The Mitsubishi Ki-20 is a Japanese bomber variant of the Junkers G.38 airliner. Mitsubishi manufactured six aircraft under license from Junkers. These aircraft, designated Army Type 92 Heavy Bomber, served through the 1930s. During World War II, the Ki-20 served in a variety of transport and support roles.
Design and development
In the late-1920s, as Junkers developed the Junkers G.38, Mitsubishi representatives in Germany expressed an interest in a military version of this civilian transport. At the time, the G.38 was the largest landplane in the world. Junkers completed a design study for a military bomber/transport, based on the G.38, designated the K.51. This design was not accepted by the Reichsluftfahrtministerium.
The K.51 design study was of interest to Japan. A licensing and manufacturing agreement was reached and in 1932, the first two Ki-20s were completed by Mitsubishi, utilizing Junkers-made parts. A prototype was successfully flown in Japan by a German test pilot in that year.
Four additional Ki-20s were built between 1933 and 1935. All of these subsequent models used Mitsubishi-built parts. Ongoing development focused on engine upgrades to all examples to address the persistent issue of the aircraft being underpowered. Several engine upgrades were completed during the lifetime of these aircraft. The initial Junkers L88 engines were replaced by the more powerful Jumo 204 engines, also built under license by Mitsubishi. Additionally, Kawasaki Ha-9 engines were utilized for testing purposes.
Operational history
During World War II, the Japanese originally intended to utilize the Ki-20s to attack the forts at the entrance to Manila Bay in the Philippines, as well as for deep penetration missions into Siberia. For these purposes, they were armed with six gun positions and structurally enabled to carry a bomb load. These aircraft were the largest operated by the Imperial Japanese Army Air Service and their existence within it was kept secret. As a result, they were issued their out-of-sequence Kitai number '20' only when they were finally revealed in 1940.
Surviving aircraft
A single example survived to the end of hostilities as a museum piece in the Tokorozawa Aviation Memorial Hall.
|prime units?=met
<!--
General characteristics
-->
|crew=10
|length m=23.2
|length note=
|span m=44
|span note=
|height m=7
|height note=
|wing area sqm=294
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil=<!--root: NACA ; tip: NACA -->
|empty weight kg=14912
|empty weight note=
|gross weight kg=25448
|gross weight note=
|max takeoff weight kg=
|max takeoff weight note=
|fuel capacity=
|more general=
<!--
Powerplant
-->
|eng1 number=4
|eng1 name=Junkers Jumo 204 (Type Ju)
|eng1 type=6-cylinder liquid-cooled opposed-piston diesel engines
|eng1 kw=<!-- prop engines -->
|eng1 hp=750
|eng1 shp=<!-- prop engines -->
|eng1 kn=<!-- jet/rocket engines -->
|eng1 lbf=<!-- jet/rocket engines -->
|eng1 note=
|prop blade number=4
|prop name=wooden fixed-pitch propellers
|prop dia m=<!-- propeller aircraft -->
|prop dia note=
<!--
Performance
-->
|max speed kmh=200
|max speed note=
|cruise speed kmh=
|cruise speed note=
|stall speed kmh=
|stall speed note=
|never exceed speed kmh=
|never exceed speed note=
|minimum control speed kmh=
|minimum control speed note=
|range km=
|range note=
|combat range km=
|combat range note=
|ferry range km=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ms=
|climb rate note=
|time to altitude=
|wing loading kg/m2=86.6
|wing loading note=
|fuel consumption kg/km=
|power/mass=
|more performance=
<!--
Armament
-->
|guns=<br>
- 2 × machine guns in nose
- 1 × cannon on dorsal position
- 2 × machine guns in each of two upper wing turrets
- 1 × machine gun in each of one lower wing turret
|bombs=<br>
- Up to bombs carried externally
|avionics=