanishi N1K1 "Rex" floatplane fighter photographed by the Japanese Navy prior to 1945.

1045:  A Kawanishi N1K Shiden, Allied code name George (probably N1K4-J Shiden Kai Model 32 - only two prototypes were built).

Captured Kawanishi N1K2-Js having their Homare engines run up by former IJNAS groundcrew.

2007: Kawanishi N1K2-J Shiden Kai, Naval Aviation Museum, Pensacola, Florida.

The 343 Kōkūtai's Shiden-Kai, discovered on November 18, 1978, in Jyoen Hisayoshi Bay. The aircraft is displayed at Nanreku Misho Koen, Ehime Prefecture, Japan. It is possible that it is the one was flown by ace-pilot Kaneyoshi Muto.

N1K1 Kyōfū (s/n 562) at the National Museum of the Pacific War.

1945: Kanno's Shidenn Kai 21.

Circa 1946-1947:  U.S. Navy Ensign Philiip F. Kelly pictured with a captured Kawanishi N1K2-J "George" at Naval Air Station Willow Grove, Pennsylvania.

 Kawanishi N1K4.

N1K2 Shiden Kai 21.

Kawanishi N1K2 at the National Museum U.S. Air Force.

Kawanishi N1K2-J at the National Museum of Naval Aviation.

Kawanishi N1K2-J at the Steven F. Udvar-Hazy Center.

1949:  A captured Japanese Kawanishi N1K1 Kyofu (Allied code name "Rex") is put to mothballs at the Naval Air Station Norfolk, Virginia.

N1K1 with contra-rotating prop.

January 1946: Corporal Ralph Hayden and Leading Aircraftman Harry Pearce of No. 80 Squadron RAF amongst parts of a Mitsubishi F1M, bearing Indonesian markings, at an airfield and seaplane base in Surabaya (Soerabaja), Java. In the background are Kawanishi N1K floatplanes.

1945: A Kawanishi N1K1-J "George" painted in the markings of the Army Air Forces Technical Air Intelligence Unit, Southwest Pacific Area pictured on the ground.

 Kawanishi N1K1-J "Shiden" Model 11 operated by Chief Petty Officer Kōji Ōhara, Yokosuka Kokutai.

Kawanishi N1K2-J Shiden, serial number 7102, TAIC-SWPA, S9, at Clark Field, Luzon, Philippines, 1945.

Kawanishi N1K1 Kyufu floatplane, IJNAF.

Kawanishi N1K1 Kyufu, serial number unknown.  One shipped to the USA after the war was designated USAAF FE-324.  It was scrapped at Park Ridge, circa 1950. 

Kawanishi N1K1 Kyufu, serial number 565, when it was on display at NAS Willow Grove, Pennsylvania. This aircraft is now with the National Museum of Naval Aviation, Pensacola, Florida.

Kawanishi N1K2-Ja Shiden Kai.

Prototype N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1.

N1K1 cockpit.

N1K1.

N1K1.

 

Mitsubishi Ki-21 Type 97 Heavy Bomber "Sally"/"Gwen"

Mitsubishi Ki-21 Japanese Air Force “Sally.”

The Mitsubishi Ki-21, formal designation "Type 97 Heavy Bomber was a Japanese heavy bomber during World War II. It began operations during the Second Sino-Japanese War participating in the Nomonhan Incident, and in the first stages of the Pacific War, including the Malayan, Burmese, Dutch East Indies and New Guinea Campaigns. It was also used to attack targets as far-flung as western China, India and northern Australia. The Allies designated it under the reporting names "Sally" /"Gwen". 

In 1936, the Imperial Japanese Army Air Service issued a requirement for a new heavy bomber to replace both the Ki-20 (Army Type 92 Heavy Bomber) and the Ki-1 (Army Type 93 Heavy Bomber). The design called for a crew of at least four, top speed of 400 km/h (250 mph), endurance of at least five hours, and a bombload of 750 kg (1,650 lb). The design parameters were very ambitious for the mid-1930's; few twin-engine bombers anywhere in the world could exceed such performance at that time.

