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Aichi B7A Ryusei (Grace) - Imperial Japan, 1944

Detailing the development and operational history of the Aichi B7A Ryusei (Grace) Torpedo Bomber / Dive Bomber.

 Entry last updated on 4/22/2016; Authored by Staff Writer; Content ¬©

  Aichi B7A Ryusei (Grace)  
Picture of Aichi B7A Ryusei (Grace)

By the time the Aichi B7A series made it to operational status, Japan no longer had her aircraft carriers.

The Aichi-produced B7A "Ryusei" (translated to "Shooting Star" and nicknamed "Grace" by the Allies) was a limited-production torpedo/dive bomber in service with the Imperial Japanese Navy (IJN) during the late stages of World War 2. Unfortunately for the design, the aircraft arrived too late to be fielded in force as the Japanese Navy was now without any viable carrier options by the time of the B7A's adoption. With just a scant 114 production aircraft resulting, the series became an overlooked Aichi wartime design that would never have a chance to live up to its perceived potential as a new, all-modern carrier-based torpedo/dive bombing platform.

The B7A Ryusei was conceived of to fulfill a new Japanese Navy requirement for a carrier-based torpedo/dive bomber as early as 1941. A prototype was flown during 1942 but the aircraft, seeing prolonged delays from engine development issues and natural causes (an earthquake on the island), was forced to await receiving its official operational status until 1944. By then, the Japanese Navy was all but crippled of her strategic, and vastly important, aircraft carriers across the Pacific Theater that the B7A would instead see limited-duty from land-based airfields.

At its core, the Aichi B7A Ryusei was a single engined, two-seat, low monoplane aircraft design. A dorsal arrangement allowed for the carrying of a single 1,764lb torpedo or an equal amount of standard drop ordnance. Additionally, two forward-firing, fixed 20mm cannons were mounted in the leading wing edges while a single, defensive-minded, 7.92mm or 13mm machine gun was fitted to a flexible mounting at the rear cockpit position for added defense.

Power was served through a Nakajima NK9C Homare 12 model, 18-cylinder, air-cooled, radial piston engine of 1,825 horsepower providing for a top speed of 352 miles per hour, a range out to 1,890 miles and a service ceiling up to 36,910 feet. The engine drove a four-bladed propeller assembly.

Dimensions included a length of 37 feet, 8 inches, a wingspan of 47 feet, 3 inches, and a height of 13 feet, 5 inches. As the B7A was intended for carrier service, it came complete with hinged wing sections to allow for folding on space-strapped aircraft carriers of the IJN.

Prototypes were recognized as B7A1 and a total of nine were produced. The B7A2 designation marked production quality bombers for the IJN to which 105 examples emerged. One model served as an experimental product fitting the Nakajima Homare 23 series engine. The B7A3 designation was a proposed mark outfitted with the Mitsubishi MK9A (Ha-43) engine - none of this mark were constructed.

Aichi B7A Ryusei (Grace) Specifications

Service Year: 1944
Type: Torpedo Bomber / Dive Bomber
National Origin: Imperial Japan
Manufacturer(s): Aichi Kokuki KK - Japan
Total Production: 114

Structural (Crew, Dimensions, Weights)

Operating Crew (Typical): 2
Overall Length: 37.73 feet (11.5 meters)
Overall Width: 47.24 feet (14.40 meters)
Overall Height: 13.35 feet (4.07 meters)

Weight (Empty): 8,378 lb (3,800 kg)
Weight (MTOW): 14,330 lb (6,500 kg)

Power / Performance (Engine Type, Top Speed)

Engine: 1 x Nakajima NK9C Homare 12 series 18-cylinder radial engine developing 2,000 horsepower.

Maximum Speed: 305 knots (351 mph; 565 kph)
Maximum Range: 1,641 nautical miles (1,889 miles; 3,040 km)
Service Ceiling: 36,909 feet (11,250 meters; 6.99 miles)
Rate-of-Climb: 1,890 feet-per-minute (576 m/min)

Armament / Mission Payload

2 x 20mm Type 99 cannons in wings
1 x 7,92mm Type 1 OR 13mm Type 2 machine gun in rear cockpit position.

Up to 1,765lbs of drop ordnance including 1 x "Long Lance" torpedo.

Global Operators (Customers, Users)

Imperial Japan

Model Variants

B7A "Ryusei" - Base Series Designation
B7A1 - Prototype designation; nine examples completed.
B7A2 - IJN production bomber designation
B7A2X - Experimental mount fitted with Nakajima Jomare 23 series radial piston engine of 1,490 horsepower; single example of B7A2 model.
B7A3 - Proposed variant fitting Mitsubishi MK9A engine of 2,200 horsepower; not produced.

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