Thursday, 16 October 2025

Nakajima Ki-43 "Hayabusa" (Oscar), "Tsubasa no Gaika" - video


A clip today from the movie "Tsubasa no Gaika" featuring a Nakajima Ki-43 "Hayabusa" with Okawa Takashi, played by actor Tsukita Ichiro* "in the cockpit"**. An absolute pleasure to see a "Hayabusa" doing all these aerobatics! 
A shortened version of the clip has appeared on various FB pages without the original sound or any credit. The info below is from the Japanese Wiki:

Tsubasa no Gaika』 (The Triumph of Wings) is a war film produced by Toho and released on 15 October 1942.
Synopsis
Two boys, orphaned at a young age when their father—a pilot and aviation engineer—perished in a storm during a crash, were raised as foster brothers by the wife of the crashed pilot. The elder brother aspired to become a juvenile air cadet and rose to become an ace pilot (fighter pilot) in the Imperial Japanese Army Air Force. The younger brother, after training at an aircrew training school, developed into a test pilot for the Nakajima Aircraft Company's Ki-43 (later the Type 1 Fighter "Hayabusa") at Nakajima Aircraft, growing into test pilot who excel both in development and on the battlefield. 
The narrative weaves in the untold story of developing the Army's primary fighter of the era. By featuring stepbrothers who pursue distinct paths – one as an Army pilot, the other as a civilian pilot – it crafts a success story depicting their growth: one as a frontline soldier, the other as a civilian on the home front. Furthermore, by introducing a widow who watches over the two men, it illustrates the mindset of the beautiful Yamato Nadeshiko, the quintessential Japanese woman, during wartime. 
The film was sponsored by the Army Air Headquarters. All aircraft used in filming were actual aircraft, with the exception of some special effects scenes. Furthermore, the aircraft's details, such as the sighting device and oil cooler, scenes from engine start-up through take-off to landing, and aerobatic flight, are depicted with remarkable clarity. The "Hayabusa", arguably the third protagonist, is filmed extensively and without omission over a long duration, making this work akin to a promotional video for the "Hayabusa". In this respect, it stands alongside the 1940 film "Burning Skies" and the 1944 film "Kato's Hayabusa Fighter Squadron" – both of which also utilised real aircraft extensively for filming – as an extremely valuable visual historical document. 
Furthermore, the screenplay was co-written by Akira Kurosawa, who would later become a world-renowned director, and Bōhei Toyama. The special effects scenes, like those in contemporary war films such as "The Battle of Hawaii-Malay" and "The Kato Hayabusa Combat Squadron", were handled by Eiji Tsuburaya. However, due to the cooperation of the Army, many scenes featured actual aircraft, meaning the special effects scenes were limited to crashes and shoot-downs. 

Director: Yamamoto Satsuo
Screenplay: Toyama Bonpei, Kurosawa Akira
Cast: Oka Jōji, Tsukita Ichirō, Irie Takako
Music: Hattori Ryōichi
Cinematography: Kanakura Taiichi
Production Company: Toho Film
Released 15 October 1942
Running time 109 minutes 

The dialogue between the pilot and ground crew members goes like this:
GC1: Hatsudoki no choshi was do deshita 
         (How was the engine?)
P: Aa, ii yo 
   (Oh, it was fine)
GC1: Ah so desu ka 
       (Oh, really!)
GC2: Dodai guwai wa? 
        (How do you feel?)
P: Kesaku da yo 
   (Great!)
PC2: Kaji no kiki wa? 
       (How about the controls?)
P: Mmm, ii, shikashi teppo tsunde minai to wakaran na, ima wa sukoshi karui kara 
(Hmmm, good but I'm not sure without having the guns installed, 'cause it's a bit light now) 
GC2: Sore mo so da. Shindo wa? 
       (That's right. Any vibration?)
P: Daijobu da 
   (It's okay)
GC2: Hatsudoki no kaiten wa 
       (how is the engine behaving?)
P: Yoku wo ieba, sukoshi tarinai kimo suru kedo, ma tonikaku kesaku dayo. Hisashiburi ni omou zombun tonde mita yo! 
(If I'm being picky, it feels a tad underpowered, but it's a masterpiece nonetheless. It's been ages since I've flown to my heart's content!)

