The most important of the Yokosuka-designed trainers, was the Yokosuka K5Y1, first flown during December 1933. Adopted in January 1934 as the Navy Type 93 Intermediate Trainer, it was built to a total of 5,770 by the end of the Pacific war, being allocated the Allied codename ‘Willow’. Built in three versions, with float and wheel landing gear, the 11.00m span K5Y1 with a 254kW Hitachi Amakaze radial engine had a maximum speed of 212km/h.
Produced by seven different manufacturers over 12 years the K5Y was called Akatombo or Red Dragon by the Japanese as the Type 93 basic trainers were painted bright red-orange.
K5Y1 Engine: 1 x Hitachi Amakaze-11, 255kW Max take-off weight: 1500 kg / 3307 lb Empty weight: 1000 kg / 2205 lb Wingspan: 11.0 m / 36 ft 1 in Length: 8.05 m / 26 ft 5 in Height: 3.2 m / 11 ft 6 in Wing area: 27.7 sq.m / 298.16 sq ft Max. speed: 212 km/h / 132 mph Cruise speed: 140 km/h / 87 mph Ceiling: 5700 m / 18700 ft Range: 1020 km / 634 miles Crew: 2 Armament: 2 x 7.7mm machine-guns Bombload: 2 x 30-kg and 10 x 10-kg
In 1934 the staff of the Yokosuka Navy Arsenal turned their hand to the design of a twin-engined flying-boat, the Yokosuka H5Y powered by two 895kW Mitsubishi Shinten 21 radial engines. Although built to a total of 20 during 1936-40 as the Navy Type 99 Flying-Boat, its performance was disappointing and, consequently, was deployed only on second-line duties.
Early in the war an unidentified twin-engined flying boat was spotted on non-combat duty around Japanese Naval bases. The allied code name ‘Cherry’ permitted identification before the manufacturer’s name and designation was discovered through prisoner interrogation over a year later.
H5Y1 Engine: 2 x Mitsubishi Shinten-21, 895kW Max take-off weight: 12500 kg / 27558 lb Wingspan: 31.57 m / 104 ft 7 in Length: 20.52 m / 67 ft 4 in Max. speed: 305 km/h / 190 mph Ceiling: 5200 m / 17050 ft Range: 4700 km / 2921 miles Crew: 6 Armament: 3 x 7.9mm machine-guns Bombload: 500kg
The Yokosuka E14Y1 was built to a total of 126 as the Navy Type 0 Small Reconnaissance Seaplane. Used aboard ocean-going submarines of the Japanese fleet, these aircraft made some notable flights: one from the submarine 1-7 made a post-attack assessment of damage at Pearl Harbor.
On 9 September 1942, launched from the Japanese submarine I-25 under Frigate Captain Meija Tagami, Naval pilot N.Fujita used a Yokosuka E14Y1 seaplane to bomb forests in Oregan, USA. The first raid on the United States of America. On 29 September a second raid was made at the same spot, 50 miles west of Cape Blanco. This was the last raid made on the USA.
E14Y1 Engine: 1 x Hitachi Tempu-12, 255kW Max take-off weight: 1450 kg / 3197 lb Empty weight: 1119 kg / 2467 lb Wingspan: 11.0 m / 36 ft 1 in Length: 8.54 m / 28 ft 0 in Height: 3.8 m / 12 ft 6 in Wing area: 19.0 sq.m / 204.51 sq ft Max. speed: 245 km/h / 152 mph Cruise speed: 165 km/h / 103 mph Ceiling: 5420 m / 17800 ft Range: 880 km / 547 miles Crew: 2 Armament: 7.7mm machine-guns, 60kg of bombs
Influenced by flight tests with a Heinkel He 118 in 1938, the Japanese navy decided that future carrier based aircraft should be much cleaner aerodynamically. A 13 Shi (1938) specification was issued to the Yokosuka naval air arsenal for a carrier-based dive bomber of exceptionally high performance. It had to operate from small carriers and carry a 250 kg (551 lb) bombload for 800 nautical miles (1481 km) and reach 280 knots (519 km/h).
Designed as a fast carrier-based attack bomber and powered by an imported Daimler-Benz DB 600G engine, the D4Y1 was first flown in December 1941.
