Mitsubishi Ki-30, part three

The Mitshubishi Ki-30 was designed and developed in response to an Imperial Japanese Army specification issued in May 1936 for a replacement of the Kawasaki Ki-3 light bomber. The scope of the issue was to replace it with a complete indigenous bomber both in design and manufacture.
Both Mitsubishi and Kawasaki were requested to build two prototypes each by December 1936. The specification requested a top speed of 400km/h (250mph) at 3000m (9840ft) high, a normal operating altitude from 2000m (6560ft) to 4000m (13130ft) high, the ability to climb to 3000m in 8 minutes and an engine which had to be either the 850hp Mitsubishi Ha-6, the 825hp Nakajima Ha-5 or the 850 Kawasaki Ha-9IIb, all of them radial and liquid cooled. The requisition also requested a normal bomb load of 300kg (660lb), with a maximum of 450kg (990lb), one forward-firing machine gun and another rearward-firing one in a defensive position with the ability to perform 60º dives for dive bombing and a loaded weight less than 3300kg (7280lb).
The first Mitsubishi prototype flew on 28th February 1937 and was powered by the Mitsubishi Ha-6 radial engine which drove a three-bladed propeller. It was originally designed with a retractable landing gear but the wind tunnel tests showed that the gain in speed was marginal due to the landing gear's extra weight. Therefore a fixed and spatted main wheels system arrangement was chosen instead. The wing was mounted at a point above the line of the aircraft's belly to fully enclose the bomb bay within the fuselage. The pilot sat just above the leading edge of the wing and the rear gunner/radio-operator just behind the wing trailing edge, in a long canopy which gave an excellent all-around vision.
A second prototype was completed the next month, this time fitted with the slightly more powerful Nakajima Ha-5 engine. Both were completed two months behind schedule and were overweight, however, both of them met or exceded the requirement's minimum specifications. As the second prototype could achieve a top speed of 423km/h (263mph) at 4000m high, the Imperial Japanese Army Air Force placed an evaluation order of 16 exemplars. Those were delivered in January 1938 and, after passing trials, the Army ordered the Ki-30 into production in March under the designation of Army Type 97 Light Bomber.
A total of 704 Ki-30s were built. Most of them, 636, were built by Mitsubishi Heavy Industries at the city of Nagoya from February 1937 until April 1940 and the 1st Army Air Arsenal --AKA Army Air Supply Workshop-- located at the city of Tachikawa manufactured 68 exemplars from 1939 until September 1941 when production of the type ceased.
The Ki-30 was used in combat for the first time in the Second Sino-Japanse War in spring 1938. It showed enough reliability to operate in rough airfields and it was highly effective when operated escorted by fighters. This success continued in the early stages of the Pacific War and the type saw extensive use in the Invasion of the Philippines. However, once unescorted, their losses quickly mounted up and the type was withdrawn to second line duties. During 1942 they served in the China-Burma-India Theatre of War, operating from Thailand. Anyway, by the end of 1942 the type was deemed as obsolete and was relegated to training roles only. Many of them were used as kamikaze aircraft towards the end of the war.

Sources:
1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-30
2. https://www.valka.cz/Micubisi-Ki-30-Ann-t1289
3. The Hamlyn Concise Guide To Axis Aircraft Of World War II

