A STUDY OF CONVENTIONAL AIRPLANE HANDLING QUALITIES REQUIREMENTS PART I. ROLL HANDLING QUALITIES

摘要

This report is a codification in two parts of conventional aircraft handling qualities criteria. The results of this effort are to serve as an intermediate design guide in the areas of lateral-directional oscillatory and roll control. All available data applicable to these problem areas were considered in developing the recommended new criteria. Working papers were sent to knowledgeable individuals in industry and research agencies for comments and suggestions, and these were incorpo-rated in the final version of this report. The roll handling qualities portion of this report uses as a point of departure the concept that control of bank angle is the primary piloting task' in maintaining or changing heading. Regulation of the bank angle to maintain heading is a closed-loop tracking task in which the pilot applies aileron control as a function of observed bank angle error. For large heading changes, the steady-state bank angle consistent with available or desired load factor is attained in an open-loop fashion;it is then regulated in a closed-loop fashion throughout the remainder of the turn. For the transient entry and exit from the turn, the pilot is not concerned with bank angle per se, but rather with attaining a mentally commanded bank angle with tolerable accuracy in a reasonable time, and with an easily learned and comfortable program of aileron movements. In the lateral oscillatory portion of this effort, in defining requirements for satis¬factory Dutch roll characteristics, a fundamental consideration is the fact that the motions characterizing this mode are ordinarily not the pilot's chief objective. That is, he is not deliberately inducing Dutch roll motions in the sense that he induces rolling and longitudi¬nal short-period motions. Dutch roll oscillations are side products of his attempts to control the airplane in some other mode of response, and they are in the nature of nuisance effects which should be reduced to an acceptable level. In spite of its distinction as a side effect, adequate control of Dutch roll is a persistent handling qualities research area and a difficult practical design requirement. The diffi¬culties stem from the many maneuver and control situations which can excite the Dutch roll, and from its inherently low damping. Since any excitation of the Dutch roll is undesirable, the effects of disturbance inputs are almost uniformly degrading to pilot opinion rating. Never¬theless, removal of such influence does not eliminate the need for some basic level of damping. A worthwhile approach to establishment of Dutch roll damping requirements is to first establish the basic level, and then to study the varied influences of the disturbance parameters. This approach provides the basis for the material contained in this report.