Hasegawa 1/48 Ki-61-1c 'Hien'

    The Japanese Army Air Force was extremely conservative in its view of what constituted a good fighter.  As a result, when the JAAF entered the Pacific War, its main fighter was the obsolete (by Western standards) Nakajima Ki.27 (Nate), and its newest fighter - which only equipped one fighter Sentai - was the already-obsolescent Ki.43 Hayabusa (Oscar).  While both fighter were highly-maneuverable and could give Western opponents fits, an Allied fighter pilot had only to keep his speed up and avoid high-g "dogfight" maneuvering in the horizontal plane to neutralize the good qualities of either fighter, with the Allied pilot able to break off combat at will through use of superior speed overall, and higher diving speeds.

      The first JAAF fighter to meet Western standards to see combat in the Pacific War was the Kawasaki Ki.61, known as the Type 3 Model 1 land-based interceptor.  The Japanese name was Hien, which translates as "Flying Swallow"; the Allied code name was "Tony."  First encountered over New Guinea in 1943, the Tony would give good account of itself through the remainder of the Pacific War, and was considered by its opponents to be one of the most dangerous Japanese fighters, and very difficult to shoot down.

      Kawasaki had acquired the manufacturing rights to the new series of Daimler-Benz aircraft engines in 1937, though it would not be until 1940 that the JAAF would take advantage of this fact.  In February 1940, Kawasaki received development contracts for two fighter designs to be powered by the Daimler-Benz DB601A - the Ki.60 and Ki.61.  Of the two, the Ki.60 was a very straightforward attempt to emulate European design standards, with the result being a "heavy" fighter with a top speed of 350 mph - the fastest of any JAAF aircraft to date when it first flew in March 1941 with a German DB601A engine.  It was, however, ahead of its time so far as the JAAF was concerned, and further development was given over to the lighter, more "Japanese" Ki.61.

      Kawasaki had simultaneously been working on the Ha.40, an indigenous development of the DB601A that was lighter than the original German engine, and rated at 1,175 h.p.  Unfortunately, this lightness of design would ultimately be the downfall of the engine, because it could not stand up to prolonged operational use, in addition to being subject to poor quality control in production.    

     The Ha.40 powered the Ki.61 prototype which first flew in December 1941.  In early tests the aircraft achieved a top speed of 368 mph, though this would never be matched by production versions until the introduction of the higher-powered Ki.61-II in 1943. Twelve additional prototypes were built, and were flown in comparison with captured U.S. P-40Es from the Philippines and a German Bf-109E; the Ki.61s were superior to both. 

      The first production Ki.61, powered by the production version of the Ha.40, the Type 2 Ha.60/22, rated at 1,100 hp and providing a top speed of 348 mph. The initial production version, the Model 1, was armed with two 7.62mm machine guns in the fuselage, and two 12.7mm weapons in the wings. The Model 1 entered combat over New Guinea in April, 1943, where it was first assumed by the Allies to be a development of the Bf-109.

      In August, 1943, production switched to the Model 1A, in which the 12.7mm wing guns were replaced by German 20mm Mauser cannon.  Only 800 of these weapons were obtained from Germany, limiting production of the Model 1A to 400 aircraft. An interim production version, the Model 1B, replaced the previous armament with 4 12.7mm weapons in both the fuselage and wings.  In January 1944, production switched to the Model 1C, with substituted domestically-designed Ho-5 20mm cannon for the wing armament. 

     After fighting in New Guinea, the Ki.61 next appeared over Rabaul, followed by deployment to China, where it proved more than a match for the P-40s of the 23rd Fighter Group, which in turn led to expedited equipment of the 23rd FG with the P-51 Mustang in early 1944. The Ki.61 equipped units based in the Philippines in 1944.

      Allied fighter pilots respected the Ki.61, which provided better armor protection for the pilot and engine than other Japanese fighters, while providing excellent maneuverability and a diving speed that allowed it to keep up with any Allied fighter that attempted to disengage by diving.  

     The appearance of the B-29 in significant numbers over Japan, beginning in November 1944, led to the return of as many Ki.61-equipped units to the Home Islands as possible.  In limited combat against the China-based B-29s in the summer of 1944, the Ki.61 had proven to be one of the few Japanese fighters capable of meeting the B-29 at altitudes over 30,000 feet.  It equipped Japanese Taiatari (special attack) units, such as the 244th Sentai based outside Tokyo; its design allowed for ramming attacks against B-29s that gave the pilot a good chance of a successful bailout just before impact. 

     Unfortunately for the Ki.61, the Ha.40 engine became an ever-increasing source of trouble, varying greatly in rated power between specific engines due to poor production quality control.  The designed-in lightness of the engine led to main-bearing failures and oil system faults.  By the Spring of 1944, production of the Ki.61 was lagging due to the fact that production of the Ha.40 had been cut back in an attempt to restore production quality.  Production of the engine stalled out completely in the summer of 1944 due to a severe shortage of cylinder blocks and crankcases. Further development of the Ki.61 in the Ki.61-II and -III versions with a higher-powered development of the Ha.40 - the Ha.140 - were completely unsuccessful due to the failure of the engine, though when the engine worked the Ki.61-II was the only Japanese interceptor capable of maintaining combat formation up to 33,000 feet.

     To my mind, the Ki.61 Hien is the best-looking Japanese fighter of the Pacific War, from a strictly-aesthetic point of view, with its narrow fuselage and pointed nose, and graceful wings. Tamiya produced a 1/50 Ki.61 in the late 1960s, but this suffered major fuselage outline irregularities due to the fact it was designed to take an electric motor inside, which additionally meant that interior cockpit detail was non-existant. Otaki released a Ki.61 in the early 1970s in 1/48 scale, which is accurate and still available, though it has a bit more recessed surface detail - in the form of rivets - than one might care for today, as well as a cockpit in need of detailing. Hasegawa first released a Ki.61 in 1/72 scale in 1974.  This was the first accurate kit of this airplane released by any manufacturer, with very nice (for the time) cockpit detail.  This kit is still in production nearly 30 years later, and can be safely recommended to any modeler who builds in the smaller scale.