MItsubishi MC-21

 

The Mitsubishi MC-21 was a transport aircraft made by converting surplus Mitsubishi Ki-21-Ia (and later Ki-21-II) bombers that were withdrawn from frontline service due to their obsolescence. 

This machine was an interim design that pending the completion of the Mitsubishi Ki-57/MC-20, which was a purpose-built transport aircraft based on the design of the Ki-21 bomber. 

The exact number of converted machines remains unknown but some of them were converted from 1941 (though some sources state that, by 1940 some machines were already converted) onwards. According to our own research, there were already at least five MC-21-I registered in 1940, with the earliest machine registered in November 1939. A total of nine machines were ordered, but two of them were cancelled on February 1940 and August 1940, making a total of five MC-21-I. Regarding the MC-21-II (the transport conversion of the Ki-21-II bomber, powered by the more powerful Mitsubishi Ha-101 1.500 hp radial engine) there were approximately a total of 11 machines with the earliest examples being converted in July 1943. 

The MC-21 was produced by removing all military equipment and armament from the Ki-21. Some very initial version (posted here ) retained the glazed nose and dorsal greenhouse canopy of the bomber version, but both were later removed and the gaps faired over. With these changes, the MC-21 outperformed both the original Ki-21 and the Ki-57 purpose-built transport plane. 

Most of the MC-21s served with Dai Nippon Kokku Kabushiki Kaisha (DNKKK or Imperial Japanese Airways) as freighters, ferrying supplies between Japan, Korea and Manchuria. It was also possible to refit the interior of the aircraft to fit nine passengers. It's possible that an unknown number of Ki-21 bombers were also converted in the field, and served with the Imperial Japanese Army Air Force.

Sources:

1. http://www.historyofwar.org/articles/weapons_mitsubishi_MC-21.html 

2. https://en.wikipedia.org/wiki/Mitsubishi_Ki-21

3. https://www.valka.cz/Micubisi-MC-21-t41742

4. http://www.airhistory.org.uk/gy/reg_J-.html

Mitsubishi Ki-57, foreign users

 

The Mitsubishi Ki-57 was a Japanese transport aircraft that was developed from the Ki-21 bomber. It was used by Japan but also by many other countries, like the following ones:

• People's Republic of China: After World War II and the subsequent follow-up of the Chinese Civil War, the Red Army of China took over many Ki-57 transports, left over by the Japanese, mostly in Manchuria, left overs at Changchun airfield. They were employed during the last part of the conflict in the mainland, mainly as trainers, in the flight academy that the Red Army of China (forerunner of the People's Liberation Army) had set in that region. After the war ended, in 1949, they were still being used as trainers until 1952, when they were written off due to their age.
• Republic of China: Just like their Communist foes, the Republic of China Air Force (ROCAF) used some captured MC-20s (the civilian version of the Ki-57 military transport) after the Japanese retreat in 1945. Those were captured mainly in the Mukden airfield, they were also used during the latest stages of the Chinese Civil War, however, they were mostly either destroyed or captured by the Red Army when the Nationalists retreated to Taiwan. 
• Reorganized National Government of the Republic of China: The Japanese collaborationist puppet government had, theoretically, one MC-20 in strength which was used as the presidential transport of Wang Jingwei (president of the collaborationist government). Further details are unknown and, as we couldn't find graphical information, the drawing should be considered as speculative.
• Dutch East Indies: In order to repatriate and liberate Allied civilian and soldiers prisoners of war the Rescue of Allied Prisoners of War and Internees (RAPWI) commission, set up a RAPWI-Air transport company. This was founded by Captain Arens, a former KNILM (the official airline of the Dutch East Indies) pilot and was composed of dozens of left-over Japanese airplanes, among them four Ki-57 machines as well as Japanese airmen. A number of those repatriation flights were conducted by Japanese pilots, often accompanied by Dutch soldiers. For example, one of those service repatriation flights was set up between the cities of Bali and Bandung.
• Manchukuo: The Manchukuo National Airways, more known by its Japanese acronym MKKK (a paramilitary organization working for the Japanese Kwantung Army), had in inventory a total of 20 MC-20 machines. These were supplied by Japan and were used as transport and VIP aircraft. During the last stages of World War II, they were taken over by the Manchukuo Imperial Air Force and flew with Japanese markings, though they kept their Manchurian numbers and pilots. Most of them were either destroyed during the Soviet Invasion of Manchuria or captured and given to the Chinese Red Army.
• Second Philippine Republic: The Japanese puppet government set up in the Philippines had one MC-20 which was used as the presidential transport of José P. Laurel (the president of that republic). As we couldn't find further info nor pics of this aircraft, the drawing should be considered as speculative.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-57

