The Yak-123-1 prototype was developed from the subsonic
Yak-25, and in parallel with the
Yak-27 aircraft family, with the main goal of operating at supersonic speed. Although the Yak-123 kept the Yak-25's layout, it had a more streamlined and longer fuselage with a glazed nose for a navigator-bombardier, replacing the Yak-25's
radome. The engines were upgraded to the much more powerful RD-9AK afterburning turbojets and the wings modified. The
Nudelman N-37 cannon was replaced with two
NR-23 23 mm guns. The next prototype, designated Yak-26-3, had a tail
barbette with two more such guns, but it was removed altogether after testing. An internal weapons bay was added for of bombs, including the nuclear
RDS-4 Tatyana. Additional bombs could be carried on underwing pylons. Engines were upgraded to RD-9F. Although these designs showed potential for a supersonic bomber, they did not feature a radar, limiting their usefulness, and suffered from insufficient stability at high velocities, being prone to
aileron reversals. This led to a refinement of the design, resulting in the preproduction-series Yak-26. Although flown at the
Tushino air show on 24 June 1956, only ten were produced, and the type did not enter service. ==Operators==