The Northrop KD2R5 "Shelduck" basic training drone was used by the armed forces of at least countries. The KD2R5 was used as a training device for ground-to-air gunnery practice. It was also used as a training target for surface-to-air missiles such as the Seacat, Tigercat, Redeye, Blowpipe, Sparrow, Chaparral, Hawk, Sidewinder and Nike.

Design of the drone was started in 1946 and the prototype flew for the first time in 1947. Since then, more than 55,000 of this type, including early KD2R versions were built.