11-Shi Navy Type 99 Carrier Bomber competition (D3A, D3N)


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20 January 2008
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Hello everyone
Looking for more information of the Aichi D3A Val dive bomber competition with Mitsubishi and Nakajima or the 11-Shi Programme.
Enyone knowing more ?

Source : Aichi D3A1/2 Val Peter C.Smith
The two competitors for 11-shi were the Mitsubishi D3M1 and Nakajima D3N1.

The latter was powered by a 730 hp Nakajima Hakari 1 radial (like the Aichi D3A1 prototype).

Article/photo (attached): Arawasi Magazine (Issue 2, Oct 2005)

Specs from the web (in Czech): http://forum.valka.cz/viewtopic.php/t/30090

Side view & details: http://www.samoloty.ow.pl/str252.htm

No details on the Mitsubishi entry, I'm afraid


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Thank you my dear Blackkite,

in 1936 for 11-shi carrier bomber,the tenders were Aichi D3A1,
Nakajima D3N1 and Mitsubishi (suppose D3M1),and after the
mock-up was comlpeted in 1937,it was abandoned.
Who know more about it ?.
Hi my dear hesham!
You are absolutely right.
11-shi Carrier Dive Bomber was born from the competition between Aichi D3A and Nakajima D3N1.
D3N1 had retractable undercarriage with speed brake and under wing perforated speed brake panel same as SBD.
Chief designer was Ryozo Yamamoto.
Engine was Hikari-1 type.(Max power 820HP 3,400m).
MTOW:3,400kg, Wing span:14.5m, Overall length:8.8m, Wing area:34m2, Max speed:352km/h(3,000m), Range:1,519km.
3 planes were manufactured and 1 was survived till the end of the war.
Unfortunately all pictures and drawings were lost.
About the Nakajima D3N1...

In the Japanese magazine-English text- ARAWASI issue 2-October 2005 is
an article written by Mike Goodwin ,of J-Aircraft fame, about the Nakajima D3N1
Navy Experimental 11-Shi Carrier bomber.
In this well written account is a photo showing this bomber.The picture is taken
3-quarters from the rear.There are also a few detail shots, probably taken from the main picture.
Also mentioned is a sideview drawing of this plane by Mr.Shorzoe Abe in
Japanese Aircraft 1910-1941-Putnam.
As far as I saw , the drawing is on page 237.
Japanese text says that this was a Mitsubishi 11-shi dive bomber D3M1 mockup or strength test model with her design team.
Middle was Jiro Horikoshi. Mitsubishi gave up to develop D3M1 soon because they found that it was impossible to manufacture D3M1 until time limit, and began to develop 12-shi carrier fighter A6M.
source:Maru magazine special edition "JIRO HORIKOSHI WAY OF THE ZERO FIGHTER" in 15/8/2013


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Very nice. And also I love the friendly attitude of the workers.

Thanks a lot for sharing, blackkite!
So the D3M1 had inverted gull wings? Amyone have any other pics or drawings of this plane?
windswords said:
So the D3M1 had inverted gull wings? Amyone have any other pics or drawings of this plane?
The 11-Shi mock-up appears to have straight wings.
The aircraft illustrated on the magazine cover is the first Mitsubishi Ka-14 prototype built to the 9-Shi specification and is depicted as originally flown with the short-chord cowling, which was later supplanted by a closer fitting, longer chord cowling incorporating fairings for the cylinder rocker arms.
Hi! Nakajima D3N1 wind tunnel test model.


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The Experimental 11-shi Carrier Dive Bomber D3N1 spin test model thtree side view dtrawing.


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Hi! (Japanese Wikipedia)
The experimental 11-shi carrier dive bomber was a shipboard bomber prototyped by Aichi Kokuki and Nakajima Aircraft for the Japanese Navy.
The prototype of Aichi Kokuki was later adopted as the Aichi D3A bomber.
Here, I will describe the aircraft (D3N) prototyped in Nakajima.
The aircraft prototyped in Nakajima had an interesting function that the main landing gear was rotated 90 degrees and retracted backward, and the main landing gear that was pulled down doubled as a dive brake during a sudden descent.
Although it was judged by comparison with the prototype of Aichi Kokuki, this machine was rejected in 1945 because the aircraft made by Aichi was superior in performance.
After that, the prototype returned to Nakajima Aircraft and was used as a test bed for the engine.
In 1936 (Showa 11), the Japanese Navy ordered Aichi, Nakajima, and Mitsubishi to develop the 11-shi experimental carrier dive bomber (Mitsubishi later declined). The 11-shi experimental carrier dive bomber was required to have a solid design for practical use, and the engine was decided to use an improved version of the Nakajima "Hikari" type 1 equipped with the existing Type 96 carrier bomber. Nakajima decided to develop a metal low-wing monoplane. The appearance was similar to that of the Aichi aircraft (D3A), but the biggest difference was that the main landing gear was retractable. This main landing gear is a type that rotates the wheel 90 degrees and pulls it backward (the same type as the American P-36), which was the first attempt in Japan. In addition, this main landing gear was to be pulled down and used as a dive brake. However, in reality, it was found that the deceleration during a sudden descent was insufficient with this method, so it was decided to add a dive brake with fine holes to the underside of the main wing later.
The first prototype was completed in March 1938, but the delivery date specified by the Navy had already passed and the Aichi aircraft had been received.
However, Nakajima's aircraft was also received by the Navy for the time being, and a comparative examination with Aichi's aircraft was conducted.
After that, in 1939 (Showa 14), the second prototype was completed and participated in the examination.
Nakajima's aircraft was a progressive design at that time and was not bad in terms of performance, but it was not adopted in December 1939 (Showa 14) because it was inferior in speed and operability compared to Aichi aircraft.
After that, the prototype was refunded to Nakajima, but Nakajima used this machine as an experimental aircraft.
In particular, as a test bed for its own engine, it played a major role in the maturation such as Sakae and Homare.
In addition, it was used for various experiments, and one was alive until the end of the war.
The Army, which had been considering the adoption of a dive bomber for attacking pillboxes since around 1938, considered diversion of Nakajima's 11-shi experimental carrier dive bomber after making improvements as a dive bomber that could be prepared immediately.
However, this Army-specification aircraft, which was designated as the "Ki 52," was abandoned in the fall of 1941 (Showa 16) because it was possible to obtain an aircraft capable of swooping bombing by improving the conventional light bomber.
• Overall length: 8.80 m
• Overall width: 14.50 m
• Overall height: 2.80 m
• Main wing area: 34.00 m2
• Weight: 1,800 kg
• Total weight: 3,400 kg
• Engine: Hikaru Nakajima Type 1 modified air-cooled radial 9 cylinder
• Output: 820 hp
• Maximum speed: 352 km / h
• Range: 1,519 km
• Ceiling: 7,000 m
• Armament
7.7mm machine gun x 2
Bomb 250kg x 1 or 30kg x 4
•Crew: 2 people


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