Aviation of World War II

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G4M "Betty"

G4M Betty
  • Long Range Bomber
  • Mitsubishi

Twin-engine cantilever all-metal monoplane, long-range high-speed torpedo bomber with a crew of 7-8 people. Mitsubishi G4M took an active part in the fighting in the Pacific from the first to the last day of the war. They combined long flight range, high speed and perfect aerodynamic forms, and thanks to this they became a real symbol of Japanese naval aviation - on a par with the famous A6M Reisen, or Zero.

Construction Fuselage - oval cross-section (midships - 2.5 m × 2 m), riveted monocoque construction. The wing is trapezoidal in plan, with rounded tips without kinks along the leading and trailing edges. The middle position of the wing made it possible to exclude interference with the fuselage without the use of developed fairings. In addition, the mid-wing, with large reserves and fuel production, did not change the aircraft alignment. The design is all-metal, two-spar, with a working skin and riveting in the back. Wing profile - Mitsubishi MAC 118.

Power plant - two radial two-row 14-cylinder air-cooled engines "Kasei" 11. Takeoff power 1530 hp / 2450 rpm at the second speed of the supercharger, maximum power 1410 hp / 2350 rpm at 2000 m and 1340 hp / 2350 rpm at 4000 m. The engine is equipped with a two-speed single stage supercharger. Weight 632 kg. The gear ratio of the gearbox is 0.684. Propeller "Sumitomo Hamilton" with constant speed mechanism CS-3B, three-bladed, metal. Diameter 3.4 m, range of step change 20-40 °, weight 175 kg.

The fuel system consists of eight unprotected tanks with a total capacity of 4780 liters, located between the wing spars, as well as fuel lines and electric petrol pumps. Two tanks with a capacity of 690 liters are located in the center section (inside the fuselage); in the inner wing consoles (between the fuselage and the engine nacelle) 630-liter; two more tanks with a capacity of 640 and 430 liters are located between the engine nacelle and the joint with the outer console.

DC generators provide operation of landing gear drives, flaps and other systems and equipment. The aircraft is equipped with a Sperry autopilot and a radio compass. The navigator uses the Type 90 optical bomb sight when bombing.

Small arms defensive armament consisted of four (and two spare) 7.69 mm machine guns and a 20 mm cannon. Machine guns were placed in the navigator's cockpit, upper blister and two side blisters. Machine guns Marine Type 92 were a copy of the English Vickers machine gun of the same caliber and were equipped with disk magazines with a capacity of 97 rounds (magazines for 47 rounds could also be used). Blister of the upper shooting point, Ammunition - seven disk magazines, 97 rounds each. The side blisters are similar in design to the top, Ammunition - six magazines (for each). Another spare machine gun could be mounted on the ceiling between the blisters. Cannon "Megumi" Special Marine Type 99 model 1, placed in the tail of the aircraft. Ammunition - eight drums with 45 shells each.

At the initial stage of the war, the G4M achieved great success, contributing to a large extent to the capture of vast territories by the Japanese. They bombed targets in the Philippines and China, Port Darwin in Australia and Port Moresby in New Guinea, participated in the sinking of the British battleships Prince of Wales and Ripals. This should be said separately. On December 10, 1941, two of the largest and most powerful British warships - the new battleship Prince of Wales and the battle cruiser Repulse - were sunk by a Japanese torpedo off the coast of Malaya.

Gradually G4M began to lose ground. So, in January 1942, 17 bombers, taking off from Rabaul, tried to attack the American aircraft carrier Lexington without fighter cover. The Wildcat carrier-based fighters that met them shot down 15 Japanese aircraft with minimal losses of their own. Later the situation worsened even more. The lack of armor and sealed fuel tanks made the G4M a relatively easy target. They even received the unofficial nickname "Disposable Lighter" or "Flying Cigar". The Japanese command did not take timely measures to strengthen the protection of their best bombers. The G4M3 modification appeared too late, when it was already impossible to rectify the situation.

It is highly symbolic that the last bitter page in the military history of Japan is associated with G4M. August 19, 1945 on two G4M1s with green crosses on the fuselage, a Japanese delegation headed by Lieutenant General Torashiro Kawabe flew to the island of Yesima to work out the terms of surrender.

The G4M bomber was built during the war only at Mitsubishi, which supplied 2,446 aircraft of this type: 2 experimental, 30 G6M1 fighters, 1200 - G4M1, 1154 - G4M2, including 640 aircraft from the Nagoya plant and 514 from the Okayama plant, 60 - G4M3.

G4M2 model22 + MXY7

G4M2 and MXY7

G4M1 'Betty' Specification
G4M2mod22 G4M2mod24 G4M3mod34
Crew 6-7 6-7 6-7
Fuselage length, m 19,630 19,630 19,500
Wing span, m 24,890 24,890 25,000
Wing area, m2 78,000 78,000 78,000
Height, m 4,898 4,898 4,898
Empty weight, kg 7300 7420 8300
Маximum takeoff weight, kg 15395 15170 1300
Capacity of petrol tanks, l 6200 6200 4400
Power Plant
Two Mitsubishi Kasei Radial Kasei-21 Kasei-25 Kasei-25
Power, hp/at alt. m at take-off 2x1800 2x1825 2x1825
1 border 1575/1800 1680/2100 1680/2100
2 border 1410/4800 1540/5500 1540/5500
Speed, km/h at altitude m maximum 437/4600 438/4600 481/5065
cruise 322/4000 322/4000 376/4700
landing 130 130 130
Rate of climb, m/min 14/5000 13/57000 20/7000
Ceiling, m 8950 8950 9700
Maximum range, km 5400 5400 4330
Torpedo, (pc.) 1 1 1
Bombs, kg 1000 1000 1000
Cannon, machine guns 2×20, 3×7,71 4×20, 1×7,71 4×20, 1×13,1
Photo Description
Drawing G4M2 Model 22

Drawing G4M2 Model 22

Mitsubishi G4M1 Betty

Mitsubishi G4M1 Betty


  • G4M Prototype with two Mitsubishi Kasei 11 (1,530-hp) radial engines. First flown on October 23, 1939. After satisfactory trials it was ordered into production as the G4M1 Model 11.
  • G4M1 Model 11 The first production aircraft entered operational service during the Summer of 1941.
  • G4M2 Model 22 is equipped with two Mitsubishi MK4P Kasei 21 (1,800-hp) radial engines, leading to two subvariants, the 22A and 22B models which varied only in armament configurations.
  • G4M2a Model 24 is equipped with two Mitsubishi MK4T Kasei 25 (1,825-hp) radial engines and bulged bomb bay doors, leading to two subvariants, the 24A and 24B models which varied only in armament configurations.
  • G4M2e Model 24J is a significant modification of navy G4M2a Model 24B & 24C aircraft which allowed the aircraft to carry the MXY7 piloted missle.
  • G4M3 Model 34 was intended to fix several design flaws by introducing self-sealing fuel tanks and armor protection. However, this model appeared too late in the war to have any significant impact.
  • G6M1 fulfilled an urgent requirement for an long range escort fighter during the Sino-Japanese war. 30 airframes were produced in this major variant but proved to be unsuccessful in this role. Most of the airframes were later converted to G6M1-K trainers or G6M10L2 transports.


  • "Encyclopedia of military engineering " /Aerospace Publising/
  • "Japan Warplanes of World War II" /Oleg Doroshkevich/