The FB-5 was the most produced model of the Navy version of the Model 15 fighter and was noticeably different from earlier FBs. The wing stagger was changed, with the upper wing place further forward and the lower wing place further to the rear. This arrangement required the development of a completely new undercarriage so that the strut would still attach to the fuselage at the front lower wing spar fitting. On FB-5s designed for high-impact landings on aircraft carriers, the axles pivoted about the point of a rigid triangle below the fuselage. Land-based FB-5s used undercarriages like those on the FB-1. During the late 1920s, fighters were usually flown to their destination, but all 27 FB-5s were delivered to the Navy at the same time and in an unusual way. They were tilted onto their noses, rolled through the factory doors, and barged directly to a waiting aircraft carrier.. Boeing built a total of 157 of the PW/FB series fighters between 1923 and 1928.