Mitsubishi G4M, foreign users

 

The Mitsubishi G4M was a Japanese twin-engined medium bomber designed to success to former G3M. Its main user was the Imperial Japanese Navy (IJN), but as the war went on, it saw service with some other countries as well:

• Communist China: Apparently, among the many aircraft left over by the Japanese, the Communists managed to capture some machines, probably in the Southern part of the country, as that's where the IJN had some aerial bases at the end of the conflict. As we couldn't find neither graphical nor text information about the G4M serving with the Chinese, the drawing should be considered as speculative.
• United Kingdom: The British Allied Technical Air Intelligence Unit South East Asia (ATAIU SEA) operated one captured G4M2 Model 22, registered as FI-11 for evaluation purposes at Tebrau airfield, in Malaysia. It belonged originally to the 13th Koku Kantai Yuso Tai. Its ultimate fate is unknown, but it was most probably scrapped.
• Indonesia: Among the aircraft used by the Indonesian Air Force, was, apparently, at least one G4M captured by Indonesian guerrillas, left over by the Japanese in some remote area of the country. It was probably used by the Indonesians during their Independence War, but its ultimate fate is unknown. As we couldn't find information on the subject, the drawing and the information written here should be considered as speculative.
• United States: The Technical Air Intelligence Unit, operated some captured G4M for evaluation purposes at Eagle Farm airfield, in Brisbane, Australia in 1945. The evaluated bomber was painted with exaggerated American markings and rudder stripes even if they were eliminated three years earlier. 

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_G4M

2. https://captured-wings.wikia.org/wiki/FI-11

3. https://captured-wings.wikia.org/wiki/ATAIU-SEA

4. https://en.wikipedia.org/wiki/Indonesian_Air_Force#Before_Indonesian_independence_(1941–1945)

5. https://ww2db.com/photo.php?list=search&sp&startRow=40&keyword&source=colorall&color&foreigntype=A&foreigntype_id=12&dt&image_id

6. https://j-aircraft.com/captured/capturedfrom/TAIC/TAICSG4M/mitsubishi_g4m2_betty.htm

Mitsubishi G6M

 

Japanese operational experience on the Second Sino-Japanese War made evident the need for a fighter escort for their G3M bombers.

As there were no fighter with the range of the G4M, Yokosuka Naval Air Technical Arsenal proposed the adoption of the G4M for this task. The resulting proposal was called a 'Wingtip Convoy Fighter' (a transliteration of the Japanese term, which in fact was just an escort bomber). Bomb bays were replaced by a ventral gondola equipped with forward and rearward firing 20 mm Type 99 cannons. Beam guns were replaced as well by a Type 99 one and both nose and tail positions retained their 7.7 mm Type 92 and Type 99 guns respectively. Dorsal gun was removed and the aircraft were loaded with additional ammo for every gun, however, in order to compensate for the increased take off weight, the fuel capacity was reduced to 3.640 liters (961.58 gallons). It was powered by two Mistubishi MK4A Kasei 11 radial engines which delivered 1.509 hp at take off and drove three-bladed propellers.

Flight tests couldn't keep up with the expectatives and it showed to be too heavy to keep up the pace with the G3M and G4M bombers, specially after having released the bombs, which made the bombers lighter and faster than the still heavy loaded G6M. Only 30 machines were converted from existing G4M1 at Mitsubishi's factory in Nagoya from August to December 1940.

After the operational failure, the remaining machines were used for crew training purposes, for which purposes they were labelled as G6M1-K or as paratroop aircraft, G6M1-L2. On this variant they were used in the Battle of Menado, the first airborne assault conducted by Japan, in early January 1942. For the rest of the war they served as general-purpose transports.

Sources:

1. https://www.valka.cz/Micubisi-G6M1-Betty-t29092

2. http://www.airwar.ru/enc/fww2/g6m.html (translated)

Martin B-10

 

The B-10 waged a revolution in bomber design with its all-metal monoplane airframe, enclosed cockpits, rotating gun turrets, retractable landing gear, internal bomb bay and full engine cowlings. With all those features, the bomber marked the standard for the designs to come in the following decades, making the existing designs obsolete and Martin receiving the 1932 Collier Trophy for designing the XB-10.