2. http://cwlam2000.epizy.com/manchu_x.htm#6、三菱陸軍百式運輸機_/_MC-20_（1945）（Mitsubishi_Ki-57_,_MC-20）(M-600,_601,602,_603,_604,_605...) (translated as much as we could)

3. https://www.ipms.nl/artikelen/nedmil-luchtvaart/vliegtuigen-m/vliegtuigen-m-mitsubishi-ki57 (translated)

4. http://www.airhistory.org.uk/gy/reg_M-.html

Caproni Ca.310, foreign users, part two

 

The Caproni Ca.310 Libeccio, was an Italian twin-engine reconnaissance aircraft used during the World War II. It was mainly employed by Italy, but it also had many other foreign users, among them, those in the previous post, and the following ones:

• United Kingdom: The United Kingdom was going to be the most important foreign customer for the Ca.310, as the Royal Air Force (RAF) was undergoing major expansion programme after the Munich crisis in 1938. An element of that programme included enlarging the RAF's bomber force, which required an effective crew trainer aircraft. The RAF's high command decided that the Ca.310 could fit that role in late 1938 (albeit with some minor modifications, like for instance, replacing the 12,7 Breda-SAFAT defensive machine-gun with a British Vickers K gun). Negotiations continued well after the beginning of the World War II, when Italy was still neutral. The order wasn't cancelled even after 3rd September, when France and Great Britain declared war on Germany. However, Germany issued a formal protest to Italian government and, Caproni, which apparently was sympathetic to the Allied cause, tried to sell the aircraft through their Portuguese subsidiary. In December 1939 the British government, informed Caproni that they were going to buy 200 examples of the Ca.310 plus 300 of the Ca.313. Eventually, the order was changed to replace the Ca.310 with Ca.311, which was better. When Italy entered the War on 10th June 1940, all plans were scrapped.
• Peru: The Peruvian Cuerpo Aeronáutico del Perú (Peruvian Aeronautical Corps) bought 16 Ca.310s in 1938. Fifteen of them were shipped in May and the last one was ferried from Italy to Peru. The flight took place on 2nd August 1939, but the aircraft crashed on his way killing its pilot, Captain Pedro Canga Rodriguez. The Peruvian Ca.310s were employed during the Ecuadorian-Peruvian War of July 1941 as part of various bombing squadrons. They often flew bombing missions against Ecuadorian cities, escorted by the North American NA-50 "Torito" (Spanish for 'Little Bull') fighters. After that war ended, they were used as trainers.
• Nationalist Spain: It was during the Spanish Civil War that the Ca.310 was used in combat for the first time. A total of 16 Ca.310 were employed by the Aviación Nacional (Spanish Nationalist Air Force during the civil war) from July 1938 until the end of the conflict. They were assigned to Grupo 18 (Group 18) and were used in the reconnaissance-bomber role, and saw little action, mainly in the Catalonian front.
• Yugoslavia: This country was the first foreign customer of the type when, in 1938, they bought 12 Ca.310. While every other country bought the Ca.310 as a light bombers, Yugoslavia bought them as bomber trainers, as the Royal Yugoslav Air Force was undergoing a modernization process with more modern bombers such as the Bristol Blenheim, the Dornier Do.17k and the Savoia-Marchetti Sm.79, so they needed a multi-engined crew-trainer aircraft with retractable landing gear. 
  Apparently Yugoslavia was the only foreign customer satisfied with the Ca.310's performance, so they ordered a second batch of 12 Ca.310bis machines in 1939, which was a developed variant with an unstepped glazed cockpit (it would eventually serve as the prototype for the Ca.311) which was delivered at the end of the year. After the country was invaded by Axis forces, the Ca.310 were divided between the Independent State of Croatia, Italy and Germany. 
  During the late stages of the war, Yugoslav partisans seem to have re-captured some ex-Croatian machines and sent them to serve with the Yugoslav Partisan Air Force and its subsequent postwar air force. As we couldn't find graphical info about the Ca.310 serving with the SFR Yugoslav Air Force, the drawing should be regarded as speculative.

Sources:

1. https://www.britmodeller.com/forums/index.php?/topic/235096763-caproni-ca310/

2. https://en.wikipedia.org/wiki/Caproni_Ca.310

Caproni Ca.310, foreign users, part one

 The Caproni Ca.310 'Libeccio' (Italian word for "south-western wind") , was an Italian twin-engined reconnaissance monoplane used during World War II. The aircraft itself was a derivation of the previous Ca.309 and it was employed by many users around the world. Among them, the following ones:

• Independent State of Croatia: The Air Force of the Independent State of Croatia (whose acronym was ZNDH) employed 6 (seven, according to some other sources) Ca.310. Five of them were bought from German stocks, which were ex-Yugoslav machines and one machine captured by themselves, plus one Ca.310bis (which was a variant with an unstepped glazed nose, which would eventually become the prototype for the Ca.311). 
  A single ZNDH Ca.310 fleed to Italy on 31st October 1943 and landed at Tortorella airfield, controlled by the South African Air Force. That airplane was loaded with 7 Yugoslav and one Gestapo officer. Of those people, the most important was Cpt. Janko Dobnikar a Slovene pilot working for Zemun WNF (ex Ikarus) who was arrested the previous day by the Gestapo for cooperating with partisans but the flight was hijacked and sent to Italy.
• Hungary: Hungary bought a total of 36 Ca.310 in 1938. Three of them were soon lost to accidents and the Hungarians were not satisfied with the type's performance, so during the next year (according to some other sources it was in 1940) the remaining 33 machines were sent back to Caproni. They were taken into account for the MKHL's (Hungarian acronym for Magyar Királyi Honvéd Légiero - Royal Hungarian Air Force) purchase of the Caproni Ca.135bis medium bomber. Returned aircraft were refurbished and assigned to the 50º Stormo Assalto, to replace the Breda Ba.65 as part of the 12º Gruppo of the Regia Aeronautica (Italian Royal Air Force)
• Norway: Norway ordered 24 Ca.310 as part of a dried and salted cod barter between Norway and Italy. After the delivery of the first four aircraft, testing revealed that flying characteristics weren't as satisfactory as Caproni had promised and build quality fell way behind too. Therefore, Norwegian authorities cancelled the order and any further Ca.310 wasn't delivered. The four Norwegian machines received the following serial numbers: 501, 503, 505 and 507. Aircraft No. 503 was bought by the Norwegian national airline Norske Luftfartselskap and was employed as a fast mail aircraft in the Oslo-Göteburg (Sweden)-Copenhagen (Denmark) night route during summer 1939. By the start of the war it was recalled by the Haerens Flyvevaaben (Norwegian Army Air Service) and was put back into military service.
  When Germany attacked Norway on 9th April 1940, all four Norwegian Ca.310 were based at Sola airfield, where they were called to move to Oslo, to defend the capital, but two of them, numbers 503 and 507 were destroyed on the ground by the Luftwaffe. One Ca.310, number 505 managed to take off, but it was destroyed by its own crew after having to perform an emergency landing at Opstad. The other surviving machine, number 501 managed to take off from Sola, although having been damaged, but eventually it crashed in lake Vangsmjosa, in the region of Valdres on 19th April 1940. This aircraft was recovered and restored and is nowadays on exhbition at the Sola aircraft museum.

Sources:

1. https://www.britmodeller.com/forums/index.php?/topic/235096763-caproni-ca310/

2. https://en.wikipedia.org/wiki/Caproni_Ca.310

Mitsubishi Ki-21, part three

 

To compensate for the heavy losses against both the Hawker Hurricane and the Curtiss P-40 which the Ki-21 had to fight after Pearl Harbor, the Imperial Japanese Army Air Force (IJAAF) introduced the Ki-21-IIb, which replaced the long greenhouse style dorsal canopy by a turret equipped with a single 12,7 mm (0,5 in) Type 1 machine gun. Cockpit canopies were redesigned as well and fuel capacity was also increased. Although the Ki-21 was used in every front of the Pacific War, it was obvious that by, as early as 1942, the design was starting to be obsolete and was increasingly being shifted away from front-line service. 