Achieving excellent performance despite having only a 960 hp DB 600G, the D4Y1-C reconnaissance aircraft were ordered into production at Aichi’s Nagoya plant, the first of 660 aircraft being completed in the late spring of 1942.
It was not until March 1942 that the first production D4Y1 Model 11 emerged from the Aichi factory at Nagoya (the Allies later thought this an Aichi design). Powered by the 1200 hp, Aichi AE1A Atsuta 12 inverted V 12 (licence built modified DB 601A) the aircraft had such speed and range it was ordered as the D4Y1 C reconnaissance aircraft, with rear fuselage camera(s) and underwing drop tanks, and the C model remained in use until Japan’s final surrender. Work continued to perfect the basic D4Y1 and eventually it entered service in March 1943. The first service aircraft were lost when the Soryu was sunk at Midway. The Model 21 was generally similiar. Many D4Y1s were completed as dive-bombers, and 174 Suiseis of the 1st, 2nd and 3rd Koku Sentais were embarked in nine carriers before the Battle of the Philippine Sea. However, they were intercepted by American carriers, and suffered heavy casualties without achieving any success.
Production amounted to 660 by Aichi, with the Japanese name Suisei (Comet) and the Allied code name ‘Judy’, but in the first big action at the Marianas ‘turkey shoot’ they suffered severe casualties at the hands of US Navy fighters and failed to sink any major warships. Their chief faults were complete absence of armour or self sealing tanks and the armament of two fixed 7.7 mm (0.303 in) Type 97 machine guns in the nose and a 7.92 nun (0.312 in) Type 1 aimed by the radio operator/navigator/gunner in the rear seat. Normal bombload was 310 kg (683 lb), but for short ranges 560 kg (1234 lb) could be accommodated.
Like many of the best Japanese aircraft of the Second World War, the D4Y had the misfortune to enter service just as the era of Japanese superiority was coming abruptly to an end. The fleet carriers were fairly soon all sent to the bottom of the Pacific, and most of the total of 2038 of all versions of D4Y operated from escort carriers and shore bases, often in roles quite different from those for which the type was designed. The first new sub type, other than the C, was the D4Y2 (Model 22), which had the 1400 hp Atsuta 32 engine, and the fin and rudder were modified and increased in area, and, in the main D4Y2a variant, a 13mm (0.51 in) Type 2 gun in the rear cockpit. Entering service just in time for the Leyte Gulf and Philippines battles in October 1944, the new model was coolly received, because it still had neither armour nor tank protection. Aichi built 326, plus about 100 by Dai Juichi Kaigun Kokusho (Hiro Naval Air Arsenal), but they were shot out of the sky and soon appeared as kamikaze suicide attackers, usually with an 800 kg (1764 lb) bombload, carried externally.
D4Y3
From the start the liquid cooled engine had been unpopular, owing to its difficult main¬tenance and poor reliability. The general feeling about the trim Suisei had been that there was not much wrong with it that proper protection and a radial engine would not cure, and in the winter of 1943/4 the Aichi team schemed an installation for the 14 ¬cylinder two row Mitsubishi Mk8P Kinsei 62.
The D4Y3 prototype, flown in May 1944, showed acceptable handling qualities and almost identical performance to the earlier models, with marginally lower speed but longer range and improved takeoff and climb capability. Production was authorized at once, and both Aichi and Hiro arsenal deli¬vered a total of about 350 in all. These still did not have any protection for crew or fuel, and only the later D4Y3a had a 13 mm (0.51in) rear gun. Most had provision for catapulting but as there were virtually no carriers, the majority were also equipped to have three RATO rockets clipped below the rear fuselage to assist takeoff from island airstrips.
The last sub type was the D4Y4, a pur¬pose designed kamikaze aircraft. A single-¬seater, it carried an 800 kg (1764 lb) bomb or explosive charge (made from a mine or tor¬pedo) semi externally. 296 were deli¬vered by Aichi in 1945.
The proposed D4Y5, with 1825¬hp NK9C Homare engine and proper armour and protected tanks, did not fly. The D4Y2 was later converted to a night fighter.
A total of 2,319 D4Ys was completed. Aichi handled most of the payroll and 500 were completed by Hiro Arsenal.
