Yokosuka D4Y

https://en.wikipedia.org/wiki/Yokosuka_D4Y

The Yokosuka (???) D4Y Suisei (?? "Comet") Navy Carrier dive bomber was operated
by the Imperial Japanese Navy. Its Allied reporting name was "Judy". The D4Y was
one of the fastest dive bombers of the war and only the delays in its
development hindered its service while its predecessor, the slower fixed-gear
Aichi D3A, remained in service much longer than intended. Despite limited use,
the speed and the range of the D4Y were nevertheless valuable, and the type was
used with success as reconnaissance aircraft as well as for kamikaze missions.

Development of the aircraft began in 1938 at the Yokosuka Naval Air Technical
Arsenal as a carrier-based dive bomber to replace the Aichi D3A. The aircraft
was a single-engine, all-metal low-wing monoplane, with a wide-track retractable
undercarriage and wing-mounted dive brakes. It had a crew of two: a pilot and a
navigator/radio-operator/gunner, seated under a long, glazed canopy which
provided good all-round visibility. The pilot of bomber versions was provided
with a telescopic bombsight. The aircraft was powered by an Aichi Atsuta
liquid-cooled inverted V12 engine, a licensed copy of the German DB 601, rated
at 895 kW (1,200 hp). The radiator was behind and below the three-blade
propeller, as in the P-40 Warhawk.

The aircraft had a slim fuselage that enabled it to reach high speeds in
horizontal flight and in dives, while it had excellent maneuverability despite
high wing loading, with the Suisei having superior performance to contemporary
dive bombers such as the Curtiss SB2C Helldiver. In order to conform with the
Japanese Navy's requirement for long range, weight was minimized by not fitting
the D4Y with self-sealing fuel tanks or armour. In consequence, the D4Y was
extremely vulnerable and tended to catch fire when hit.

Early versions of the D4Y were difficult to keep operational because the Atsuta
engines were unreliable in front-line service. From the beginning, some had
argued that the D4Y should be powered by an air-cooled radial engine which
Japanese engineers and maintenance crew had experience with, and trusted. The
aircraft was re-engined with the reliable Mitsubishi MK8P Kinsei 62, a
14-cylinder two-row radial engine as the Yokosuka D4Y3 Model 33.

Although the new engine improved ceiling and rate of climb (over 10,000 m/32,800
ft, and climb to 3,000 m/9,800 ft in 4.5 minutes, instead of 9,400 m/30,800 ft
and 5 minutes), the higher fuel consumption resulted in reduced range and
cruising speed and the engine obstructed the forward and downward view of the
pilot, hampering carrier operations. These problems were tolerated because of
the increased availability of the new variant.


Role
Dive bomber

Manufacturer
Yokosuka

First flight
December 1940

Introduction
1942

Retired
1945

Primary user
Imperial Japanese Navy Air Service

Produced
1942–1945

Number built
2,038

Lacking armor and self-sealing fuel tanks, the Suiseis did not fare well against
Allied fighters. They did, however, cause considerable damage to ships,
including the carrier USS Franklin which was nearly sunk by an assumed single
D4Y and the light carrier USS Princeton which was sunk by a single D4Y.

The D4Y was faster than the A6M Zero and some were employed as D4Y2-S night
fighters against Boeing B-29 Superfortress bombers late in the war. The night
fighter conversions were made at the 11th Naval Aviation Arsenal at Hiro. Each
D4Y2-S had its bombing systems and equipment removed, and replaced by a 20 mm
Type 99 cannon installed in the rear cockpit, with the barrel slanted up and
forwards in a similar manner to the German Schräge Musik armament fitting
(pioneered by the IJNAS in May 1943 on the Nakajima J1N). Some examples also
carried two or four 10 cm air-to-air rockets under the wings; lack of radar for
night interceptions, inadequate climb rate and the B-29's high ceiling limited
the D4Y2-S effectiveness as a night fighter. Little is known of their
operations.

At the end of the war, D4Ys were still being used operationally against the U.S.
Navy. Among the last of these were 11 aircraft led by Vice Admiral Matome Ugaki
on a search mission on 15 August 1945, of which all but three were lost.

Specifications (D4Y2)

General characteristics
Crew: two (pilot & gunner/radio operator)
Length: 10.22 m (33 ft 6 in)
Wingspan: 11.50 m (37 ft 9 in)
Height: 3.74 m (12 ft 3 in)
Wing area: 23.6 m² (254 ft²)
Empty weight: 2,440 kg (5,379 lb)
Loaded weight: 4,250 kg (9,370 lb)
Powerplant: 1 × Aichi Atsuta AE1P 32 liquid-cooled inverted V12 piston engine,
1,400 hp (1,044 kW)

Performance
Maximum speed: 550 km/h (342 mph)
Range: 1,465 km (910 mi)
Service ceiling: 10,700 m (35,105 ft)
Rate of climb: 14 m/s (2,700 ft/min)
Wing loading: 180 kg/m² (37 lb/ft²)
Power/mass: 0.25 kW/kg (0.15 hp/lb)

Armament

2× forward-firing 7.7 mm Type 97 aircraft machine guns
1× rearward-firing 7.92 mm Type 1 machine gun
500 kg (1,102 lb) of bombs (design), 800 kg (1,764 lb) of bombs (kamikaze)




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