*Shortly after the end of the war, on September 27, 1945, he died from methanol poisoning. He was only 35 years old.
**At 00:47 and 02:35 he is actually sitting in the rear cockpit of a Tachikawa Ki-55 trainer. But from 04:21 he is indeed bringing the plane to a standstill on his own!!!

Tuesday, 14 October 2025

Mitsubishi Zero-sen, 381 Kokutai - video


An unbelievably clear video today featuring pilots, ground crews and Mitsubishi Zero fighters. 
The original is here. The narator speaks Indonesian, we tried to translate what he says and we were able to come up with this: 
"In one of the airforce stations of Dainippon [Great Japan], from sunset to sunset, we always hear the sound of a plane flying. Which shows that the members of the Dainippon Navy keep training enthusiastically."
So, unfortunately no exact location is mentioned. The unit is the 381 Kokutai as indicated by the number "81" on the tail marking of one of the Zeros, let's try to figure out where the video might have been shot from the unit's history.
The 381 Kokutai was organised on October 1, 1943, in Tateyama Airfield, Chiba Prefecture, and was incorporated into the 13th Air Fleet, 23rd Air Squadron. The unit was to be assigned to the protection of the Balikpapan oil fields of Borneo so, in early January 1944, an advance party of 10 aircraft deployed to Balikpapan Airfield.
On February 20, received 36 Zero fighters and 12 Nakajima J1N "Gekko" (Irving) night fighters from the 202nd Kokutai, which relocated to the Inner South Seas.
Around that time, the main force of the 381 was based at Kendari Airfield, Celebes Island, with detachments at Sumba Island, and Ambon Island
In early March, former seaplane fighter pilots were incorporated into the 381 following the disbandment of the fighter squadron of the 934th Kokutai.
On March 31, the 381 suffered casualties during "Operation Desecrate One" and relocated to Davao, Philippines.
On April 1, the unit organized three hikotai: the 602 Hikotai with 48 fighter-bombers with c/o Lt Kurosawa Takeo, the 902 Hikotai with 24 night fighters with c/o Lt Matsumura Hideo and the 311 Hikotai with 48 Zero Model 52 fighters with c/o Lt Kanzaki Kunio. 
On May 15, abandoned Kendari and the main force withdrew to Balikpapan, Borneo. 
The publication "Nankai No Umiwashi-tachi" (The Imperial Japanese Navy Air Groups in the Southwest Pacific Theater) by DaiNipponKaiga, features 381 Kokutai photos taken by photographer Abe Tetsuo when he visited Sorong base, West Papua in May 1944. While the earlier photos of 381Ku Zeros show bigger and more visible tail markings like the Zeros seen seen in the video, those aircraft featured in "Nankai", show a smaller tail marking placed higher on the tail. So, if these different tail markings is any indication then the video was shot sometime between January and May 1944, probably at Kendari Airfield, the main base of the unit. 

Let's see some stills.
The begining of the video features a Model 52 Zero, fresh out of the Mitsubishi factories, with tail marking "81-165". The same aircraft can be seen in a photo taken when the unit was based in Toyohashi base, Aichi Prefecture, before the unit was dispatched to Borneo.

Another Mitsubishi-built Model 52 has tail marking "81-171" and again can also be seen in Toyohashi.

A third Model 52 with tail marking "81-163", also seen in Toyohashi. All these photos indicate that the video was shot on a date close to the relocation from Toyohashi to Borneo and Celebes.

Note the very very interesting white wing tips on these Zeros, and how irregular they have been applied.

From 00:44 two pilots are seen playing "shogi".

The sign at 00:54 says "Kaigun Sentoki-tai Shikisho" (Navy Fighter Unit Headquarters).

Saturday, 11 October 2025

Aichi E16A "Zuiun" (Paul) - video


Here's a video I recently discovered of the ultimate Aichi seaplane; the Aichi E16A "Zuiun" (Paul).
Actually it's three videos from NARA I stiched together, showing the seaplane first discovered under heavy camouflage by the US 77th Infantry Division on the shores of Ormok Bay on the island of Leyte, then roughly brought to sea getting examined by US soldiers.
Note the Type 97 Mk.1 Drift Sight at 00:47.

