MANUFACTURER(S): Nakajima - Japan
OPERATORS: Imperial Japan; Indonesia; Thailand
LENGTH: 54.13 feet (16.5 meters)
WIDTH: 66.99 feet (20.42 meters)
HEIGHT: 13.94 feet (4.25 meters)
WEIGHT (EMPTY): 14,396 pounds (6,530 kilograms)
WEIGHT (MTOW): 25,133 pounds (11,400 kilograms)
ENGINE: 2 x Nakajima Ha-109 radial piston engines developing 1,450 horsepower each.
SPEED (MAX): 306 miles-per-hour (492 kilometers-per-hour; 266 knots)
RANGE: 1,833 miles (2,950 kilometers; 1,593 nautical miles)
CEILING: 30,512 feet (9,300 meters; 5.78 miles)
RATE-OF-CLIMB: 1,225 feet-per-minute (373 meters-per-minute)
Detailing the development and operational history of the Nakajima Ki-49 Donryu (Helen) Medium Bomber Aircraft.
Entry last updated on 5/10/2016.
Authored by Staff Writer. Content ©www.MilitaryFactory.com.
The Nakajima Ki-49 Donryu (meaning "storm dragon" and codenamed "Helen" by the Allies) heavy bomber was intended as a replacement for the out-classed Mitsubishi Ki-21 series of medium bomber. In reality, the newer Ki-49 design proved to be something of a disappointment to the Imperial Japanese Army Air Force as the type was a slow performer that - like most Japanese aircraft of the war - was ill-armed and under-armored. As a result, the type saw very limited production numbers (being limited to just over 800), appeared in a few variants and quickly was dismissed as a partner to the successful ki-21 instead of its direct replacement.
The Nakajima Ki-49 was drawn up by 1938 as a very utilitarian heavy bomber design. The term "heavy bomber" in this instance was carried quite loosely as the production Ki-49 could carry barely above 2,000 pounds of internal ordnance. The aircrafts design followed along the same lines of previous twin engine bomber attempts of Japanese ordnance that saw a slender fuselage with clean lines, a middle-mounted monoplane wing assembly, various gun positions adorning the design and a single vertical tail surface. Crew accommodations amounted to seven (or in some cases eight) personnel. Defensive armament (always an issue with Japanese bomber aircraft designs throughout the war) consisted of a nose-mounted 7.7mm machine gun, a 7.7mm machine gun in a tail gun position, 2 x 7.7mm machine guns in beam positions (1 gun per side), a 7.7mm machine gun in a ventral position and a 20mm cannon in a flexible dorsal mounting.
The first Ki-49 prototype went airborne in 1939 with Nakajima Ha-5 KAI radial engines of 950 horsepower each. Pre-production and the first production models would be mated with 2 x Nakajima Ha-41 radial engines of 1,250 horsepower each, increasing performance capabilities as a result. The Ki-49 would enter service in 1941 with mixed results, forcing the aircraft to undergo some much needed upgrades to armor and armament by 1942. The "improved" Ki-49 appeared in form as the Ki-49-IIa and was followed by another improved version in the Ki-49-IIb variant.
The Ki-49 was fielded extensively against China, Australia and the Burma region but the aircraft was generally outclassed by the latest crop of American and British fighters. As a result, the Ki-49 suffered heavy losses throughout the conflict and their reach was lessened by 1944. Afterwards, the Ki-49 - like most of the mid-sized Japanese aircraft of limited potential - could be seen focused on kamikaze attacks against Allied interests.
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Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.
Relative Maximum Speed Rating
This entry's maximum listed speed (306mph).
Graph average of 300 miles-per-hour.
Graph showcases the Nakajima Ki-49-IIa Donryu (Helen)'s operational range (on internal fuel) when compared to distances between major cities.
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units