In the first year of the war some types were given more than one code name due to inaccurate descriptions. ‘Dot’ was assigned to a carrier dive bomber, later also assigned the name ‘Judy’. ‘Dot’ was dropped in favour of the more accepted ‘Judy’.
D4Y2 Engine: 1 x Aichi AE1P Atsuta, 1050kW Max take-off weight: 3840 kg / 8466 lb Empty weight: 2640 kg / 5820 lb Wingspan: 11.5 m / 38 ft 9 in Length: 10.2 m / 33 ft 6 in Height: 3.75 m / 12 ft 4 in Wing area: 22.8 sq.m / 245.42 sq ft Max. speed: 575 km/h / 357 mph Cruise speed: 425 km/h / 264 mph Ceiling: 10700 m / 35100 ft Range: 3600 km / 2237 miles Crew: 2 Armament: 7.92 or 13mm machine-guns Bombload: 1 x 500-kg, 2 x 30-kg
D4Y3 Engine: Mitsubishi Kinsi 62, 1560 hp Span: 11.5 m (37ft 8.75in) Length: 10.22 m (33 ft 6.5 in) Height: 10 ft 9.5 in Empty weight: 5514 lb Gross weight. 4657 kg (10267 lb) Maximum speed: 575 km/h (357 mph) at 19,360 ft Service ceilig: 34,450 ft Max range: 944 miles Armament: 1 x 7.9mm mg, 2 x 7.7mm mg Bombload: 1650 lb Crew: 2
The Yokosuka B4Y1 three-seat carrier attack bomber was designed to meet a requirement of 1934, the evaluation of five prototypes with different power-plant being followed by 205 production aircraft built during 1937-38. Designated officially as the Navy Type 96 Carrier Attacker, these aircraft were used as advanced trainers after Pearl Harbor but, as the Allies believed they were still in first-line service, the type was allocated the code-name ‘Jean’.
B4Y1 Engine: 1 x Nakajima Hikari-2, 630kW Max take-off weight: 3600 kg / 7937 lb Empty weight: 2000 kg / 4409 lb Wingspan: 15.0 m / 49 ft 3 in Length: 10.15 m / 33 ft 4 in Height: 4.36 m / 14 ft 4 in Wing area: 50.0 sq.m / 538.20 sq ft Max. speed: 278 km/h / 173 mph Ceiling: 6000 m / 19700 ft Range: 1580 km / 982 miles Crew: 3 Armament: 1 x 7.7mm machine-guns Bombload: 800-kg torpedo or 500kg of bombs
Yokosuka’s B3Y1 Navy Type 32 carrier biplane first flew in 1932. Some 200 B4Y1 attack aircraft followed, those remaining in service Second World War known as “Jean” to the Allies. The D4Y Suisei (“Judy” two-seat carrier dive-bomber was in service by the Battle of Midway in 1942 and appeared also in D4Y2-S nightfighter and D4Y4 suicide attack variants. The P1Y1 Ginga (“Frances”) twin-engined naval attack bomber/nightfighter entered production in 1943 at Nakajima factories. Yokosuka developed also the MXY-7 Ohka (Cherry Blossom) kamikaze piloted missile-bomb, derisively dubbed Baka (“fool” in Japanese) by the U.S. Navy, and of which production by various manufacturers totalled about 800.
Roberto Bartini had designed and built the Stal-7 airliner whilst he was the chief designer at the ZOK NII GVF (Russian: Zavod Opytno Konstrooktorskoye Naoochno-Issledovatel’skiy Institoot Grazdahnskovo Vozdooshnovo Flota — “Factory for Special Construction at the Scientific Test Institute for the Civil Air Fleet”). The performance of the Stal-7 was extremely good, particularly in respect to its payload; at gross overload weight over 56% of the total weight was payload. During flight trials with maximum all-up weight the prototype crashed on take-off in early 1938, resulting in the arrest of Bartini and his imprisonment in a Siberian Gulag in February 1938. The Stal-7 lay unrepaired until Vladimir Yermolaev was appointed as chief designer at OKB-240 after Bartini’s arrest, with the task of transforming the Stal-7 design into a long-range bomber, a task made easier since Bartini had reserved space for a bomb bay in the fuselage. After repair the Stal-7 carried on with the flight-test programme, including a record-breaking non-stop flight on 28 August 1939 when it flew Moscow—Sverdlovsk—Sevastopol—Moscow; a distance of 5,086 km (3,160 mi) at an average speed of 405 km/h (252 mph).
