Trailing edge flap control methodology for vibration reduction of helicopter with dissimilar blades

2001 ◽  
Author(s):  
Beatrice Roget ◽  
Inderjit Chopra
Keyword(s):  
Vibration Reduction ◽  
Trailing Edge ◽  
Trailing Edge Flap ◽  
Control Methodology

scholarly journals A comparative assessment of vibration control capabilities of a L-shaped Gurney flap

2016 ◽  
Vol 120 (1233) ◽  
pp. 1812-1831 ◽  
Author(s):  
V. Motta ◽  
G. Quaranta
Keyword(s):  
Vibration Reduction ◽  
Rotor Blades ◽  
Vertical Force ◽  
Trailing Edge ◽  
Helicopter Blade ◽  
Reduced Frequency ◽  
Gurney Flap ◽  
Alternative Means ◽  
Higher Harmonic Control ◽  
Trailing Edge Flap

ABSTRACTThis work presents the capabilities of a novel L-shaped trailing-edge Gurney flap as a device for vibration reduction. The primary effect of this L-tab is represented by a modification of the reference aerofoil mean line shape through by two counter-rotating vortical structures created at the trailing edge. The comparison of the aerodynamic loads generated by the novel L-tab Gurney flap and a classical trailing-edge flap allows to estimate the ranges of reduced frequency where the L-tab is expected to perform better than a trailing edge flap and vice versa. Linear aerostructural models for a typical section representative of a helicopter blade equipped with a partial-span L-tab or a trailing-edge flap are built, and a higher harmonic control algorithm is applied. Performance are compared between the two devices to reduce separately the N/rev harmonics of the blade root rotating frame vertical force, flapping and feathering moments. The attainment of similar results with classical trailing-edge device is a further confirmation of the potential feasibility of this novel L-tab as an effective alternative means for vibration reduction on rotor blades.

Performance enhancement evaluation of an actuated trailing edge flap

2001 ◽  
Vol 105 (1049) ◽  
pp. 391-399 ◽  
Author(s):  
W. Chan ◽  
A. Brocklehurst
Keyword(s):  
Adverse Effect ◽  
Performance Enhancement ◽  
Optimal Configuration ◽  
Analytical Evaluation ◽  
Trailing Edge ◽  
Design Constraints ◽  
Flight Condition ◽  
Trailing Edge Flap

Abstract An analytical evaluation of the performance enhancement due to a servo-actuated trailing edge flap was carried out using the coupled rotor-fuselage model (CRFM). The performance enhancement from a trailing edge flap is achieved by introducing effective camber around the azimuth for a nominal aerofoil. An investigation on the best combination of flap parameters, namely the span, position, chord and deflection was carried out in order to identify an optimal configuration within given design constraints. The effects on vibratory control loads over a range of speed for a flap of 10% span, 20% chord, actuated at once per rev has expanded the retreating blade envelope for a Lynx aircraft by some 20kt. The flap hinge load was also examined and it was found not to be excessive. It was also confirmed that an actuated trailing edge flap does not have adverse effect on the pilot's control inputs to trim to a particular flight condition. This paper will discuss the aerodynamic enhancements derived from the application of the trailing edge flap and present conclusions drawn from this study.

Upper Trailing-Edge Flap for Transonic Buffet Control

2018 ◽  
Vol 55 (1) ◽  
pp. 382-389 ◽  
Author(s):  
Y. Tian ◽  
Z. Li ◽  
P. Q. Liu
Keyword(s):  
Trailing Edge ◽  
Trailing Edge Flap ◽  
Transonic Buffet

Effect of Trailing-Edge Flap Deflection on a Symmetric Airfoil Over a Wavy Ground

2018 ◽  
Vol 141 (6) ◽  
Author(s):  
V. Tremblay-Dionne ◽  
T. Lee
Keyword(s):  
Experimental Investigation ◽  
Pitching Moment ◽  
Cyclic Variation ◽  
Trailing Edge ◽  
Opposite Trend ◽  
Aerodynamic Properties ◽  
Trailing Edge Flap ◽  
Flap Deflection ◽  
Naca 0015

The effect of trailing-edge flap (TEF) deflection on the aerodynamic properties and flowfield of a symmetric airfoil over a wavy ground was investigated experimentally. This Technical Brief is a continuation of Lee and Tremblay-Dionne (2018, “Experimental Investigation of the Aerodynamics and Flowfield of a NACA 0015 Airfoil Over a Wavy Ground,” ASME J. Fluids Eng., 140(7), p. 071202) in which an unflapped airfoil was employed. Regardless of the flap deflection, the cyclic variation in the sectional lift Cl and pitching moment Cm coefficients over the wavy ground always persists. The Cm also has an opposite trend to Cl. The flap deflection, however, produces an increased maximum and minimum Cl and Cm with a reduced fluctuation compared to their unflapped counterparts. The Cd increase outperforms the Cl increase, leading to a lowered Cl/Cd of the flapped airfoil.

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