 {| |} the nakajima b6n tenzan (japanese: ä¸­å³¶ b6n å¤©å±±â"heavenly mountain", allied reporting name: "jill") was the imperial japanese navy's standard carrier-borne torpedo bomber during the final years of world war ii and the successor to the b5n "kate". due to its protracted development, a shortage of experienced pilots and the united states navy's achievement of air superiority by the time of its introduction, the b6n was never able to fully demonstrate its combat potential. ==design and development== thumb|right|a b6n2 before starting the engine. the b5n carrier torpedo-bomber's weaknesses had shown themselves early in the second sino-japanese war and, as well as updating that aircraft, the imperial japanese navy began seeking a faster longer-ranged replacement. in december 1939 it issued a specification to nakajima for a navy experimental 14-shi carrier attack aircraft capable of carrying the same external weapons load as the b5n. the new plane was to carry a crew of three (pilot, navigator/bombardier and radio operator/gunner) and be of low wing, cantilevered, all-metal construction (though control surfaces were fabric-covered). further requirements included a top speed of , a cruising speed of  and a range of  with an  bomb load or  without external armament.wieliczko 2003, p. 4. the navy had requested installation of the proven mitsubishi kasei engine as the b6n's powerplant but engineer kenichi matsumara insisted on using nakajima's new  mamori 11 14-cylinder air-cooled radial due to its lower fuel consumption and greater adaptability. this became an unfortunate choice as the mamori engine was plagued with mechanical defects and never achieved its expected power rating.francillon 1979, p. 429. constrained by the standard-sized aircraft elevators then in use on most japanese carriers, designer matsumara was obliged to use a wing similar in span and area as that of the b5n and to limit the aircraft's overall length to . this latter restriction accounted for the b6n's distinctive swept-forward tail fin and rudder. the outer wing p
Carrier-based_aircraft Japanese_bomber_aircraft_1940a1949 Nakajima_aircraft World_War_II_Japanese_torpedo_bombers