It began initially as a private venture with the Martin Type 123, by Glenn L. Martin Company in Baltimore, Maryland. It was manned by a crew of four, pilot, co-pilot, nose gunner and fuselage gunner. At first, all four crew compartments were open, but it had a number of design innovations as well.

Innovations included a deep belly for an internal bomb bay and a retractable landing gear. The Type 123 was powered by two 600 hp Wright SR-1820-E Cyclone radial engines and flew for the first time on 16th February 1932. It was delivered to the US Army on 20th March as the XB-907 for testing. After evaluation by the US Army, it was sent back to Martin for redesign and improvement and it was rebuilt as the XB-10.

The XB-10 was later delivered to the US Army and it differed in many ways from the original aircraft. It had full NACA cowlings to decrease drag, while the XB-10 had Townend rings. It also was powered by two 675 hp Wright R-1820-19 engines and had a larger wingspan, together with an enclosed nose turret. When further trials were performed on the XB-10 in June 1932, it achieved a speed of 197 mph (317 km/h) at 6.000 ft (1.830 m) high, quite an impressive performance for the time. 

After the success of the XB-10, some changes were made to the design. The number of crew members was reduced to three and canopies for all of them were added. The US Army ordered an initial batch of 48 of these on 17th January 1933. The first 14 of them were labelled as YB-10 and were delivered to Wright Field, Ohio, from November 1933 onwards and used in the Army Air Corps Mail Operation.

Later, in 1935, the Army ordered an additional 103 aircraft, named as the Martin B-10B, which differed only in minor details from the YB-10. Deliveries began in July 1935 and they served with the 2nd Bomb Group at Langley Field, Virginia, the 9th Bomb Group at Mitchel Field, New York, the 19th Bomb Group at March Field, California, the 6th Composite Group in the Panama Canal Zone and the 4th Composite Group in the Philippines. Some modified YB-10s and B-12 (the remaining aircraft of the original order, which were powered by two Pratt & Whitney R-1690-11 Hornet radial engines) were operated with twin floats for coastal patrol duties.

In February 1936 thirteen B-10Bs belonging to the 49th Bomb Squadron dropped supplies to the residents of Tangier Island, in Virginia and Smith Island, in Maryland as ships couldn't reach due to heavy ice in the Chesapeake Bay and the inhabitants faced starvation after a sever winter storm. 

Although at the time of its creation it was a very advanced design (General Henry H. Arnold referred the bomber as the airpower wonder of its day), rapid advances in bomber design during later 1930s meant that the bomber was completely obsolete by the time the World War 2 began. A modernisation effort was made with the Martin 146, but it was superseeded by the Boeing B-17 and the Douglas B-18. 

Ironically, although by the time the USA entered the war the B-10 was retired from active service long ago, an export model used by the Dutch East Indies escaped to Australia on 7th March 1942 and was taken on strength by the USAAF to serve as an utility aircraft. That was the only Type 139WH-3/Type 166 to serve with the United States Army Air Forces.

Sources:

1. https://en.wikipedia.org/wiki/Martin_B-10

2. http://www.joebaugher.com/usaf_bombers/b10.html

Martin 139 in Dutch hands

 

The Martin Type 139 was an all-metal bomber monoplane, whose exportations were cleared in 1936. It was exported to many countries, most of them covered in previous posts, except for one, the Dutch East Indies.

The largest customer for the Martin Type 139 was the Dutch colony. They ordered twelve Type 139WH-1 (where the letter 'H' stands for Holland - the export version destined to serve in the Dutch East Indies) powered by two Wright R-1820-F53 Cyclone engines which delivered 750 hp of power each which were delivered between September 1936 and February 1937. This order was followed by additional 26 Type 139WH-2, a refined version, this time powered by R-1820-G3 engines which delivered up to 850 hp of power. This second batch was delivered between November 1937 and March 1938. The final export version, the Type 139WH-3, AKA Type 166 was powered by the R-1820 G-102 radial engines, capable of delivering up to 900 hp of power. This version featured also a redesigned fuselage with a long unbroken canopy "greenhouse" that ran all the way from the pilot's cockpit until the rear gunner's position. A total of 78 of the Type 166 were manufactured at Martin's factory in Baltimore between August 1936 and March 1938 before the production line was shut down. All of them had been delivered in the Dutch East Indies by 5th May 1939.

