Effects on Longitudinal Stability and Control Characteristics of a B-29 Airplane of Variations in Stick-Force and Control-Rate Characteristics Obtained Through Use of a Booster in the Elevator-Control System

摘要

The longitudinal stability and control characteristics of a B-29 airplane have been measured with a booster incorporated in the elevator-control system. Tests were made to determine the effects on the handling qualities of the test airplane of variations in the pilot's control-force gradients as well as the effects of variations in the maximum rate of control motion supplied by the booster system. The variations of elevator-control force with normal acceleration for the test airplane without boost were about 90 pounds per g at an indicated airspeed of l60 miles per hour and about l40 pounds per g at 25O miles per hour. These control forces were considered by the pilots to be tolerable but heavy. Use' of the booster to reduce these control- force gradients by a factor of about 2.8 appreciably improved the control characteristics of the test airplane. Reduction of the force gradients by a factor of about 4.6 through use of the booster also resulted in satisfactory control characteristics in terms of the pilots' opinions of their ability to control the airplane precisely in normal flight maneuvers, although these force gradients were not so desirable as with the boost ratio of 2.8. The effect of these lower force gradients on the probability of e%ceeding the limit load factor could not be investigated.