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The Aichi B7A (Allied reporting name Grace) was a large attack aircraft designed for the Imperial Japanese Navy but came too late and in too few numbers to have an impact on the Pacific War. It was a successful design but is obscure and remains relatively unknown.
The design was intended to replace both dive bomber and torpedo bomber types currently in IJN service. Nine prototypes were built, the first of which flew for the first time in May 1942. Teething problems with the new 1,800 hp Homare 11 engine delayed the program. This is the seventh prototype, finished in a scheme of overall orange-yellow to make it easier to locate in case of a forced landing.
A gull wing design was selected to provide sufficient clearance for the four-bladed propeller, a parallel to the Chance-Vought F4U Corsair design. The Grace was much larger than the Corsair with a 47 foot (14.4 meter) wingspan.
The wings of the B7A were equipped with a hydraulic folding mechanism just outboard of the landing gear. With the wings folded the span was reduced to 26 feet (7.9 meters). The ailerons could both deflect downwards up to ten degrees to function as additional landing flaps.
The B7A was intended to be the primary attack aircraft on the Taiho and Shinano, but both aircraft carriers were sunk before the Grace could enter service. The aircraft was too large to accommodate on the surviving Japanese carriers and so was obliged to operate entirely from shore bases. The fighter component of the air wings were intended to be composed of N1K3 Shiden-Kai (George). This is an aircraft of the Yokosuka Naval Air Group with a Type 91 torpedo, the dual horizontal tail stripes indicate a flight leader.
The B7A could carry two 250 kg (551 pound) bombs in an internal bomb bay in the dive- or level bombing role, or one 800 kg (1,764 pound) torpedo mounted externally. Two Type 99 cannon were mounted in the wings, along with a 7.9 mm or 13 mm machine gun mounted in the rear cockpit for defense.
The Grace was fast and maneuverable, the specification required agility consistent with the famous Mitsubishi A6M Zero fighter. Maximum speed was 367 mph (592 kph) which was quite fast for an attack aircraft of the time and on par with several fighter types. Handling was reported to be excellent.
The only unit which was equipped solely with the B7A was the 752 nd Kokutai which operated from Katori in Chiba from February 1945. The unit was engaged in conventional attack missions and was eventually also utilized in Kamikaze attacks.
Even after the design had been finalized, Japan’s deteriorating war situation prevented production on a meaningful scale. The Aichi plant at Funakata produced only 89 examples (including prototypes) before it was destroyed by an earthquake in May 1945. Another 25 were completed by the 21 st Naval Air Arsenal at Omura.
After the war the B7A was one of the types returned to the United States for evaluation. One example survives today in unrestored condition at the National Air and Space Museum Storage Facility. The survivor is one of the 25 examples produced at 21st Naval Air Arsenal at Omura. This 752 nd Kokutai aircraft is seen being wheeled out of a hanger by American personnel after the war.