Preliminary design of the DB-240 (Russian: dahl’niy bombardirovschik—”long-range bomber”), as the bomber version was designated, was complete by the beginning of 1939 and the construction of two prototypes began the following July. The DB-240 retained little apart from the general layout of the Stal-7 as the structure was almost completely redesigned. An all-metal mid-wing monoplane of inverted gull-wing configuration and with a twin fin-and-rudder tail unit, the Yer-2 had tail-wheel landing gear, the main units retracting into the nacelles of its two M-105 engines; accommodation was provided for a crew of four. The pilot’s cockpit was offset to port to improve his downward view and the navigator/bomb aimer sat in the extensively glazed nose with a 7.62-millimeter (0.300 in) ShKAS machine gun, the radio operator sat below and to starboard of the pilot and the dorsal gunner in a partially retractable turret with one 12.7-millimeter (0.50 in) Berezin UBT machine gun. Another ShKAS was fitted in a ventral hatch. Up to 2,000 kg (4,409 lb) of bombs could be carried in the bomb bay and two 500-kilogram (1,102 lb) bombs could be carried externally. Up to 4,600 kg (10,141 lb) of fuel could be carried. The DB-240 had been designed to use the experimental Klimov M-106 V12 engines, but the less-powerful Klimov M-105 engine had to be substituted because the M-106 was not available.
The DB-240 prototype flew for the first time on 14 May 1940 and began its State acceptance tests on 27 September 1940. The weaker engines prevented the DB-240 from reaching its designed performance. It could only attain 445 km/h (277 mph) at 4,250 m (13,944 ft) instead of the expected 500 km/h (311 mph) at 6,000 meters (19,685 ft). Its defensive armament was deemed inadequate and other problems included an excessively long take-off run and engine defects. However, these did not offset its virtues of a heavy bomb load and long-range (4,100 kilometers (2,548 mi) carrying 1,000 kg (2,205 lb) of bombs). It was ordered into production at Factory No. 18, in Voronezh, as the Yermolayev Yer-2.
A second prototype followed in September, by which time preparations for mass production at Voronezh were in hand. Manufacture began in March 1941, with approximately 50 aircraft delivered by 22 June 1941. These aircraft were about 5–8 km/h (3.1–5.0 mph) slower than the prototype and their normal weight increased 1,220 kg (2,690 lb) to 12,520 kg (27,602 lb). Production was terminated in August to allow the factory to concentrate on the higher-priority Ilyushin Il-2 ground-attack aircraft. By July 1941, 128 examples of the DB-240 had been delivered under the designation Yermolayev Yer-2
A Yer-2 was modified with experimental Mikulin AM-37 engines, a reinforced undercarriage, armored seats for the navigator and gunner, and 12.7 mm UBT machine guns in place of its original ShKAS weapons. It first flew in July 1941 and was able to reach 505 km/h (314 mph) at 6,000 m (19,685 ft), but the range was reduced to (3,500 km (2,175 mi) carrying 1,000 kg (2,205 lb) of bombs. One significant problem with this version was the excessive take-off roll which hindered operations from grass airstrips. The engine was unreliable, however, and had cooling problems that the Mikulin OKB did not have the resources to resolve so it was cancelled in October when the factory was forced to evacuate from Moscow by the German advance.
The Charomskiy M-40F Diesel engine was also evaluated in a Yer-2 in 1941. This engine, like all Diesels, offered a greatly reduced fuel consumption compared to a standard gasoline-powered engine, but at a great penalty in weight. These engines increased the gross take-off weight to 13,500 kg (29,762 lb) which required the undercarriage to be reinforced and the wing area increased to keep the same wing loading. The M-40F-powered aircraft reached a maximum speed of 430 km/h (267 mph) at 6,050 m (19,849 ft). However, the M-40 was not yet ready for service use and the project was cancelled.