Mitsubishi Ki-30 - Foreign users, part two - Thai users

Due to the American embargo, the Royal Thai Air Force (RTAF) switched to Japan for their new suppliers in October 1940. They sent a purchasing commision to Japan where they were shown both the Mitsubishi Ki-21 and the Mitsubishi Ki-30. They were greatly impressed by the performance of the Ki-30 so they ordered nine Ki-21s and 24 Ki-30s. Apparently an unknown number of fighters were ordered too, but were never delivered.
The Ki-30 filled the void that the North American NA-69 (a light attack plane) would've filled if it had been delivered. The Ki-30 was found to be easy to fly and maintain and it performed notably much better than the obsolete Vought O2U Corsair. It had a much better bombload and twice the range, compared to the Corsair and its fixed landing gear allowed the type to operate in the rough airfields located specially in the Northern and Eastern parts of the country. They received the nickname of Nagoya by their Thai pilots.
All 24 of them were delivered in November 1940 and, to operate them, two squadrons were formed at the city of Don Muang. Thai crews completed their training quickly and on 7th January 1941, in the context of Franco-Thai War, twenty-three Ki-30s attacked French targets in Cambodia. The next day, 9 Nagoyas, escorted by three Curtiss Hawk 75Ns attacked the airfield at the city of Siem Reap and two days later, they sustained their first casualty as one Ki-30 was shot down by a Morane-Saulnier M.S.406. The Ki-30s took part also in the last air raid of the conflict ,on 24th January, as nine Ki-30s and three Martin 139WS medium bombers, raided the same airfield of Siem Reap, hoping to destroy the M.S.406 fighters. During that raid, one Ki-30 was attacked by two M.S.406s but the Ki-30 managed to scape.
On 22nd December 1941, the RTAF underwent reforms and shortly later, in January 1942 they were rebased to Lampang, to become part of the Northern Air Wing. They were extensively used in the Burmese front, flying both attack and reconnaissance missions without, surprisingly, no Chinese fighter opposition at all. However, the occasional anti-air fire and hazardous weather and terrain conditions, made those missions dangerous.
One of those raids, took place on 29th January 1943 when a mixed force of Ki-21s and Ki-30s raided the Chinese base at Mong Sae, managing to inflict severe damage at the cost of just some damaged bombers. That was the last Thai raid of the Northern campaign because, technically, Thailand wasn't at war with China and a truce was arranged. Thailand had invaded the Burmese Shan States, following orders coming from Japan, and fought Chinese forces present there but, when Thailand signed the declaration of war against the Allies, China didn't respond.
In spite of the efforts to obatin more Japanese bombers, like the Ki-21 and the Ki-30, no more aircraft of either was supplied.
 In April 1945 there were still 21 Ki-30s in active service of which 14 of them were in flying conditions. The last Ki-30 was written off active service in 1950.

Sources:
1. http://www.j-aircraft.com/research/jan_forsgren/j-aircraft_royal_thai.htm
2. https://en.wikipedia.org/wiki/Mitsubishi_Ki-30
3. https://www.valka.cz/Micubisi-Ki-30-Ann-t1289

Mitsubishi Ki-30 Foreign users, part one

The Mitsubishi Ki-30 was a Japanese light bomber of World War II that also served with other countries.

• France: After the end of the World War II, many Ki-30s were left behind in Indochina. French authorities pushed them into service and some of them served in liaision duties in the First Indochina War, with the Escadrille de Liaison 99 (Liaison Flight 99). Their fate is unknown, but they were most probably destroyed and/or scrapped.
• China: As the Ki-30 served in mainland China during World War II, and specially in the Manchurian region, when the region was taken over by the USSR in 1945 and handed over to Chinese Communists, three Ki-30s that were based there were taken over by Chinese Communist authorities, that set up a flying school using (along with many other types) Ki-30s in the city of Harbin (capital city of Manchuria). They served during the 1945-1949 period of the Chinese Civil War as trainers and were withdrawn from service in the early 1950s.
  EDIT: It seems that the Republic of China Air Force, also employed them, we found some photos and profiles and updated the drawings. Apparently, they were employed during the late stages of World War II in China and the subsequent Chinese Civil War.
• Indonesia: As another theatre of operation where the Ki-30s served was the Indonesia islands, some of them were captured by Indonesian rebels when the Japanese authorities left and pushed them into service with their newly created army. They served during the Indonesian National Revolution from 1945 until 1949. 

Sources:
1. https://en.wikipedia.org/wiki/Mitsubishi_Ki-30
2. http://www.traditions-air.fr/index.htm (translated)