The B4N1 was an unsuccessful Nakajima entry in an Imperial Japanese navy (IJN) 1932 carrier attack bomber contest. The IJN wanted the usual biplane, and Nakajima produced this stunning aircraft characterised by its drum-shaped welded steel tube fuselage and a bizarre backwards folding wooden “X-wing” structures. Two prototypes appeared in 1933. Their performance proved to be poor, thanks to their asthmatic and troublesome Hikari II engines, and they also suffered stability problems produced, it seems, by the straight outer sections in the lower pair fo wings. In the end neither the B4N1 nor its Mitsubishi competitor gained acceptance into service.
It was really something, don’t you think so?