Both Mitsubishi and Nakajima were asked to build two prototypes each, a further proposal from Kawasaki was rejected. The Mitsubishi design was an all-metal mid-wing cantilever monoplane with retractable landing gear, ventral bomb bay and two radial engines. The first prototype flew on 18 December 1936, with the second prototype, which differed in replacing the dorsal turret of the first prototype with a long greenhouse canopy, following later in the month.[4] In the resulting competition, Mitsubishi's Ki-21 and Nakajima's Ki-19 were found to be similar, with the Ki-21 having better performance, while the Nakajima design was a better bombing platform and had more reliable engines. In order to make a final decision, two further prototypes were ordered from both Mitsubishi and Nakajima, with Mitsubishi instructed to change its own 615 kW (825 hp) Mitsubishi Ha-6 radial engines for the Nakajima Ha-5 engines used by the Nakajima design and vice versa, while the Ki-21 gained a revised glazed nose similar to that of the Ki-19 and revised tail surfaces. Thus modified, the Ki-21 proved superior and was ordered into production in November 1937 as the "Army Type 97 Heavy Bomber Model 1A".

Production aircraft began to enter service in August 1938, supplementing and then replacing the Fiat BR.20 bombers which had been purchased as an interim measure.

Several improved versions followed before the production of the type ended in September 1944. A total of 2,064 aircraft were built, 1,713 by Mitsubishi and 351 by Nakajima.

The Ki-21-Ia was used in combat in the war with China by the 60th Sentai from autumn 1938, carrying out long-range unescorted bombing missions in conjunction with the BR.20 equipped 12th and 98th Sentais. The Ki-21 proved to be more successful than the BR.20, having a longer range and being more robust and reliable. Two more Sentais, the 58th and 61st deployed to Manchuria in the summer of 1939 for operations against China, with aircraft from the 61st also being heavily used against Russian and Mongolian Forces during the Nomonhan Incident in June–July 1939.

Losses were high during early combat operations, with weaknesses including a lack of armament and self-sealing fuel tanks, while the aircraft's oxygen system also proved unreliable. The Ki-21-Ib was an improved version designed to address the armament issue by increasing the number of 7.7 mm (0.303 in) Type 89 machine guns to five, and incorporating improvements to the horizontal tail surfaces and trailing edge flaps. In addition, the bomb bay was enlarged. The tail gun was a 'stinger' installation and was remotely controlled. Also, the fuel tanks were partially protected with laminated rubber sheets.

This was followed in production by the Ki-21-Ic with provision for a 500 L (130 US gal) auxiliary fuel tank, fitted in the rear weapons bay and one more 7.7 mm (0.303 in) machine gun, bringing the total to six. Four 50 kg (110 lb) bombs were carried externally. To offset the increase in weight, the main wheels of the Ki-21-IC were increased in size.

However, by the attack on Pearl Harbor and the start of the Pacific War, improvements in the ROC Air Force caused losses to mount, and most Ki-21-1a, -1b and -1c were relegated to training or second-line duties.

Front line units from mid-1940 were equipped with the Ki-21-IIa ("Army Type 97 Heavy Bomber Model 2A") with the more powerful 1,118 kW (1,500 hp) Mitsubishi Ha-101 air-cooled engines and larger horizontal tail surfaces. This became the main version operated by most IJAAF heavy bomber squadrons at the beginning of the Pacific War and played a major role in many early campaigns. For operations over the Philippines, the JAAF's 5th, 14th and 62nd Air Groups, based in Taiwan, attacked American targets at Aparri, Tuguegarao, Vigan and other targets in Luzon on 8 December 1941. The 3rd, 12th, 60th, and 98th Air Groups, based in French Indochina, struck British and Australian targets in Thailand and Malaya, bombing Alor Star, Sungai Petani and Butterworth under escort by Nakajima Ki-27 and Ki-43 fighters. However, starting from operations over Burma in December 1941 and early 1942, the Ki-21 began to suffer heavy casualties from Curtiss P-40s and Hawker Hurricanes.

To partially compensate, the IJAAF introduced the Ki-21-IIb, with a pedal-operated upper turret with one 12.7 mm (0.50 in) Type 1 machine gun, redesigned cockpit canopies and increased fuel capacity. Although used in all fronts in the Pacific theater, it became clear by 1942 that the design was rapidly becoming obsolete, and was increasingly shifted away from front-line service.

