Yokosuka E14Y

 

During the 1930s the Imperial Japanese Navy (IJN) built a hangar-equipped-submarine fleet to perform reconnaissance duties with small recon aircraft. This was considered a tactical advantage as it allowed to carry out surveys without being detected.

For this task, some submarines were modified and the IJN issued a specification (named 12-shi) for a submarine-based airplane with reduced dimensions and detachable parts that could be assembled and disassembled in 10 minutes or less. For this project the Yokosuka Naval Air Technical Arsenal was contacted and tasked with the design of such aircraft. 

The E14Y 12-shi, designed by Mitsuo Yamada, and powered by a single Hitachi GK-2 Tempu 12 radial engine which yielded 335 hp of power, 296 hp at sea level, droving a two-bladed propeller, flew for the first time in September 1939 and was tested against the Watanabe E14W1, against the which, showed good performance with, however, some faults like stability problems and a lower range than expected. Those problems were solved in early 1940 by modifying the empennage and applying additional drift at the lower part of the fuselage. Once modified, it was tested again by the IJN showing satisfactory results and being accepted into production. 

Mass-production of the type was assigned to Watanabe which manufactured a total of 125 E14Y1 (the production variant of the type) between 1941 and 1943, when production of the type ceased. The E14Y1 (code-named 'Glen' by the Allied) was powered by a single Hitachi Tempu 12-cylinder radial engine rated at 340 hp for take-off and 300 hp at sea level. It was armed with one flexible rearward-firing 0.303 in machine gun placed at the observer's post and could carry up to 60 kg (132 lbs) of underwing bombs. The fuselage was made of steel tube structure covered with canvas, wooden panels and light alloy metals. It had a cockpit enclosed in a glazed long canopy which run up to the rear part of the fuselage. It had a crew of two, pilot and observer, sitting in a tandem configuration. The wings, of rectangular shape, were made out of wood with light alloy spars and covered in cloth. They were mounted low on the fuselage and had two pair of ailerons mounted outside of the wings trailing edge. Floats were metallic and were connected to the lower part of the fuselage by a removable tubular frame.

The E14Y1 was used extensively in the I-7, I-9 and I-15 submarine classes of the IJN. It was operationally used for the first time on 17th December 1941 to fly a recon mission over Pearl Harbor, launched from submarine I-7 to evaluate the damage inflicted on the US Navy ten days before. 
During the whole war it was used to perform recon flights over Allied territory. On 26th February 1942 the submarine I-25 emerged off the northern tip of King Island in Bass Strait, off the coast of Victoria, Australia and a E14Y was launched on a recon mission over the port of Melbourne. The flight took three hours over the course of which they successfully flew over Port Phillip Bay and observed the ships anchored off Melbourne before returning to I-25 and landing on its floats besides the submarine.
The E14Y1 was also the only Japanese aircraft to fly over New Zealand during World War 2, and second enemy aircraft to do so since the German Friedrichshafen FF.33 'Wölfchen' in World War 1. On 8th March 1942 Nobuo Fujita from I-25, photographed the Allied-build up at Wellington harbour. On 13th March he flew again over New Zealand, this time over Auckland, before the I-25 proceeded to Australia. A second flight over Auckland took place on the night of 24-25th May, this time by Warrant Officer Susumo Ito who flew its E14Y1 over the city, before returning to the I-21 submarine. Ten days later, on 1st June, Ito flew the reconnaissance flight which preceded the Japanese attack on Sydney harbour which sank the HMAS Kuttabul depot ship killing 21 seamen.
The submarine I-9 was also observed off the coast of New Zealand in early 1943, however, there are no records of any recon flight having been launched.
But its most famous flight was the incursion on mainland USA that took place on 9th September 1942, near Cape Blanco, Oregon.
On that day, submarine I-25 approached the western coast of the United States and, at the command of Nobuo Fujita and observer Shoji Okuda, the E14Y1 was equipped with four phosphorous incendiary bombs weighing 76 kg (168 lbs) each. They took off and flew 50 miles (81 km) inland, where the bombs were dropped, intended to cause forest fires, although the initial plan was to just drop propaganda leaflets in a nearby town. This first incursion was followed by a second one, which didn't cause any serious damage and was aimed to have an important psychological impact on the American population. 

Sources:

1st https://it.wikipedia.org/wiki/Yokosuka_E14Y (translated)

2nd https://en.wikipedia.org/wiki/Yokosuka_E14Y

3rd https://www.valka.cz/Jokosuka-E14Y1-Glen-t27318

4th https://www.valka.cz/Jokosuka-E14Y-12-Si-t45930