Accession Number : ADA194156

Title :   Using Frequency-Domain Methods to Identify XV-15 Aeroelastic Modes.

Descriptive Note : Technical memo.,

Corporate Author : NATIONAL AERONUATICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCH CENTER

Personal Author(s) : Acree, C W , Jr ; Tischler, Mark B

PDF Url : ADA194156

Report Date : Nov 1987

Pagination or Media Count : 25

Abstract : The XV-15 Tilt-Rotor wing has six major aeroelastic modes that are close in frequency. To precisely excite individual modes during flight test, dual flaperon exciters with automatic frequency-sweep controls were installed. The resulting structural data were analyzed in the frequency domain (Fourier transformed) with cross-spectral and transfer-function methods. Modal frequencies and damping were determined by performing curve fits to transfer-function magnitude and phase data and to cross-spectral magnitude data. Results are given for the XV-15 with its original metal rotor blades. Frequency and damping values are also compared with earlier predictions. Keywords: Tilt rotor aircraft.

Descriptors :   *AEROELASTICITY, *TILT ROTOR AIRCRAFT, AUTOMATIC, CONTROL, DAMPING, FLIGHT TESTING, FREQUENCY, METALS, PHASE, ROTOR BLADES, STRUCTURAL PROPERTIES, SWEEP FREQUENCY TECHNIQUES, TRANSFER FUNCTIONS

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE