Country of origin:

Japan

Description:

Long-range reconnaissance monoplane

Power Plant:

[Ki-46-II]

Two 806 kw (1,080 hp) Mitsubishi Ha.102 fourteen-cylinder two-row air-cooled radial engines

Specifications:

Armament:

One 7.62 mm (0.30 in) Type 89 machine gun on flexible mount

History:

One of the most attractive aircraft to be operated during World War II, the Mitsubishi type 100 Command Reconnaissance Aircraft, or Ki-46, was designed by Tomio Kubo from the outset specifically for the strategic reconnaissance role. It saw service throughout the Pacific, particularly over Malaya, the Dutch East Indies, New Guinea, Burma, China and the Philippines. It regularly made flights over northern Australia. These latter aircraft were Ki46-IIs flying from Timor Island.

The prototype was completed at the Nagoya plant of Mitsubishi in November 1939 and transported to Kagamigahara airfield where, powered by two 653 kw (875 hp) Mitsubishi Ha-26-I engines, it made its first flight. Provision had been made for one 7.62 mm (0.30 in) Type 89 machine gun to be operated by the radio operator. During flight testing a speed of 540 km/h (335.5 mph) was attained at 4,000 m (13,125 ft). Performance was not up to expectations and the more powerful Ha-102 engine was fitted in production aircraft, which were known as the Army Type 100 Model 1 (Ki-46-I). These aircraft were used for pilot training and intensive service evaluation.

Full scale production was launched at Nagoya, the first of the Ki-46-Otsu (Ki-46-II) models being flown in March 1941 and differing in having the Ha-102 engines and larger propellers, fuel capacity being augmented by the introduction of wing leading edge tanks, increasing capacity to 1,657 litres (364 Imp gals). A speed of 604 km/h (375 mph) was achieved at 5,800 m (19,028 ft) and endurance was 5.8 hours at 426 km/h (265 mph). Wherever Japanese forces struck in South East Asia the area was first reconnoitred by aircraft of this type, usually evading fighter interception due to the height at which it flew, its performance, and the fact that radar was not available at the time to detect its approach early.

Mitsubishi took advantage of the Ha-112-Otsu (Army type 4) engine which provided 1,119 kw (1,500-hp) for take-off and developed the Ki-46-Hei (Ki-46-III). In this variant the fuel capacity was increased to 1,895 litres (417 Imp gals) and provision was made for a 460 litre (101 Imp gal) ventral tank. The machine gun was not installed and the stepped pilot’s windscreen gave way to an unbroken curve from the extreme nose to the rear of the radio operator’s glazed canopy. Two prototypes were built at Nagoya and a speed of 630 km/h (391 mph) at 6,000 m (19,685 ft) was achieved, with a range of 4,000 km (2,485 miles) at 414 km/h (257 mph). Final variant was the Ki-46-IVA with 1,119 kw (1,500 hp) supercharged Mitsubishi Ha.112-IIRu engines with exhaust driven turbines and with water methanol injection.

A number were captured and tested by the Allies. One Ki-46-IIIA, tested by the USAF at Hollandia in what was the Dutch East Indies, with the benefit of high-octane fuel, recorded 684 km/h (425 mph) at altitude, easily outpacing the Lockheed P-38 Lightning chase plane. In May 1944, when the first Boeing B-29s were making raids on the Japanese homeland, modifications were made to deliver ‘Dinah’ fighters fitted with two 20 mm Ho-5 cannon in the nose, an obliquely mounted 37 mm Ho-203 cannon, the re-introduction of the stepped windscreen, and a decrease in the fuel capacity. These aircraft were known as the Ki-47-HeiKAI and some 200 conversions were made but they did not enjoy a great amount of success. A total of 1,742 Ki-46s was built and only one is known to survive, this being a Ki-46-III (serial 5439) preserved at the RAF Museum at Cosford, UK this aircraft being restored in 1993 with aid provided by the Japanese company Mitsubishi.

Many reconnaissance flights were made over Australia by the type and at least nine examples are known to have been shot down. Most were operated by the 70th Independent Squadron of the Imperial Japanese Army, and at least one by the 202nd Kokutai of the Japanese Navy. The first was intercepted on 6 February 1943 by a Spitfire of No 54 Squadron, crashing into the sea near Darwin, NT. The second was shot down on 7 March 1943 by a No 457 Squadron aircraft near Lee Point north of Darwin. On 18 July 1943 serial 2414 was shot down by a No 457 Squadron aircraft near Coomalie, NT and parts were recovered to Darwin.

On 17 August 1943 serial 2273 was shot down over Fenton Airstrip, NT by a No 457 Squadron aircraft; serial 2250 was shot down by a 457 Squadron aircraft near Melville Island; and Wing Commander C R Caldwell of No 452 Squadron shot one down near Cape Fourcroy. On 20 July 1944 whilst reconnoitering Drysdale River Mission another was shot down and crashed near Truscott Strip. The wreck of another is known to be at Gasmata on New Britain.

Parts of serial 2250 have been recovered and delivered to the 70th Japanese Reconnaissance Squadron Association in Tokyo and parts of another have been recovered and placed on display at the RAAF Association Museum at Bulls Creek, WA.

One example (serial 2783) was surrendered to New Zealand forces at Jacquinot Bay, New Britain at the end of the war but, due to lack of shipping space, the whole aircraft could not be shipped for preservation and only the engines and propellers ended up in New Zealand. In 2003 the wreck of the ‘Dinah’ was conveyed to Lae and eventually was exported to Melbourne, VIC. Its eventual fate is not known. A Ki-46-II of the 10th Dokuritsu Dai Shijugo Chutai was noted at Gasmata in April 1944 almost complete and is believed to have been recovered to Australia for exhibition but was destroyed ‘in one of the great scrap drives of the 1950s.’

Major components of a ‘Sonia’, ‘Betty’ and ‘Dinah’ were recovered to Australia in about 1943 for the ATAIU (Allied Technical Air Intelligence Unit) for technical evaluation at the unit’s Hangar 7 at Eagle Farm, Brisbane, QLD but nothing seems to have come of any of them. They certainly were not rebuilt and it is assumed they were eventually scrapped.