Estimation of Full‐Scale Rotor Performance from Model Rotor Test Data

Keys, Charles N.; McVeigh, Michael A.; Dadone, Leo; McHugh, Francis J.

doi:10.4050/jahs.30.22

Cited by 8 publications

(2 citation statements)

References 1 publication

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“…This further raises a question about the accuracy of rotor performance estimates at the extreme edges of a rotor's operating envelope A few e ects of Reynolds number on model-scale rotor testing are known. Keys,4 states that in air, even though model rotors are tested at full-scale tip Mach numbers, the Reynolds numb e r i s l o w b y the ratio of the geometric scale factor. This is the primary cause of di erences between full-scale rotor performance and model-scale rotor test data.…”

Section: Introductionmentioning

confidence: 99%

“…rotor tip Mach n umber in hover, R=a M 1;90 rotor tip Mach n umber at = 9 0 N balance normal force, lbs Q R rotor shaft torque, ft, lb R rotor radius, ft r spanwise distance along blade radius from center of rotation, ft Re Reynolds number, per foot , V= o Re 1;90 rotor tip Reynolds number at = 9 0 , per foot V free-stream velocity, ft=sec z distance from wind-tunnel oor to rotor plane of rotation, ft s rotor shaft angle of attack, degrees rotor blade Lock n umber, a o cR 4 =I b rotor blade collective pitch angle at r=R = 0 :75, degrees 1 twist angle built into rotor blade, positive nose up, degrees rotor advance ratio, V= R o viscosity, lb, sec=ft 2 test-medium mass density, slugs=ft 3 rotor blade azimuth angle, degrees rotor rotational velocity, radians=sec…”

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Important scaling parameters for testing model-scale helicopter rotors

Singleton

Yeager

1998

20th AIAA Advanced Measurement and Ground Testing Technology Conference

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An investigation into the e ects of aerodynamic and aeroelastic scaling parameters on model scale helicopter rotors has been conducted in the NASA Langley Transonic Dynamics Tunnel. The e ect of varying Reynolds number, blade Lock n umber, and structural elasticity on rotor performance has been studied and the performance results are discussed herein for two di erent rotor blade sets at two rotor advance ratios. One set of rotor blades were rigid and the other set of blades were dynamically scaled to be representative of a main rotor design for a utility class helicopter. The investigation was conducted in forward ight at rotor advance ratios of 0.15 and 0.35. Additionally, the rotors were tested over a range of nominal test medium densities from 0.00382 slugs=ft 3 to 0.009 slugs=ft 3 . This range of densities permits the acquisition of data for several Reynolds and Lock n umber combinations. NomenclaturePositive directions for forces, moments, angles, and velocities are shown in Figure 1

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Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Important scaling parameters for testing model-scale helicopter rotors

Singleton

Yeager

1998

20th AIAA Advanced Measurement and Ground Testing Technology Conference

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Twin-rotor hover performance examination using overlap tests

Shahmiri

2017

AEAT

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Purpose The aim of this paper was to experimentally examine twin-rotor hover performance for different rotor overlap ratios at practical rotor loading. Design/methodology/approach The methodology was formed based on data measurements for a designed twin-rotor test model and development of hover performance mathematical models. Thus, measurements were made using a central composite test plan, and then mathematical models for thrust power required power loading (PL) and figure of merit (FM) as functions of collective pitch tip speed; rotor overlap ratio was obtained. In the present paper, the test model consisted of two three-bladed rotors with a diameter of 220 mm and a blade aspect ratio of 16.05. The blades were of a rectangular planform with NACA 0012 cross sections and had no twist or taper. The model was built such that the rear rotor was fixed on the fuselage, and the front rotor could move longitudinally for tests up to about 40 per cent overlap ratio in hover. Findings The best hover aerodynamic efficiency (maximum PL of 14.6 kg/kW) was achieved for non-overlapped rotors at a low value of disc loading (DL) and also at FM of 0.6 at that DL. This result was in agreement with blade element momentum theory predictions. Practical implications Results for the twin-rotor test model can be generalized for actual tandem helicopters through the Reynolds number transformation technique and also some modifications. Originality/value Design and construction of the twin-rotor test model and experimental measurements of hover performance based on an optimal test plan were performed for the first time.

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Aerodynamic Characteristics of SC1095 and SC1094 R8 Airfoils

Bousman

2003

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Two airfoils are used on the main rotor blade of the UH-60A Black Hawk helicopter, the SC1095 and the SC1094 R8. Measurements of the section lift, drag, and pitching moment were obtained in ten wind tunnel tests for the SC1095 airfoil, and in five of these tests, measurements were also obtained for the SC1094 R8. The ten wind tunnel tests are characterized and described in the present study. Fundamental parameters derived from test measurements are compared and an assessment is made of the adequacy of the test data for use in look-up tables required by lifting-line calculation methods.

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Estimation of Full‐Scale Rotor Performance from Model Rotor Test Data

Cited by 8 publications

References 1 publication

Important scaling parameters for testing model-scale helicopter rotors

Important scaling parameters for testing model-scale helicopter rotors

Twin-rotor hover performance examination using overlap tests

Aerodynamic Characteristics of SC1095 and SC1094 R8 Airfoils

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