Aichi B7A The ( " Shooting Star " , Allied reporting name " Grace " ) was a large and powerful carrier - borne torpedo - dive bomber produced by Aichi Kokuki KK for the Imperial Japanese Navy Air Service during the Second World War . Built in only small numbers and deprived of the aircraft carriers it was intended to operate from , the type had little chance to distinguish itself in combat before the war ended in August 1945 . Design and development . The B7A " Ryusei " ( originally designated AM - 23 by Aichi ) was designed in response to a 1941 16 - Shi requirement issued by the Imperial Japanese Navy Air Service for a carrier attack bomber that would replace both the Nakajima B6N " Tenzan " torpedo plane and the Yokosuka D4Y " Suisei " dive bomber in IJN service . It was intended for use aboard a new generation of Taihō - class carriers , the first of which was laid down in July 1941 . Because the deck elevators on the Taihōs had a larger square area than those of older Japanese carriers , the longstanding maximum limit of on carrier aircraft length could now be lifted . Chief Engineer Norio Ozaki chose a mid - wing arrangement for the B7A to provide for an internal bomb - bay and to ensure enough clearance for the plane ' s four - bladed propeller . This in turn necessitated the adoption of an inverted gull wing , reminiscent of the F4U Corsair , in order to shorten the length of the main landing gear . The wing featured extendable ailerons with a ten - degree range of deflection , enabling them to act as auxiliary flaps . Dive brakes were fitted underneath just outboard of the fuselage . The B7A ' s outer wing panels were designed to fold upwards hydraulically for carrier stowage , reducing its overall span from to approximately . Selection of a powerplant was dictated by the Japanese Navy which requested that Aichi design the aircraft around the 1 , 360 kW ( 1 , 825 hp ) Nakajima NK9C " Homare " 12 18 - cylinder two - row air - cooled radial engine . This was expected to become the Navy ' s standard aircraft engine in the 1 , 340 kW ( 1 , 800 hp ) to 1 , 641 kW ( 2 , 200 hp ) range . One production model B7A2 was later fitted with a 1 , 491 kW ( 2 , 000 hp ) Nakajima " Homare " 23 radial engine and plans were also made to fit the 1 , 641 kW ( 2 , 200 hp ) Mitsubishi MK9 radial to an advanced version of the " Ryusei " ( designated B7A3 " Ryusei Kai " ) but the latter effort never came to fruition . The B7A had a weight - carrying capacity stemming from its requirements , resulting in a weapons load no greater than its predecessors . The presence of an internal bomb bay with two high - load - capability attachment points allowed the aircraft to carry two 250 kg ( 550 lb ) or six 60 kg ( 132 lb ) bomb s . Alternatively , it could carry a single 800 kg ( 1 , 764 lb ) torpedo mounted externally . Defensive armament initially consisted of two 20mm Type 99 Model 2 cannons in the wing roots and one flexible 7 . 92mm Type 1 machine - gun mounted in the rear cockpit . Later production models of the B7A2 featured a 13mm Type 2 machine - gun in place of the 7 . 92mm gun . Despite the plane ' s weight and size , it displayed fighter - like handling and performance , besting the version of the A6M Zero in service at the time . It was fast and highly maneuverable . Given the codename " Grace " by the Allies , the B7A first flew as a prototype in May 1942 , but teething problems with the experimental NK9C " Homare " engine and necessary modifications to the airframe meant that the type did not enter into production until two years later in May 1944 . Nine prototype B7A1s were built and 80 production version B7A2s completed by Aichi before a severe earthquake in May 1945 destroyed the factory at Funakata where they were being assembled . A further 25 examples were produced at the 21st Naval Air Arsenal at Omura . Operational history . In June 1944 , IJN " Taihō " , the only Imperial Japanese Navy aircraft carrier then large enough to operate the B7A " Ryusei " in its intended role , was sunk during the Battle of the Philippine Sea before enough B7As were even available to embark . Thereafter , the B7A was relegated to operating from land bases , primarily with the Yokosuka and 752nd Kokutais . The Japanese completed only one other carrier capable of operating the B7A , IJN " Shinano " , but she was sunk by an American submarine in November 1944 , just ten days after being commissioned .