Mitsubishi G4M

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Mitsubishi G4M
Mitsubishi G4M1 of 801st Kokutai
Type	Twin-engine medium bomber
Manufacturer	Mitsubishi
Designed by	Kiro Honjo
Maiden flight	23 October 1939
Introduced	June 1941
Retired	1945
Primary user	IJN Air Service
Number built	2,435

The Mitsubishi G4M (一式陸攻 Ishikirikko: "Type 1 land-based attack aircraft", with the Allied identification name of Betty^[1]was a twin-engined, land-based bomber aircraft used by the Imperial Japanese Navy in World War II. The bomber was nicknamed "Betty" by the Allies, who usually gave Japanese fighters and float-planes male code names, while typically giving female names to Japanese bombers and reconnaissance planes.

Contents 1 Design and development 1.1 Production 2 Operational history 3 Versions 3.1 G4M1 3.2 G4M2 3.3 G4M3 3.4 G6M1 4 Operators 5 Specifications (Mitsubishi G4M2 Type 22) 6 See also 7 References 7.1 Notes 7.2 Bibliography 8 External links

[edit] Design and development

The G4M had a long range and high-speed at the time of its introduction. However, it was most known for its poorly-protected aviation gasoline tanks—that earned her the derisive nicknames "one-shot lighter", "flying Zippo" and "flying cigar" from Allied fighter pilots. Similarly, pilots of the Imperial Japanese Navy called the G4M the "Type One Lighter". This was due to the fact that on many occasions, it was used for low-altitude torpedo attacks where its performance advantages were negated. The "Betty"'s relatively-large size made it a large target to shoot at, and the simplified approach path on a torpedo run to attack a ship, meant for a generally easy interception.

When used for medium- to high-altitude bombing against stationary targets like a supply depots, seaports, or airfields, "ease of interception" was another matter entirely. Using its long range and high speed, the G4M could appear from any direction, and then be gone before many fighters could intercept them. The 20 mm cannon in the tail turret was much heavier armament than commonly installed in bombers, making dead astern attacks very dangerous. Sometimes, assuming they did not catch fire in the first place, G4Ms also proved to be able to remain airborne despite being badly shot up. For example, after 751 Kokutai's attack during the Battle of Rennell Island, three out of four survivors (of eleven aircraft that went to attack) returned flying on one engine only. Near the end of the war the "Betty" was used as a common kamikaze-carrying and launching platform, and was the usual aircraft for carrying the Ohka kamikaze rocket aircraft.

[edit] Production

• Total production of G4M1 Model 11: 1172 examples including prototypes.
• Total production of G4M2 Models 22, 22 Ko and 22 Otsu: 429 examples.
• Total production of G4M2a, Models 24, 24 Ko, 24 Otsu, 24 Hei, and 24 Tei: 713 examples.
• Total production of G4M3 Models 34 Ko, 34 Otsu, and 34 Hei: 91 examples.
• Total production of G6M1: 30 examples.
• Total production of all versions: 2,435 examples.

[edit] Operational history

The G4M was similar in performance and missions to other contemporary twin-engine bombers such as the German Junkers Ju 88 and Heinkel He 111, the North American B-25 Mitchell, and the American Martin B-26 Marauder. These were all commonly used in the anti-shipping role, and all but the B-25 were used as torpedo-bombers. The G4M Model 11 was prominent in attacks on Allied shipping in the 1941 to early 1944 time-frame, but beyond that time, it was increasingly the easy prey of the ever-improving enemy fighters.

The G4M's baptism by fire occurred September 13, 1940 in Mainland China, when 27 Bettys and Mitsubishi C5M1 of 1st Rengo Kokutai (a composite force including elements of Kanoya and Kizarazu Kokutais) departed from Taipei, Omura and Cheju to attack Hankow. The bombers and reconnaissance aircraft were escorted by 13 Mitsubishi A6Ms of 12st Kokutai led by Navy Lt. Saburo Shindo. A similar operation occurred in May 1941. In December 1941, 120 Taiwan-based G4Ms of 1st Kokutai and Kanoya Kokutai belonging to the 21st Koku Sentai crossed the Luzon Strait en route to bombing the Philippines, the beginning to widespread Southeast Asia operations.

