Designed to a 1935 requirement, and already in service for four years when Japan entered the war, the prototype B5N first flew in January 1937. A low-wing three-crew monoplane with inwards-retracting wide-track landing gear, powered by a 770 hp Hikari engine, and entered production as a 1000 hp Nakajima Sakae 11-powered light or torpedo-bomber. The following year production B5N1 aircraft were embarking in Japan's carriers and shore-based units were deployed in China.
In 1939 the improved B5N2 appeared with a more powerful Sakae 11 engine in a smaller cowling, although armament and bombload were unchanged, and this version remained in production until 1943.
Many were converted to B5N1-K trainers when production switched to B5N2.
When Japan attacked the USA the B5N2 had wholly replaced the B5N1 with operational units, and 144 B5N2s were involved in the attack on Pearl Harbour, and within the next 12 months aircraft of this type sank the American carriers USS Hornet, Lexington and Yorktown.
Given the reporting name 'Kate' by the Allies, with its defensive armament of a single machine-gun and laden with a large bomb or torpedo, the B5N began to suffer very heavily, and although the type was fully committed during the Solomons campaign the survivors were withdrawn from combat after the Philippine battles of 1944.
Thereafter, on account of their excellent range, they were assigned to antisubmarine and maritime reconnaissance duties in areas beyond the range of Allied fighters. Production of all B5Ns reached 1,149.
Nakajima B5N1 Engine: 1 x 840 hp Nakajima Hikari 3 Prop: 3 blade Constant speed Wingspan: 50 ft 11 in Length: 33 ft 9.5 in Height: 12 ft 1.5 in Wing area: 405.8 sq.ft Wing loading: 20.1 lb/sq.ft Loaded weight: 4640 lb Max weight: 8150 lb Max speed: 229 mph at 6,500 ft Cruise speed: 159 mph at 6500 ft Climb to 10,000 ft: 8 min Service ceiling; 24,280 ft Normal range: 590 nm Max range: 1220 nm
Nakajima B5N2 Engine: 1 x Nakajima NK1B "Sakae", 746kW Wingspan: 15.52 m / 50 ft 11 in Length: 10.3 m / 33 ft 10 in Height: 3.7 m / 12 ft 2 in Wing area: 37.7 sq.m / 405.80 sq ft Max take-off weight: 4100 kg / 9039 lb Empty weight: 2279 kg / 5024 lb Max. speed: 378 km/h / 235 mph Ceiling: 8260 m / 27100 ft Range w/max.fuel: 1990 km / 1237 miles Armament: 1 x 7.7mm machine-guns, 800kg of bombs Crew: 3