Main Menu
User Menu

Military history website

Kawasaki Ki 48 Sókei [Lily]

Kawasaki Ki-48 Sokei

川崎 キ48 ・ 九九式双发轻爆击机

Kawasaki Ki-48 - list of versions

キ 崎 キ -48

ū 式 双 発 軽 爆 撃 機 - Kyūkyūshiki sōhatsu kei bakugekiki - Army twin-engine light bomber Type 99

Japanese name: Sokei

Allied reporting name: Lily

Designation Aircraft design - description
Kawasaki Ki-48 prototypes 4 prototypes and five pre-production aircraft, the first prototype was completed in July 1939
Kawasaki Ki-48-Ia a Ki-48-Ib 557 aircraft, since June 1940, both versions differed from each other only machine gun hangers.
Kawasaki Ki-48-IIa[/b :aaaaaa] A total of 1,408 Version II aircraft were delivered. Assembly of Ha-115 engines with higher power, allowed the installation of armor plates
to protect the crew, engines and fuel tanks.
Kawasaki Ki-48-IIb ] got into the wings of the lattice aerodynamic brakes, to reduce speed in a dive (it was the end of the prototype Kawasaki Ki-66).
The weight of the bombs increased to 800 kg.
Kawasaki Ki-48-IIc [col:aaaaaa ] the last mass-produced version, end of production October 1944, improved defense by mounting a machine gun Ho-103 in the dorsal shooting range,
or additionally another to the bow. The plane was overloaded.
Kawasaki Ki-48-II KAI suicide modification, the crew was two-seater, 800 kg of explosives and a long detonator on a pole in front of the bow.
Kawasaki Ki-81 [ col:aaaaaa] project and unfinished prototype of a multi-seat fighter, designed on the basis of Kawasaki Ki-48-II
Kawasaki Ki-174 [ col:aaaaaa] project of attack aircraft for suicide raids was designed on the basis of Kawasaki Ki-48-II

Made a total of 1,997 aircraft of this type.
Prototype production took place in the factory Kaw 崎 航空 工 機 業 株式会社 - Kawasaki Kōkūki Kōgyō Kabushiki Kaisha, Kagamigahara, near Gifu [img_6:aaaaaa comment = Japan (JPN)][/img_6:aaaaaa]

Sources used:
René J. Francillon Ph.D., Japanese Aircraft of the Pacific War, 2nd edition, London, Putnam & Company Ltd., 1979, ISBN 0-370-30251-6.
Richard M. Bueschel, Kawasaki Ki.48-I/II Sokei in Japanese Army Air Force-CNAF & IPSF Service, Aircam No.32, Canterbury, Kent, UK, Osprey Publishing Ltd., 1972, ISBN 0-85045-133- 7.
URL : : 0
Kawasaki Ki-48
創形 - Sokei
九九式双発軽爆撃機 / Kyukyúshiki sohacu keibaku gekiki / army light bomber type 99
Allied codename: Lily

The Japanese Army Air Force had overwhelming air superiority during its war campaign in China. The Chinese air force was weak and the Japanese aircraft were thus superior to almost anything the enemy could deploy against them. The word almost means that there were few exceptions. These exceptions were the Soviet I-153 and I-16 fighters and the light bomber Tupolev SB-2 (Skoroknoi bombardirovschik). The Soviet Union, as part of its international aid, supplied China with several dozen of these modern aircraft (there were about 62 SB-2s). The aircraft with Chinese insignia flew with both experienced Soviet and freshly trained Chinese crews from November 1937. The training center was in Xinjiang Province, and it was here that these aircraft also first intervened in combat. The fast light bomber SB-2 really impressed the Japanese pilots, the speed of these bombers was almost the same as the most advanced Japanese army fighters Nakajima Ki-27, this speed was an important defensive feature of the SB-2.

The command of the Imperial Army Air Force (大日本帝国陸軍航空本部 Dai-Nippon Teikoku Rikugun Kōkū Hombu) carefully analyzed the deployment and characteristics of these bombers and very soon concluded that it needed a bomber of similar quality for its army units.

The company 川崎航空工機業株式会社 - Kawasaki Kōkūki Kōgyō Kabushiki Kaisha (hereafter Kawasaki) received an order for a light fast bomber as early as the end of December 1937, It was to have a top speed of at least 480 km/h, a cruising speed of at least 350 km/h, a defence of three to four 7.7 mm movable machine guns and a bomb load of at least 400 kg. The Kawasaki factory design team was advised that the installation of inline water-cooled engines was not desirable (their use was advocated by the Kawasaki factory), as emphasis was placed on the ability to operate in areas with cold climates (Dai-Nippon Teikoku Rikugun Kōkū Hombu considered fighting the USSR in the Siberian region).

