Following flight trials of the XKD4R target drone, developed for the United States Navy, Radioplane redesigned the aircraft into an improved version, designated RP-76, which first flew in 1959.[2] Compared to the XKD4R, the RP-76 had redesigned wing fairings, with the vertical control fin being moved to the underside of the missile, as opposed to being on top.[3]
The RP-76 was designed to fly a pre-programmed trajectory on autopilot, with radio command guidance being optional.[2] As with the XKD4R, control was provided by three fins located forwards on the body of the craft. A Luneburg lens was included to augment the drone's radar signature, and recovery at the end of the flight was by parachute.[2]
Operational history
Following its first flight in 1959,[3] the RP-76 was most often launched from a F-89 Scorpion fighter of the United States Air Force, and was extensively used by the U.S. Army for training the operators of surface-to-air missiles;[2] it saw additional use in training USAF fighter pilots in air-to-air gunnery, as well.[4]
A slightly modified version, designated RP-78, was supplied to the U.S. Navy; it used a more powerful rocket, producing 99,000 lbf (440 kN) of thrust,[4] to propel the drone to a top speed of Mach 1.25.[2]
In 1963, the RP-76 and RP-78 received the designations AQM-38A and AQM-38, respectively, in the new "tri-service" missile designation system.[4] In all, over 2,000 examples of the drone were built by Northrop, with the missile remaining in service with the U.S. Military until they were retired in the mid-1970s.[2]
Parsch, Andreas (2003a). "Northrop (Radioplane) AQM-38". Directory of U.S. Military Rockets and Missiles. designation-systems.net. Retrieved 2011-01-28.
Parsch, Andreas (2003b). "Radioplane KD4R". Directory of U.S. Military Rockets and Missiles Appendix 1: Early Missiles and Drones. designation-systems.net. Retrieved 2011-01-28.
Taylor, John W.R., ed. (1967). Jane's All The World's Aircraft 1967-1968. London: Jane's Information Group.