Wind Tunnel Tests and Further Analysis of the Floating Wing Fuel Tanks for Helicopter Range Extension. Volume 3. Wing Flutter Analysis 45 Degree Skewed Hinge
Abstract
Anti-symmetric and symmetric flutter investigations are performed on the Range Extension floating wing for various fuel loading conditions and combinations of wing modes. The method makes use of Theodorsen's oscillating aerodynamic loads for the generalized excitation. Mechanical equations of the system are obtained with Lagrange's method using several combinations of three wing modes and two rigid fuselage modes as generalized coordinates. Solution of the flutter determinant is obtained by an IBM 650 computer program. Results of flutter calculations are presented as plots of airspeed against wing modes frequency ratio, from which the flutter speed is determined. Results of the analysis indicate that the flutter characteristics of the delta hinge wing arrangement are unacceptable. The investigation shows that for both the 0% and 100% fuel configurations the flutter speeds are below the cruise speed of 80 knots. It is indicated that the low flutter critical speeds are closely associated with the aircraft roll-wing rigid body flap instability which was determined to be an aircraft flight instability. The wing design is being revised to a straight hinge configuration in which the necessary aerodynamic wing spring is being furnished by a differential flap system.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1961
- Accession Number
- AD0267342
Entities
People
- R. Gabel
- R. Ricks
- V. Capurso
Organizations
- Boeing Rotorcraft Systems