Effect of the Simultaneous Variation in Blade Root Chord Length and Blade Taper on Helicopter Flight Control Effort

Abstract

In this study, the effect of simultaneous variation in blade root chord length and blade taper on the control effort of helicopter flight control system (i.e., FCS) of a helicopter is investigated. Therefore, helicopter models (i.e., complex, control-oriented, and physicsbased models) including the main physics and essential dynamics are used. The effect of simultaneous variation in the blade root chord length and blade taper (i.e., in both chordwise and lengthwise directions dependently) on the control effort of an FCS of a helicopter and also on the closed-loop responses is studied. Comparisons in terms of the control effort and peak values with and without variations in the blade root chord and blade taper changes are carried out. For helicopter FCS variance-constrained controllers, specific output variance-constrained controllers are beneficial.

Effects of the actively morphing root chord and taper on helicopter energy

“…hover and 80 kts straight and level flight). Overall, the results found for the actively morphing case are similar to those obtained for the passively morphing case (Oktay and Sal, 2017b for the results of the passively morphing case). The focal alteration between the passive and active cases is that in the active case the magnitudes of the control inputs required are much smaller than those required in the passive case.…”

“…In Figure 3, the results reported in Oktay and Sal (2017b) as found in the case of passive morphing are illustrated. In Figure 4, the effects of actively morphing taper and root chord length of the blades on the control energy required for the FCS for the flight conditions of hover, and speeds of 40 and 80 kts during straight and level flight, respectively, are illustrated.…”

Effect of the Simultaneous Variation in Blade Root Chord Length and Blade Taper on Maneuvering Manned Helicopter Control Effort

“…In this article, the helicopter models summarized in (Tugrul Oktay & Sal, 2015;Tugrul Oktay & Sal, 2017;T Oktay & Şal, 2015) are benefited. These models are concisely summarized next.…”

Full-Field Displacement Measurements of Helicopter Rotor Blades Using Stereophotogrammetry

“…Imperfect rotor design will greatly affect the aerodynamic, balance, and dynamic response characteristics of the helicopter and generate unexpected blade displacements during its highspeed rotation. Therefore, detailed understanding of the rotor motion under dynamic loading due to rotation is of crucial importance, which can be used for the validation and improvement of the rotor's structure and aerodynamic characteristics, and further provides a great quantity of information for helicopter flight control system design [1][2][3].…”