When Japan invaded the Dutch East Indies in December 1941, a total of six squadrons of Type 139 were present in the Dutch East Indies. They were flown in tactical bombing missions in a futile attempt to stop the Japanese advance during early 1942. By this time, the 139 was considerably obsolete with a speed, armour and weaponry completely inadequate to defend against the superior Japanese Mitsubishi A6M Zero, which the Type 139 couldn't stand against. Most of the Dutch 139 or 166 were either destroyed in aerial combat or on the ground. 

Sources:

1. http://www.joebaugher.com/usaf_bombers/b10.html

2. https://en.wikipedia.org/wiki/Martin_B-10

3. https://www.valka.cz/Martin-139W-t159440

4. https://www.valka.cz/Martin-166-t159445

Martin Type 139 - Various Foreign Users

 

The Martin Type 139 was an all-metal monoplane bomber that was used by the United States Army Air Corps and by many other countries:

• China: The National Revolutionary Army, (Kuomingtan's Armed Forces) ordered six 139s which Martin called them 'Type 139WC' (the letter 'C' standing for 'China'). This version was powered by two Wright R-1820 Cyclone engines which could deliver up to 850 hp of power each. 
  They arrived in China in February 1937 and were used in August against the Japanese in the Battle of Shanghai, where the Chinese Nationalist Air Force (CNAF) launched a major strike with a formation of various types of aircraft. One of such attacks took place on 14th October 1937 when three 139WC, two Heinkel He.111A, five Douglas O-2MCs, five Northrop Gammas and three Curtiss Hawk IIIs, based in Nanjing, bombed Japanese positions.
  Later, on 19th May 1938, the Type 139WC has the honour of being the first aircraft to conduct a raid into Japanese mainland. On that day, two 139WC belonging to the 2nd Bomber Group, 14th Squadron, commanded by Cpt. Hsu Huan-Sheng and Lt. Teng Yen-bo successfully flew a nighttime raid over Japan. However, instead of dropping bombs, they dropped propaganda leaflets over the cities of Nagasaki, Fukuoka, Kurume, Saga and some others, while making reconnaissance duties over ports, airports, warships and factories. 
  Most of the 139WC were destroyed during the course of the war.
• Japan: After the fall of the Dutch East Indies, three Type 139WH (the export version made for the Dutch colony) and Type 166 were captured intact by the Nippons and shipped to Haneda, Tokyo to be evaluated by the Testing Division of the Army Aircraft Authority. Their ultimate fate is unknown, but they were most likely destroyed during an air raid.
• Philippines: Apparently, some few B-10B (regular production variant) were leased to the Philippine Army Air Corps (PAAC) by the 4th Composite Group. They were most likely, destroyed during the Japanese invasion of the Philippines. As we couldn't find graphical evidence of a B-10B serving with the PAAC, the drawing should be considered as speculative.
• Thailand: Six Type 139WS (the 'S' standing for 'Siam') were sold to Thailand in April 1937. They saw action against the French in the Franco-Thai War in late 1940 and January 1941 and later they were used to support Japanese troops in their advance towards Burma in early 1942. They were complemented by an amount of ex-Dutch airplanes given by the Japanese later that same year. They were kept in active service until 1949.
• Turkey: When fascist Italy sought to expand their empire in the Mediterranean, the Turkish Government, decided to equip their air force with a long-range bomber. Therefore Cpt. Enver Akoglu was sent in a mission to the United States to purchase 20 Type 139WT ('T' standing for 'Turkey'). This variant was powered with uprated engines which could, theoretically, deliver up to 1.000 hp of power instead of the regular 750 hp. They arrived to Turkey in September 1937 and were assigned to 55 and 56th Tayyare Bölügü (Flying detachment, a squadron-sized unit) based at the city of Çorlu, in the Marmara region. Those were part of the higher 9th Tayyare Taburu unit. During 1941 and 1942 they were employed extensively in reconnaissance patrols over the Black Sea. When the type was showing its obsolescence, they were reassigned to other secondary and transport units. They were in active until 1946 with four of them crashing in 1945.

