Japanese medium & heavy bombers

I know the Japanese had the Betty and I also believe the Nell was another bomber they used, but they would have both been a medium bomber perhaps with decent range but not bomb load. If the Japanese desire was to have such a vast empire, why would they not have had a long-range heavy bomber in the works either before or during the war to if not help expand the empire then to at least try and hold what they had gained?

 

Japan, much like Germany, designed their aircraft to act as a support for the rest of their military, and to be honest none of their neighbors close to them had the kinds of targets (Industry) that merited the payload of a true Heavy Bomber. For anything within their reach a "Medium" bomber fit the bill and was within their budget.

 

As already mentioned by “belasar”, the Japanese used much the same, or probably much the same reason that the Luftwaffe went for medium and tactical bombers, the Japanese didn’t foresee a time when they might absolutely need a heavy four engined bomber.

When the need for an “America Bomber, or even the “Ural Bomber” became apparent to Nazi Germany, it was too late in the game to fill the niche. The Japanese didn’t even entertain the idea until the middle of ’44, and by then the jig really was up and wouldn’t have made a bit of difference.

Goto:
Nakajima G8N Renzan (Rita) Heavy Bomber - History, Specs and Pictures - Military Aircraft

 

AmericanEagle,

The Japanese had foreseen the need for a long-range heavy bomber prior to the war, it was the NakaJima G5N "Shinzan"(trans. - "Mountain Recess"/Allied codename "Liz"). The IJNAF began looking into the feasibility of a heavy bomber in 1938. In September, 1939, the IJN, using the Dai Nippon Koku K.K.(Imperial Japanese Airways) as a "front" company, purchased the only copy of the failed DC-4E to serve as the basis for their long-range heavy bomber. The DC-4E was promptly handed over to Nakajima where it was disassembled and studied(what is nowadays called "reverse engineering"). However, Nakajima was in unfamiliar territory in designing a long-range heavy bomber, so not only did they include all the design faults that scuttled the DC-4E project, but they added a few of their own. Thus, not only was the G5M overly complicated, but overweight as well. Further, the intended powerplant, the Nakajima NK7A Mamoru 11(1,870 HP) engine proved quite unreliable. In an effort to keep the project on track, the less powerful Mitsubishi Kasei 12 engines(1,530 HP). While the G5N was now airborne, not only was it overweight, it was now drastically underpowered. In the end, the project was cancelled, and the few completed aircraft were converted to transports. had the project met with success the Imperial Japanese Army was looking to acquire a similar design, either the Nakajima Ki-68 or the Kawasaki Ki-85. However with the faliure of the Navy's project, the Army quickly lost interest.

Given time, the Japanese likely could have developed a long-range heavy bomber. However, their early efforts at developing a heavy bomber, indeed early-war efforts in all types of aircraft, were handicapped by the Japanese inability to design a reliable high-horsepower engine. By the time the Japanese were able to produce reliable high horsepower engines, the war & logistical situations had turned irrecoverably against them.

 

The other bombers Japan had were the Sally and lilly to start and then they added the Helen. The bombers were close to the Marauder. Since Japan was fighting China and thought about a war with the Soviets there was a need for a medium bomber. BTW In the early thirties Germany did some preliminary research on an Amerika bomber, but it never got beyond that stage.

 

A huge mistake by Germany and Japan. They both wanted to conquer far away countries without long range bombers, or cargo flyers ?

 

it takes a lot or resources and people to make them and both countries had more urgent needs

 

The Germans and Japanese thought WW 2 could be won with Infantry and Navy... The Allies realized early on it would be won with Infantry and Air Force.... IMO

 

Heavy bombers to be really useful need at least long range fighters in sufficient numbers to protect them air supremacy is even better. If either of the Axis powers had put much effort into heavy bombers it would likely have been about as useful as the V-1 or V-2. Which is to say not at all.

 

Germany didn't really have much of a Navy, especially when compared to Britain, the US and Japan. They did initially have one of the better airforces, so I don't think the first part of your statement is accurate.
In the Pacific the Navy allowed all other services to do their job, the United States had a massive pre-war shipbuilding program underway, and Britain had a world class navy so how did "The Allies realized early on it would be won with Infantry and Air Force" Was it not an island base, seized by naval and land forces, built up by men and equipment brought in by ships, that the B-29's flew from to drop the atomic bombs and end the war?

Seems to me it was naval power that allowed for the massive transfer of equipment and materials to Britain and Russia. Seems it was Britain's naval fight for the Med that kept it from being an Axis lake. Seems to me that the Allied invasions of North Africa, Sicily, Italy, Southern France and Normandy would not have been possible without naval supremacy. Nor would the bombers have been much use, flying from Britain, without the navy to get the munitions, equipment, fuel and personnel there to support them.

