Mitsubishi Ki-46 Dinah
The Mitsubishi Ki-46 'Dinah' was a twin-engine reconnaissance aircraft flown by the Imperial Japanese Army Air Force throughout the Second World War. Designed to outrun interception, it first flew in November 1939 and ranged across the Pacific at high altitude, photographing Allied positions from China to the Mariana Islands; 1,742 were built in all. One complete example survives, displayed by the RAF Museum at its London site.
Why It Mattered
The Ki-46 — Army designation Type 100 Command Reconnaissance Aircraft, Allied reporting name 'Dinah' — was the Imperial Japanese Army's long-range strategic reconnaissance aircraft of the Second World War. It paired high speed with long range, and in the Pacific War's early stages Allied fighters found it difficult to intercept. The RAF Museum calls it one of the most elegant aircraft of the Second World War, and its success was such that Germany tried, in vain, to acquire manufacturing rights from Japan. It excelled in the high-altitude photographic reconnaissance role, ranging over the entire Pacific theatre with little opposition.
Design Notes
In December 1937 the Army issued Mitsubishi a specification for a long-range strategic reconnaissance aircraft to replace the Ki-15. The specification demanded an endurance of six hours and speed sufficient to evade interception by any fighter in existence or development, but otherwise did not constrain the design. The design team, led by Tomio Kubo and Jojo Hattori, answered with a twin-engined, low-winged monoplane whose pilot and observer sat in individual cockpits. The prototype first flew from Mitsubishi's Kakamigahara factory in November 1939, reaching only 540 km/h against a specified 600 km/h. Even so it outpaced the newest Japanese fighters of the day, so an initial production batch was ordered; to solve the performance problems Mitsubishi fitted Ha-102 engines, and the resulting Ki-46-II first flew in March 1941. A later Ki-46-III had more powerful, fuel-injected Ha-112 engines and a redesigned nose.
Operational History
The type was first used operationally over China and Manchukuo, its speed letting it avoid interception by the few fighters available to the Chinese. Before the Japanese campaign against the British in Malaya, a Ki-46 unit carried out detailed reconnaissance of the area, giving the Japanese vital intelligence ahead of the campaign. Detachments soon covered most of South-east Asia; the type flew high-altitude reconnaissance over Burma, Indochina, Thailand and the Indian Ocean, and the Japanese Navy operated a small number of Dinahs. Deliveries of the Ki-46-II began in July 1941, and production of all versions totalled 1,742 aircraft, built from 1941 to 1944. At first the Ki-46 proved almost immune from interception, but newer Allied fighters such as the Spitfire and the P-38 Lightning could challenge this superiority. Towards the end of the war Dinahs became vulnerable to fast-climbing Allied fighters, yet in 1944 and 1945 Ki-46s still reconnoitred the big American airbases in the Mariana Islands used for massed bomber raids against Japan. Small numbers were converted late in the war: some Ki-46-IIs became three-seat trainers for radio and navigation training, and in 1944–45 others were modified as high-altitude interceptors, with two 20 mm cannon in the nose, for fighting USAAF B-29 Superfortresses.
Afterlife
The only complete survivor is a Ki-46-III, built around 1943, which served with the 81st Sentai's 3rd Chutai. The British captured it in Malaya as the war ended and had it assessed by their Allied Technical Air Intelligence Unit for South East Asia; it then came to Britain as a museum object. Japanese personnel at Kuruan airfield restored it to airworthy condition for the intelligence unit, a Japanese pilot flew it to Seletar, Singapore, in early 1946, and it was shipped to the United Kingdom in mid-1946. In 1989 it left RAF St Athan, where it had been kept alongside other historic aircraft, and joined the Royal Air Force Museum at Cosford. On display at Cosford until 2022, it then moved to the RAF Museum's London site, where it is shown in Hangar Five. In 2003 the wreckage of a Ki-46-II abandoned at Jacquinot Bay, New Britain, was also recovered.