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The effects of aeroelastic deformation on the unaugmented stopped-rotor dynamics of an X-Wing aircraftA new design concept in the development of vertical takeoff and landing aircraft with high forward flight speed capability is that of the X-Wing. The X-Wing is a stiff, bearingless helicopter rotor system which can be stopped in flight and the blades used as two forward-swept wings and two aft-swept wings. Because of the unusual configuration in the fixed-wing mode, there is a high potential for aeroelastic divergence or flutter and coupling of blade vibration modes with rigid-body modes. An aeroelastic stability analysis of an X-Wing configuration aircraft was undertaken to determine if these problems could exist. This paper reports on the results of dynamic stability analyses in the lateral and longitudinal directions including the vehicle rigid-body and flexible modes. A static aeroelastic analysis using the normal vibration mode equations of motion was performed to determine the cause of a loss of longitudinal static margin with increasing airspeed. This loss of static margin was found to be due to aeroelastic 'washin' of the forward-swept blades and 'washout' of the aft-swept blades moving the aircraft aerodynamic center forward of the center of gravity. This phenomenon is likely to be generic to X-Wing aircraft.
Document ID
19870062339
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Gilbert, Michael G.
(NASA Langley Research Center Hampton, VA, United States)
Silva, Walter A.
(PRC Kentron, Inc. Hampton, VA, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1987
Subject Category
Aircraft Stability And Control
Report/Patent Number
AIAA PAPER 87-2563
Accession Number
87A49613
Distribution Limits
Public
Copyright
Other

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