EFFECTS OF WING POSITION AND VERTICAL-TAIL CONFIGURATION ON STABILITY AND CONTROL CHARACTERISTICS OF A JET-POWERED DELTA-WING VERTICALLY RISING AIRPLANE MODEL

摘要

An investigation has been conducted to determine the effects of wing position and vertical-tail configuration on the stability and control characteristics of a jet-powered delta-wing vertically rising airplane model. A ducted-fan powerplant was used because there was no hot-Jet powerplant of sufficiently small size and adequate reliability available. In addition to conventional flap-type control surfaces on the wings and vertical tails, the model had jet-reaction controls provided by movable eyelids at the rear of the tail pipe and by air bled from the main duct and exhausted through movable nozzles near the wing tips. The investiga¬tion consisted of flight and force tests of three model configurations:a-high wing with a top-mounted vertical tail, a high wing with top- and. bottom-mounted vertical tails, and a low wing with a top-mounted vertical tail. The flight tests, which were made in the Langley full-scale tunnel, represented slow constant-altitude transitions from hovering to normal unstalled forward flight.nAbout half the transition flights made with the configuration with the high wing and top-mounted vertical tail without artificial stabiliza¬tion were unsuccessful because of a lateral divergence at angles of attack between about 50° and 60°. The use of artificial damping in roll greatly improved the lateral stability and made the model easy to fly throughout the entire speed range. No successful transition flights could be made with the configuration with the high wing with both top- and bottom-mounted vertical tails because of an uncontrollable rolling divergence at low air¬speeds. Artificial damping in roll did not provide any noticeable improve¬ment in the lateral stability of this configuration. No successful transi¬tion flights could be made with the configuration with the low wing and top-mounted vertical tail without artificial stabilization because of an unstable lateral oscillation at angles of attack near 60°. The use of artificial damping in roll or yaw made it possible to perform the transi¬tion successfully.