Much like the Germans during World War 2 (1939-1945), the Empire of Japan never truly found a notable four-engined "heavy", a long-ranging multi-engined strategic bomber capable of dropping considerable war loads on enemy targets over distance. Projects were had by both parties but none materialized beyond paper drawings or prototypes. In the early-war period, the Nakajima Aircraft Company attempted such a project based around the proven framework of the American Douglas DC-4E that it had acquired - but even this initiative fell to naught as just six of the type were produced in all.
The DC-4E was, itself, a developmental model arranged by the Douglas Aircraft Company and eventually operated by American Airlines in the United States and, later, Imperial Japanese Airways. The original aircraft was powered by 4 x Pratt & Whitney R-2180-S1A1-G "Twin Hornet" air-cooled radial piston engines driving three-bladed propeller units and outputting 1,450 horsepower each and one notable physical characteristic of the design was the three-finned tail unit. The aircraft was crewed by three and could carry as many as 42 passengers over distances of 2,200 miles. A first-flight was recorded on June 9th, 1939 - this before World War 2 officially began.
After some testing, Douglas decided against the DC-4E and this led Japan to procure the abandoned prototype while Douglas pursued another in-house design that became the classic "DC-4" aircraft of the World War 2 period. As such, the DC-4E initially fell to Imperial Japanese Airways in the latter part of 1939 and was seen by the Imperial Japanese Navy (IJN) as a possible candidate for conversion into a long-range bomber. The Japanese reverse-engineered the American airliner to become the short-lived "G5N" under the Nakajima Aircraft Company brand label. To cover the work, Japanese media reported the DC-4E as crashed while the true aircraft could be reviewed under cover and modified by Japanese industry to produce the proposed bomber form. As the DC-4E was readily available for the conversion work, it was selected as no local solution could be had from Japanese aero-industry at the time.
The G5N was drawn up to fulfill an IJN requirement for a long-range strategic bombing platform capable of crossing the vast distances of the Pacific. The service, like the Imperial Japanese Army (IJA), lacked such a performer while other powers of the world had already embraced the concept of a strategic bomber force built on range and firepower. For the IJN, the minimum acceptable operational range became 3,500 miles, giving what would become their next bomber excellent "legs" in the air.
While the bomb bay would be used to hold the proposed conventional drop ordnance, the aircraft itself would be defensed through traditional ballistic weapons - machine guns and automatic cannons. This included 1 x 7.7mm Type 92 machine gun on a trainable mounting at the nose, another at a rear-facing ventral position, and one machine gun side-facing at each waist position. Beyond this was to be 1 x 20mm Type 99 Model 1 automatic cannon installed at the nose in a power-operated dorsal turret and similar armament installed at the tail in its own powered emplacement. All told, the bomber would have been well-defended through this network of guns.
The G5N, in its initial form as "G5N1" (and further classified as "Type 13 Land-Based Attack Bomber "Shinzan"), achieved its first-flight on April 8th, 1941 but the heavy design, coupled with the underperforming engines, left much to be desired of the large bomber (just two were built to the original standard). Engineers attempted to rectify the issues and three additional prototypes eventually joined the development phase bringing the airframe count to four. At one point, another pair of aircraft were added to the mix and re-engined to take 4 x Mitsubishi MK4B 12 "Kasei" radials of 1,530 horsepower - resulting in the switch to the "G5N2" test production designation. By this point, the war had engulfed Japan industry completely and aero-related resources were allocated to the ongoing war effort, leaving little room for development of a whole new bomber like the G5N.
So not all would be lost, of the six available airframes, four were reconstituted as long-range transports by the IJN and served as "G5N2-L" (further named "Shinzan-Kai"). These were identified by American military observers and afforded the codename of "Liz" for their time in service.
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(OPERATORS list includes past, present, and future operators when applicable)
✓Ground Attack (Bombing, Strafing)
Ability to conduct aerial bombing of ground targets by way of (but not limited to) guns, bombs, missiles, rockets, and the like.
Equipped to search, track, and engage enemy surface elements through visual acquisition, radar support, and onboard weaponry.
✓Intelligence-Surveillance-Reconnaissance (ISR), Scout
Surveil ground targets / target areas to assess environmental threat levels, enemy strength, or enemy movement.
✓X-Plane (Developmental, Prototype, Technology Demonstrator)
Aircraft developed for the role of prototyping, technology demonstration, or research / data collection.
101.8 ft (31.02 m)
138.2 ft (42.12 m)
28.9 ft (8.80 m)
44,313 lb (20,100 kg)
70,548 lb (32,000 kg)
+26,235 lb (+11,900 kg)
(Showcased structural values pertain to the Nakajima G5N production variant)
4 x Nakajima NK7A "Mamori 11" 14-cylinder air-cooled radial piston engines developing 1,871 horsepower each driving four-bladed propeller units.
(Showcased performance specifications pertain to the Nakajima G5N production variant. Performance specifications showcased above are subject to environmental factors as well as aircraft configuration. Estimates are made when Real Data not available. Compare this aircraft entry against any other in our database or View aircraft by powerplant type)
1 x 20mm Type 99 Model 1 automatic cannon in powered dorsal turret at the nose.
1 x 7.7mm Type 92 machine gun on trainable mounting in nose position.
1 x 7.7mm Type 92 machine gun on trainable mounting in ventral, rear-facing position.
1 x 7.7mm Type 92 machine gun on trainable mounting at port side waist position.
1 x 7.7mm Type 92 machine gun on trainable mounting at starboard side waist position.
1 x 20mm Type 99 Model 1 automatic cannon in powered turret at tail position.
Internal bomb load of unknown rating consisting of conventional drop bombs and possibly torpedoes.
(Not all ordnance types may be represented in the showcase above)
Hardpoint Mountings: 0
G5N "Shinzan" ("Deep Mountain") - Base Series Designation.
"Experimental 13-Shi Attack Bomber" - Imperial Japanese Navy (IJN) designation.
G5N1 - Initial prototypes; two completed to the standard.
G5N2 - Secondary prototypes; four completed to the standard with 4 x Mitsubishi MK4B 12 "Kaisei" radial engines driving four-bladed propeller units.
G5N2-L "Shinzen-Kai" - Reconstituted G5N2 bombers for the long-range transport role by the IJN.
Ki-68 - Proposed IJA model with either Mitsubishi or Nakajima engines.
Ki-85 - Proposed IJA model with Mitsubishi Ha-111M engines; mock-up completed in 1942 but design cancelled i May of 1943.
"Liz" - Allied Codename.
Ribbon graphics not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective aerial campaigns / operations / aviation periods.
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