Accession Number : ADA297210

Title :   An Investigation of the Effects of Pitch-Roll (De)Coupling on Helicopter Handling Qualities.

Descriptive Note : Technical memo,

Corporate Author : ARMY AVIATION RESEARCH AND TECHNOLOGY ACTIVITY MOFFETT FIELD CA AEROFLIGHTDYN AMICS DIRECTORATE

Personal Author(s) : Blanken, C. L. ; Pausder, H. J. ; Ockier, C. J.

PDF Url : ADA297210

Report Date : MAY 1995

Pagination or Media Count : 120

Abstract : An extensive investigation of the effects of pitch-roll coupling on helicopter handling qualities was performed by the U.S. Army and Deutsche Forschungsanstalt fur Luft- und Raumfahrt (DLR), using a NASA ground-based and a DLR in-flight simulator. Over 90 different coupling configurations were evaluated using a high gain roll-axis tracking task. The results show that although the current ADS-33C coupling criterion discriminates against those types of coupling typical of conventionally controlled helicopters, it not always suited for the prediction of handling qualities of helicopters with modern control systems. Based on the observation that high frequency inputs during tracking are used to alleviate coupling, a frequency domain pitch-roll coupling criterion that uses the average coupling ratio between the bandwidth and neutral stability frequency is formulated. This criterion provides a more comprehensive coverage with respect to the different types of coupling, shows excellent consistency, and has the additional benefit that compliance testing data are obtained from the bandwidth/phase delay tests, so that no additional flight testing is needed.

Descriptors :   *PITCH(MOTION), *FLIGHT CONTROL SYSTEMS, TEST AND EVALUATION, COUPLING(INTERACTION), FREQUENCY, FLIGHT TESTING, RATIOS, STABILITY, HIGH FREQUENCY, NEUTRAL, OBSERVATION, TRACKING, QUALITY, HELICOPTERS, CONFIGURATIONS, INFLIGHT, DELAY, FLIGHT SIMULATORS, HANDLING, BANDWIDTH, FUR.

Subject Categories : Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE