Mitsubishi G4M2 Type 1 Attack-Bomber Model 24c (Betty)

From The Air Combat Wiki

Contents 1 Fighter Ace Screenshots 2 Fighter Ace Ratings 3 Fighter Ace Performance 4 Historical Statistics 5 Strengths 6 Weaknesses 7 History 8 Sources 9 See Also

Fighter Ace Screenshots

Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ
Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ	Fighter Ace museum screenshot by Doug@HQ

Fighter Ace Ratings

Durability: 5

Speed: 4

Maneuverability: 7

Firepower: 1

Climb Rate: 2

Ground Attack: 5

Fighter Ace Performance

Top Speeds						Climb Rates
	Sea Level	4921' 1500m	9843' 3000m	19685' 6000m	Best Speed	Best IAS	to 1000m	to 3000m	to 6000m
mph	242	257	260	265	270@ 15092'	146 mph	2:46	8:00	20:36
mph WEP	245	260	264	268	273@ 15092'
kph	389	413	419	427	434@ 4800m	235 kph
kph WEP	394	419	425	432	439@ 4600m

Historical Statistics

Service Date: September 1943

Primary Guns: 1x Type 92 7.7 mm flex machine gun with 1000 rpg

Defensive Guns: 1x 13.3 mm Ho-103 Type 3 flex machine gun with 400 rpg in nose, 1x Type 99 model 2 20 mm cannon with 250 rpg in dorsal turret, 1x Type 99-2 20 mm flex cannon with 200 rpg in port waist, 1x Type 99-2 20 mm flex cannon with 200 rpg in starboard waist, 1x Type 99-2 20 mm flex cannon with 250 rpg in tail

Ordnance: 1x 1,842 lb (835 kg) torpedo or 3x 1,764 lb (800 kg) or 4x 1103 lb (500 kg) or 8x 551 lb (250 kg) or 18x 220 lb (100 kg) or 24x 110 lb (50 kg) bombs

Engine(s): 2x Mitsubishi MK4P Kasei 25 radials rated for 1,850 hp each at sea level (2,000 hp with WEP)

Int Fuel Capacity: 10,282 lbs (4,664 kg)

Ext Fuel Capacity: none

Maximum Speeds: 272 mph (437 kph) at 15,090 ft (4,600 m)

Ceiling: 29,360 ft (8,950 m)

Loaded Weight: 27,557 lbs (12,500 kg)

Wing Area: 840.9 sq ft (78.2 sq m)

Wing Loading: 32.8 lbs/sq ft (159.8 kg/sq m)

Strengths

Defensive Firepower: Its four 20 mm cannon and single 13 mm machine gun makes the Betty the best defended medium bomber in the game.

Weaknesses

Speed: Its top speed of only 272 mph at altitude means that the Betty wonít be making fast hit and run attacks.

History

By 1937 Japan was already deeply entrenched in the "China Incident" and there was a real possibility of eventual conflict with the United States. However, if they were seen to be openly preparing for a war against the West, the US would cut off all shipments of the vital raw materials and specialized equipment they needed to affect the build-up. To solve this dilemma, the decision was made to continue with the build-up, but under a cloak of extreme secrecy. To this end, an expansion program was launched at Mitsubishi with a series of Army and Navy planes being developed entirely in secret.

Along with the specification for the A6M Zero, the Navy issued a demand for a long-range strategic bomber capable of carrying a standard Bomb Load of 800 kg. to a distance of over 2,300 miles. Utilizing one of their most talented design crews headed by Kiro Honjo, Mitsubishi originally proposed a four-engine design, but the Navy frowned on the idea and suggested they accomplish the task with a twin-engine plane.

Design of the fuselage section was given to the 1st Naval Arsenal, which turned out a fuselage large enough for a four-engine plane, which visiting Heinkel engineers commented upon in 1939. Meanwhile, Mitsubishi designed a two-spar wing utilizing the same patented "Mitsubishi 118" airfoil section that they used on the Rei-sen. To get the necessary power the team chose the new 1,530 hp Mitsubishi Kasei 14-cylinder radial engine.

The first prototype G4M was completed in September 1939 with flight tests the following month revealing only a few minor problems that needed to be corrected before the plane entered quantity production. However, events in China were to delay production of the bomber for a year.

The G3M2 bombers then in service in China were having a tough time defending themselves against the ever larger and improving Chinese Air Force. A few outspoken officers thought that the best solution was to design a "fighter-gunship" that could fly in the same formation and thus escort the bombers to and from their targets. Over their strenuous objections, the G4M1 was converted into a "long range convoy fighter" and given the designation G6M1. However, as the USAAF would learn three years later over the skies of Europe, the "convoy fighter" was heavy, difficult to fly, and was left behind when the bombers dropped their bombs and headed for home. After building thirty examples of the G6M the folly of the idea was realized and the planes were relegated to training and paratroop transport duties.

Production of the G4M1 Navy Type 1 Attack Bomber Model 11 was finally authorized in April 1941 and the first production plane was completed before the month was over. Six weeks later the 1st Kokutai completed conversion and launched the G4M's combat career with an attack on Chunking, which also marked the combat debut of the A6M2. Operating against deep range targets throughout the summer, both planes enjoyed considerable success.

Prior to commencing hostilities against the West, twenty-seven G4M1s were transferred to Indo-China with another ninety-three being sent to Formosa. After only a week of combat the "Betty", as it was known to the Allies, had sunk the HMS Prince of Wales and HMS Repulse and had completely eliminated Allied air-power in the Philippines. But at Port Moresby the G4M1 came up against better prepared air defenses and losses mounted sharply due almost entirely to the lack of crew and fuel protection.

To address these deficiencies design on the Model 22 was undertaken. The wing was completely redesigned to use a new, laminar-flow airfoil section and the engines were replaced with the improved 1,800 hp Kasei 21, which featured water-methanol injection. A new 350-gallon fuel tank was installed in the fuselage, which was protected from leakage by layers of runner sheeting. Rubber sheeting was installed on the underside of the wing tanks and a carbon-dioxide fire extinguishing system was installed. Defensive armament was greatly improved by the addition of a hydraulically-operated dorsal turret mounting a 20 mm Type 99-1 cannon.

By late 1943 the G4M2 had completely replaced the G4M1 in front-line service, the older plane being relegated to reconnaissance, transport and training duties. Meanwhile, various improvements to the defensive armament were made in the Model 22A and 22B, the latter possessing four 20 mm Type 99-2 cannon distributed in the dorsal turret, tail cone and both beam positions.

In May 1944 the Model 24 was introduced using the 1,850 hp Kasei 25 engine, which not only had more power but also much better fuel consumption than the Kasei 21. The Models 24A and 24B had armament identical to the Models 22A and 22B, while the Model 24C replaced the 7.7 mm machine gun in the nose with a 13 mm Ho-103 machine gun.

Numerically the Models 24B and 24C were the most important of the G4M2 and by the end of the war 2,479 G4Ms had been built. The Betty's last mission ended at 12:44 pm on August 19, 1945. Painted white all over and wearing large green ìsurrender crossesî on their wings, fuselages and tails, a pair of G4M1s delivered Lt. Gen. Torashiro Kawabe and the rest of the surrender delegation to Ie Shima.

Sources

Francillon, Rene J.; Japanese Aircraft of the Pacific War; Naval Institute Press, Annapolis, MD; 1979.

Green, William; Famous Bombers of the Second World War, Second Series; Hanover House, Garden City, NY; 1960.

See Also

Mitsubishi Jukogyo K.K.

Aircraft Manufacturers During World War II

Japanese Aircraft Designation System

Fighter Ace Planes Inventory