The Yokosuka B4Y1 was a Japanese, metal-structure, metal-structure, on-board bomber bomber from the interwar period. The drive was provided by a single N radial motor akajima Hikari 2 with 843 hp. The flight of the prototype took place in 1935, and serial production continued in 1936-1938. Approximately 205 examples of this aircraft were built in its course. The deck armament consisted of a single 7.7 mm Type 92 machine gun. The plane could carry a torpedo weighing up to 80 kg or a load of bombs weighing up to 500 kg.
B4Y1 was created based on the technical requirements of the Japanese Navy command from 1934 for new on-board aircraft. The team of designers was headed by Sanae Kawasaki, who decided to use as many components and components as possible in the new aircraft - for example, the B4Y1 wings were almost entirely taken over from the E7K1 seaplane. Ultimately, the B4Y1 aircraft turned out to be a successful machine with good aerodynamic properties. Several plants were responsible for its production, mainly Nakajima and Mitsubishi. Aircraft of this type were embarked on the aircraft carriers Akagi, Hosho, Kaga, Ryujo and Soryu. It was also very heavily used at the beginning of the war in China (1937-1945).
The Nakajima E4N was a Japanese biplane seaplane from the interwar period. The drive (in the E4N2 version) was provided by a single engine Nakajima Kotobuki with a power of 580 hp. The prototype flight took place in 1930, and serial production continued in the years 1931-1933, ending with the production of about 150 copies of this aircraft. The deck armament consisted of two 7.7 mm machine guns. The machine could also carry a load of bombs weighing up to 60 kilograms.
The Nakajima E4N was commissioned by the Japanese Navy command to replace the E2N seaplane in the line. The new design still had a biplane layout, but mostly had slightly improved flight characteristics and a more durable structure. Several versions of the Nakajima E4N were created in the course of serial production. The first was the basic production version, the E4N2, which was adapted to operate from air catapults of large ships of the Japanese Navy. The second version (A4N2-C) operated from on-board aircraft carriers and had a wheeled instead of a float undercarriage. It could also operate from land bases. A version of the Nakajima P-1, which was a mail plane, also appeared. Nakajima E4N planes, especially in the E4N2 version, were replaced by Nakajima E8N planes.
Very often, the date of birth of naval aviation in the Imperial Japanese Navy (IJN for short, Japanese Nippon Kaigun) is March 16, 1923, when Lieutenant Sunishi Kira landed in his plane on board the Hosho aircraft carrier, which, moreover, entered service a year earlier (1922). It should be added, however, that in the course of the 1920s, many Japanese naval officers saw aircraft carriers as supporters of battleships and battleships, bearing in mind the great success of Admiral Heihachiro Togo at Tsushima in 1905. The technical level of the then Japanese on-board aircraft was also not the highest. However, this state of affairs began to change in the 30s of the 20th century, among others, due to the later Admiral Isoroku Yamamoto, who perceived the main weapon in the naval war in aircraft carriers. He was a strong supporter of the development of Japanese on-board aviation, which translated into the construction or modernization of such ships as Kaga, Akagi, Hiryu, Soryu and Zuikaku. Also, Japanese aviation structures not only reached the world leaders, but began to set standards in them, including the famous Mitsubishi A6M Zeke fighter or the Nakajima B5N Kate torpedo plane. This intense development led to the fact that when the war in the Pacific broke out, the IJN had 10 aircraft carriers, on which over 500 on-board machines were based, with well-trained crews. The first months of struggle in the Pacific showed how dangerous this weapon was. It should be remembered, however, that already during that war, the IJN had considerable problems, for example, to replace the A6M Zeke plane on a mass scale or to introduce a successful B5N successor to the line, i.e. the B6N Tenzen torpedo plane. Also, the process of training sea pilots turned out to be flawed and was distanced by the solutions used in the US Navy.