The cockpit was modified to accommodate two pilots side-by-side and the wing and tailplane areas were increased. The 12.7 mm UBT machine gun in the dorsal turret was replaced by a 20-millimeter (0.79 in) ShVAK cannon and the nose and ventral ShKAS machine guns were exchanged for 12.7 mm UBT machine guns. Up to 5,460 kg (12,037 lb) of fuel could be carried. The Yer-2/ACh-30B was placed into production at Factory No. 39 in Irkutsk at the end of 1943 and the first production aircraft was submitted to its State acceptance trials the following month. Some excess aircraft were converted as Yer-2ON VIP transports.
The Yer-2 was not in squadron service when Germany invaded on 22 June 1941, but the 420th and 421st Long-Range Bomber Regiments (Russian: Dahl’niy Bombardirovchnyy Aviapolk—DBAP) were formed shortly afterwards. However neither regiment flew any operational missions until later in the summer. On the evening of 10 August Yer-2s of the 420th DBAP, accompanied by Petlyakov Pe-8s of the 432nd DBAP, attempted to bomb Berlin from Pushkino Airfield near Leningrad. The airfield was too short to accommodate a fully loaded Yer-2, but three bombers did manage to take-off regardless. Two managed to bomb Berlin, or its outskirts, but only one successfully returned; the other was shot down by ‘friendly’ Polikarpov I-16s when it reentered Soviet airspace and the third aircraft went missing. Three crews from the 420th DBAP bombed Königsberg during the nights of 28–29 August and 30 August–1 September from Ramenskoye Airport, southeast of Moscow.
Yer-2 2M-105
On 1 October 1941 sixty-three Yer-2s were in service, but only thirty-four were operational. The 420th DBAP had flown 154 sorties by the beginning of November (6 in August, 81 in September, 67 in October) and had lost thirty of its forty aircraft. Over half of these (nineteen) were due to non-combat losses. Losses were extremely high over the autumn and winter as they were inappropriately committed against German tactical front-line targets during the Battle of Moscow at low altitudes and only twelve were in service on 18 March 1942. On 4 August 1942 the 747th DBAP had only ten Yer-2s on hand and it was briefly committed during the Battle of Stalingrad. The survivors were flown, in ever dwindling numbers, until August 1943 when the last few aircraft were transferred to schools by the 2nd Guards DBAP and the 747th DBAP.
The Yer-2 was placed back into production at the end of 1943, but none of the new bombers had been issued to combat units by 1 June 1944. However forty-two were in service on 1 January 1945 and one hundred and one on 10 May 1945 after the war ended. The first combat mission undertaken by Yer-2s after they returned to production was a raid on Königsberg on 7 April 1945 by the 327th and 329th Bomber Aviation Regiments (Russian: Bombardirovchnyy Aviatsionyy Polk). It remained in service with Long-Range Aviation units until replaced by four-engined bombers like the Tupolev Tu-4 in the late 1940s.
A Yer-20N special-purpose long-range transport version, which carried 18 passengers, was developed from the bomber.
DB-240 Two prototypes of the Yer-2 series with two 1,050 hp M-105 engines.
Yer-2 Production version with two M-105 engines, 128 built.
Yer-2/AM-37 One aircraft re-engined with two prototype 1,380 hp Mikulin AM-37 engines, the fastest of all Yer-2s.
Yer-2/M-40F The first diesel-powered Yer-2, with modified wings. One converted with two 1,500 hp Charomskiy M-40F diesel engines.
Yer-2/ACh-30B Production model of the diesel-engined version. Performance was excellent despite the poor reliability and rough running of the Charomskiy ACh-30B diesel engines. Range increased 1,500 km (930 mi) from the version with M-105 engines.
Yer-2ON (Russian: Osobogo Naznachyeniya–Special Assignment) Two aircraft from the Yer-2/ACh-30B production line were modified with a 12-seat VIP cabin, military equipment removed and long-range fuel tanks in the bomb-bay. A third aircraft was converted from a Yer-2 (1941 production) and used for shuttle flights between Irkutsk and Moscow.
Yer-2N (Russian: Nositel—Carrier) One aircraft was modified as an engine test-bed for captured Argus As 014 pulse jet engines.
Yer-2/MB-100 One production aircraft used as a test-bed for the 2,200 horsepower (1,600 kW) Dobrotvorskii MB-100 engine in 1945.