In spite of its shortcomings, the Ki-21 remained in service until the end of the war, being utilized as transport (along with the civil transport version MC-21), bomber crew and paratrooper trainer, glider towing, liaison and communications, special commando and secret missions, and kamikaze operations.

Nine Ki-21-Ia/b's were sold by Japan to Thailand in 1940 for use by the Royal Thai Air Force against Vichy French forces in French Indochina but did not participate in the French-Thai War as its crews had not completed training.

Towards the end of the war, remaining Ki-21s were used by Giretsu Special Forces in strikes against American forces in Okinawa and the Ryūkyū Islands. One of the noted operations was an attack on the Allied-held Yontan airfield and Kadena airfield on the night of 24 May 1945. Twelve Ki-21-IIb's of the Daisan Dokuritsu Hikōtai were dispatched for a strike, each with 14 commandos. Five managed to crash-land on the Yontan airfield. Only one plane landed successfully. The surviving raiders, armed with submachine guns and explosives, then wrought havoc on the supplies and nearby aircraft, destroyed 70,000 US gallons (260,000 L) of fuel and nine aircraft, and damaged 26 more.

A number of Ki-21-Ia were modified to serve as military transports for use by Greater Japan Airways, which was under contract by the Japanese Army in China for transportation. Designated "MC-21", these aircraft had all armament and military equipment removed. Used primarily as cargo transports, each could also seat nine paratroopers. Aircraft built from the start as transports were given the separate designation of Mitsubishi Ki-57, with equivalent civil aircraft being designated MC-20.

Code Names

The Ki-21 had more than one Allied code name. Initially called "Jane", the name was quickly changed to "Sally" when General Douglas MacArthur objected that the name was the same as that of his wife. When the Ki-21-IIb entered service, the absence of the long dorsal "greenhouse" led Allied observers to mistake it for a completely new type, which was designated "Gwen". However, when it was realized that "Gwen" was a new version of the Ki-21, it was renamed "Sally 3", with "Sally 1" referring to the earlier Ha-5 powered models, and "Sally 2" referring to the Ha-101 powered Ki-21-IIa.

Variants

Ki-21: Prototype models with various engines and armament combinations for evaluation. Final version with Nakajima Ha-5 engine. 8 built.

Ki-21-Ia (Army Type 97 Heavy Bomber, Model IA): First production model, with 634 kW (850 hp) Nakajima Ha-5-kai engines. Most were built by Mitsubishi, 143 manufactured by Nakajima.

Ki-21-Ib (Army Type 97 Heavy Bomber, Model IB): Improved version with additional 7.7 mm (0.303 in) machine guns, larger bomb compartment and flaps, redesigned tail. 120 built by Mitsubishi, 351 (including Ki-21 Ib and Ic) by Nakajima.

Ki-21-Ic (Army Type 97 Heavy Bomber, Model IC): Improved type with one additional 7.7 mm (0.303 in) machine gun, increased fuel capacity, 160 built by Mitsubishi.

Ki-21-II: Evaluation model with more powerful engines, 4 built.

Ki-21-IIa (Army Type 97 Heavy Bomber, Model IIA): Production model based on Ki-21-II, 590 built.

Ki-21-IIb (Army Type 97 Heavy Bomber, Model IIB): Final production version based on Ki-21-IIa with modified canopy, clear upper cabin replaced by rotating turret, 688 built.

MC-20-I (Army Type 100 Transport, Model I): Unarmed civilian transport version, converted from Ki-21-Ia; approximately 100 aircraft were converted.

Mitsubishi Ki-21.

 Japanese Ki-21 of Daisan Dokuritsu Hikotai at Yontan Airfield, 25 May 1945.

October 1941: Mitsubishi Ki-21. Some details may not be accurate.

Mitsubishi Ki-21.

 Mitsubishi Ki-21: Air raid scene from "Kato hayabusa sento-tai (Colonel Kato's Falcon Squadron)".

 Mitsubishi Ki-21: Air raid scene from "Kato hayabusa sento-tai (Colonel Kato's Falcon Squadron)".