In spite of its obsolescence, it remained in service until the end of the war in various roles, like transport, bomber crew and paratroop trainer, liaison and communications, special commando and secret missions and kamikaze operations. 

Near the end of the war, during the Battle of Okinawa, the remaining Ki-21s were used by Giretsu Special Forces (Giretsu was an special forces unit comprised of paratroopers) were used in strikes in Okinawa and American targets on Ryukyu islands. One noted operation was an strike on the American-held Yontan and Kadena airfields on the night of 24th May 1945. Twelve modified Ki-21-IIb with their turrets removed, of the Daisan Dokuritsu Hokutai were sent to strike, each airplane loaded with 14 commandos. Five Ki-21s managed to crash land on Yontan, only one landed successfully. The remaining raiders, armed with sub-machine guns and explosives wrought havoc on the supplies and nearby aircraft, destroying 264.979 L (70.000 US Gal) of fuel and nine aircraft, and damaging 26 more on what was the last operational usage of this Japanese bomber.

The Allied codename for the type, initially was "Jane", but it was quickly changed to "Sally" as "Jane" was the name of Douglas McArthur's wife. When the Ki-21-IIb entered service, the absence of the long greenhouse canopy confused Allied observers, who thought it was a completely new type and named it "Gwen", however, it was quickly switched back to "Sally" when they realized their mistake. 

A total of 2.064 units of every variant were manufactured,  between March 1938 and 1944 when the last Ki-21-IIb was completed.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-21

2. https://www.valka.cz/Micubisi-Ki-21-Sally-t31499 (translated)

3. http://www.asisbiz.com/il2/Ki-21-Sally/Mitsubishi-Ki-21-Sally.html

Mitsubishi Ki-21, part two

 

Losses for the Ki-21 were high during early combat operations due to an insufficient defensive armament - the Ki-21-Ia was armed with three 7.7mm Type 89 machine guns in nose, ventral and dorsal positions - and self-sealing fuel tanks, with the aircraft's fuel system proving to be unreliable. To address those problems, the Ki-21-Ib was introduced. An additional defensive machine gun was introduced in the tail in an 'stinger' arrangement and was remotely controlled. Both horizontal tail surfaces and trailing edge flaps were improved and the bomb bay was enlarged. Fuel tanks were also partially protected with laminated rubber sheets. 

A third variant of the Ki-21-I was introduced in 1940. This variant had an additional 500 L (130 US Gal) auxiliary fuel tank, fitted in the rear weapons bay and two more machine gun placed in the beam position, making a total of six. Underwing hardpoints were also fitted to carry a total of four 50 Kg (110 lb) bombs externally and, in order to compensate for the increase in weight, the wheels were increased in size. 

By the time of the attack on Pearl Harbor and the start of the Pacific War, the Imperial Japanese Army Air Force's (IJAAF) main antagonist until then, the Republic of China Air Force (ROCAF) had been greatly improved to the point that the Ki-21-I's losses were mounting too high, so most Ki-21-Ia and some 21-Ib were relegated to second line and training duties. 

Front line units were equipped, from mid 1940 onwards with the Ki-21-IIa (Army Type 97 Heavy Bomber Model 2A). This variant was powered by the much powerful Mitsubishi Ha-101 radial engine which yielded up to 1.500 hp of power and was also equipped with larger horizontal tail surfaces. This variant was the standard for many IJAAF's heavy bomber squadrons at the beginning of the Pacific War and played a major role in the early campaigns of the War. For operations over the Philippines, IJAAF's 5th, 14th and 62nd Sentais (a Japanese unit equivalent to a Wing or Group), based in Formosa, attacked American targets at Aparri, Tuguegarao, Vigan and other targets in Luzon island on 8th December 1941. The 3rd, 12th, 60th and 98th Sentais, based in French Indochina bombed British and Australian positions in Thailand and Malaya attacking Alor Star, Sungai Petani and Butterworth (Penang) escorted by Nakajima Ki-27 and Ki-43 fighters. However, during those operations, the Ki-21 suffered heavy losses both from the Hawker Hurricane and the Curtiss P-40 Warhawk.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-21