The particular seaplane belonged to the 301 Hikotai as indicated by the number "301-02" on the tail. The unit was organised in July 1944 and was assigned to the "Zuiun" Squadron at Yokosuka. It got transferred to the 801st Kokutai in October and advanced to Cavite, Philippines, later that month. While there, it got transferred to the 634th Kokutai in November 1944.

The 634 Kokutai was organised as an unconventional seaplane and carrier-based aircraft unit operating from an aircraft carrier as its mother ship. 
During "Operation Ro" (the Bougainville Island Naval Air Battle) in November 1943, the Imperial Japanese Navy's carrier task force (Third Fleet, under Commander-in-Chief Vice Admiral Ozawa Jisaburō) suffered heavy losses when its carrier-based aircraft were dispatched to land bases.
The Navy, urgently rebuilding the "Kido Butai" (機動部隊, "Mobile Strike Force"), allocated the nine aircraft carriers usable as mobile force carriers into three groups: the First Carrier Division with three aircraft carriers, the Second Carrier Division with two passenger-cargo ship-converted carriers and one light carrier, and the Third Carrier Division with three light carriers. Each group within this First "Kido Butai" was assigned one air group. As the second phase of its rebuilding and reinforcement strategy, the 634th Kokutai was organised as a carrier-based air group operating from the battleship-converted carriers ‘Ise’ and ‘Hyuga’. The aircraft assigned were the "Zuiun" seaplane, which could also serve as a carrier-based dive bomber, and the carrier-based bomber (dive bomber) Yokosuka D4Y "Suisei" (Judy). The "Suisei", lacking seaplane landing capability, was intended for one-way operations: launched from its carrier (aircraft battleship) via catapult, it would land on another carrier or at a land-based airfield.
On May 1, 1944, the 634 Kokutai was established at Kure Airfield, with Iwakuni Airfield as its home base. It operated under the Fourth Air Fleet. Its standard complement was to be 18 "Zuiun" and 18 "Suisei" but by May 12, not a single aircraft was available. The commander of the Fourth Air Fleet, Rear Admiral Matsuda Chiaki, urgently requested from headquarters: ‘For training purposes, unmodified "Suisei" will suffice, but please send them immediately’. Subsequently, training commenced with "Zuiun" at Kure and "Suisei" at Iwakuni (using Aichi D3A "Val" Dive Bombers due to the shortage of actual aircraft). 
On May 22, the carrier assignments were finalised: the "Zuiun" unit would be assigned to the Ise (under the direct command of Commander Amaya), and the "Suisei" unit to the Hyuga (under the command of Flight Commander Hideo Emura). On June 15, orders were issued for deployment to Saipan Island. This was later cancelled. While the Fourth Carrier Division and the 634Ku were on standby, the Battle of the Philippine Sea erupted from June 19. Ozawa's "Kido Butai" suffered a major defeat, losing three carriers and the majority of its carrier-based aircraft. 
On June 23, catapult launch trials commenced. All launches were successful. "Operation East" was ordered on July 5. The "Zuiun" Squadron advanced to Yokosuka Airfield, and the "Suisei" Squadron to Katori Airfield. Fighter and attack squadrons were incorporated from the 652nd Kokutai, which was disbanded on August 1. Depending on the situation, the Fourth Carrier Division would be assigned to the Second Raiding Force, centred on the Fifth Fleet, serving as the vanguard or escort for the main mobile force.
On October 12, 1944, the Taiwan Air Battle erupted. The "Zuiun" Squadron advanced to Ibusuki Airfield, while the carrier-based aircraft squadron advanced to Kanoya Airfield. Three days later , the "Zuiun" Squadron received orders to return to its original unit. Participation in the "Kido Butai" was considered, but it was decided not to embark the aircraft. On October 19, the two carrier ships of the Fourth Air Fleet, without embarking aircraft from the 634Ku, departed from Beppu Bay as the Ozawa "Kido Butai" bound for the Philippines. They arrived in the Philippines on October 22, and were stationed at Cavite. Thereafter, they engaged in night anti-ship attacks and anti-ship patrols under Operation "Ta".
When the Kamikaze Special Attack Force commenced operations in the Philippines at the end of October, the 634Ku also formed the "Baika" Squadron and ordered special attacks on November 6.
On November 15, the unit was incorporated into the Second Air Fleet. Carrier-based aircraft squadrons disbanded (transferred to the 201st and 701 Kokutai), reconnaissance squadrons reinforced. Thereafter, in addition to its previous night anti-ship attacks, it engaged in bombing San Jose Airfield. 
On January 8, 1945, it was transferred to the First Air Fleet. It withdrew to Tung-Kang Airfield in Taiwan. Subsequently, it shifted its base from Tung-Kang to Tamsui Airfield and engaged in patrols near Taiwan and Okinawa. 
On March 26, ‘Operation Kikusui No. 1’ was launched. The 634Ku engaged in night anti-ship attacks near Okinawa. Withdrew from Taiwan to the mainland in April. Deployed Reconnaissance Squadrons 301 and 302 to Fukuoka and Kagoshima, using Koniya  in the southernmost part of Amami Oshima as a forward base to conduct repeated attacks on Okinawa.
On August 3, incorporated into the Fifth Air Fleet and formed the 32nd Kokutai.
Commanders
Amagai Takahisa, CAPT: 1 May 1944 -
Emura Hideo, LCDR : 15 November 1944 -
立見孝六郎 (Tatami Korokuro?): August 1945 - Disbanded

