Abstract:

ESDU Aero C.04.01.03 provides graphs from which the effect of a nose balance on the rates of change of hinge moment coefficient with incidence and with control deflection may be determined for three control nose shapes: round, elliptical and sharp. They apply to NACA 0009, 0012 and 66009 sections. One graph plots the ratio of the rates of change of hinge moment coefficient with incidence with and without balance against balance ratio. Section shape has little effect on the curves. The second graph plots the ratio of the rates of change of hinge moment coefficient with control deflection with and without balance against balance ratio. Here section shape is significant. In the two graphs the values for the control without balance may be determined respectively from ESDU Aero C.04.01.01 and C.04.01.02. ESDU 89009 may be used to correct to finite aspect ratio or, if there is a spanwise variation of geometrical properties, the method of ESDU Aero C.04.01.06 may be required. The balance may be cut away for hinge brackets, etc. If the cut out exceeds 0.003 of chord it is recommended that a span of three to four times that of the cut out should be treated as not contributing to balance.