Sources:

1. en.wikipedia.org/wiki/Martin_B-10

2. http://www.joebaugher.com/usaf_bombers/b10.html

3. http://www.tayyareci.com/digerucaklar/turkiye/1923ve50/martin139wt.asp

Martin 139, South American and European Users

 

The Martin 139 (known in service with the United States Army Air Corps - USAAC) as B-10, was an American all-metal bomber, one of the first mass-produced in the 1930s that saw service with various countries. On this post we're covering the next ones:

• Argentina: Both Argentine Comando de Aviación del Ejército (Army Aviation Command) and Armada Argentina (Argentine Navy) used the Type 139. 
  In the mid-1930 the Army Aviation Command sought to modernise their bomber fleet and, in February 1937, after having studied other choices, they signed a contract with Martin for a total of 22 machines, which were designated by the company as Martin Type 139WAA (with the demonstrator being denominated just as Type 139WA). The bombers were assigned to the Regimiento de Aviación Nº1 (No.1 Aviation Regiment) at El Palomar Air Base, close to the capital, Buenos Aires and Regimiento 1 de Bombardeo (Bombing Regiment 1) of Villa Reynolds in the province of San Luis. They served until 1954, however, by that year the last three ones were being used as target tows. They were replaced by the native IAe-24 Calquin.
  The Argentine Navy acquired also a total of 12 new aircraft, plus a demonstrator, designated by the company as Type 139WAN. The contract was signed on 24th December 1936 and they were delivered in November 1937. They were assigned to two newly-formed bomber squadrons, one based at Punta Indio Naval Air Base, close to Buenos Aires and other one based at Comandante Espora Naval Air Base, close to Buenos Aires too. 
  This type was chosen by the Navy as the fuselage featured watertight compartments that could help with floatability in case of an emergency landing on sea and the type could also be fitted with EDO-made floaters. They also were the first airplane to feature a retractable landing gear to operate with the Argentine Navy. They all served until 1949.
• USSR: One aircraft, denominated by Martin as Martin Type 139WR, powered by two Wright R-1820-F53 Cyclone engines and Hamilton screws was bought by the Soviet Union for evaluation purposes. It seems that the performance of this machine wasn't satisfactory as no further machines were ordered by the Soviets and nothing is known about the fate of the aircraft. As there doesn't seem to be any graphical evidence of the type serving in Soviet colours, the drawing should be considered as speculative.
• Republic of Spain: The Spanish Republican Government had closed a deal for several Martin 139WSP (denomination given by the company), just before the outbreak of the Spanish Civil War. This deal also included the licensed production of the type by CASA, however, it was eventually blocked by the US State Department and the type was never delivered. When the Soviet Tupolev SB Katyusha appeared over the Spanish skies, many sources initially misidentified it as a "Martin Bomber"(which shouldn't come as a surprise as the Soviet aircraft types were kept under secrecy back in the 1930s).
  The presence of the 139WSP in the Spanish Civil War is even quoted by many authors and there are even some manipulated photographs, made with obvious propaganda purposes. We decided to draw a fictional version of the type serving with the Republican side.

Sources:

1. https://en.wikipedia.org/wiki/Martin_B-10

2. http://www.amilarg.com.ar/martin-139.html (translated)

3. https://web.archive.org/web/20200920135216/http://bioold.science.ku.dk/drnash/model/Spain/didnt.html

4. https://www.globalsecurity.org/military/systems/aircraft/b-10-foreign.htm

Mitsubishi G3M, part four

 

The Mitsubishi G3M2 Model 21 was a variant with improved Kinsei 41 or 42 engines, yielding 1.075 hp of power each, increased fuel capacity and modified dorsal turrets. The G3M2 Model 22 was fitted with 1.075 hp Kinsei 45 engines (some Model 21 were retrofitted with that engine as well) and featured a complete re-arrangement of the defensive weapons. Retractable ventral and rear dorsal turrets were completely eliminated replacing the later one with a large turtleback enclosure canopy which housed a 20 mm Type 99 cannon. The ventral turret was replaced by two blisters, one on each side of the fuselage, which housed a single Type 92 machine gun. A total of 343 Model 21 were manufactured plus 238 Model 22 between 1937 and 1941.

