PTV-N-2 Gorgon IV ramjet-powered missile dropped from a Northrop P-61C Black Widow during trials

The PTV-N-2 Gorgon IV was a subsonic ramjet-powered missile developed by the Glenn L. Martin Company for the United States Navy. Originally intended as an air-to-surface weapon, it materialized as a propulsion test vehicle, and between 1947 and 1950 was used for test purposes and, as the KDM Plover, as a target drone.

The PTV-N-2 was of fairly conventional design, with mildly-swept wings and a conventional empennage; roll control was through spoilerons. The Marquardt XRJ30 ramjet engine was mounted below the aft fuselage, and the vehicle was fitted with drag brakes to prevent exceeding the engine's design limits.

Flight control was through a combination of a preset course via autopilot and radio command guidance; the vehicle was equipped with radio telemetry to transmit data. Following the end of each test flight, the vehicle would deploy a parachute for recovery in the ocean; the vehicles were said to be in such good condition that it would be possible to re-fly them after cleaning them of salt water residue.

Shortly after the war, the US Navy borrowed two Northrop P-61Cs (AAF Ser. No. 43-8336 and No. 43-8347) night fighters from the USAAF and used them for air-launches of the experimental missile, the first launch taking place on November 14th 1947. While carrying a Gorgon under each wing, the P-61C would go into a slight dive during launch to reach the speed necessary for the ramjet to start. These two naval Black Widows were returned to the Air Force in 1948, and transferred to storage shortly afterwards.