Pulsejet-powered and intended to allow an aircraft to launch a torpedo or bomb from stand-off range, it was flight-tested but failed to enter operational service.

In 1944 the U.S. Navy and the National Bureau of Standards initiated Project Kingfisher,[1] intended to develop a family of missiles for attacking enemy ships and surfaced submarines with torpedoes or other weapons intended to strike below the waterline, while allowing the launching aircraft or ship to avoid exposing themselves to enemy defensive fire.

[2] Weighing 1,300 pounds (590 kg),[1] the missile was of conventional small-aircraft design with a high-mounted wing and V-tail, a pulsejet engine being mounted in the rear of a streamlined fuselage.

[3] Guidance was by active radar homing; after release from the launching aircraft, the missile – redesignated AUM-6 in September 1947, and AUM-N-6 Puffin in 1948 – would cruise at an altitude of 200 feet (61 m),[3] traveling up to 20 miles (32 km) at Mach 0.7.

[1] The onboard radar in the missile's nose selecting a target and steering the missile into position to release its payload, carried in the mid-fuselage;[3] while some sources state that a torpedo was intended to be carried,[3] the specification for Kingfisher F called for the missile to carry a 500-pound (230 kg) plunge bomb, intended to be dropped alongside the target ship and detonate underwater, holing the target vessel below the waterline and causing flooding.