Aichi S1A Denko (Bolt of Lightning)

Aichi S1A Electrician (Lightning) Story

The Aichi S1A "Denko" was developed with Imperial Japan during World War II (1939-1945) as the successor to the Nakajima J1N1 "Gekkou" or "Gekko". Since its introduction in May 1941, the Flying Gecko has proven itself to be a very capable twin-engine heavy fighter.

It served as a long-range reconnaissance platform, but more importantly, as a night fighter, armed with radar and a 20mm cannon angled at 30 degrees to hit the vulnerable underbelly of Allied bombers.

While Gekko was good, the arrival of the American Boeing B-29 "Superfortress" over Japanese Pacific territory in May 1944 began to outperform the earlier war Nakajima designs - it lacked altitude performance and more powerful radar Adaptation requires dealing with new threats. Therefore, a new twin-engine heavy aircraft of modern quality and superior capability was considered, and the task fell to Aichi Prefecture, as other more prominent aircraft manufacturers of the war were associated with other production commitments of the Empire.

The resulting design became the "S1A", carrying a crew of two and equipped with the mission gear required for a night fighter. Dimensions include an overall length of 15 meters, a wingspan of 17.5 meters and a height of 4.6 meters. Structurally, the S1A1 will be Japan's largest war fighter. The kerb weight is 7,320kg and the maximum take-off weight (MTOW) is 11,510kg.

Power comes from 2 Nakajima NK9K-S air-cooled, twin-row, 18-cylinder radial-piston engines, each producing 2,000 horsepower and driving a four-blade propeller unit.

The overall configuration of the aircraft is typical of Japanese heavy fighters during World War II. It uses a central fuselage that houses two crew members, avionics, fuel storage and basic mission equipment. The cockpit is located amidships and aft of the short nose cone assembly.

The nose section contains standard fixed forward weapons. Midship is a framed observation dome in front of the turret position. The empennage relies on a single vertical fin with a low horizontal plane mounted along the rear side of the fuselage.

The main-wing aircraft are located forward amidships, and each aircraft contains a base engine nacelle - the pilots have unobstructed views of both facilities. The general design of the main aircraft itself is straight, with truncated wingtips. The landing gear is a typical "tail" arrangement.

Performance of the S1A in prototype form includes a top speed of 360 mph, a cruising speed of 275 mph, a range of up to 1,555 miles (ferry) and a service ceiling of 39,370 feet.

The armament is centred on 2 x 30mm Type 5 and 2 x 99 Type 1 cannons, mounted on the nose section to provide strong forward fire. The aforementioned turret locations along the fuselage spine are equipped with 2 x 20mm Type 99 Type 2 cannons, providing trainable weapon placement.

The S1A was a promising design by wartime standards, but its projected weight began to suffer as more and more mission equipment was added. Also, the scheduled Nakajima Meridian did not offer the performance required by IJN authorities, so a production model S1A1 with a Mitsubishi engine was considered.

On December 7, 1944, there was also a powerful earthquake off the coast of Japan - the "Tokai Earthquake" (magnitude 8.1) - which severely damaged two ordered prototypes, including production facilities. All hopes for the aircraft were ended by Allied bombing raids in June and July 1945, as both prototypes were destroyed and returned to work.

Japan surrendered to the Allies in August 1945, ending World War II once and for all.

Specification

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