Kawasaki's chief designer, engineer Takeo Doi, took over work on the bomber project as early as January 1938. He designed a twin-engine all-metal aircraft with a centre-flat wing arrangement, which was powered by two Nakajima Ha-25 radial engines with a take-off power of 950 hp. The crew consisted of four men and for its defence it had three Type 89 7.7 mm calibre movable machine guns, a weapon already old but still quite popular in the Japanese Army Air Force. One machine gun was in the forward gunnery position, the second in the gunnery position on the back of the fuselage and the third in the flapping gunnery position in the fuselage extension behind the bomb bay. Various combinations of bombs up to a total weight of 400 kg could be hung in the bomb bay, most commonly used in attacks on infantry were 24 bombs of 15 kg each or in the case of attacks on protected targets 6 bombs of 50 kg or 4 bombs of 100 kg.

Construction of the first four prototypes was delayed so much that the first prototype was not flown until July 1939, with army trials beginning the following month. The first prototypes struggled with vibration and tail flutter in addition to the usual childhood ailments. Five preproduction machines were soon involved in the tests, Takeo Doi and his design team modified the tail surfaces, and the aircraft, so modified, was accepted into the Army Air Force's armament in December 1939 under the designation "Army Type 99 Model 1A twin-engine light bomber", or Kitai for short in the designation system Ki-48-Ia.

Mass production got underway at the Gifu factory in early summer 1940, and by the autumn of that year it was recognized as the first combat-capable unit to be armed with the new light bombers; it was the 45th Sentai operating in northern China, and Allied intelligence named the new bomber with the female name Lily. The first combat experience was great, the aircraft was designed specifically for the Chinese battlefield, the Chinese air force was already very weak and ineffective, the Sokei aircraft, that was its combat name. The Ki-48 bombers flew, moreover, accompanied by their own fighters. This almost idyllic situation was soon to change, however, for once the Ki-48-Is reached the battlefield, where more modern Allied fighters were operating against them, the weak and ineffective armament, inadequate passive protection, and already lagging performance became apparent.

To help, a new version designated Ki-48-II was flown as early as February 1942, a prototype of this version was flown, powered by more powerful Nakajima Ha-115 engines of 1,150 hp. The higher power of the engines was used to eliminate the increase in take-off weight, as armour protection for the crew compartment was introduced and protective fuel tank covers were also installed. The situation was often paradoxical, as the lightweight Ki-48 structure was disproportionately loaded with armour plates of 6.5 to 16.5 mm thickness! The hull structure was also strengthened, but the machine gun armament remained weak.

The new machines Ki-48-IIa were produced from April to October 1942. From July 1942 to October 1944, another version Ki-48-IIb was produced, which was originally intended to supplement the previous version but eventually replaced it entirely in production. This version had flip-up braking grilles in the wings to reduce the speed of dive flight. The introduction of this version into production and its relatively successful deployment eventually led to the cancellation of the dedicated dive bomber project Ki-66. The bomb load could be increased to 800 kg at the expense of range, but the weak defensive armament of three rifle-calibre machine guns still remained.

This weakness was at least partially addressed by the designers in the next version, the Ki-48-IIc of 1943. This version carried a single half-inch Ho-103 machine gun in the dorsal gunnery, the same weapon was installed by the armourers in the field workshops in the nose, this retrofitted machine gun could be fired from the side windows in the nose. Here, however, the development of the aircraft has already come full circle, the effectiveness of the defensive armament has increased, but the performance and payload of the bombs have decreased.

The Ki-48 was a typical pre-war light bomber that carried with it certain design limitations, but in the Japanese Army Air Force, despite these limitations, it performed tactical missions throughout the war. Ki-48s suffered the sad fate of many Japanese aircraft - suicide attacks, many machines were disarmed and the weight saved was used for the higher weight of bombs or explosives carried, there was also a special purely suicide modification (not a production model) designated as Ki-48-II KAI, the aircraft was loaded with 800 kg of explosives, the crew was two-man, and the aircraft was recognizable by its distinctive detonator mounted on a two-meter pole in the nose.

Further development: the design team began work on a project for an escort fighter aircraft based on the Ki-48-II version, this project was designated the Ki-81 and was soon discontinued by the Army Air Corps.

There was also the Ki-174 project, which was to be a factory-produced suicide version of the Ki-48-II.

At least one aircraft, more often written of as four machines, the Ki-48-IIb was used to test guided glide anti-ship bombs Mitsubishi Ki-148 I-Go-1B.

A total of 1,997 Ki-48 aircraft of all versions were produced.

Sources used:
René J. Francillon Ph.D., Japanese Aircraft of the Pacific War, Naval Institute Press, 1987, ISBN: 0 87021 313 X
Robert C. Mikesh and Shorzoe Abe, Japanese Aircraft 1910-1941, Putnam Aeronautical Books, 1990, ISBN: 1 55750 563 2
Lubomír Vejřík, The Rise and Fall of the Eagles of Nippon - Prologue, Edition-World of Wings Cheb, ISBN 80-85280-26-4
Václav Němeček, Vojenská letadla 3 vol., second supplemented edition, Naše Vojsko, Prague 1992, ISBN 80-206-0117-1
Richard M. Bueschel, Kawasaki Ki.48-I/II Sokei in Japanese Army Air Force-CNAF & IPSF Service, Aircam No.32. Canterbury, Kent, UK, Osprey Publishing Ltd., 1972 ISBN 0-85045-133-7
L+K 23/1978, Aircraft 39-45, Václav Němeček
author's archive
URL : : 0