Sunday, 5 October 2025

Kawasaki Ki-48 "Lily" and "Ne0"

The sole prototype Kawasaki Ki-48-II "Lily" with the Ne0 ramjet engine hanging under its fuselage. The pod beneath the fuselage was hollow, with the fuel and nozzle housed within the bomb bay.

As the Second World War intensified, the front lines demanded higher-performance propeller aircraft, leading to increased interest in jet engines. Almost simultaneously with the Navy commencing development of its turbojet engine, designated ‘TR’, the Army and the University of Tokyo Aeronautical Research Institute also established specialised departments and began research.
Engineer Hayashi Teisuke was appointed from the Army's Second Aeronautical Research Institute to lead the jet engine development effort on a one-year contract basis. In mid-November 1942, a team led by Hayashi, comprising nine subordinates from Kawasaki, commenced development. Alongside the main engine concepts proposed by the Tokyo Aviation Research Institute – the Ne* 101 motorjet and the Ne 201 turboprop – it was decided to develop motorjets and turbojets for auxiliary engines. As the characteristics of the engine types were unknown, it was decided to produce both compressor types: axial-flow and centrifugal:
1. ‘Ne1’ two-stage axial-flow motor jet
2. ‘Ne2’ single-stage centrifugal motor jet
3. ‘Ne3’ three-stage axial-flow turbojet
4.  ‘Ne4’ single-stage centrifugal turbojet, and
5.  ‘Ne0’ ramjet for fundamental research.
The Ne1 and Ne2 were auxiliary engine variants of the Caproni Campini-type engine-jet. They were intended for installation either aft of the fuselage in single-engine propeller fighters or behind the engine nacelle in twin-engine propeller aircraft.
The Ne3 and Ne4 were both primarily targeted for installation in single-engine or twin-engine propeller-driven fighters.
Work proceeded at considerable speed, with drawings largely completed within approximately six months. 

The Kawasaki Ne0 ramjet engine.

The Ki-61 "Hien" was proposed as the primary candidate for a test aircraft**, with the Ki-45 Kai "Toryu" twin-engine fighter as the second choice. However, at a time when even a single front-line aircraft was desperately needed, neither could be obtained. Consequently, the slow-speed Ki-48 Type II twin-engine bomber "Lily" had to be used.
To minimise airframe modifications, a design utilising bomb racks to suspend the engine beneath the fuselage was developed with the cooperation of aircraft designers Imachi Isamu and Kitano Jun.

Illustration from Encyclopedia Vol. #IV

Ne0 was finished in November 1943, and on the morning of 23 December 1943, test pilot Kataoka Saizaburo*** took off from Kawasaki with engineers Hayashi and Nozu aboard. However, ignition of the combustor failed, necessitating a landing. After servicing the ignition plug, they took off again in the afternoon.
This time, the combustor ignited easily. The aircraft accelerated, delivering considerable shock to the passenger seats and momentarily causing the nose to pitch up. It then maintained high-speed cruise at an altitude of 800 to 1000 metres for approximately ten minutes before landing.
Subsequent multiple flights reportedly yielded preliminary results. Though abandoned after flight testing concluded, the entire airframe was transferred to the Army's Second Aeronautical Research Institute in July 1944. 
Following Ne0 testing, research focus shifted to two of the four Ne1 to Ne4 variants—Ne3 and Ne4—with ground-running tests conducted on prototypes. However, due to the worsening war situation and the acquisition of engine data from Germany, all development of these Kawasaki jet engines was suspended during the prototype consolidation in July 1944. Consequently, no aerial tests were conducted before the war's end.

