Yokosuka P1Y

The Yokosuka P1Y Ginga (銀河, "Galaxy") was a twin-engine, land-based bomber developed for the Japanese Imperial Navy in World War II. It was the successor to the Mitsubishi G4M and given the Allied reporting name "Frances".

Design and development
The P1Y was designed by the Yokosuka Naval Air Technical Arsenal to Navy specification 15-Shi, calling for a fast bomber with speed matching the Zero, range matching the G4M, a 907 kg (2,000 lb) bombload, and the ability to dive-bomb as well as carry torpedoes. As the result, the construction suffered from excess complexity, difficulty of manufacture, and poor serviceability. Problems with the availability of enough reliable Nakajima Homare engines led to their replacement by the Mitsubishi Kasei in the P1Y2-S night-fighter version.

The streamlined design of the Ginga is attributed to Miki Tadanao, an engineer who, after World War II, went on to create a similar aerodynamic design for Japan's earliest `bullet trains` (Shinkansen), while working with the Japan National Railways (JNR).

Operational history
The first flight was in August 1943. Nakajima manufactured 1,002 examples, which were operated by five Kokutais (Air Groups), and acted as land-based medium and torpedo bombers from airfields in China, Taiwan, Marianas, Philippines, Ryukyu, Shikoku, and Kyūshū. During the last stages of the war the P1Y was utilized as a kamikaze aircraft against the United States Navy during the Okinawa Campaign in Operation Tan No. 2.

A night fighter version, the P1Y2-S Kyokko (極光, "Aurora"), with Mitsubishi Kasei engines, was equipped with radar and Schräge Musik-style upward-firing -- as well as forward-firing -- 20 mm cannon. A total of 96 were produced by Kawanishi, but due to inadequate high-altitude performance against B-29s, many were converted back to Ginga bombers.

Variants

 * P1Y1 Experimental Type 15 land-based bomber (15試陸上爆撃機, 15-Shi Rikujō Bakugekiki)
 * 3 of prototypes and 9 of supplementary prototypes with 1,357 kW (1,820 hp) NK9C Nakajima NK9B Homare 11 engines. Prototype #3 was later used for Ishikawajima Tsu-11 testbed.




 * P1Y1 Ginga ("Milky Way") Model 11' (銀河11型, Ginga 11-gata'')
 * First model of the series. Mounted Homare 11 or Homare 12.


 * P1Y1a Ginga Model 11A (銀河11甲型, Ginga 11 Kō-gata)
 * Mounted Homare 12, and fitted 1 × 13 mm (.51 in) Type 2 machine gun in the back defensive position.


 * P1Y1b Provisional name Ginga Model 11B (仮称銀河11乙型, Kashō Ginga 11 Otsu-gata)
 * Converted from P1Y1a, mounted Homare 12, and fitted 2 × 13 mm (.51 in) Type 4 machine guns in the back defensive position.


 * P1Y1c Provisional name Ginga Model 11C (仮称銀河11丙型, Kashō Ginga 11 Hei-gata)
 * Converted from P1Y1b, mounted Homare 12, and fitted 1 × 13 mm (.51 in) Type 2 machine gun in the forward position, prototype only.


 * P1Y1 Ginga Model 11 Night-fighter variant (銀河11型改造夜戦, Ginga 11-gata Kaizō yasen)
 * Converted from P1Y1. Armed with 2 × 20 mm Type 99 machine guns. Equipped 302nd Kokutai only. This is not a naval regulation equipment.


 * P1Y1-S Provisional name Ginga Model 21 (仮称銀河21型, Kashō Ginga 21-gata)
 * Night fighter variant. Armed with 4 × 20 mm Type 99 cannons firing obliquely forward, and 1 × 13 mm (.51 in) Type 2 machine gun in the back defensive position. Only a project.


 * P1Y1 Ground attack variant
 * Converted from P1Y1/P1Y1a, installed up to 20 × 20 mm Type 99 machine guns bomb bay for land strikes against B-29 bases in the Marianas. Approx. 30 rebuilt.


