Ki-61-I-Hei Hien

### Armament

2× wing mounted 20 mm (0.79 in) MG 151 cannons2× nose mounted 12.7 mm (0.50 in) Ho-103 machine guns

### Loaded Weight

3,130kg

The ***Kawasaki Ki-61-I-Hei Hien*** (飛燕, "flying swallow") is a fighter plane fielded by the Imperial Japanese Army Air Service during WWII. The aircraft's designation is "***Army Type 3 Fighter***" (三式戦闘機). It was the only mass-produced Japanese fighter of the war to use a liquid-cooled inline V engine. Initially, the Hien was often mistaken for the Messerschmitt Bf 109, Heinkel He 100 or the Macchi C.202 Folgore, this led to the Allied reporting name of "***Tony***".

## Background

The Ki-61 Hien is the brainchild of  Takeo Doi and his deputy Shin Owada in response to a late 1939 tender by the IJAAF for two fighters. Each is to be built around the Kawasaki Ha-40, a licensed version of the Daimler-Benz DB 601A. The resulting aircrafts were the Ki-60 and the Ki-61. Both single-seat, single-engine fighters used the same basic construction, being of all-metal alloys with semi-monocoque fuselages and three-spar wings, with alloy-framed, fabric-covered ailerons, elevators and rudders. Although the former was to be a heavily armed specialised interceptor, with a high wing loading; while the latter was to be a more lightly loaded and armed general-purpose fighter, intended to be used mainly in an offensive, air superiority role at low to medium altitudes.

Priority was given to the Ki-60, which first flew in April 1941. And the result was a total mess. The aircraft's takeoff distance was too long, the climb rate was disappointing, the controls were too heavy and unresponsive, the stalling speed was extremely high, in flight the aircraft displayed some lateral instability and the spinning characteristics were described as "dangerous". The Ki-60 was only able to achieve 548 km/h which is way lower than the projected 600km/h. Modifications were hastily made to the second and third prototype to counter these flaws, while the top speed increased slightly, the flight characteristics were still disappointing. In the end the IJAAF had already chosen the Ki-44 Shoki, and the Ki-60 was out of the picture. And by December 1940, Takeo Doi and Shin Owada focused entirely on the Ki-61, hoping to exploit lessons learned from the disappointing flight characteristics of the earlier design and come up with a better plane.

Unlike most other Japanese fighter planes, the Hien has some form of protections, the plane has a self-sealing fuel tanks, an armored windshield as well as 13 mm (.51 in) of armor plating behind the pilot. The evenly-tapered wings had an aspect ratio of 7.2 with a gross area of 20 m² (215.28 ft²) and featured three spars, compared to the Bf 109 E which has just one and the C.202 which has two. While this design made the wing rather heavy, it also made it very sturdy and capable of mounting high caliber guns.

The first prototype of the Ki-61 first flew in December 1941 at Kagamigahara Airfield. Although test pilots were enthusiastic about its self-sealing fuel tanks, upgraded armament, and good dive performance, the wing loading of 146.3 kg/m² (30 lb/ft²) at an all-up weight of 2,950 kg (6,500 lb) was viewed with scepticism by many of the senior officers of the IJAAF, who still believed in the light, highly manoeuvrable, lightly armed fighter epitomised by the then new Nakajima Ki-43-I-*Hei* which had a wing loading of 92.6 kg/m² (19 lb/ft²) (and even that was considered borderline compared to the earlier Ki-27).

To address these concerns, Kawasaki staged a fly-off between two Ki-61 prototypes and a Ki-43-I Hayabusa, a pre-production Ki-44-I Shoki, a defector-flown LaGG-3, a Bf 109E-7, and a captured P-40E Warhawk. The Ki-61 proved the fastest of all the aircraft and was inferior only to the Hayabusa in manoeuvrability.

