Analysis of horizontal-tail loads in pitching maneuvers on a flexible swept-wing jet bomber

William S. Aiken, Jr.
naca-tn-4191
Dec 1957


Horizontal-tail loads measured by means of strain gages in pitching maneuvers are analyzed to determine wing-fuselage aerodynamic-center position, zero-lift pitching-moment coefficient, airplane pitching moment of inertia, and radius of gyration. A similar analysis is made of the time-history data for the elevator angles and the results were found to agree with those from the tail-load analysis. The flight-determined values of aerodynamic-center position for rigid conditions and the zero-lift pitching-moment coefficients were in some disagreement with the wind-tunnel data over the Mach number range of the tests (0.42 to 0.81). The pitching moment of inertia determined from the flight data for rigid-wing conditions agreed with calculations based on ground tests. The effective pitching moment of inertia computed from theoretical consideration for flexible flight conditions was in disagreement with flight data. Details of the analysis procedures and least-squares methods used are given.

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