2. https://www.valka.cz/Micubisi-Ki-21-Sally-t31499 (translated)

3. http://www.asisbiz.com/il2/Ki-21-Sally/Mitsubishi-Ki-21-Sally.html

MItsubishi Ki-21, part one

 

Back in 1936, the Imperial Japanese Army issued a requirement for a new heavy bomber to replace the Mitsubishi Ki-20 and the Mitsubishi Ki-1 bombers which were clearly outdated for the time. The requirement called for a crew of at least four men, a top speed of 400 km/h (250 mph) with an endurance of at least five hours and a bomb payload of 750 kg (1.650 lb). Those technical requirements were very ambitious for the time and very few twin-engine bombers could achieve such performance numbers.

Mitsubishi and Nakajima were asked to submit their proposals, with Kawasaki's one being rejected. Mitsubishi's design was an all-metal mid-wing cantilever monoplane with a retractable landing gear, ventral bomb bay and two Mitsubishi Ha-6 radial engines. 

The first prototype flew for the first time on 18th December 1936, with the second prototype, which differed from the first one in having a long greenhouse canopy instead of a ventral turret, flying in January 1937. In the ensuing competition against Nakajima Ki-19 (Nakajima's proposal), they found to be similar in performance numbers, being the Ki-21 better in speed and endurance and the Ki-19 being better as a bombing platform and its Nakajima Ha-5 engines being more reliable. In order to make a decision, two more prototypes were ordered from both Mitsubishi and Nakajima, with Mitsubishi ordered to switch its own 825 hp Ha-6 engines for the Ha-5 ones, used by Nakajima and vice versa. That third prototype of the Ki-21 featured a glazed nose similar to the Ki-19 and revised tail surfaces. Therefore, the Ki-21 proved to be superior and was ordered into production as the "Army Type 97 Heavy Bomber Model 1A" in November 1937.

Production aircraft began to enter service in August 1938, supplementing and replacing the Fiat Br.20 Italian bombers that had been purchased as an interim measure. 

The Ki-21-Ia was used in combat for the first time during the Second Sino-Japanese War by the 60th Sentai (an unit equivalent to an aviation Group or Wing in other air forces) from autumn 1938, performing long-range unescorted missions together with the Br.20 of the 12th and 98th Sentais. The Ki-21 proved to be more reliable, robust and better suited for the long Asian distances than the Br.20. Two additional Sentais, the 58th and the 61st were deployed to Manchuria in the summer of 1939 to operate against China, with aircraft of the 61st being heavily employed against Soviet and Mongolian forces during the Nomohan incident (AKA Battles of Khalkin Gol) in June-July 1939, when the Japanese forces launched their main attack.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-21

2. https://www.valka.cz/Micubisi-Ki-21-Sally-t31499 (translated)

Mitsubishi Ki-21, foreign users

 

The Mitsubishi Ki-21 was a Japanese twin-engined bomber which took part in the World War II. Its main user was Japan, however, it was used by some other users:

• France: After the War, some few Ki-21 were used in Indochina by the French Armée de l'Air (French Air Force) during the First Indochina War. They were originally Ki-21-IIb bombers converted ad-hoc into transports with their defensive armament removed. These machines were very worn out so their usage through that conflict wasn't very prolonged and they were most likely, replaced. 
• Manchukuo: The Manchukuo Imperial Air Force had 6 Ki-21-Ia bombers in strength in the year 1941. They were assigned to 2nd Air Unit, based in Fengtian, but, most probably, they were not used very much and were either destroyed on ground or left to rot. 
• Thailand: Nine Ki-21-IIa bombers were sold to the Kingdom of Thailand in 1940 to be used by the Royal Thai Air Force against the Vichy French forces in Indochina. However they couldn't take part in the Franco-Thai War as crews didn't complete training in time. They were part of the 62nd Squadron and were based at Don Muang, in Bangkok. In 1942, when the Japanese Army invaded Burma, the Thai Army invaded the Shan States, using their Ki-21 extensively against the defending Chinese forces. Two Thai Ki-21s were lost on air raids on 2nd May 1943 and 30th November 1944 when they were based in Lampang, North-West of Thailand. The remaining seven were kept in active after the war and it wasn't until 1949 that they were written off service and were immediately scrapped.