Specifications

Ne0
• Type: Ramjet
• Overall length: 2,100mm
• Maximum cross-sectional diameter: 600mm
• Thrust: 60kg (altitude 2,800m)
• Air flow rate: 8.1kg/s (altitude 2,800m)
• Compression ratio: 1.12 (altitude 5,800m, 550km/h)

Ne1
• Type: Motorjet
• Compressor: Two-stage axial flow, contra-flow type
• Length from rear edge of impeller to jet nozzle: 1,050mm
• Outer casing diameter: 600mm
• Thrust: 185.5kg × 2 (altitude 2,800m)
• Airflow: 10.4kg/s (altitude 2,800m)

Ne2
• Type: Motorjet
• Compressor: Single-stage centrifugal
• Thrust: 150kg (planned)

Ne3
• Type: Turbojet
• Overall length: 2,321mm
• Casing outer diameter: 760mm
• Total weight: 309 kg + (casing weight)
• Compressor: 3-stage axial-flow
• Turbine: 1-stage axial-flow
• Thrust: 348 kg (altitude 2,800 m)
• Air flow rate: 14.9 kg/s (altitude 2,800 m)
• Compression ratio: 1.71 (5,800 m, 550 km/h)
• Rotational speed: 8,300 rpm (altitude 2,800 m)

Ne4
• Type: Turbojet
• Overall length: 1,700 mm
• Casing outer diameter: 750 mm
• Total weight: 270 kg + (casing weight)
• Compressor: Single-stage centrifugal
• Turbine: Single-stage axial
• Thrust: 276 kg (altitude 2,800 m)
• Airflow: 10.35 kg/s (altitude 2,800 m)
• Compression Ratio: 1.98 (5,800 m, 550 km/h)
• Rotational Speed: 1,100 rpm (altitude 2,800 m)

*"ネ" (NE) was a common designation used by both the IJAAF and the IJNAF. At the time, both jet and rocket engines were collectively referred to as "燃焼ロケット" ("NEnsho roketo" combustion rockets).

**One can only imagine what a "Hien" would look like with a jet engine on its tail.

***A test pilot for the Imperial Japanese Army Air Force, he was responsible for the maiden flights of prototypes such as the Ki-61-II "Hien" and the Ki-78, manufactured by Kawasaki Aircraft. During the Ki-78 (Ken-3) test flight in January 1944, he recorded a top speed of 699.9 km/h, which remained Japan's speed record until the end of the war.

Tuesday, 30 September 2025

Kobeseiko "Te-Go" Experimental Observation Aircraft


Designed by Professor Miki Tetsuo of the Department of Aeronautics, Faculty of Engineering, Osaka Imperial University, at the request of the Army, as a short take-off and landing aircraft for artillery spotting by the Army Artillery Corps. As it was outside the jurisdiction of the IJAAF, it was not assigned a Ki number. It featured a distinctive high-wing monoplane configuration, equipped with automatic leading-edge slats spanning the entire main wing, trailing-edge Fowler flaps, and ailerons doubling as flaps. To achieve a large wing angle of attack during take-off and landing runs, the main landing gear was raised high. Large windows were fitted to the fuselage to provide a wide field of view. 
The wings were wooden with fabric covering and could be folded rearward. The fuselage featured a mixed wooden and metal frame covered in fabric, with only the nose section clad in light metal. Priority was given to short take-off and landing performance for use from hastily constructed frontline airfields, riverbanks, open spaces, and roads. Seating was arranged in a single file.
The engine was the same type as that fitted to the Kayaba "Ka-go" Type 1 observation autogyro, the Kobe Steel Argus As-10 24OH. For the "Te-go" observation aircraft, Kobe Steel also manufactured the airframe, with the prototype completed in 1942. However, it had a landing gear failure during test flights. Consequently, the Army adopted the "Ka-go" observation autogyro for this role, and development of the "Te-go" was cancelled.
Plans also existed for a three-seat Army artillery observation aircraft (abbreviated RGK), but only the design was completed and no actual aircraft were built. It would be a large observation aircraft equipped with the Nakajima ‘Kotobuki’ Type 3 5501P engine, with a wingspan of 21.00m, length 12.80m, and height 2.70m.