As torpedo bombers, the G4M's most notable use was in the sinking of Prince of Wales and the Repulse off the coast of Malaya. They carried out the attacks alongside the older Japanese bombers, the Mitsubishi G3M "Nells" who were doing high-level bombing runs. The Prince of Wales and the Repulse were the first two capital ships ever to be sunk exclusively by air attack during a war, while at sea. The same squadron which sunk the British capital ships later engaged in a similar attack on the USS Lexington (CV-2), but the carrier's combat air patrol and anti-aircraft guns downed 17 of the Japanese planes.

Probably the best-known incident involving a G4M during the war was the attack resulting in the death of Isoroku Yamamoto of T1-323 carrying IJN Admiral Isoroku Yamamoto by American P-38 Lightnings on April 18, 1943.

The G4M Model 11 was replaced by Models 22,22a/b,24a/b,25,26 and 27 after June 1943, following service in New Guinea, the Solomons, and the South Pacific area, in defense of Marianas and finally in Okinawa, with field modifications resulting in the Model 24j which carried suicide flying bombs Yokosuka MXY7 Ohka Model 11 beginning on March 21, 1945, with disastrous results due to heavy Allied fighter opposition. Following the loss of Okinawa, G4Ms constituted the main weapon of the land-based Japanese naval bomber force, consisting of 20 Kokutais when at war's end, including the testing air group equipped in 1944-45 with the latest version G4M3 Model 34 and 36, arriving too late to change the course of the war.

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After more advanced G4M2s models arrived in november 1943, the first planes was consigned to "Combined Fleet" along in December 1943 the "761rd Kokutai" (Ryu Butai = Dragon Force) receiving ones 5 examples (of originally 7) for first operative tests,the older Model 11 aircraft served in long-range sea reconnaissance missions, and as transports and trainer aircraft.

Between Betty squadrons the most distacated was the "Kanoya Kokutai",were acted with tail code "K" from 1937-42 (with G4M1s) over China, Philippines, French Indochina, Malaya, Singapore, South China Sea and Dutch Indies, such unit changed tail code to "753rd" since 1942-45 (with G4M1/2s) during actions in New Guinea,Australia,Salomon, Gilberts, Marshall, Marianas, returned to Philippines and Formosa, Okinawa, among from your main airfield in Kyushu was used for departed Kamikaze units.

Your most distacated pilots in unit as Lt. Miyoshi Nabeta led the "1st Chutai",(9 units), Lt.Higashi Moritaka and Lt.Higashi Takashimori led the "2nd Chutai"(8 units), and "3rd" was command for Lt. Haruki Iki,(9 units),Lt Cdr Shichiso Miyauchi as "Hikotaicho" were led all unit in the obervation post aboard of "1st Chutai" s leader plane.Lt.Iki used the "K-301" plane ,but in Prince of Wales/Repulse strike he used plane "K-310",others planes as the units identified with tail codes "316","324","330" to "384".anothers important "Betty" crewmembers are Captain Kameo Sonokawa,fligth leader in "Genzan"/"775th" and "Takao Kokutai", LtCdr.Higai guided the "701st Kokutai", PO.Naganori Furuyama, gunmen of "702rd Kokutai", Aioi Takaida as "Hikotaicho" of "3rd Kokutai", LtCdr.Takazo Ito led the "4th Kokutai" were PO1 Misao Sugii managed the F-378 plane inside of Lt.Kuniharu Kobayashi s "2nd Chutai", Lt.Sadao Takai, as "Hikotaicho" of "761rd Kokutai" (aboard in 316 plane along with RAdm.Masafumi Arima) and Mjr.Goro Nonaka led the "Jinrai Butai" in wartimes.

