Radioplane RP-77

The development of the RP-77 began in 1955. Similar in outline to Radioplane's earlier OQ-19, four prototypes of the RP-77 were constructed, two each of the RP-77, powered by a four-cylinder McCulloch piston engine, and of the RP-77A, powered by a six-cylinder Lycoming engine. The drone was launched using a rocket-assisted take-off system consisting of four Loki rockets, and was fitted with a radio control apparatus that, with the assistance of radar tracking, allowed the drone to be operated at a considerable distance from its launching point. Tip tanks allowed for carriage of additional fuel to extend the aircraft's range, and recovery at the end of the flight was by parachute. An improved version of the RP-77D was projected, with provision for launching RP-76 target missiles. ==Operational history==

Following its maiden flight in March 1958, evaluation of the RP-77D by the U.S. Army took place throughout the remainder of that year, nearly 40 test flights being conducted. Although the test results were generally satisfactory, it was determined that the performance of the aircraft was an insufficient improvement over existing types in service to have the aircraft ordered into production, and the project was cancelled, along with the improved RP-86, a dedicated reconnaissance variant. Following the termination of the Army's evaluation, Radioplane, as a private venture, conducted an improvement program for the RP-77D, fitting the aircraft with a larger wing, along with other modifications that improved the performance of the drone. However these improvements were insufficient to produce a renewed interest from the Army. ==Variants==

;RP-77 :Prototype model powered by McCulloch piston engine; two built. ;RP-77B :Proposed version of RP-77 with turbo-supercharged McCulloch engine, none built. ;RP-77D :Production prototype with Boeing 502 turboprop; twenty built for evaluation. ;RP-86 :Proposed reconnaissance version of RP-77D; none built. ==Specifications (RP-77D)==