General characteristics
Single-engine, high-wing monoplane, land-based aircraft
Crew: 2
Length: 9.50m
Height: 3.00m
Wingspan: 13.00m
Wing area: 20sq m
Maximum take-off weight: 1,130 kg
Wing loading: 56kg/sq m
Power loading: 4.52kg/hp
Powerplant: 1 X Kobe Steel Argus As-10 air-cooled inverted V-8, nominal output 240 hp, take-off output 250 hp.
Propeller: Wooden fixed-pitch, 2-bladed, diameter 2.75 m

Performance
Maximum speed: 180 km/h
Endurance: 6 hours
Service ceiling: 8,2 80m (27,165 ft)
Armament: One 7.7 mm flexible machine gun (mounted above rear seat, retractable, with two spare magazines)

Illustration from "Nihon Rikugun Shisakuki Taikan" (All the Experimental Aircraft in Japanese Army), by Akimoto Minoru, Kantosha 2008

Monday, 29 September 2025

Mitsubishi Army Experimental "Tobi" Reconnaissance Aircraft (Company designation 2MR1)


In 1926, the IJAAF sought competitive proposals from Nakajima, Kawasaki, Ishikawajima, and Mitsubishi to replace the Type Otsu 1 Reconnaissance Aircraft (Salmson 2-A.2s). Mitsubishi, with the assistance of Dr Alexander Baumann, a professor at Stuttgart University, and former designer of Riesenflugzeug for Zeppelin-Staaken, assigned Nobushiro Nakata as chief designer and Satsuo Tokunaga as his assistant. The result was a radical design for a sesquiplane, having the upper wing set unusually high above the slender fuselage, connected with a unique type of center-section and interplane struts. As one of the Mitsubishi bird series projects in 1925-27, this aircraft was given the name “Tobi” (black kite ).
The first prototype was completed in July 1927. In the hands of test pilot Jiro Itoh the aircraft achieved speed of 227km/h (123kt) faster than the Army's specified 200km/h (108kt). Mitsubishi had high expectations for the new aircraft, but during an official qualifying test flight by the Army at Tokorozawa, an undercarriage shock strut failed and during the landing the aircraft was badly damaged and eliminated from the competition. The Nakajima and Ishikawajima entries also failed, but the Kawasaki aircraft met the requirements and was accepted as the Type 88 Reconnaissance Aircraft (KDA-2). 

General characteristics
Single-engine sesquiplane with large gap. Metal fuselage structure with wood and metal wings, fabric covered with some plywood and thin metal on the forward fuselage.
Crew: 2 in open cockpits
Length: 9.55m (31ft 4in)
Height: 4.35m (14ft 31/2in)
Wingspan: 17.40m (57ft)
Wing area: 50sq m (538.213sq ft), upper 34.50sq m (371.367sq ft), lower 15.50sq m (166.846sq ft)
Empty weight: 1,350kg (2,9761b)
Gross weight: 2,500kg (5,5111b)
Wing loading: 50kg/sq m (10.2411b/sq ft)
Power loading: 3.5kg/hp (7.71b/hp)
Powerplant: 1 X 450-600hp Mitsubishi-Hispano-Suiza twelve-cylinder vee water-cooled engine, driving a Mitsubishi-Reed fixed-pitch two-bladed metal propeller

Performance
Maximum speed: 123kt (142mph) at 5,000m (16,404ft)
Endurance: 6 hours
Service ceiling: 8,2 80m (27,165 ft)

Armament
Guns: Two forward-firing fixed 7.7mm machine-guns and twin dorsal flexible 7.7mm machine-guns

*Note that the Wiki entry for the "Mitsubishi Experimental Tobi-type Reconnaissance Aircraft" links to the IJNAF Mitsubishi 2MR Carrier-based Reconnaissance Aircraft, a completely unrelated aircraft type which first flew in 1922.

Sunday, 28 September 2025

Experimental 7-Shi Carrier Attack Aircraft (Nakajima B4N1, Y3B)


In April 1932, the Navy issued instructions to Mitsubishi and Nakajima to prototype a new carrier-based attack aircraft to replace the unpopular Type 89 Carrier Attacker. Nakajima, with Engineer Yoshida Takao as chief designer, developed the distinctive biplane Y3B equipped with the newly designed “Hikari” 73O engine. Two prototypes were built in 1933 and submitted for Navy evaluation. This aircraft featured a Gal-type upper wing and an inverted Gal-type lower wing, with the central section crossing in an X-shape relative to the slender fuselage. Furthermore, the landing gear struts were cantilevered from the lower wing's bend, representing an extremely bold structural design. The fuel tanks were exposed and removable, mounted on both sides of the fuselage, similar to those on the Nakajima E4N2 Reconnaissance Seaplane and the Nakajima A2N Carrier Fighter Model 2. At the time, the development of tri-seat carrier-based attack aircraft was a major challenge not only for Mitsubishi and Nakajima but also for Aichi and the Naval Technical Arsenal. Particularly, the selection of a reliable, high-horsepower engine proved difficult, preventing the establishment of a definitive design. Two prototypes were built in 1933 with the short designation B4N1*, and delivered to the Navy for evaluation but they failed to win Navy approval. Mitsubishi submitted its 7-Shi Carrier Attack Aircraft but it crashed on takeoff due to engine failure. Because of these failings, the Navy began with a new design competition for a 9- Shi Carrier Attack Aircraft.

Check this amazing scratch-built model here.

General characteristics
Crew: 3 (pilot, navigator/bomb aimer and gunner)
Length: 10 m (32 ft 10 in)
Wingspan: 14 m (45 ft 11 in)
Height: 3.80 m (12 ft 6 in)
Wing area: 50.0 m2 (538 sq ft)
Empty weight: 2,000 kg (4,409 lb)
Gross weight: 3,800 kg (8,378 lb)
Powerplant: 1 × Nakajima Hikari 2 9-cylinder radial engine, 520 kW (700 hp)
Propellers: 3-bladed

Performance
Maximum speed: 220 km/h (140 mph, 120 kn)
Stall speed: 93 km/h (58 mph, 50 kn)
Endurance: 6 hr
Service ceiling: 5,500 m (18,000 ft)
Time to altitude: 12 minutes to 3,000 m (9,800 ft)

Armament
Guns: 1 × flexibly mounted 7.7 mm machine gun
Bombs: 1 × 800 kg (1,760 lb) torpedo, or 1 × 800 kg bomb, or 2 × 250 kg bombs

*Francillon, Model Art #327 and others mention that the designation was "B4N1", only Mikesh-Abe mention that it was "B3N1". Considering that the Mitsubishi entry in the 7-Shi competition was designated B4M1 agreed by everyone including Mikesh-Abe and that the officially adopted type was the B4Y1 (also agreed by everyone), it is safe to conclude that the "B3N1" designation mentioned in the Mikesh-Abe book was a missprint. The Wiki entry needs correcting...

Saturday, 27 September 2025

Nakajima Bulldog Fighter


Nakajima's design for a parasol-wing fighter, along with those of other companies competing for the Army's requirement for a new fighter, met with early uncertainties. Eventually, Nakajima's design was further developed and became the successful Army Type 91 Fighter, but in the interim, Nakajima, in 1930, bought the licence-manufacturing rights for the Bristol Bulldog. This aircraft was thought by Nakajima to be an ideal replacement for the ageing Type Ko 4 Fighters. Like the earlier N-35 Reconnaissance Aircraft, this project was supervised by the same French team headed by Andre Marie, assisted by Maxime Robin and others. Because this was a British-designed aircraft, Leslie G. Frise of the Bristol Aeroplane Co and his assistant H.W. Dunn were invited to Japan to assist. The first prototype was completed in June 1930, followed soon after by the second prototype. The design was based upon the Bristol Bulldog Mk. II, but differed by having each engine cylinder covered by separate fairings, the interplane struts were changed to the N type as used on the Bristol Bullpup, and struts were used to brace the tailplane. The Nakajima Jupiter engine was substituted for the Bristol-built Jupiter. After two prototypes were built, some of the parts were found to have insufficient strength for safe flight, therefore Nakajima Chikuhei grounded them. As a consequence, they were never submitted to the Army for evaluation; however, Nakajima's design for the parasol-wing Type 91 Fighter had by now achieved success. The two Bulldogs were eventually donated to the Navy, at the outbreak of the Shanghai Incident, for structural research purposes.