A special version was made out from a G3M2 Model 21. This version was not armed at all and had the most advanced kind of autopilot Japan had back then. It was commissioned by the newspaper Manichi Shimbun to make a round-the-world flight in 1939. This aircraft took off on 25th August 1939 from Haneda airport, in Tokyo and, after 55 days of flight, on 20th October, it landed back at Haneda.

The Mitsubishi G3M3 Model 23 was a development carried out by Nakajima, when Mitsubishi's production was switched towards the more advanced G4M. A total of 412 G3M3 were manufactured at Koizumi, in Japan. This variant was powered by two Kinsei 51 radial engines yielding 1.300 hp of power each, a further increase in fuel tankage which extended the type's maximum range up to 6.230 km (3.870 milles), compared with the 4.380 km (2.720 milles) of the G3M2 Model 22. 

The L3Y was a transport conversion made by Yokosuka in two models, L3Y1 Model 11 and L3Y2 Model 12. They were converted from outdated G3M1 and G3M2 bombers at First Naval Air Arsenal, at Kasurnigaura, thought the number of converted machines is not known. These could carry up to 10 passengers and some few were fitted with a single defensive Type 92 machine gun. Some were used by commercial companies, and some others were used by the Imperial Japanese Army (IJA) in the invasion of the Dutch East Indies in late 1941, early 1942.

When Japan attacked Pearl Harbor in December 1941, the G3M2 was already considered as obsolete. However, a total of 204 of them were still in active service with three front-line squadrons, in four Kokutais based in the central Pacific region. Fifty-four of those, belonging to the Takao Kokutai, were deployed to Formosa in the opening phases of the Battle of the Philippines. On 8th December 1941 (7th accross the International Date Line) G3Ms from the Mihoro Kokutai bombed Singapor from bases in Indochina, in one of the many aerial raids of the Battle of Singapore, causing the death of thousands of British and Asian civilians. That same day, Wake Island was also bombed by G3Ms belonging to the Chitose Kokutai causing serious damage to both civilian and US Navy infrastructure present on the atoll. Other G3Ms of that same Kokutai, based at Kwajalein Atoll stroke US Navy and civilian facilities at Howland Island, that same period.

The most famous strike this bomber took part on, along with the more advanced Mistubishi G4M, was in the sinking of two British Capital ships, HMS Prince of Wales (King George V-class Battleship) and HMS Repulse (Renown-class Battlecruiser) on 10th December 1941. Sixty G3Ms belonging to the Genzan and Minoro Kokutais, with 26 G4M of the Kanoya Kokutai, took off from bases in Indochina, found and sank the British ships which were steaming around Malayan coast without fighter protection. They were the first two capital ships to be sunk exclusively by air attack while at sea during war.

The attack on Darwin, Australia, took place on 19th February 1942. A force of 188 Japanese aircraft, among them 27 G3Ms of the 1st Kokutai, based at Ambon, in the Dutch East Indies, attacked the Australian port alongside 27 Mitsubishi G4M bombers. These followed a 81-strong first wave composed of Mitsubishi A6M Zero fighters, Aichi D3A dive bombers and Nakajima B5N torpedo bombers.

Later in the war, on 29th January 1943, G3Ms of the 701st Kokutai managed to put two torpedoes into the American Heavy Cruiser USS Chicago, during the Battle of Rennell Island. The ship was sunk the next day by further torpedoes dropped by G4Ms. 

From 1943 until the end of the war, the G3M was greatly regarded as obsolete and most of them served as glider tugs, aircrew and paratroop trainers and VIP transport between Japanese home islands, occupied territories and front-lines.

After the war, it seems that some few of them were used by the Red Army of China during the late periods of the Chinese Civil War (1945-1949) and also by the Indonesian Rebels during the Indonesian War of Independence (1945-1949). However, as we couldn't find pictures of G3Ms with those owners, both models, colours and information should be considered as speculative.

Sources:

1. http://all-aero.com/index.php/contactus/53-planes-l-m-n-o/6919-mitsubishi-g3m--ka-15--l3y

2. https://en.wikipedia.org/wiki/Mitsubishi_G3M

3. https://en.wikipedia.org/wiki/Nippon_(aircraft)

4. http://www.aviastar.org/air/japan/yokosuka_l3y.php