Others users of Betty througth the war as "Takao", "Toko", "Kizarazu", "Misawa", "Chitose","Yokosuka" (short period), "Genzan", "Mihoro", "1st", "3rd", "4th", "701st", "702nd", "705th", "751st", "761rd", "775th", "801st Kokutais", among "1st Rengo Kokutai" (testing unit), "Midway expeditionary force" (unit based in Wake during Battle of Midway period), "721st Kokutai" (Junrai Butai) (Kamikaze unit) between others in period.

As part of the negotiations for the surrender of Japan, two demilitarized G4Ms, given the call-signs Bataan 1 and Bataan 2 were sent to Ie Shima carrying the first surrender delegations as the first leg of their flight to Manila.

In 1945, Indonesian guerrillas captured numerous ex-Japanese air bases including Bugis Air Base in Malang (repatriated 18 September 1945). Several G4Ms were seized and flown by the Indonesians. Most of the aircraft were destroyed during 1945–1949 when the former Dutch East Indies and the Netherlands were engaged in a military conflict in Indonesia.

[edit] Versions

[edit] G4M1

G4M1 Prototypes

Japanese Navy land Based Bomber Type 1. Two prototypes built.

G4M1 Model 11

Japanese Navy Land Attack Bomber Type 1. The first bomber model of series, with 1,530 hp (1,140 kW) Mitsubishi MK4A Kasei Model 11 engines driving three-bladed propellers. Following modifications were made during the production:

• March 1942: The first aircraft (241st production example) fitted with MK4E Kasei Model 15 engines with larger superchargers for better high altitude performance, became standard in August 1942 from 406th aircraft onwards. These MK4E-engined aircraft have been often, erroneously, referred as the G4M1 Model 12.
• Summer 1942: Propeller spinners introduced.
• March 1943: From 663rd machine onwards, 30 mm rubber ply sheets installed beneath the wing outer surfaces to protect the undersides of the fuel tanks (speed reduced by 9 km/h and range by 315 km), 5 mm armour plates added into tail gunner's compartment.
• Spring 1943: Outer half of the tail cone cut away in order to improve tail gunner's field of fire.
• August 1943: A completely redesigned tail cone, with reduced framing and wide V-shaped cut out; this form of tail cone was also used in all G4M2 models.
• September 1943: Individual exhaust stacks from 954th airframe onwards.

Production of the G4M1 ended in January 1944.

[edit] G4M2

The first of the four G4M2 prototypes flew in December 1942. It differed from the preceding model in having MK4P Kasei Model 21 engines with four-bladed propellers, laminar flow wings and a power-operated dorsal turret featuring a 20 mm cannon in place of G4M1's dorsal position with a 7.7 mm machine gun. External differences also included increased nose glazing, flush side gun positions instead of blisters, and rounded tips of wings and tail surfaces.

G4M2 Model 22

The base model, the first production example completed in July 1943. Introduced bulged bomb bay doors from 65th aircraft onwards, and an optically flat panel in the nose cone from the 105th aircraft onwards.

G4M2 Model 22 Ko

Very similar to previous model. Carried Type 3 Ku Mark 6 search radar and was armed with two Type 99 20 mm Mark 1 cannons replacing the 7.7 mm machine guns in the lateral positions.

G4M2 Model 22 Otsu

Dorsal turret cannon changed to longer-barreled Type 99 20 mm Mark 2.

G4M2a Model 24

Modified Model 22, MK4T Kasei 25 1,800 hp (1,340 kW) engine, with bulged bomb bay doors as standard for larger bomb capacity. Externally distinguishable from the Model 22 by a carburettor air intake on the top of the engine cowling.

G4M2a Model 24 Ko/Otsu

Armament similar to Model 22 Ko/Otsu respectively.

G4M2a Model 24 Hei

Modified 24 Otsu, with one 13 mm Type 2 machine gun mounted in tip of the nose cone, radar antenna relocated from that position to above the nose cone.

G4M2b Model 25

One G4M2a modified to MK4T-B Kasei 25 Otsu 1,825 hp (1,360 kW) engines. Only experimental.

G4M2c Model 26

Two G4M2a modified to MK4T-B Ru Kasei 25b 1,825 hp (1,360 kW) engines with Turbo compressors.