The Ki-61 was the last of the fighters powered by the DB-601 or its foreign derivatives, while initially it caused some pain and consternation among Allied pilots whose P-40 Warhawks were simply outclassed by it. The Hien was soon overshadowed by fighters with more powerful engines. By the time it first flew in December 1941 (one year after the Macchi C.202's first flight and three years after the first Bf 109E), the engine was already underpowered compared to the new 1,120 kW (1,500 hp) inline or 1,491 kW (2,000 hp) radial engines being developed (and already nearing the mass-production stage) to power the next generation of combat aircraft such as the Republic P-47 Thunderbolt. Moreover, the inline Ha-40 engine proved to be an unreliable powerplant that's rushed into service, this resulted in the obsolescent Ki-43 still forming the bulk of the JAAF's fighter capability.

## Performance

### Advantages

The Hien is best described as a "Jack of all trades", while not outstanding at anything, it's instead even across the board. While it may loose in a turn fight against the more agile Hayabusa, the Hien is still generally good at standard maneuvers. The Hien can also carry a decent amount of explosives, up to 500 kg of bombs, but doing so will weigh down the aircraft and hamper its performance. The diving speed of the Hien is also rather decent, and rivals who will try and dive away from a Hien will likely learn that the hard way. The overall firepower is also good, having both 12.7mm machines guns as well as imported MG 151 20 mm cannons that can fire lethal *Minengeschoß* explosive shells*.* Ammunition is also plentiful, with the cannons holding a total of 300 rounds and the machine guns hold 800 rounds. Having a self-sealing fuel tank mean that the Hien is less prone to fires when struck by enemy bullets, but it's still rather vulnerable to fire.

### Drawbacks

Despite being better armored than most other fighters in Ijitsu's skies, the Ki-61 is no Thunderbolt and some well placed rounds will be enough to bring it down. The speed advantaged of the Ki-61's powerful V12 engine is not all that evident, as it's only about 20km/h faster than early model Zeros. Also, unlike most Japanese fighters, the Hien doesn't have a bubble canopy, giving the pilot limited rear vision. The engine of the Hien also poses several problems, as it's an inline engine which is rather rare amongst Japanese aircrafts which tend to prefer radial engines, it's likely that most technicians are fairly inexperienced with this engine type and have trouble maintaining/repairing it, and the Ha-40's various reliability issues certainly don't help.

## Variants

Interestingly, the Ki-61 appears to be even more common than its predecessor in the world of Ijitsu. Three known factions are known to operate Ki-61 Hiens.

The Shirokuma sky pirate clan flew Ki-61s, originally they were known to fly Mitsubishi A5Ms instead, the methods behind their rapid acquisition of vasty superior fighter planes are unclear, but it was highly likely they acquired it via mercenary contracts. A Shirokuma's Hien is painted mostly white, while the top of the nose is colored black, the propeller hub and blades are painted brown and the tail is painted green. A blue stripe runs along the center of the fuselage on both sides. The Shirokuma's icon: the head of a red eyed bobcat (strange considering that the clan's name Shirokuma/シロクマ means "polar bear") licking the corner of its mouth positioned within a black circle and flank by two vertical blue stripes, can be found on both sides of the fuselage near the tail section and on the tips of both wings. Several rows of yellow stripes decorate the Hien's rudder and elevators. The paint on the aircraft is somewhat worn, hinting either these Hiens are second hand ones or simply poor paint quality.

The Aleshma City's guard forces also fly Hiens, this version of the Hien is painted plain white, although the top of the nose is painted black and the of the propeller is painted brown like the Shirokuma Hien. The emblem found on this version of the Ki-61 is the Japanese character "荒" (meaning "rough") painted in dark blue in a circular fashion, it can be found on the both sides of the fuselage and on the tips of both wings. On the vertical stabilizer, an orange character resembling a modified version of the globus cruciger (♁) with two additioal orange dots, making it resemble the Japanese character of denial (否).

The Shouto Vigilantes' Hien sports a camouflage scheme almost identical to that of a Polish Air Force's Hawker Hurricane Mk I's. Although the Shouto's emblem is circular whereas the Polish emblem is rectangular.