"Bombs for Chiang Kai-shek."

Penfoei, Timor, October 10, Timforce. Lieutenant General K. Yamada, Commander of the Japanese 48th Division, flew into Penfoei to attend surrender ceremony. The undercarriage of his twin engined Mitsubishi Ki-21 bomber collapsed on landing but nobody was injured. The plane is painted in the agreed surrender colors, green crosses on a white background.

Mitsubishi Ki-21. Sortie of Giretsu Kuteitai (May 24, 1945). From newsreel.

May 24, 1945: Wreckage of Giretsu Kuteitai plane that crashed on Yontan Field.

1942: Japanese bombers over Corregidor.

1944: Japanese Ki-21-3 ready for war.

 Air-to-air view of a Mitsubishi Ki-21 bomber (Allied code name: "Sally") in flight over China with unidentified red cross insignia on the aircraft as seen from a U.S. Navy Consolidated PB4Y-1 Liberator aircraft from Patrol Bombing Squadron VPB-104. The squadron operated from Clark Field, Luzon (Philippines), from March to October 1945.

Mitsubishi Ki-21, Hamamatsu Flight School of the Imperial Japanese Army Air Force.

 Imperial Japanese Air Force Mitsubishi Ki-21-II bombers (Allied code name "Sally") pictured in flight over a mountain range.

July 15, 1944: A 3-view silhouette of the Mitsubishi Ki-21.

Mitsubishi Ki-21.

1943:  A camouflaged Japanese Mitsubishi Ki-21-IIb bomber seconds before its destruction by parafrag bombs dropped by a U.S. Army Air Force Douglas A-20 Havoc.

June 16, 1940: Mitsubishi Ki-21 bombing the Chinese capital Chungking.

 

Yokosuka B4Y Navy Type 96 Carrier Attack Bomber "Jean"

Yokosuka B4Y1 Type 96 (“135”) Imperial Japanese Navy.

The Yokosuka B4Y (Navy Type 96 Carrier Attack Bomber) was a carrier-borne torpedo bomber used by the Imperial Japanese Navy Air Service from 1936 to 1943. The B4Y replaced the Mitsubishi B2M2 and the Yokosuka B3Y, and was the last biplane bomber used operationally by the Imperial Japanese Navy. The Allied reporting name was "Jean". This aircraft was mistakenly identified by the British as the Nakajima Navy G-96.

In 1932, the Imperial Japanese Navy issued a requirement for a new carrier-borne attack aircraft. Aichi, Mitsubishi and Nakajima responded to this requirement and each built a prototype. None of these aircraft were deemed satisfactory, and the service thus issued in 1934 a new requirement, 9-Shi, for a more capable aircraft to replace the obsolescent Yokosuka B3Y. 

The B4Y was designed by Sanae Kawasaki at the First Naval Air Technical Arsenal at Yokosuka. Regarded only as an interim type, the Navy wanted a torpedo bomber offering performance comparable to the Mitsubishi A5M monoplane fighter. The result was a biplane with fixed landing gear and an all-metal structure with metal or fabric skin. To speed development and production, the B4Y utilised the wings from the Kawanishi E7K. The B4Y1 was also the first Navy carrier attack aircraft to utilize an air-cooled engine, as the prototype that was equipped with the Nakajima Hikari 2 radial engine performed better than its competitors.

The crew of three occupied two cockpits. The pilot in the open front cockpit and the other two crewmen, (navigator and radio operator/gunner), in the enclosed rear cockpit. 

On 12 December 1937 3 B4Y1s were involved in the Panay incident during a Japanese attack on the United States Navy gunboat Panay while she was anchored in the Yangtze River outside of Nanjing.

Although primarily used as a carrier-based aircraft, the B4Y1 was also used as a land-based bomber on occasion. In 1940, the Nakajima B5N replaced the B4Y1 as the primary carrier attack aircraft, though the B4Y1 did remain in service as an advanced trainer, and flew from Hōshō and Unyō until 1943.

