Nakajima Ki-49 Donryu (Helen) - Imperial Japan, 1941
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 was destined to replace the ill-equipped Ki-21 though the Ki-49 itself was a general failure in design.
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.