Yer-4 The final iteration of the Yer-2 series was a 1941 production aircraft re-engined with ACh-30BF engines and redesignated as the Yer-4. It had a slightly larger wingspan, increased take-off weight and improved armament. The prototype was tested in December 1943, but did not enter production.
Operators:
Soviet Union
VVS (Russian: Voyenno-Vozdooshnyye Seely—Soviet Air Forces)
ADD (Russian: Aviahtsiya Dahl’nevo Deystviya—Long Range Aviation) 420th Long-Range Bomber Aviation Regiment, later the 748th Long-Range Bomber Aviation
Regiment 421st Long-Range Bomber Aviation Regiment, later the 747th Long-Range Bomber Aviation
Yer-2 Engine: 2 x M-105, 770kW Max take-off weight: 11300-13700 kg / 24912 – 30203 lb Max. speed: 445 km/h / 277 mph Cruise speed: 380 km/h / 236 mph Ceiling: 7500 m / 24600 ft Range w/max.fuel: 3000-4500 km / 1864 – 2796 miles Armament: 1 x 20mm machine-guns, 2 x 12.7mm machine-guns Bombload: 1000-5000kg Crew: 4
Yer-2/ACh-30B Engines: 2 × Charomskiy ACh-30B V12 diesel engines, 1,118 kW (1,500 hp) each Wingspan: 23 m (75 ft 5.5 in) Wing area: 79 sq.m (850 sq.ft) Length: 16.42 m (53 ft 10½ in) Height: 4.82 m (15 ft 10 in) Empty weight: 10,455 kg (23,049 lb) Gross weight: 18,580 kg (40,961 lb) Maximum speed: 420 km/h (261 mph) Range: 5,500 km (3,418 miles) Service ceiling: 7,200 m (23,620 ft) Crew: 4 Armament: 1 x 12.7 mm UBT machine-gun in nose flexible mount. 1 x 12.7 mm UBT machine-gun in ventral flexible mount. 1 x 20 mm ShVAK cannon in a TUM-5 dorsal turret. Up to 5,000 kg (11,023 lb) of bombs in the internal bomb-bay.
USSR On Stalin’s orders Vladimir Gregorovich Yermolaev began design work on a long-range bomber, the DB-240 prototype of which first flew in 1940. This twin diesel-engined low-wing monoplane was based on the design of R. L. Bartini’s Stal’ 7 and had the same distinctive inverted-gull wings. Designated Yer-2, more than 400 were built 1940-1944 and used principally as long-range night bombers. A Yer-20N special-purpose long-range transport version, which carried 18 passengers, was developed from the bomber.
Designed by Pavel Yeyemeyev as a single-seater aerobatic trainer, the Yeremeyev Staliniets-3 (Russian: Еремеев “Сталинец-3”) was built between March and May 1935 by enthusiasts in Yeisk.
The Staliniets-3 was an all-wood single-seater glider, unlike its previous model, the “Staliniets-3” was conceived as a high-low-wing monoplane using inverted V-uprights. The wing design used the TsAGI R-II profile proposed by the engineer PP Krasilschikov and had a trapezoidal shape in the plane, with rounded ends.
The fuselage, with an oval section and covered in plywood, made the transition in the tail area towards a small keel to which the offset and elliptical rudder was attached. The stabilizers were located in the middle of the empennage, braced by uprights to the rear fuselage structure.
The pilot was located in an open cockpit in the forward region of the fuselage. The landing gear was of the conventional type and featured small wheels located on the sides of the fuselage.
Built in Yeisk by Yeremeyev in 1935, the Staliniets-3 glider was entered in the XI National Sailing Competitions held in Koktebel between September 6 and October 6, 1935. In these competitions its performance was good.
The pilots who flew it highlighted that it presented good control and was able to respond without problems to the controls during the execution of school piloting figures. Its landing speed was considered high, but the glider handled the manoeuvre meekly.
The only problem pointed out by the pilots was that the pedals in the cockpit were very close to each other, which brought confusion and fatigue on long flights.
Staliniets-3 Wingspan: 10.09 m Wing area: 9.25 m² Aspect ratio: 12.8 Length: 4.60 m Height: 1.20 m Empty weight: 131 kg Ailerons area: 0.90 m² Wing loading: 22.8 kg / m² Accommodation: 1
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