Analysis of X-15 Landing Approach and Flare Characteristics Determined from the First 30 Flights

Abstract

The approach and flare maneuvers for the first 30 flights of the X-15 airplane and the various control problems encountered are discussed. Depending on configuration, the peak lift-drag ratios from flight varied from 3.5 to 4.5 as compared with a predicted range of from 3.0 to 4.2. By employing overhead, spiral-type patterns beginning at altitudes as high as 40,000 ft, the pilots were consistently able to touch down within about + or - 1,000 ft of a designated point. A typical flare was initiated at a comfortable altitude of about 800 ft and an indicated airspeed of approximately 300 knots, which allowed a margin of excess speed. The flap and gear were extended when the flare was essentially completed, and an average touchdown was accomplished at a speed of about 185 knots indicated airspeed, an angle of attack of about 7 degrees and a rate of descent of about 4 fps. In general, the approach and landing characteristics were predicted with good accuracy in extensive preflight simulations. F-104 airplanes which simulated the X-15 landing characteristics were particularly valuable for pilot training. (Author)