Aichi M6A

The Aichi M6A is a two-seater single-engined aircraft of attack Japanese of the Second world war. This float seaplane had the characteristic to be embarked on submarines.

Origin

In May 1942 the Japanese imperial Marine ordered the construction of a new class of submarines, baptized I-400. These submarines were to be able to transport a bomber in order to reach the continent of North America or others target strategic largely out of reach Japanese fleet or aviation. Measuring 5.670 tons with a crew of 144 men, able to cross with 18,7 nodes (30 km/h) surfaces some and 14 nodes (22,5 km/h) in diving, these submarines ready to traverse 60.000 km largest were ever built until 1962, date on which was launched the USA Lafayette. The Imperial Marine Japanese used already reconnaissance aircraft embarked on submarines, and the September 9th, 1942 a Yokosuka E14Y1 Glen catapulted by the I-25 submarine released 4 bombs with phosphorus improvised on a forest of the Oregon. But I-400 was to embark 3 planes of attack in a 30,5 m length tight compartment, the seaplanes being installed on carriages of catapult-launching and being launched by means of a 29,8 m length catapult located on the bridge before submarine. This one also had 8 torpedo tubes of 530 mm, of a gun of 140 and 10 anti-aircraft guns of various gauges.

Shortly after the launching of the I-400 program the Imperial Marine required of Aichi Kokuki KK to develop a special plane of attack with the quite particular characteristics: carrying a bomb of 250 kg or a bomb or torpedoes of 800 kg, the apparatus was to rest on two releasable floats and to reach 475 km/h with its floats, or 560 km/h the released floats. Moreover L `assembly and the catapult-launching of three planes were to be able to be done in less than 30 minutes. To be able to place the bomber in the cylinder 3,5 m in diameter which constituted its hangar on the bridge of the submarine, the chief engineer Toshio Ozaki drew a monoplane with low wing cantilever assembled on two floats in the catamaran. After disassembling of the two floats, the aerofoil was to swivel to 90° before coming to plate itself along the fuselage. The horizontal stabilizer was folded up to approximately 2/3 of the scale, like the drift, and the floats with their masts lined up in a separate compartment.

Production

First prototype M6A Seiran began its in-flight tests in November 1943. It was joined by a second prototype in February 1944 and the Imperial Marine, very satisfied with the first tests, ordered the launching of the series production and the realization of two terrestrial apparatuses before even the delivery of the last prototypes. But a violent one seism in the area of Nagoya in December 1944 then the American bombardments disturbed the production, and in March 1945 the evolution of the war forced the Imperial Marine to modify the I-400 program. On five submarines put in building site two only were completed, I-400 which had been launched on December 30th, 1944 and I-401 which had followed at the beginning of 1945. I-402 was modified for the transport of fuel and the two last abandoned. In compensation two smaller submarines, class AM, were modified to embark each one 2 M6A, but the Imperial Marine did not need more many planes. Using the already produced parts, Aichi completed finally 26 M6A1:

Aichi M6A1 : 8 prototypes, driving Aichi Atsuta 30 or 31 (Daimler-Benz DB-601 licensed product) of 1 400 ch.

Aichi M6A1 Seiran (晴嵐, `Orage per time calms') : catapult-launched Seaplane of attack embarked on aircraft carrier. 18 built specimens.

Aichi M6A1-K Nanzan (南山, `Mountain of the South') : terrestrial Apparatus of conversion and drive, 2 prototypes built. In addition to the retractable landing gear, the drift was appreciably shorter.

Aichi M6A2 : a specimen modified with an engine Mitsubishi Kinsei MK8P of 1 560 ch actuating a three-bladed propeller at constant speed.

In operations

The staff of the Imperial Navy having decided to block the Panama Canal, the 1e underwater flotilla (submarines I-400, I-401, I-13 and I-14) was made up under the orders of the Captain Tatsunoke Ariizumi, also ordering the 631e Air Corps which had 10 Seiran. 6 torpedes and 4 bombs were to destroy the lock of Gatun. While the pilots studied the objective by means of a model with large scales, the mechanics involved themselves to reduce to the maximum the set-up time of the planes. Enough quickly, it became possible with 4 men to prepare an apparatus with the launching of night in 7 minutes, to even catapult the three M6A1 and 15 minutes but without the floats, which involved the loss of the plane ineluctably once the mission accomplished. But whereas these preparations went good progress, Ariizumi accepted on June 25th, 1945 the order to attack the American fleet with damping in the atoll of Ulithi.

The 1e underwater flotilla installed on July 23rd but the Opération Hikari was a total fiasco. The submarines I-13 and I-14 were to deposit each one two Nakajima C6N1 Myrt on the island of Truk to carry out the recognitions necessary and to guide the bombers towards the largest ships, aircraft carrier or transport of troops. I-13 was damaged by an air attack then run by an American destroyer, and I-400 missed its go to have let pass a message. August 16th, 1945, Ariizumi learned that the war was finished and accepted order to travel towards Japan after having scuttled its planes. Seiran of I-400 had passed over edge after the floats were bored, and M6A1 of I-401 catapulted at sea.

An survivor

Only one M6A1 was captured by the Allies. Last built cell, this apparatus was found in the Aichi factory, was dispatched in the United States, and was regularly exposed to the air and sea base of Alameda, California. Transferred to the National Air & Space Museum in 1962, this apparatus then spent 12 years outside, no place not being available to the warehouse Paul E. Garber de Silver Hill, Maryland. The restoration of this single specimen finally began in June 1989 to be completed in June 2000. It is exposed today to Steven F. Udvar-Hazy Center, with Chantilly, Virginia.

Sources

Tadeusz Januszewski, Japanese Submarine Aircraft. Sandomierz, Poland/Redbourn, the U.K.: Mushroom Model Publications, 2002. ISBN 83-91632-72-5.
Robert C. Mikesh, Aichi M6A1 Seiran, Japan' S Submarine-Launched Panama Channel To bend. Bolyston, MY: Monogram Aviation Publications, 1975. ISBN 0-914144-13-8

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