Aichi M6A

Aichi M6A
Name	Aichi M6A
Caption	An Aichi M6A1 Seiran in United States markings after the war.
Type	Submarine-launched attack floatplane
National origin	Empire of Japan
Manufacturer	Aichi Kokuki
Designer	Norio Ozaki
First flight	1943
Introduced	1945
Retired	1945
Primary user	Imperial Japanese Navy Air Service
Number built	28

Aichi M6A. The Aichi M6A Seiran was a specialized submarine-launched attack floatplane developed by the Aichi Kokuki company for the Imperial Japanese Navy during the latter stages of World War II. Designed to operate from the massive I-400-class submarine aircraft carriers, its primary mission was to conduct surprise aerial attacks against strategic targets such as the Panama Canal. The aircraft represented a pinnacle of Japanese aeronautical engineering, combining folding wings for storage, a powerful engine, and the ability to carry a substantial warload, though it saw extremely limited combat use before the war's end.

Development and design

The development of the M6A was directly tied to the ambitious I-400-class submarine program, conceived to project Japanese naval air power across vast distances. Under the leadership of chief designer Norio Ozaki at Aichi Kokuki, engineers created a compact, all-metal monoplane that could be stored in a watertight hangar aboard the submarine. Key design features included hydraulically folding wings, detachable floats, and jettisonable landing gear for a wheels-down configuration on land bases. The aircraft was powered by a single Aichi Atsuta engine, a licensed version of the German Daimler-Benz DB 601, providing strong performance. To facilitate rapid deployment, the Seiran could be assembled, armed, and launched from the submarine's deck in approximately seven minutes, a remarkable feat of operational planning intended for missions like the planned strike on the Panama Canal.

Operational history

The operational history of the Seiran was brief and anticlimactic due to the deteriorating war situation for Japan. By the time the I-400 and I-401 submarines were operational with their complement of Seiran aircraft in mid-1945, strategic priorities had shifted. The original mission against the Panama Canal was abandoned, and a new plan was formulated to attack United States Navy aircraft carriers at Ulithi atoll. However, before this attack could be launched, Japan surrendered following the atomic bombings of Hiroshima and Nagasaki and the Soviet invasion of Manchuria. The submarines were ordered to surrender, and their aircraft were jettisoned overboard or destroyed to prevent capture by Allied forces, resulting in no confirmed combat missions for the type.

Variants

Two primary variants of the M6A were produced. The main production model was the **M6A1 Seiran**, equipped with floats for submarine operations. A small number of aircraft were completed as the **M6A1-K Seiran Kai**, a land-based trainer version which featured a fixed, conventional undercarriage and a second cockpit for an instructor, intended to maintain pilot proficiency without the complexity of float operations. Plans for a dedicated land-based attack version without floats were discussed but never realized before the end of the war.

Operators

The sole operator of the Aichi M6A Seiran was the Imperial Japanese Navy Air Service. The aircraft were specifically assigned to the 631st Naval Air Group, which was formed to operate from the I-400-class submarine fleet. No aircraft were exported or transferred to other services, and all were rendered inoperative or destroyed by the conclusion of World War II.

Specifications (M6A1 Seiran)

* **Crew:** 2 * **Length:** 11.64 m (38 ft 2 in) * **Wingspan:** 12.26 m (40 ft 3 in) * **Height:** 4.58 m (15 ft 0 in) * **Empty weight:** 3,301 kg (7,277 lb) * **Gross weight:** 4,250 kg (9,370 lb) * **Powerplant:** 1 × Aichi Atsuta Model 32 liquid-cooled inverted V-12 engine, 1,100 kW (1,400 hp) * **Maximum speed:** 474 km/h (295 mph, 256 kn) * **Range:** 1,190 km (740 mi, 640 nmi) * **Service ceiling:** 9,640 m (31,630 ft) * **Armament:** 1 × 13 mm Type 2 machine gun in rear cockpit; 1 × 850 kg (1,874 lb) Type 91 torpedo or 800 kg (1,764 lb) bomb or 2 × 250 kg (551 lb) bombs

Surviving aircraft

Only a single, incomplete Aichi M6A1 Seiran airframe survives today. It is displayed at the Steven F. Udvar-Hazy Center, part of the National Air and Space Museum in Chantilly, Virginia. This aircraft was discovered at the Aichi Kokuki factory in Nagoya after the war by American occupation forces, missing its wings and tail surfaces, which were later reconstructed for display. It remains a rare and significant artifact of Japanese aviation technology and the Imperial Japanese Navy's unconventional weapon projects.

Category:Aircraft manufactured in Japan Category:Carrier-based aircraft Category:World War II Japanese attack aircraft