A review of helicopter rotor blade tip shapes

Brocklehurst, A.; Barakos, George N.

doi:10.1016/j.paerosci.2012.06.003

Cited by 106 publications

(78 citation statements)

References 96 publications

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“…The results show potential to increase the aerodynamic efficiency of the rotor and to reduce its acoustics (aero-acoustic noise). Brocklehurst and Barakos (2012) present a recent review of works dedicated to different aspects of blade tip design. In (Yen, 1994) swept-tapered blade tips were compared with swept, tapered and rectangular versions.…”

Section: Introductionmentioning

confidence: 99%

“…This tip has some benefits in hover efficiency and noise performance but use on heavier, faster helicopters may be limited by advancing side compressibility effects and retreating side blade stall. According to (Brocklehurst and Barakos, 2012) three families of blade tips (Figure 1) have so far received attention: parabolic, swept and BERP tips. Further improvements and a reduction of the blade noise can be achieved by modifying the rest of the blade plan form.…”

Section: Introductionmentioning

confidence: 99%

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Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover

Garipova

Batrakov

Kusyumov

et al. 2016

HFF

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Purpose -The design of main rotor blade tips is of interest to helicopter manufacturers since the tip details affect the aerodynamic performance and acoustics of the rotor. The aim of this paper is the numerical simulation the flow around hovering helicopter blades with different tip designs.Design/methodology/approach -In this paper, CFD is used to simulate the flow around hovering helicopter blades with different tip designs. For each type of blade tip a parametric study on the shape is also conducted. For comparison, calculations were performed at the same rotor thrust. The collective pitch of the blades and the coning angle of the rotor were determined by an iterative trimming process. The aeroacoustic characteristics of the rotors were obtained using the Ffowcs Williams -Hawkings equation.Findings -Analysis of the distributed blade loads shows that the tip geometry has a significant influence on aerodynamics and aeroacoustics especially for stations where blade loading is high.Originality/value -The results are useful for design new blades with high performance and low acoustic emission. INTRODUCTIONResearch into helicopter blade tips is important for helicopter manufacturers. Past and recent papers demonstrate the constant interest of researchers in this problem. The results show potential to increase the aerodynamic efficiency of the rotor and to reduce its acoustics (aero-acoustic noise). Brocklehurst and Barakos (2012) present a recent review of works dedicated to different aspects of blade tip design. In (Yen, 1994) swept-tapered blade tips were compared with swept, tapered and rectangular versions. In high speed flight the swept-tapered tip reduced the pitch link loads and the blade vibration. Trailing vortex measurements in hover have also been reported in (Martin and Leishman, 2002) for various tip shapes including rectangular, tapered, swept, and a sub-wing tips. One of the primary differences noted was the dependence of wake geometry on the tip shape. The tapered tip reduced the initial swirl velocity, increased the radial convection and decreased the axial convection. The quiet Helicopter demonstrator is discussed in (Allongue et al., 1999). The blade tip shape has a parabolic leading edge and is highly tapered, and therefore has low volume. This tip has some benefits in hover efficiency and noise performance but use on heavier, faster helicopters may be limited by advancing side compressibility effects and retreating side blade stall. According to (Brocklehurst and Barakos, 2012) three families of blade tips (Figure 1) have so far received attention: parabolic, swept and BERP tips. Further improvements and a reduction of the blade noise can be achieved by modifying the rest of the blade plan form. This was attempted with the "ERATO" (Beaumier and Delrieux, 2003) and "Blue Edge" (Rauch et al., 2011) designs. On the ERATO rotor, the blade curves forward and the main sweep-back starts inboard. The aim of this blade design is to reduce blade-vortex interaction (BVI) noise. Anhedral has been...

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover

Garipova

Batrakov

Kusyumov

et al. 2016

HFF

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“…It has been concluded that 3 types of main rotor propeller blade tip designs have been identified (Brocklehurst & Barakos, 2013). The 3 types are: i) the simple sheared-swept tip or swept-tapered-anhedral blade tip represents the propeller blade tip of the state of the art in the USA, while ii) the parabolic tip has been widely adopted in Europe, and iii) the BERP (British Experiment Research Program) tip remains a unique option in the UK.…”

Section: The Helicopter-like Blade Tips and Triangular Finsmentioning

confidence: 99%

Performances and Stall Delays of Three Dimensional Wind Turbine Blade Plate-Models with Helicopter-Like Propeller Blade Tips

Sutrisno

Deendarlianto

Indarto

et al. 2017

MAS

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The research on three dimensional (3-D) wind turbine blades has been introduced (Sutrisno, Prajitno, Purnomo, & B.W. Setyawan, 2016). In the current experiment, the 3-D wind turbine blades would be fitted with helicopter-like blade tips and additional fins to the blade hubs to demonstrate some laminarizing features.It was found that additional helicopter-like blade tip to the turbine blade creates strong laminar flows over the surface of the blade tips. Supplementary, finned hub, fitted to the blade body, creates rolled-up vortex flows, weakens the blade stall growth development, especially for blades at high-speed wind. A proposed mathematical form of modified lifting line model has been developed to pursue further 3-d blade development study of 3-d wind turbine blade.Rolled up vortex effects, developed by finned of the base hub, has been acknowledged could demolish the turbulent region, as well as laminarize the stall domain to intensify the induced wind turbine blade lift.

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“…The shape of the blade tip of a helicopter rotor is known to have a considerable impact on the overall performance of the rotor, blade airloads, noise, and tip-vortex trajectory. Experimental and computational studies have been carried out to improve the hover performance according to variations in the rotor tip shapes [1][2][3][4][5][6]. Of the various blade configurations that are possible, tapered, swept and anhedral tip shapes have been widely used for modern helicopters.…”

Section: Introductionmentioning

confidence: 99%

“…A tapered tip improves the rotor efficiency, such as the Figure of Merit, since it reduces the outboard profile drag. However, this tip shape is prone to enter a premature stall, and also increases the risk of a high vibration in the cruising flight [2,6]. The swept tip blade reduces the tip Mach number, allowing the rotor to obtain a higher advance ratio and to operate at tip Mach numbers before the compressibility effect is manifested [7].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Tip Shape Effect on Rotor Aerodynamic Performance in Hover

Hwang¹,

Kwon²

2015

International Journal of Aeronautical and Space Sciences

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In the present study, an unstructured mixed mesh flow solver was used to conduct a numerical prediction of the aerodynamic performance of the S-76 rotor in hover. For the present mixed mesh methodology, the near-body flow domain was modeled by using body-fitted prismatic/tetrahedral cells while Cartesian mesh cells were filled in the off-body region. A high-order accurate weighted essentially non-oscillatory (WENO) scheme was employed to better resolve the flow characteristics in the off-body flow region. An overset mesh technique was adopted to transfer the flow variables between the two different mesh regions, and computations were carried out for three different blade configurations including swept-taper, rectangular, and swept-taper-anhedral tip shapes. The results of the simulation were compared against experimental data, and the computations were also made to investigate the effect of the blade tip Mach number. The detailed flow characteristics were also examined, including the tip-vortex trajectory, vortex core size, and first-passing tip vortex position that depended on the tip shape.

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A review of helicopter rotor blade tip shapes

Cited by 106 publications

References 96 publications

Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover

Aerodynamic and acoustic analysis of helicopter main rotor blade tips in hover

Performances and Stall Delays of Three Dimensional Wind Turbine Blade Plate-Models with Helicopter-Like Propeller Blade Tips

Assessment of Tip Shape Effect on Rotor Aerodynamic Performance in Hover

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