The Berliner-Joyce XFJ was a United States prototype biplane fighter aircraft that first flew in May 1930.

At the same time, they submitted a similar design to the Navy, modified to meet the differing requirements, which included a metal-skinned semi-monocoque fuselage, shoulder-mounted upper wings and a lower wing underslung on cabane-type struts.

[2] The prototype, XFJ-1, was sent to Anacostia for testing after its initial flights, where the ground-looping habit was noted, and eventually resulted in a landing accident, necessitating return and repair.

[2] This and other improvements boosted speed from 177 to 193 mph, and the Navy gave the reconstructed aircraft the designation XFJ-2.

[2] However, improved performance came at the expense of stability, and the ground loop problem persisted, and there was no interest in continuing with this design.