Ki-48 Sokei Type 99 was supposed to be a worthy response to the Soviet high-speed bomber SB-2, which showed its complete superiority in the battles on Khalkin Gol. Developed under the leadership of Takeo Doi, the light twin-engine bomber was a two-spar cantilever midwing plane with an internal bomb bay and a retractable landing gear with a tail wheel. The power plant consisted of two 950 hp Nakajima Ha-25 radial engines. with., with screws of variable pitch. The crew of the aircraft - four people, in addition to the pilot - navigator, bombardier and radio operator could perform the functions of gunners. For this, the aircraft was equipped with three 7.7-mm Type 89 machine guns in the bow, upper and lower firing points. The bombs were suspended in the bomb bay, either 24 bombs weighing 15 kg, or 6 bombs weighing 50 kg.

Due to the workload of the company with work on fine-tuning the Ki-45, the design of the new bomber was constantly delayed, so the first four prototypes were ready only by July 1939, at the end of November the aircraft went into series, officially adopted by the JAAF on May 11, 1940 of the year.

Modifications

• Ki-48-I - the first serial modification with Nakajima Na-25 engines, produced from spring 1940 to June 1942. During this time, 557 aircraft of the Ki-48-Ia and Ki-48-Ib variants were built. which in their characteristics were close to the pre-production vehicles, but differed only in small details and the design of the rifle installations. The maximum speed is 480 km / h at an altitude of 3500 m, the bomb load is 400 kg.

• Ki-48-II is the second serial modification, developed taking into account the experience of the combat use of Ki-48-I bombers. The aircraft of this version received more powerful (1150 hp) Nakajima Ha-115 engines with two-stage superchargers, due to which the maximum speed, even despite the increase in the empty weight of the aircraft by 500 kg, increased to 503 km / h. In addition, sealed fuel tanks were installed on the new vehicles. The workplaces of the pilot and the bombardier were covered with armor plates 6.5-12.5 and 16.5 mm thick, 16.5 mm armor plates were also protected by boxes with ammunition. The bomb load has increased to 800 kg. Externally, the Ki-48-II differed from its predecessors only in the increased fuselage length by 15 cm. From April 1942 to October 1944, 1408 bombers of three variants were produced: Ki-48-IIa, Ki-48-IIb and Ki-48-IIc. Ki-48-IIb aircraft could be used as dive bombers, for which perforated brake flaps were installed under the wing consoles. The Ki-48-IIс model bombers were distinguished by enhanced defensive armament: on them the upper 7.7-mm Type 89 machine gun was replaced by a 12.7-mm Type 1 machine gun, and an additional 7.7-mm machine gun was located in the bombardier's cockpit - for shooting through side windows.

• Ki-48-II KAI - at the final stage of the war, most of the surviving bombers were used as kamikaze aircraft. The aircraft received the designation "Special Army Attack aircraft Type 99" and was equipped for the installation of an 800-kg bomb with a long fuse bar protruding in front of the fuselage.

Combat use. Ki-48 aircraft, which by the end of 1941 turned out to be the most widespread light bombers of the Japanese army aviation outside the Chinese front, operated in the Philippines, Burma, Malaya and the Dutch East Indies, where faced serious resistance and began to suffer huge losses. In battles with formidable, in comparison with Chinese, allied fighters, the Ki-48-I's shortcomings were clearly manifested: weak defensive weapons, low speed and strong vulnerability due to the lack of crew armor and the use of unprotected fuel tanks. To reduce combat losses, bombers began to be used only at night, which further reduced their effectiveness, which was already low due to the low bomb load of 400 kg.

The creation of the Ki-48-II modification was a big step forward in comparison with the Ki-48-I, but this did not radically correct the situation, since it was not possible to eliminate the main drawback - the weakness of small arms. Ki-48s were still easy prey for the more advanced and numerous Allied fighters. In the summer of 1944, further attempts to modernize the Ki-48 were abandoned, and the aircraft was deemed completely obsolete.

The allies have given the plane a codename - "Lily" ("Lily"). A total of 1977 aircraft were produced.

Photo	Description
	Drawing Ki-48-II Sokei type 99
	Ki-48 in flight

In September 1941, in "Kawasaki Kokuki Koge KK" began work on a specialized dive bomber designed to support troops on the battlefield. On assignment, the aircraft was supposed to be two-engine, carry armament from two 12.7-mm machine guns in the nose and one movable defensive 7.7-mm machine gun, firing back. Normal bomb load was determined at 300 kg, maximum - at 500 kg.

Using the experience of work on the Ki-45 fighter and the Ki-48 light bomber, Takeo Doi in October 1940 began work on the new Ki-66 aircraft, according to the requirements of the army. The bomber had a lot in common with his predecessors. It was a midplane for 1130-horsepower Hakajima Na-115 engines. Under the wing behind the engine nacelles, lattice-type air brakes were mounted. Armament consisted of two 12.7-mm type 1 machine guns in the nose of the fuselage and two 7.7-mm type 89 machine guns in the upper and hatch defensive installations. The crew consisted of a pilot and a radist arrow.

From October 1942 to April 1943, six experimental aircraft flew around, but, despite successful tests, the Ki-66-Ia was never launched into serial production, since it was only slightly superior to the already produced Ki-48-II. In the latter, air brakes were used, which were worked out on the Ki-66.

By the end of the work in October 1943, several projects based on the Ki-66 were considered - one prototype was converted to the Ki-66-Ib under the Hakajima HA 315-1 air-cooled engines with a capacity of 1360 hp, still under construction Ki-66-Ic for Nakajima Na-39 engines with a capacity of 2100 hp, Ki-66-Id for Nakajima Na-45 engines with a capacity of 1900 hp. and the Ki-66-II heavy fighter under the Na-315.

Armament. Two 12.7-mm type 1 machine guns in the forward fuselage and two 7.7-mm type 89 machine guns in the upper and hatch mountings; 300-500kg bombs.

Bibliography

• Kawasaki Ki-48 Sokei. / Evgeny Aranov /
• Japan Aviation. /A. Firsov /
• World War II Japanese aircraft. /Oleg Doroshkevich /
• Bombers of the Second World War / Vladimir Kotelnikov /