 

With the Luftwaffe producing the Fw-190 and bombers like the Ju-88 and He-111, couldn't the Japanese have asked Germany for either plans or actual engines to copy for their own aircraft if they were partners? Near the end of the war I know germany either sent engines or plans for such for the Me-262 to Japan. I don't know how reliable the German engines were, as I don't remember hearing of any major issues with engines on the shows I've seen. Getting either plans or components to Japan probably also weren't high on Germany's "to do list", but any help Germany could have given Japan could have also forced the allies to commit more resources to the PTO if Japan was able to capitlize on the new technology and aid their own war effort.

 

The aircraft were developed for different operational needs. The Japanese, initially went with range and speed as their most important aircraft traits. This was due to the enormous expanses they operated in. For instance, the distance that Japan had to operate at between Guadalcanal and Rabaul was 650 miles, 1300 miles round trip. The distance from London to Berlin is only 590 miles and it was considered a long range target and during the first half of the war our "heavy", long range, bombers had to go it alone lacking fighter escorts with sufficient range! That is also the primary reason for Japan's early war fighter, the A6M Zero was built as lightly as possible. Range was at a premium. You mentioned the FW-190. It first became operational in August of 1941, four months later and for some time thereafter, the Zero ruled the skies over the Pacific. It was easily as dominant over the western fighters it faced, if not more so, as the FW-190 during that time frame. Japan's Zero was better suited for the tasks that it was being asked to perform than either the ME-109 or FW-190 would have been for the same mission profile. But then again, Japan wasn't fighting in continental europe.

Belasar also gave you one of the primary reasons they didn't initially develop a four engine "heavy":

Other than China, there were no huge population centers or large industrial targets that Japan foresaw needing to conduct a strategic bombing campaign against. Most large targets were also located along or near to coastlines where a battleship throwing 2-3000 lb shells is much more efficient.

Japan also did not use the same parameters for designating an aircraft as a "heavy" or a "medium" bomber that the allies did, so they can't be compared directly.

You have the G3M "Nell", it was a long range navy bomber and was a pretty decent aircraft based upon its time of design and initial employment.
http://www.daveswarbirds.com/Nippon/aircraft/Nell.htm

It was superseded by the G4M "Betty", that was designed to operate with the A6M Zero fighter. It was required to be able to carry one Type 91 torpedo, internally. The initial G4M1 model had a range of 3749 miles (round trip) and a top speed of 266 mph at 13.780 feet, it mounted two 1530 hp MK4A Kasei 11 engines. The first bomber you mentioned was the JU 88, the contemporary version would be the JU-88 A4. It had a total range of 1696 miles, with a max speed of 269 mph at 14,765 ft. It mounted two Jumo 211J-1 or 211J-2 engines at 1340 hp each. Comparing apples to apples it doesn't look like they needed Germany's engines. Does it? Later on they did mount self-sealing tanks and armor in the aircraft, accepting the loss in range, it was however too little too late. By this time the allies had the aircraft numbers and skilled pilots to fly them. Japan's greatest mistake was not upping their pilot training numbers until 1943, again too little too late.
Japan did attempt to design what we would consider a "heavy" bomber, the Nakajima G5N Shinzan first flew in April of '41. Because Japan lacked experience in designing such large, complex aircraft, they considered looking into a conversion. They selected the Douglas DC-4E airliner as the airframe to develop their modification from. It was not a suitable airframe for conversion to a heavy bomber and the japanese engineers attempted to use horsepower to overcome the design flaws. They attempted to mate the Nakajima NK7A Mamori 11 engine, which promised to develop 1,870 hp each. This engine itself was plagued by design problems. However, to show how a proper airframe could have given sufficient performance with a less powerful engine, compare the B-17G model. It used the Wright R-1820-97 "Cyclone engine, each rated at 1200 hp. When Japan did get around to designing a domestic four engine bomber (specification issued Feb, 1943), the result was the G8N1 Renzan. It first flew in Oct '44, but by then the American submarine campign and bombing campaign had so hampered Japanese industry that it was crippled and could not produce them in numbers. Japanese developmental test flights and post-war testing by the U.S. revealed it to be a very good and capable aircraft.




G8N bomber

The Japanese Army Air Force also fielded a number of decent medium bombers.
The KI-21 Sally was a good, capable aircraft
The KI-49 a decent aircraft, but never showing the performance of the aircraft it was to replace, the "Sally"
The KI-67 "Peggy" was a fast, maneuverable, sturdy, well armed aircraft. An excellent aircraft, easily on par with any bomber the Germans had. It wasn't however, good enough to change the course of the war by the time it was fielded (1943), but by that time no aircraft would have been.

