Details:

• Creators:
  Fletcher, Jay W.
• Corporate Creators:
  U.S. Army Aviation and Troop Command ; Ames Research Center

  U.S. Army Aviation and Troop Command ; Ames Research Center Less -
• Subject/TRT Terms:
  [+]

  Airframes Design Methods Flapping Equations Flight Control Systems Flight Dynamics Forward Flight Fuselages Helicopters Hover Linear Model Structures Rotocraft Rotors Structural Models UH-60
• DOI:
  https://doi.org/10.21949/1403587
• Resource Type:
  Tech Report
• Corporate Publisher:
  United States. National Highway Safety Bureau
• NTL Classification:
  NTL-AVIATION-AVIATION
• Abstract:
  A linear model structure applicable to identification of the UH-60 flight
  
  dynamics in hover and forward flight without rotor-state data is developed. The
  
  structure of the model is determined through consideration of the important
  
  dynamic modes of the UH-60 in the frequenty range of interest for flight control
  
  applications. Included are the six fuselage rigid body degrees of freedom
  
  (DOF), the rotor tip-path-plane flap and lead-lag dynamics, the main rotor
  
  angular velocity and induced velocity dynamics, and engine gas generator and
  
  governor dynamics. An empirical correction to the flapping equations referred
  
  to as the "aerodynamic phase lag" is inlcuded which emulates the effects of the
  
  main rotor dynamic wake on the development of flapping moments. The model
  
  structure is employed in the identification of linear models of the UH-60 from
  
  flight-test data at hover and 80 kts forward flight using a frequency-response-
  
  error identification method. The models are fit to flight-identified frequency
  
  responses through the adjustment of the values of the model parameters.
  
  Systematic model structure reduction is performed to ensure that minimally
  
  parameterized models are obtained. The identified models match the flight-test
  
  data well, predict the rigid body response of the UH-60 better than current
  
  generation blade-element simulation models, and are accurate from approximately
  
  0.5 to 20 rad/sec. The identified physical flapping parameters correlate well
  
  with theoretical results. The aerodynamic phase lag formulation is shown to be
  
  an effective approach to improving the prediction of the aircraft off-axis
  
  angular-rate responses.
  
  
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  [+]

  urn:sha256:17dd791dd350b1a02b72993b4b6a6fbe243ebde2d0a9a4a0c09a37c8673183c6
• Download URL:
  /view/dot/12941/dot_12941_DS1.pdf
• File Type:
  [PDF-458.90 KB]