Sources:

1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-21

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

3. https://www.traditions-air.fr

4. http://wings-aviation.ch/51-Profiles/M/M-Basis-en.htm (translated)

Mitsubishi B5M

 

In summer 1935, the Imperial Japanese Navy Air Service (IJNAS) issued a specification, 10-shi, for a carrier-based strike-bomber with torpedo capabilities. The specification called for a maximum speed of 330 km/h (205 mph) , an endurance of up to 7 hours unloaded and 4 loaded with a single torpedo plus folding wings to facilitate its usage in a carrier. Those requirements exceeded by far the performance numbers of the winner of the previous specification, 9-shi,  the Yokosuka B4Y. Regarding armament, the 10-shi called for a total payload of up to 800 kg (1.764 pounds) plus a rear-defensive machine-gun. The resulting machine had to be powered by the Mitsubishi MK8 Kinsei radial engine. 

Two old rivals, Mitsubishi and Nakajima (which eventually won the contest with the famous Nakajima B5N), were called to participate in the contest, with Yokosuka not taking part although they won the previous contest.

Mitsubishi's project for the 10-shi, received the internal designation of Ki-16 and was designed by Jiro Horikoshi, designer of the successful A5M and the more successful A6M Zero. Inspired by the Northrop 5A (a prototype for the Northrop YA-13 which was sold to the IJNAS by the USA), Horikoshi decided to adopt a fixed landing gear, relying on the success of the A5M, covering wheels with a massive cowling. He also refused the mechanical wing-folding drive the 5A had in order to not overload the engine with additional tasks. 

The B5M prototype was completed in January 1937, almost at the same time the B5N's prototype was completed. Both bombers were tested and the B5M showed a slower speed than the B5N, 355 km/h (221 mph) versus 368 km/h (229 mph) of the B5N.

During the year 1937, both airplanes were tested, with the IJNAS' high command divided between the two. On one hand they liked the good flying characteristics of the B5N, but on the other, they saw it as a very progressive machine, as it had many new characteristics for naval bombers of the time, such as retractable landing gear. So, in late 1937, they IJNAS' high command opted to adopt both designs under the same denomination, of "Type 97 Deck Attack Aircraft of the Fleet". To distinguish both bombers, "Type 97 Model 1" was the B5M and "Type 97 Model 2" was the B5N. 

Unfortunately for Mitsubishi, Nakajima was able to fix the problems of the earlier models of the B5N, while Mitsubishi didn't as they were more concentrated on improving the A5M and designing the A6M, therefore, the B5M was discontinued with only 125 machines having been built between 1936 and early 1941.

The B5M1 (an improved model with a new engine, from 1939) was powered by the Mitsubishi MK8D Kinsei-43 radial engine which, in its newest models, had a theoretical power of 1.080 hp, raising this way its top speed to 381 km/h (234 mph), making it faster than the B5N. However, the IJNAS still decided in favour of the B5N.

The first combat unit to be equipped with the B5M in late 1938 was the newly formed Suzuka Kokutai, based in Eastern Japan. This unit undertook the task of training and evaluating the B5M. 

Contrary to popular belief, the B5M was not deployed to China, as every machine was deployed in combat training units in mainland Japan and, in early 1941, they were assigned as follows:

• Oita Kokutai: 45 units
• Usa Kokutai: 63 units
• Omura Kokutai: 16 units

All those units were deployed at Kure Naval Base, in Tokyo and carried out anti-shipping patrols over the Pacific Ocean, after Pearl Harbour. 

As the IJNAS was in need of every aircraft they could count on, the B5M was rushed to many front-line units, so many B5Ms were assigned in early 1942 to the 33rd Kokutai which took part in the battle of Celebes Island, in the Dutch East Indies. It is not known the exact number of machines that served with the 33rd Kokutai, but by the time that unit was re-organized as the 932th Kokutai, in the summer of 1943, there were still many B5Ms active. 

One of them became famous when, at the hand of Captain Kino, rammed the leader of a formation of American B-24 bombers that bombed the city of Makassar.

From July to October 1942 some B5Ms were assigned to the escort-carrier Un'yo, serving in the area of Truk Atol. It seems too that some machines were retrofitted with forward-firing machine guns, however, as the war went on, the usage of both the B5M and the B5N decreased and, apart from a sporadic anti-submarine patrol, the B5M wasn't used. 

The last known usage in combat of a B5M was during the Kamikaze attacks in Okinawa during April-May 1945. 

Sources:

1. http://www.airwar.ru/enc/bww2/b5m.html (translated)

2. https://en.wikipedia.org/wiki/Mitsubishi_B5M

3. https://www.skytamer.com/Northrop_1933(Gamma5D).html (for the Northrop 5A)

4. https://www.valka.cz/Micubisi-B5M1-Mabel-t30172

Caproni Ca.309, Italian users

 

 The Caproni Ca.309 was an Italian aircraft used during the 1930s and the World War II. 

It was designed by Cesare Pallavicino (who would also design , after the war, the famous scooter Lambretta, along with the Piaggio Vespa) and was based on the previous Caproni Ca.308 Borea transport and passenger plane. The Ca.309 was initially intended to replace the obsolete IMAM Ro.1 biplane (itself being a license production of the Dutch Fokker C.V) with reconnaissance and ground attack capabilities.

The Ca.309 was a low-wing cantilever monoplane powered by two 390 hp Alfa-Romeo 115-II in-line engines on each wing. 

The Ca.309 served with the Regia Aeronautica (Royal Italian Air Force) in Libya, where, in June 1940, just when Italy declared war on France, many Ca.309 based on Western Libya, made some reconnaissance flights along the Libyan-Tunisian border. They took part in every battle in the North African Theatre during 1940, with good operational results, until 1943 when Axis forces were defeated in Africa. 

After that, the surviving planes were sent to Italy, where they served mainly as transports and reconnaissance trainers, in fact, in February 1943, the Scuola Osservazione Aerea (Aerial Observation School) in the town of Cerveteri, close to Rome, had a total of 6 Ca.309 in charge.

There were two main unofficial sub-variants, the Ca.309 armed with a 20 mm cannon and the Ca.309 Sanitario (Sanitary). The up-armed Ca.309 was made shortly after the Italian entrance to the war, under the request of the Comando Aviazione Libia (Libyan Aviation Command) by adding a Breda 20 mm machine gun placed under the nose. This modification was requested by Marshall Italo Balbo himself during the very first days of the hostilities in Septentrional Africa. He was looking for an effective way of attacking British reconnaissance vehicles, which constituted a serious threat for Italian  positions in the Cyrenaica region. As Balbo was killed by friendly fire on 28th June 1940, his tactics couldn't ve put into use. 

In September 1940, in Guidonia (the testing grounds for the Regia Aeronautica), the Sanitary version was tuned and tested. A revision of the internal load was in order to improve the take off characteristics and, therefore, total fuel load was reduced from 575 kg to 320 kg and the total amount of transportable patients was also reduced from three to two. By the first week of October 1940, the aircraft was ready and was sent to Libya, where any trace of its service was lost.

A total of 247 Ca.309 were manufactured at Cantieri Aeronautici Bergamaschi (Caproni's main factory) at Ponte San Pietro from 1936 until 1944, some of them being made after Italian Capitulation. There were also plans for a 'Super-Ghibli' (an improved version powered by two Isotta-Fraschini Beta engines, with a redesigned nose) which could transport either 8 paratroopers or 600 kg (1323 pounds) of bombs. Some studies were also made to convert the Ghibli in a meteorological observation plane, by completely redesigning the fuselage and engine arrangement (it would've been powered by just one engine placed at the nose) and the possibility of having the fuselage of a Ca.311, powered by the engines of the Ca.309 was also considered.

Sources:

1. https://en.wikipedia.org/wiki/Caproni_Ca.309

2. http://www.flyinglions.eu/storia/aviazione/item/233-caproni-cab-ca-309-ghibli.html (translated)

3. https://www.valka.cz/Caproni-Ca-309-Ghibli-t16152