Development of a piezoelectric actuator for trailing edge flap control of full scale rotor blades

2001 ◽  
Vol 10 (1) ◽  
pp. 25-34 ◽  
Author(s):  
F K Straub ◽  
H T Ngo ◽  
V Anand ◽  
D B Domzalski
Keyword(s):  
Piezoelectric Actuator ◽  
Full Scale ◽  
Rotor Blades ◽  
Trailing Edge ◽  
Trailing Edge Flap

Development of a piezoelectric actuator for trailing-edge flap control of rotor blades

1999 ◽  
Author(s):  
Friedrich K. Straub ◽  
Hieu T. Ngo ◽  
V. Anand ◽  
David B. Domzalski
Keyword(s):  
Piezoelectric Actuator ◽  
Rotor Blades ◽  
Trailing Edge ◽  
Trailing Edge Flap

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.

Trailing-edge flap flow control for dynamic stall

2011 ◽  
Vol 115 (1170) ◽  
pp. 493-503 ◽  
Author(s):  
R. B. Green ◽  
E. A. Gillies ◽  
Y. Wang
Keyword(s):  
Lower Surface ◽  
Rotor Blades ◽  
Surface Shape ◽  
Dynamic Stall ◽  
Limiting Factors ◽  
Trailing Edge ◽  
Oscillatory Dynamic ◽  
Trailing Edge Flap ◽  
Flap Deflection ◽  
Motion Profile

Abstract Results of a series of oscillatory dynamic stall tests of a rotor aerofoil fitted with a pulsed, trailing-edge flap are presented. Flap deflection amplitude, motion profile, duration and starting phase were investigated to assess the potential of the flap for mitigating the adverse effects of dynamic stall, which is one of the limiting factors for rotor blades on the retreating side of a helicopter rotor. The tests were a continuation of the investigations by Ref. 1 who used a computational fluid dynamics method on a symmetric NACA section, and our results broadly confirm their conclusions by experimental test, using a modern rotor section. The results presented in this paper also confirm the observations from experimental work by Refs 2 and 3, which were undertaken at lower Reynolds number and with a larger flap. In the present study, the flap mitigates the high negative pitching moment and negative pitch damping seen in dynamic stall by strong suction being generated over the aerofoil lower surface, and it is the modification to the lower surface shape by the flap that creates this effect. The dynamic stall vortex acts to enhance the lower surface suction, and careful flap phasing and flap motion profile shaping can make the control more effective.

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.

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