 

If the Japanese had thought about it a heavy bomber could have had use in the Burma theater against India.

 

Conventional strategic bombing (sustained efforts aimed at destroying enemy industry) was not part of Japanese strategy and well beyound any realistic capability they had ( the "unconventional" fire baloons where the only attempt in this area d but it failed).
What they did were minor bombing campaigns aimed at causing temporaty disruption and supporting naval or land operations.
Until the allies got their act together the G4M (Betty) and even the ealier G3M and army planes proved perfectly adequate for this , but the G4M was a very extreme design that sacrificed almost everything else for range and against strong opposition it suffered unacceptable losses. A four engined design would have allowed for similar range with better defensive qualities.

Forcing the numerically superior allies to disperse and keeping them off balance was an essential part of Japanese strategy, they attempted. with varying degrees of success, a large number of long range attacks. Besides the baloons, limited bombing camapaigns such as Darwin, the carriers raids, the submarine launched bombers and very long range operations by the four engined H6K (Mavis) floatplanes can be seen as part of this. They had no chnce of achieving decisive results but could cause local setbacks and the force the allies to disperse effort by "defending everything", a four engined land bomber may have been quite effective in this role, though it would have required more support infrastructure than the H6K.

 

My mistake in not elaborating correctly in my post about the Fw-190, He-111, and Ju-88. I was referring to the engines in those planes and not the aircraft themselves.

So with the previous posts in mind, I can understand the mentality of the Japanese in not developing a heavy bomber, but perhaps with some help from Germany they may have been able to develop some of the bomber aircraft they wanted with the performance they had hoped to achieve if they had gotten the technology necessary for better performing engines from Germany.

 

It was not the lack of an 1,870 hp engine that was the problem. It was that the aircraft was a bad design. That is what Takao and I were trying to explain. The G5N was a bad airframe that the Japanese attempted to salvage by installing a high horsepower output engine. The G4M when it debuted had the 1530 hp MK4A Kasei 11 engine, vs the 1390 hp engine on the contemporary version of the JU-88, the contemporary FW-190 had the BMW 801 C-1 producing 1539 hp and the He-111 H6 which was also the newest version during the same time period mounted the Jumo 211 F-1 producing 1350 hp. The engines for all three of the German aircraft you mentioned produced a similar or lesser power output. The 1,530 hp Mitsubishi MK4B 12 "Kasei" was the engine they attempted to use to salvage the G5N project, it was a slightly modified version of the same engine used on the Betty.
My question to you is how would German engines of the same time period, producing the same or less horsepower have aided Japan in its bomber development? The allies B-17G model, the definative version that appeared in July of 1943 only had a 1200 hp engine. That's because the airframe was a good design. Japan did not place a high priority on developing a four engine bomber. When they did see a need, and developed a good, domestic airframe, their industry lacked the ability to produce it.

If you would really like to complicate the discussion we need to get into the octane ratings of the fuel used. The Japanese standard bomber fuel octane rating was 72, and the engine was tuned for this. The Germans used 100 octane aviation fuel. If you took the BMW 801 C-1 producing 1539 hp with 100 octane gas and used the same gas in the 1530 hp MK4A Kasei 11 engine, and retuned it for that octane rating, the engine would actually produce about 1900 hp!! The Japanese Mitsubishi MK9A 'Ha-211 Ru' engine was rated at 2200hp, if they had used 100 octane fuel like the Germans that would work out to about 2700 hp.

 

USMCPrice,
I understand what you and Takao are talking about, it wasn't about the airframes or designs it was the engines that Takao mentioned that the Japanese were having difficulty in creating "reliable" engines that could produce the horsepower and relaibility they needed. I am not implying that they should have used German engines merely perhaps some of the technology to increase performance and reliability in their own engines. I honestly don't know if the German engines were more reliable, I was simply using some of the more widely known aircraft for their purposes that the Germans produced that maybe the Germans had worked thru some of the performance issues with their engines that could have helped Japanas an example. Possibly one case in point is the P-51, the original engine was adequate but lacked great performance but once it was hooked up with the Merlin engine it became the show stopper it is. So while yes you may not be able to take a German engine in install it into a Japanese airframe and create a winner, a borrowing of technology can turn a decent aircraft into a top-line one.

 

Great thread. I had not heard of the G8N before.

I put it 'G8N bomber' into google and found this clip

http://www.youtube.com/watch?v=pmj9Dw8UlTs