Nakajima Experimental Attack-Bomber "SHINZAN"

Illustrated by Shigeo Koike.

There were some early attempts to produce a long range bomber -  for example, the Mitsubishi G7M1 Taizan  (a  16-shi  project)  - plus  designs  that  were  actually  built  such  as the  Nakajima  G5N Shinzan  and  Nakajima G8N  Renzan. The Shinzan was not a success and the Renzan failed to reach operational service as a combat aircraft, let alone reach America and return.

The DC-4E was sold by Douglas to Japan's Mitsui Trading Company, Ltd. for Japan Air Lines Company, Ltd.; no more are built. The Japanese pay $950,000 for the airplane, which is shipped to Tokyo by sea on September 29. After it is reassembled by Douglas technicians, the Super Mainliner will be the model for that nation's first four-engine land plane, the unsuccessful Nakajima G5N bomber/transport Shinzan (Mountain Recess).

The design that emerged from this study was for an all-metal mid-wing monoplane with fabric-covered control surfaces and powered by four 1,870 hp Nakajima NK7A Mamori 11 air-cooled radial engines driving four-bladed propellers. Notable features included a long ventral bomb-bay, glazed nose and twin tailfins replacing the DC-4E's distinctive triple rudder. The DC-4E's retractable tricycle undercarriage was retained, as well as the original wing form and powerplant arrangement. Defensive armament comprised one 20mm Type 99 Model 1 cannon each in a power-operated dorsal and tail turret plus single-mount hand-operated 7.7mm Type 92 machine guns in the nose, ventral and waist positions.

The first prototype G5N1 made its maiden flight on 14:35 8 April 1941. Overall performance proved disappointingly poor however, due to a combination of excessive weight, the unreliability of the Mamori engines and the complexity of the design. Only three more prototypes were completed. In an attempt to salvage the project, two additional airframes were fitted with 1,530 hp Mitsubishi MK4B 12 "Kasei" engines and redesignated G5N2s. Although the Mitsubishi engines were more reliable than the original Mamori 11s, the aircraft was now even more hopelessly underpowered and further development of the type was halted.

Of the six completed Shinzans, four of them were relegated for use as long-range Navy transports under the designation G5N2-L Shinzan-Kai Transport. The Allies allocated the code-name "Liz" to the aircraft, in the expectation it would be used as a bomber.

Z Superbombers Project (1942-1944)

Similar to the Nazi ‘Amerika-Bomber’ project to develop long-range strategic bomber to strike the United States from Germany, Japan initiated the ‘Project Z’ to develop an intercontinental bomber to strike North America. The Japanese were desperate to develop something like the US B-29 Superfortress long-range heavy bomber which was introduced in 1944.

Imperial Japanese Navy had designed the four-engined ‘Nakajima G5N’ heavy bomber prior to the Second World War and introduced it in 1941. But their planners wanted something much larger, faster, heavier and capable of flying at 32,800 feet with a load of 22 one thousand pound bombs; B-29 Superfortress also had similar capabilities with a speed up to 350 mph during wartime. Imperial Japanese Army was presented several designs for the Project Z; these included- the Nakajima G10N Fugaku and Kawasaki Ki-91. Fugaku means Mount Fuji. G10N Fugaku was supposed to have a wingspan of 213 ft 2 in and a total length of 147 ft 7in. It would have been powered by six 5,000 hp engines and capable of reaching speeds of 365 mph at 25,000 ft. Nakajima Aircraft Company started developing G10N’s 4 row 36 cylinder 5,000 hp engines in 1943 but abandoned due to complexity. Z Superbombers Project was cancelled in July 1944.

Workmanship of Axis aircraft

In Richard M. Bueschel's series on Japanese WWII fighters (i.e, "Nakajima Ki-84 Hayate in Japanese Army Air Force Service) and Rene Francillon's "Japanese Aircraft of the Pacific War"), the authors repeatedly mention that the latter-day Japanese fighters, while technically equal to their Allied counterparts, were plagued by variable and poor workmanship; Bueschel writes that the Ki-84 could only rarely achieve a level speed of 400 km per hour. For example, the level speed of the Nakajima Ki-84 fighter was rated at 620 km per hour, yet reportedly most late-production specimens could not achieve even 400 km per hour due to poor workmanship of the airframe and engine.

As for the Ki-84, I remember talking to a P-51 pilot from SWPA. He said that sometimes they would try to intercept the Franks, which could and did show them a clean set of heals. If this was an overall problem I think this "legging it" would not have happened. A good question would be where did this information come from. Was it from the US, who did and still do put down aircraft that were either superior or at least on par with their own, or was this actual Japanese records showing this.

I apologize to our American Friends out there, the above comment is not an attack on you guys but just something that I have seen and heard over the years, by various Authors and Vets.

I recall reading accounts of trials of captured Japanese aircraft, in particular the Ki-84, which stated that the fitting of US spark plugs made a vast difference to the aircraft's performance. The fitting of US brake pads too, where possible was found to be a must too! Material shortages and quality problems in seemingly minor areas can have a dramatic effect on overall performance. 

Were the late war Luftwaffe fighters subject to similar inconsistencies in workmanship and quality control?

Its an accepted fact that workmanship on the production Me-262s could vary by a huge margin. With components from several sources and locations, it was impossible to get the same kind of tight tolerances that a single factory of that period could produce. There were reports of some Me-262s that were discovered to have foreign objects (tools, supplies, etc.) pushed into void spaces by their builders, no doubt in response to their slavery. Also, I read here once that a Junkers 290 crashed and it was later determined that the tail section was delivered with a very large amount of very heavy tools hidden in the tail.

The Swiss thought the 109Gs they received were terrible, as opposed to the few Fs that they received mid-war. The French thought the same about the Fw.190s they tried to operate postwar. This was partly due to wartime pressures, and partly to the influence of all the foreign (slave, if you like) workers employed in the German industry late war.

It should be added that late P-40s were much cruder than the early-war aircraft, though this is due to an intense "simplify and add more lightness" campaign rather than a decline in workmanship as such.

Bf 109 quality as perceived in Finland

The Finnish AF also observed a big decline in workmanship quality of Bf 109G-6s received in summer 1944, compared with quality of G-2s received in winter-spring 1943. All received 109s were therefore thoroughly overhauled at VL (except a few aircraft which were ferried directly to the frontline, and performed the first missions still with German transfer insignias/see Vol 6 of FAF History by Keskinen&Stenman). The FAF and VL tried very hard to negotiate a full reparation license for the 109 (including drawings, spares and tools) for the 109, but for obvious political reasons the Germans were very reluctant (it was known to the Germans that contacts had already been taken to Moscow in April 1943). Complete sets of drawings and tools for the 109 were never delivered, why VL tried to design the indigenous Pyörre-Myrsky around the Daimler-Benz 605 engine,