In the mid-1960s the MiG OKB, in cooperation with the Kazan Aviation Institute (KAI), developed versions of the MiG-21 PF and MiG-21 PFM to be operated as remotely controlled target drones for WS and PVO pilots as well as AAA gunners. For this purpose, fighters that had outlived their operational parameters were used.
The radar in these aircraft was replaced by ballast to restore the aircraft’s trimming. The ejection seats were removed to make room for remote control equipment and the drive mechanism for the control surfaces. The target drone was controlled by radio signals from the ground or from another aircraft specially equipped to steer the drone with preset routines. Those modifications were carried out in the WS ARZs (air force overhaul workshops). The remotely controlled MiG – 21Ye could take off and make maneuvers, but only within the subsonic flight envelope.
Because the MiG-21 PD was an experimental aircraft, the landing gear was not retractable.
This experimental version of the MiG-21 bis was designed to develop new on-board systems to be installed in cruise missiles and was, like the MiG-21 bis, powered by an R-25 turbojet.