Before its replacement, the B4Y1 had flown during the Second Sino-Japanese War and served at the Battle of Midway during June 1942, where eight of them were operated from Hōshō. It was one of these planes from Hōshō which took photographs of the burning Hiryū on 5 June 1942. 

Variants

First prototype: 559 kW (750 hp) Hiro Type 91 520 hp water-cooled W-12 driving a two-bladed propeller. 

Second and third prototypes: 477 kW (640 hp) Nakajima Kotobuki 3 nine-cylinder air-cooled radial driving a two-bladed propeller.

Fourth and fifth prototype and production aircraft: 636 kW (853 hp) Nakajima Hikari 2 nine-cylinder air-cooled radial driving a two-bladed propeller.

Production

First Naval Air Technical Arsenal, Yokosuka: 5 prototypes (1935–36)

Nakajima Aircraft Company: 37 production aircraft (1937–38)

Mitsubishi Heavy Industries, Nagoya: 135 production aircraft (1937–38)

11th Naval Air Arsenal, Hiro: 28 production aircraft (1938

Total: 205 aircraft

B4Y1.

Yokosuka B4Y.

An Imperial Japanese Navy Type 96 carrier attack plane flies near the aircraft carrier Kaga off China during the China incident in 1937 or 1938.

Focke-Wulf Fw 190

A German Focke-Wulf Fw 190 A-3 of 11./JG 2 after landing in the UK by mistake in June 1942.

The Focke-Wulf Fw 190, nicknamed Würger (Shrike) is a German single-seat, single-engine fighter aircraft designed by Kurt Tank at Focke-Wulf in the late 1930s and widely used during World War II. Along with its well-known counterpart, the Messerschmitt Bf 109, the Fw 190 became the backbone of the Jagdwaffe (Fighter Force) of the Luftwaffe. The twin-row BMW 801 radial engine that powered most operational versions enabled the Fw 190 to lift larger loads than the Bf 109, allowing its use as a day fighter, fighter-bomber, ground-attack aircraft and to a lesser degree, night fighter.

The Fw 190A started flying operationally over France in August 1941 and quickly proved superior in all but turn radius to the Spitfire Mk. V, the main front-line fighter of the Royal Air Force (RAF), particularly at low and medium altitudes. The 190 maintained its superiority over Allied fighters until the introduction of the improved Spitfire Mk. IX. In November/December 1942, the Fw 190 made its air combat debut on the Eastern Front, finding much success in fighter wings and specialized ground attack units (Schlachtgeschwader – Battle Wings or Strike Wings) from October 1943.

The Fw 190A series' performance decreased at high altitudes (usually 6,000 m [20,000 ft] and above), which reduced its effectiveness as a high-altitude interceptor. From the Fw 190's inception, there had been ongoing efforts to address this with a turbosupercharged BMW 801 in the B model, the much longer-nosed C model with efforts to also turbocharge its chosen Daimler-Benz DB 603 inverted V12 powerplant, and the similarly long-nosed D model with the Junkers Jumo 213. Problems with the turbocharger installations on the -B and -C sub-types meant only the D model entered service in September 1944. These high-altitude developments eventually led to the Focke-Wulf Ta 152, which was capable of extreme speeds at medium to high altitudes (755 km/h [408 kn; 469 mph] at 13,500 m [44,300 ft]). While these "long nose" 190 variants and the Ta 152 derivative especially gave the Germans parity with Allied opponents, they arrived too late to affect the outcome of the war.

The Fw 190 was well-liked by its pilots. Some of the Luftwaffe's most successful fighter aces claimed many of their kills while flying it, including Otto Kittel, Walter Nowotny and Erich Rudorffer. The Fw 190 had greater firepower than the Bf 109 and, at low to medium altitude, superior maneuverability, in the opinion of German pilots who flew both fighters. It was regarded as one of the best fighter planes of World War II.

 Focke-Wulf Fw 190 V1 in its original form.

Focke-Wulf Fw 190 V5k in its original form.

Fw 190 A-0s or A-1s of an unknown unit in France.

In 1943, the Japanese Army received one Focke-Wulf Fw 190A-5, and this aircraft was extensively tested during that year. It was most probably delivered by submarine, and also carried standard Luftwaffe camouflage, and was flown in Japanese markings.