Nakajima Ki-49
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| Nakajima Ki-49 Donryu | |
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 The Nakajima Ki-49 bomber |
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| Type | Medium bomber |
| Manufacturer | Nakajima Aircraft Company |
| Maiden flight | August 1939 |
| Introduced | 1941 |
| Retired | 1945 |
| Primary user | IJA Air Force |
| Produced | 1941-1944 |
| Number built | 819 |
The Nakajima Ki-49 Donryu (Japanese: 呑龍 "Storm Dragon") was a Japanese medium bomber of World War II. It was a twin-engine, mid-wing, cantilever monoplane of all-metal construction fitted with a retractable tailwheel undercarriage. During the Second World War, it was known to the Allies by the code-name "Helen".
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[edit] Development
The Ki-49 was designed to replace the Mitsubishi Ki-21, which entered service in the Imperial Japanese Army Air Force in 1938. Learning from service trials of the Ki-21, the Army realized that however advanced it may have been at the time, their new Mitsubishi bomber would in due course be unable to operate without fighter escorts. As a result the Japanese Army stipulated that its replacement should have the speed and defensive weaponry to enable it to operate independently.
The prototype first flew in August 1939 and the development programme continued through three prototypes and seven pre-production aircraft. This first prototype was powered by a pair of 708-kW (950-hp) Nakajima Ha-5 KA-I radial engines, but the next two had the 1,250 hp (932 kW) Nakajima Ha-41 engines that were inteded for the production version. Seven more prototypes were built, and these completed the test programme for the aircraft.
Eventually in March 1941, the Donryu went into production as the Army Type 100 Heavy Bomber Model 1.
[edit] Operational History
Going operational from autumn 1941, the Ki-49 first saw service in China. After the outbreak of the Pacific War it was active in the New Guinea area and in raids on Australia. Like the prototype, these early versions were armed with five 7.7 (0.303 in) machine guns and one 20 mm cannon.
Combat experience in China and New Guinea showed the Donryu to be underpowered with bomb capacity and speed suffering as a result. Thus, in the spring of 1942 an up-engined version was produced, fitted with more powerful Ha-109 engines, and this became the production Army Type 100 Heavy Bomber Model 2 or Ki-49-IIa. The Model 2 also introduced improved armour and self-sealing fuel tanks and was followed by the Ki-49-IIb in which 12.7-mm (0.5-in) machine guns replaced three of the 7.7 mm (0.303-in) pieces.
In spite of these improvements however, losses continued to mount as the quantity and quality of fighter opposition rose. An attempt was made to stop the rot in early 1943 by further up-engining the type. This petered out, however, owing to development difficulties with the 2,420 hp (1,805 kW) Nakajima Ha-117 engines and the Ki-49-III never entered production with only six prototypes ever being built.
In the face of its increasing vulnerability to opposing fighter aircraft while performing its intended role, the Ki-49 was used in other roles towards the end of the Pacific War, including ASW patrol, troop transport and, ultimately, as kamikaze.
After 819 aircraft had been completed, production ended in December 1944.
[edit] Variants
- Ki-49 - Prototipes and pre-series models with Nakajima Ha-5 KAI of 950 hp or Ha-41 of 1,250 hp.the pre-serie with little modifications.
- Ki-49-I - Army type 100 heavy bomber model I,firs serie type
- Ki-49-II - Two prototypes fitted with two Nakajima Ha-109 radial piston engines.
- Ki-49-IIa - a serie 2a model
- Ki-49-IIb - armed with 12.7 mm Ho-103 MGs
- Ki-49-III - six prototypes fitted with two 1805-kW (2,420-hp) Nakajima Ha-117 engines.
- Ki-58 - escort fighter with Ha-109 engines, 5x20-mm cannon, 3x12.7-mm (0.5-in) machineguns. 3 prototypes
- Ki-80 - specialised pathfinder aircraft - 2 prototypes; employed as engine test-beds
- Total production: all versions 819 examples (included ones 617 constructed by Nakajima and others 50 by Tachikawa)
[edit] Operators
- Ex-Japanese Aircraft was operated by Indonesian guerilla forces after the war.[1]
- Royal Thai Air Force utilized 1 Nakajima Ki-49 how transport post war, during 1945-46
[edit] Specifications (Ki-49-IIa)
Data from Axis Aircraft of World War II [1]
General characteristics
- Crew: 8
- Length: 16.5 m (54 ft 1.5 in)
- Wingspan: 20.42 m (67 ft 0 in)
- Height: 4.25 m (13 ft 11.25 in)
- Wing area: 69.05 m² (743.27 ft²)
- Empty weight: 6,530 kg (14,396 lb)
- Max takeoff weight: 11,400 kg (25,133 lb)
- Powerplant: 2× Nakajima Ha-109 14-cylinder radial piston, 1,119-kW (1,500-hp) each
Performance
- Maximum speed: 492 km/h (266 knots, 306 mph)
- Cruise speed: 350 km/h (189 knots, 217 mph)
- Range: 2,950 km (1,594 NM, 1,833 mi)
- Service ceiling 9,300 m (30,510 ft)
- Wing loading: kg/m² (lb/ft²)
- Power/mass: W/kg (hp/lb)
Armament
- Guns: 1 × 20 mm Type 99 cannon, 5 × 7.7-mm (0.303-in) Type 89 machine guns.
- Bombs: 1,000 kg (2,204-lb) bombload
[edit] See also
Comparable aircraft
- Junkers Ju 88
- Martin B-26 Marauder
- North American B-25 Mitchell
[edit] References
- ^ Mondey 1996, p.228.
- Mondey, David (1996). Axis Aircraft of World War II. London: Chancellor Press.
[edit] External links
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