Japan's Yokosuka D4Y Suisei dive bomber, "Comet"
Navy Type 2
Allied Code Name: Judy

Photos

Yokosuka D4Y Suisei "Judy" dive bomber:	Yokosuka D4Y Suisei "Judy" dive bomber:
Yokosuka D4Y1-C Suisei "Judy" reconnaissance plane:
Yokosuka D4Y3 Suisei "Judy" dive bomber:

Design

The design for the Yokosuka D4Y was based on the purchased design of the German He 118.^1,2,3 When the original He 118 was destroyed, the Imperial Japanese Navy as the Dai-Ichi Kaigun Koku Gijitsusho (First Technical Arsenal of Naval Aviation) in Yokosuka to design a replacement following the design of the He 118.³

The D4Y was supposed to replace the Aichi D3A but it wasn't well armed and the engines were unreliable.³

Engine

The engine was based on an imported Daimler-Benz DB 600G engine.¹ Initially there were problems with the Aichi Atsuta model, the DB 601A, and this delayed the D4Y.²

The D4Y was one of two mass produced aircraft that used liquid cooled engines in the Japanese military, the Ki-61 Hien being the other.³

The engines were the D4Y's Achilles heel.³

Prototype

The D4Y1 prototype first flew in December 1940³ / 1941.^1,2

Production

Aichi's Nagoya plant produced the D4Y1-C.¹ 660 were delivered by the spring of 1942.¹

• Prototypes: 5²
• Yokosuka D4Y: 2,033²
• Yokosuka D4Y2 Model 12:
  • Production: October 1944 - ?^2,3
• Yokosuka D4Y3: 536³
• Total: 2,033¹, 2,038^2,3
  • Manufacturer: Aichi², Aichi Kokuki K.K.³, 11th Naval Air Arsenal²
  • Production: Spring 1942 - August 1945³

Variants

• Prototype: Powered by Daimler-Benz DB 600G (950 HP).²
• Yokosuka D4Y1: First production model.¹
• Yokosuka D4Y1 Model 11: Strengthened wing spars.² Improved dive brakes.²
• Yokosuka D4Y1-C: Reconnaissance.^1,2
• Yokosuka D4Y2, Yokosuka D4Y2 Model 12²: Had a Aichi Atsuta 32 engine (1,400 HP).^1,2
• Yokosuka D4Y2-S: Night fighter.² Wasn't successful against B-29s.²
• Yokosuka D4Y3, Yokosuka D4Y3 Model 33²: Had Kinsei 62 radial engine.^1,2
• Yokosuka D4Y4: Suicide bomber.^2,3 Had one crewman.^1,2 Had Kinsei 62 radial engine.² Carried 1,764 lb / 800 kg bomb under the fuselage.²

Usage

Preproduction models were deployed in April 1942.² Due to its capabilities the D4Y1-Cs were deployed for reconnaissance.²

Midway

The first aircraft to be lost were on the Soryu when it was sunk at Midway in June 1942.¹

Battle of the Philippine Sea

The 1st, 2nd, and 3rd Kodu Sentais were equipped with 174 D4Ys.¹ They sustained heavy casualties before any could reach the American carriers.¹

One D4Y, piloted by Rear Admiral Arima, was possibly the first used in a suicide attack against the USS Franklin.²

Last Futile Attack

On August 15, 1945, eleven D4Ys were used in Kamikaze attacks off of Okinawa.² Included in these was one D4Y4 flown by Admiral Ugaki.³

Specifications

	Yokosuka D4Y Suisei1,2	Yokosuka D4Y1 Suisei2,3	Yokosuka D4Y2 Suisei2	Yokosuka D4Y3 Suisei1,2	Yokosuka D4Y4 Suisei2
Type	Carrier dive bomber 2, carrier reconnaissance2	Bomber3		Carrier dive bomber1
Crew	22	23		21
Engine (Type)		Aichi AE1A Atsuta3 Aichi AE1A Atsuta 12 (Daimler-Benz DB 601A)2	Aichi AE1P Atsuta 322	Mitsubishi MK8P Kinsei 62 piston1,3 Mitsubishi MK8P Kinsei2	Mitsubishi MK8P Kinsei2
Cylinders		Inverted V-122, V-123		Radial1,2, 142	Radial 142
Cooling		Liquid3
Net HP		1,2002,3	1,4002	1,5601,2	1,5602
Propeller blades		32	32	31	32
Dimensions
Span	37' 8.75"2 11.5 m2	37' 8"3, 37' 8.75"2 11.5 m2	37' 8.75"2 11.5 m2	37' 8.75"1,2 11.5 m1,2	37' 8.75"2 11.5 m2
Length	33' 6.5"2 10.22 m2	33' 6"3, 33' 6.5"2 10.22 m2	33' 6.5"2 10.22 m2	33' 6 3/8"1, 33' 6.5"2 10.22 m1,2	33' 6.5"2 10.22 m2
Height	12' 3.25"2 3.74 m2	12' 1"3, 12' 3.25"2 3.74 m2	12' 3.25"2 3.74 m2	12' 3.25"1,2 3.74 m1,2	12' 3.25"2 3.74 m2
Wing area				254.03 ft2 1 23.6 m2 1
Weight
Empty		5,379 lb2 2,440 kg2		5,514 lb1,2 2,501 kg1,2
Loaded		8,047 lb3, 9,370 lb2 4,250 kg2		10,267 lb1,2 4,657 kg1,2
Performance
Speed @ 15,585' / 4,750 m		343 mph2,3 552 kph2
Speed @ 19,850' / 6,050 m				357 mph1,2 575 kph1,2
Climb to 9,840' / 3,000 m		5.2 minutes2		4.6 minutes2
Climb to 9,845' / 3,000 m				4.55 minutes1
Service ceiling		32,480'2,3 9,900 m2		34,450'1,2 10,500 m1,2
Range		975 - 2,417 miles2, 978 miles3 1,570 - 3,890 km2		945 miles1, 945 - 1,796 miles2 1,520 km1, 1,520 - 2,890 km2
Armament		3: MG3
Nose		2: 7.7 mm MG2	2: 7.7 mm MG2	2: 7.7 mm MG2 2: 7.7 mm Type 97 MG1
Cockpit - rear		1: 7.92 mm MG2	1: 7.92 mm MG2	1:7.92 mm MG2 1: 13.2 mm Type 21
Bombs		683 lb3, 1,234 lb2 560 kg2	1,234 lb2 560 kg2	1,234 lb1,2 560 kg1,2	1,764 lb2 800 kg2