Miloch
September 17th 19, 03:06 PM
https://en.wikipedia.org/wiki/Mitsubishi_Ki-21
The Mitsubishi Ki-21 (or "Type 97 Heavy Bomber") (Kyunana-shiki jubakugekiki)
(Allied reporting name: "Sally" /"Gwen") 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.
In 1936, 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, and 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 being 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. 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 prototype 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 gainied 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 as the "Army Type 97 Heavy
Bomber Model 1A", being ordered into production in November 1937.
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.
Role
Heavy bomber
Manufacturer
Mitsubishi
First flight
18 December 1936
Introduction
1938
Retired
1945
Primary users
Imperial Japanese Army Air Force
Royal Thai Air Force
Number built
2,064 units (excluding Ki-57)
Variants
Mitsubishi Ki-57
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 (.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
(.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.
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.
Towards the end of the war, remaining Ki-21s were used by Giretsu Special Forces
in strikes against American forces in Okinawa and the Ryukyu 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
Hikotai 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 264,979 L (70,000 gal) of fuel
and nine aircraft, and damaged 26 more.
Code Names
The Ki-21 had more than one Allied codename. 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.
Specifications (Ki-21-IIb)
General characteristics
Crew: 5–7
Length: 16.0 m (52 ft 6 in)
Wingspan: 22.50 m (73 ft 10 in)
Height: 4.85 m (15 ft 11 in)
Wing area: 69.90 m² (752.12 ft²)
Empty weight: 6,070 kg (13,354 lb)
Loaded weight: 10,600 kg (23,320 lb)
Powerplant: 2 × Mitsubishi Army Type 100 (Ha-101)(Mitsubishi Kasei) 14 cylinder
radial engine, 1,119 kW (1,500 hp) each
Propellers: three-blade metal variable-pitch propeller
Performance
Maximum speed: 485 km/h (301 mph) at 4,700 m (15,400 ft)
Cruise speed: 380 km/h (236 mph)
Range: 2,700 km (1,680 mi)
Service ceiling: 10,000 m (32,800 ft)
Rate of climb: 13 min 13 sec to 6,000 m (19,680 ft)
Armament
Guns:
5× 7.7 mm (.303 in) flexible Type 89 machine guns in nose, ventral, beam and
tail positions
1× 12.7 mm (.50 in) Type 1 Machine Gun in dorsal turret
Bombs: 1,000 kg (2,200 lb) of bombs
*
The Mitsubishi Ki-21 (or "Type 97 Heavy Bomber") (Kyunana-shiki jubakugekiki)
(Allied reporting name: "Sally" /"Gwen") 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.
In 1936, 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, and 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 being 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. 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 prototype 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 gainied 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 as the "Army Type 97 Heavy
Bomber Model 1A", being ordered into production in November 1937.
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.
Role
Heavy bomber
Manufacturer
Mitsubishi
First flight
18 December 1936
Introduction
1938
Retired
1945
Primary users
Imperial Japanese Army Air Force
Royal Thai Air Force
Number built
2,064 units (excluding Ki-57)
Variants
Mitsubishi Ki-57
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 (.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
(.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.
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.
Towards the end of the war, remaining Ki-21s were used by Giretsu Special Forces
in strikes against American forces in Okinawa and the Ryukyu 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
Hikotai 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 264,979 L (70,000 gal) of fuel
and nine aircraft, and damaged 26 more.
Code Names
The Ki-21 had more than one Allied codename. 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.
Specifications (Ki-21-IIb)
General characteristics
Crew: 5–7
Length: 16.0 m (52 ft 6 in)
Wingspan: 22.50 m (73 ft 10 in)
Height: 4.85 m (15 ft 11 in)
Wing area: 69.90 m² (752.12 ft²)
Empty weight: 6,070 kg (13,354 lb)
Loaded weight: 10,600 kg (23,320 lb)
Powerplant: 2 × Mitsubishi Army Type 100 (Ha-101)(Mitsubishi Kasei) 14 cylinder
radial engine, 1,119 kW (1,500 hp) each
Propellers: three-blade metal variable-pitch propeller
Performance
Maximum speed: 485 km/h (301 mph) at 4,700 m (15,400 ft)
Cruise speed: 380 km/h (236 mph)
Range: 2,700 km (1,680 mi)
Service ceiling: 10,000 m (32,800 ft)
Rate of climb: 13 min 13 sec to 6,000 m (19,680 ft)
Armament
Guns:
5× 7.7 mm (.303 in) flexible Type 89 machine guns in nose, ventral, beam and
tail positions
1× 12.7 mm (.50 in) Type 1 Machine Gun in dorsal turret
Bombs: 1,000 kg (2,200 lb) of bombs
*