General characteristics
Single-engine single-seat fighter biplane. Metal structure with fabric covering.
Crew: Pilot in open cockpit.
Length: 7.54m (24ft 9in)
Span: 10.36m (34ft)
Height: 2.99m (9ft 91/2in)
Wing area: 28.5sq m (306.781sq ft)
Wing loading 56.1kg/sq m (11.51b/sq ft)
Power loading 3.55kg/hp (7.81b/hp)
Empty weight: 1,000kg (2,2041b)
Gross weight: 1,600kg (3,5271b)
Powerplant: 450-520hp Nakajima Jupiter VII nine-cylinder air-cooled radial engine, driving a two-bladed wooden propeller.

Performance
Maximum speed: 148kt (170.3mph) at 3,000m (9,843ft)
Climb to 5,000m (16,404ft) in 11 min
Service ceiling: 7,650m (25,098ft)

Saturday, 20 September 2025

Aichi B7A1 "Ryusei" (Grace) by Jan Voorbij


Aichi B7A1 "Ryusei" (Grace)
Dive bomber / Torpedobomber
Pre-production plane: 1 of 9 prototypes
Imperial Japanese Navy, Kougeki (attack) 5th Hikotai, 752nd Kokutai, April/May 1945 and later 1945 Katori Naval Air Base April 1945 till the end of May 1945, then moved to Kisarazu Naval Air base. Captured by US troops in August 1945.
Fujimi 7AF1, 1:72

- Jan Voorbij, Holand -

Thursday, 18 September 2025

Kawasaki Experimental Carrier Reconnaissance Aircraft


In March 1927, the Navy decided to manufacture an experimental aircraft funded by a program sponsored by the Kaibo Gikai (Maritime Defense Volunteer Association), and named the project: 'Research of Material for All-metal Aircraft'. Kawasaki was awarded the project by the Navy. It was to be a single-engine carrier reconnaissance aircraft having an all-metal structure with fabric covering. It had a fully cantilever parasol wing with marked sweepback, and large area slotted flaps, the first in Japan and probably the first in the world. At that time, no monoplane existed for carrier-based aircraft and there were certainly none with cantilever wings and slotted flaps. The fuselage was unusual being almost triangular in the cross section. The structure of the aircraft was heavily influenced by Dornier design practices. 
Design begun in March 1927 and completed in June 1928 under the leadership of Junichiro Nagahata and his assistant Hiroshi Sato. Both engineers had been in charge of aircraft design at the Aviation Research Department, Naval Technical Research Institute. The aircraft was built at the Kawasaki Dockyard, with the construction being completed in September 1928. Flight tests began in March 1929 at Kasumigaura under the control of Navy Cdr Sakae Yamamoto. However, tests were suspended after very few flights because of problems with flap operation. The flaps were considered to be a major feature of this aircraft and their use at such an early date deserves to be recorded in aeronautical engineering history. But early suspension of the tests without further refinements to the flaps, coupled with top-secret security, resulted in the lack of public awareness and has deprived this design of its rightful place in history. With this aircraft Kawasaki's affiliation with the Japanese Navy ended, and the company became solely a manufacturer of Army aircraft and a few civil types.

General characteristics
Single-engine cantilever parasol-monoplane with slotted flap system. All-metal construction with fabric covering.
Crew: two in open cockpits
Length: 10.65m (34ft 111/2in)
Span: 16.60m (54ft 51/2in)
Height: 3.18m (10ft 51/4in)
Wing area: 43.70sq m (470.3 98sq ft)
Wing loading: 41.2kg/sq m (8.41b/sq ft)
Power loading: 4kg/hp (8.81b/hp)
Empty weight: 1,200kg (2,6451b)
Gross weight: 1,800kg (3,9681b)
Powerplant: 450-600hp Mitsubishi-Hispano-Suiza twelve-cylinder vee water-cooled engine, driving a two-bladed wooden propeller.

Performance
Maximum speed: 142kt (164mph) at sea level
Service ceiling: 10,000m (32,808ft)
Endurance 3 hours
Multi-view illustration from Encyclopedia Vol.4