Sometimes described as a cross between a Messerschmitt Bf 109 and a North American P-51 Mustang, the Kawasaki Ki-61 certainly had the distinctive nose shape associated with an inverted V-12 inline engine, the Kawasaki Ha-40 being in effect a Daimler- Benz DB 601A built under licence. The Ki-61's designers, Takeo Doi and Shin Owada, had moreover worked under the German Richard Vogt, In December 1940 they were instructed to go ahead with the Ki-61, and one year later the prototype was flown. The first production Ki-61-I fighters were deployed operationally in April 1943 when the 68th and 78th Sentais arrived in New Guinea. Named Hien (swallow) in service (and codenamed 'Tony' by the Allies), the new aircraft proved popular with its pilots, being unusually well-armed and armoured, and the type was at least a match for opposing American fighters. Its armament (of four 12.7-mm machine-guns) proved inadequate to knock down enemy bombers, however, and the Ki- 61-I KAIc was introduced with a pair of 20-mm cannon in the nose, these being replaced in a small number of Ki-61- I KAId fighters by two 30-mm cannon. The Ki-61- I and Ki-61-I KAI remained in production until 1945, but in 1944 they were joined in service by the Ki- 61-II with more powerful Kawasaki Ha- 140 engine (producing 1119-kW); with a top speed of 610km/h this would have been an excellent fighter but for constant engine problems; yet when fully serviceable the Ki-61-II was one of the few Japanese fighters fully able to combat the Boeing B-29 at its normal operating altitude, particularly when armed with four 20-mm cannon. Excluding prototypes and development aircraft, production totalled 1,380 Ki-61-Is, 1,274 Ki- 61-I KAIs and 374 Ki-61-Ils.

General characteristics

* Crew: One
* Length: 8.94 m (29 ft 4 in)
* Wingspan: 12.00 m (39 ft 4 in)
* Height: 3.70 m (12 ft 2 in)
* Wing area: 20.00 m² (215.28 ft²)
* Airfoil: NACA 2R 16 wing root, NACA 24009 tip

* Internal fuel capacity: 550 l (121 Imp gal)
* External fuel capacity: 2 x 200 l (44 Imp gal) drop tanks

* Empty weight: 2,630 kg (5,800 lb)
* Loaded weight: 3,470 kg (7,650 lb)
* Powerplant: 1× Kawasaki Ha-40 liquid-cooled inverted V12 engine, 875 kW (1,175 hp)

Performance

* Maximum speed: 580 km/h (360 mph) at 5,000 m (16,405 ft)
* Range: 580 km (360 mi)
* Service ceiling: 11,600 m (38,100 ft)
* Rate of climb: 15.2 m/s (2,983 ft/min)
* Wing loading: 173.5 kg/m² (35.5 lb/ft²)
* Power/mass: 0.25 kW/kg (0.15 hp/lb)
* Time to altitude: 7.0 min to 5,000 m (16,405 ft)

Armament

* 2× 20 mm Ho-5 cannon, 120 rpg each
* 2× 12.7 mm (0.50 in) Ho-103 machine guns, 250 rpg each
* 2× 250 kg (551 lb) bombs