 * P1Y2-S Provisional name Ginga Model 26/Test production Kyokkō ("Aurora") (仮称銀河26型/試製極光, Kashō Ginga 26-gata/Shisei Kyokkō)
 * Night fighter variant. Initial named Hakkō ("Corona", 白光) in October 1943, renamed Kyokkō in March 1944. Converted from P1Y1/P1Y1a. Fitted Mitsubishi MK4T-A Kasei 25 engines. Armed with 2 × 20 mm Type 99 machine guns and 1 × 30 mm Type 5 cannon. Later, almost all were converted to P1Y2. 96 or 97 produced.


 * P1Y2 Provisional name Ginga Model 16 (仮称銀河16型, Kashō Ginga 16-gata)
 * Land based bomber. Converted from P1Y2-S. Mounted 1,380 kW (1,850 hp) Mitsubishi MK4T-A Kasei 25 Kō engines.


 * P1Y2a Provisional name Ginga Model 16A (仮称銀河16甲型, Kashō Ginga 16 Kō-gata)
 * Converted from P1Y1a. Mounted Mitsubishi MK4T-A Kasei 25 Kō engines.


 * P1Y2b rovisional name Ginga Model 16B (仮称銀河16乙型, Kashō Ginga 16 Otsu-gata)
 * Converted from P1Y1b. Mounted Mitsubishi MK4T-A Kasei 25 Kō engines.


 * P1Y2c Provisional name Ginga Model 16C (仮称銀河16丙型, Kashō Ginga 16 Hei-gata)
 * Converted from P1Y1c. Mounted Mitsubishi MK4T-A Kasei 25 Kō engines.


 * P1Y2 Ginga Model 16 Night-fighter variant (銀河16型改造夜戦, Ginga 16-gata Kaizō yasen)
 * Converted from P1Y2. Armed with 2 × 20 mm Type 99 machine guns or 1 × 30 mm Type 5 cannon. Equipped 302nd Kokutai only. This is not a naval regulation equipment.


 * P1Y3 Provisional name Ginga Model 13 (仮称銀河13型, Kashō Ginga 13-gata)
 * Converted from P1Y1. Mounted Homare 21 engines.


 * P1Y4 Provisional name Ginga Model 12 (仮称銀河12型, Kashō Ginga 12-gata)
 * Converted from P1Y1. Mounted Homare 23 engines.


 * P1Y5 Provisional name Ginga Model 14 (仮称銀河14型, Kashō Ginga 14-gata)
 * Converted from P1Y1. Mounted Mitsubishi Ha-43 engines.


 * P1Y6 Provisional name Ginga Model 17 (仮称銀河17型, Kashō Ginga 17-gata)
 * Converted from P1Y2. Mounted Mitsubishi MK4T-C Kasei 25 Hei engines.


 * Provisional name Ginga Model 33 (仮称銀河33型, Kashō Ginga 33-gata)
 * Long-range bomber variant. Crew: 4, bombs= up to 3,000 kg. Only a project.


 * Test production Tenga (試製天河, Shisei Tenga)
 * Proposed jet-powered bomber variant, mounted Ishikawajima Ne-30. Discontinued in 1945.


 * MXY10 Yokosuka Navy Bomber Ginga
 * Ground decoy non-flying replica of Yokosuka P1Y1.

Operators

 * Imperial Japanese Navy Air Service
 * 302nd Kokutai: Equipped night fighter variant only.
 * 521st Kokutai
 * 522nd Kokutai
 * 523rd Kokutai
 * 524th Kokutai
 * 701st Kokutai
 * 706th Kokutai
 * 752nd Kokutai
 * 761st Kokutai
 * 762nd Kokutai
 * 763rd Kokutai
 * 765th Kokutai
 * 1001st Kokutai
 * 1081st Kokutai
 * Miyazaki Kokutai
 * Toyohashi Kokutai
 * Yokosuka Kokutai
 * Kogeki 262nd Hikotai
 * Kogeki 401st Hikotai
 * Kogeki 405th Hikotai
 * Kogeki 406th Hikotai
 * Kogeki 501st Hikotai
 * Kogeki 708th Hikotai
 * Kogeki 708th Hikotai