G4M2d Model 27

One G4M2 modified to MK4V Kasei 27 1,795 hp (1,340 kW) engines.

G4M2e Model 24 Tei

Special version for the transport of the suicide bomb plane Kugisho/Yokosuka MXY-7 "Ohka" (Baka) Model 11, conversions of G4M2a Models 24 Otsu and 24 Hei. Had armour protection for the pilots and fuselage fuel tanks.

MXY11 Yokosuka Navy Type 1 Attack Bomber

Ground Decoy Non-flying replica of Mitsubishi G4M2 developed by Yokosuka

[edit] G4M3

G4M3 Model 34

Redesigned G4M2 with added self-sealing fuel tanks, improved armor protection and an entirely new tail gunner's compartment which was quite similar to that of late model American B-26 Marauders. Wings were also redesigned and horizontal tail plane was given dihedral. Armed with two Type 92 7.7 mm machine guns in nose cabin and in both side positions, and one type 99 model 1 20 mm cannon in dorsal turret and tail. Entered production in October 1944 in G4M3a Model 34 Ko form with 20 mm cannon in side positions instead of machine guns.

G4M3a Model 34 Otsu and Hei

Similar modifications as in corresponding Model 24 variants.

G4M3 Model 36

Prototype. Two G4M2 Model 34 modified to Mitsubishi MK4-T Kasei 25b Ru 1,825 hp (1,360 kW) engines.

[edit] G6M1

G6M1 Japanese Navy Long Range Heavy Fighter Type 1

Initial model of the series, armed with Type 99 20 mm cannons between each side of fuselage and in tail, one 7.7 mm machine gun in nose cabin and one 30 mm cannon in front ventral position. Thirty built.

G6M1-K Trainer, Japanese Navy Type 1

Converted G6M1s.

G6M1-L2 Transport Type 1, Japanese Navy

Modified as transports.

[edit] Operators

 Indonesia

• In 1945, Indonesian People's Security Force (IPSF) (Indonesian pro-independence guerrillas) captured a small number of aircraft at numerous Japanese air bases, including Bugis Air Base in Malang (repatriated 18 September 1945). Most aircraft were destroyed in military conflicts between the Netherlands and the newly proclaimed-Republic of Indonesia during the Indonesian National Revolution of 1945–1949.

 Japan

• Imperial Japanese Navy Air Service operated the type during 1941–1945 in total of 37 kokutais.

 United Kingdom

• Royal Air Force operated at least one captured aircraft for evaluation purposes.

 United States

• United States Air Force, like the RAF, operated captured aircraft for evaluation.<re>Captured USAAF Mitsubishi G4M Betty</ref>

[edit] Specifications (Mitsubishi G4M2 Type 22)

General characteristics

• Crew: 7: pilot, co-pilot, navigator/bombardier, radio operator/gunner, three gunners
• Length: 19.6 m (64 ft 4 in)
• Wingspan: 24.9 m (81 ft 8 in)
• Height: 6 m (19 ft 8 in)
• Empty weight: 8,160 kg (17,990 lb)
• Max takeoff weight: 12,500 kg (27,557 lb)
• Powerplant: 2× Mitsubishi Kasei 25 radial engines, 1,380 kW (1,850 hp) each

Performance

• Maximum speed: 437 km/h (270 mph)
• Range: 4,725 km (one way) (2,935 mi)
• Service ceiling 8,950 m (29,350 ft)

Armament

• Guns: 2 × 20mm Type 99 cannon, 4 × 7.7 mm Type 92 machine guns
• Bombs: Up to 1,000 kg (2,200 lb) of bombs or single Type 91 torpedo. The heaviest single bomb it can hold is 800 kg.

[edit] See also

Related development

• Mitsubishi G3M
  

Comparable aircraft

• Bristol Beaufort
• B-26 Marauder
• B-25 Mitchell
• Heinkel He 111
• Vickers Wellington
  

[edit] References

[edit] Notes

[edit] Bibliography

[edit] External links

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