Directory of U.S. Military Rockets and Missiles
Appendix 1: Early Missiles and Drones
Copyright © 2003 Andreas Parsch

Radioplane KD4R

In May 1957, Radioplane began the design work on its RP-70 rocket-propelled target drone under contract from the U.S. Navy. The first XKD4R-1 prototype flew in January 1958.

Photo: Northrop

The XKD4R-1 was air-launched and powered by an Aerojet 530NS35 solid-fueled rocket. It had a unusual set of flying surfaces, with 3 forward control fins and a fixed horizontal tailplane located below the ventral vertical tail. After launch, its autopilot held the drone on a constant heading and altitude for a powered flight duration of about 9 minutes. It was equipped with a parachute system for recovery. To facilitate visual tracking, the RP-70 was fitted with a bright flashing light in the tail.

Photo: U.S. Navy

In 1959, the RP-70 was slightly redesigned into the RP-76, which was eventually produced for the U.S. Army, and the supersonic RP-78 for the U.S. Navy (both described under their later designations AQM-38A/B). The RP-76 production model had a blunter nose with improved radar reflectors, the forward vertical fin relocated to the ventral position, straight instead of coke-bottle-shaped wing fairings, and no tracking light in the tail. Interestingly, the Navy's RP-78 was apparently never designated as KD4R-1 (or -2) although it was clearly a production development of the XKD4R-1.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for XKD4R-1:

Length2.90 m (9 ft 6 in)
Wingspan1.52 m (5 ft)
Diameter30 cm (12 in)
Weight138 kg (305 lb)
SpeedMach 0.95
Ceiling18300 m (60000 ft)
Endurance9 min
PropulsionAerojet 530NS35 solid-fueled rocket; 160 N (37 lb) for 530 s

Main Sources

[1] Richard A. Botzum: "50 Years of Target Drone Aircraft", Northrop, 1985
[2] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960

Back to Directory of U.S. Military Rockets and Missiles, Appendix 1

Last Updated: 2 April 2003