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An Investigation of Rotorcraft Stability-Phase Magin Requirements in Hover

Blanken, Chris and Lusardi, Jeff and Tischler, Mark and Decker, William and Malpica, Carlos and Höfinger, Marc and Berger, Tom and Tucker, George (2009) An Investigation of Rotorcraft Stability-Phase Magin Requirements in Hover. 65. Annual Forum of the American Helicopter Society, 2009-05-27 - 2009-05-29, Grapevine, TX (USA).

Full text not available from this repository.

Abstract

A cooperative study was performed to investigate the handling quality effects from reduced flight control system stability margins, and the trade-offs with higher disturbance rejection bandwidth (DRB). The piloted simulation study, performed on the NASA-Ames Vertical Motion Simulator, included three classes of rotorcraft in four configurations: a utility-class helicopter; a medium-lift helicopter evaluated with and without an external slung load; and a large (heavy-lift) civil tiltrotor aircraft. This large aircraft also allowed an initial assessment of ADS-33 handling quality requirements for an aircraft of this size. Ten experimental test pilots representing the U.S. Army, Marine Corps, NASA, rotorcraft industry, and the German Army (WTD 61), evaluated the four aircraft configurations, for a range of flight control stabilitymargins and turbulence levels, while primarily performing the ADS-33 Hover and Lateral Reposition MTEs. Pilot comments and aircraft-task performance data were analyzed. The preliminary stability margin results suggest higher DRB and less phase margin cases are preferred as the aircraft increases in size. Extra care will need to be taken to assess the influence of variability when nominal flight control gains start with reduced margins. Phase margins as low as 20-23 degrees resulted in low disturbanceresponse damping ratios, objectionable oscillations, PIO tendencies, and a perception of an incipient handling qualities cliff. Pilot comments on the disturbance response of the aircraft correlated well to the DRB guidelines provided in the ADS-33 Test Guide. The ADS-33 mid-term response-to-control damping ratio metrics can be measured and applied to the disturbance-response damping ratio. An initial assessment of LCTR yaw bandwidth shows the current Level 1 boundary needs to be relaxed to help account for a large pilot off-set from the c.g. Future efforts should continue to investigate the applicability/refinement of the current ADS-33 requirements to large vehicles, like an LCTR.

Item URL in elib:https://elib.dlr.de/58356/
Document Type:Conference or Workshop Item (Speech, Paper)
Title:An Investigation of Rotorcraft Stability-Phase Magin Requirements in Hover
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Blanken, ChrisAMRDEC AFDDUNSPECIFIED
Lusardi, JeffAMRDEC AFDDUNSPECIFIED
Tischler, MarkAMRDEC AFDDUNSPECIFIED
Decker, WilliamNASAUNSPECIFIED
Malpica, CarlosNASAUNSPECIFIED
Höfinger, MarcDLRUNSPECIFIED
Berger, TomUARCUNSPECIFIED
Tucker, GeorgeSan Jose State University FoundationUNSPECIFIED
Date:2009
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:helicopter, tiltrotor, handling qualities, stability margins, disturbance rejection bandwidth, ADS-33, pilot induced oscillations, Hubschrauber, Tiltrotor, Flugeigenschaften, Störgrößenunterdrückung, Stabilitätsreserven, Bandbreite, piloteninduzierte Schwingungen, ADS-33, rotorcraft, flight control systems, CH-53, Stabilität, Flugregelung
Event Title:65. Annual Forum of the American Helicopter Society
Event Location:Grapevine, TX (USA)
Event Type:international Conference
Event Dates:2009-05-27 - 2009-05-29
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Rotorcraft (old)
DLR - Research area:Aeronautics
DLR - Program:L RR - Rotorcraft Research
DLR - Research theme (Project):L - The Smart Rotorcraft (old)
Location: Braunschweig
Institutes and Institutions:Institute of Flight Systems > Rotorcraft
Deposited By: Höfinger, Marc
Deposited On:23 Jun 2009 12:22
Last Modified:02 Nov 2009 15:56

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