Stability and Control Analysis of the Slowed-Rotor Compound Helicopter Configuration

Floros, Matthew; Johnson, Wayne

doi:10.4050/jahs.52.239

Cited by 17 publications

(9 citation statements)

References 6 publications

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“…[14][15][16][17][18]. Successful flight demonstrations of three modern compounds were also carried out, namely the Sikorsky X2 with a coaxial rotor and pusher prop (Ref.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation and Fundamental Understanding of a Full-Scale Slowed Rotor at High Advance Ratios

Datta¹,

Yeo²,

Norman³

2013

J Am Helicopter Soc

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This paper describes and analyzes the measurements from a full-scale, slowed revolutions per minute (rpm), UH-60A rotor tested at the National Full-Scale Aerodynamics Complex 40-by 80-ft wind tunnel up to an advance ratio of 1.0. A comprehensive set of measurements that includes performance, blade loads, hub loads, and pressures/airloads makes this data set unique. The measurements reveal new and rich aeromechanical phenomena that are unique to this exotic regime. These include reverse chord dynamic stall, retreating side impulse in torsion load, large inboard-outboard elastic twist differential, diminishing rotor forces and yet a dramatic buildup of blade loads, and high blade loads and yet benign levels of vibratory hub loads. The objective of this research is the fundamental understanding of these unique aeromechanical phenomena. The intent is to provide useful knowledge for the design of high-speed, high-efficiency, slowed rpm rotors of the future and a database for validation of advanced analyses. Nomenclature

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“…[14][15][16][17][18]. Successful flight demonstrations of three modern compounds were also carried out, namely the Sikorsky X2 with a coaxial rotor and pusher prop (Ref.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation and Fundamental Understanding of a Full-Scale Slowed Rotor at High Advance Ratios

Datta¹,

Yeo²,

Norman³

2013

J Am Helicopter Soc

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“…Stability and control analysis of slowed-rotor compound helicopter, particularly at high advanced ratios, was presented in Ref. 13 along with the conclusion that a teetering rotor provides the most stable hub configuration.…”

Section: Analysis Of Compound Configurationsmentioning

confidence: 99%

Compound Helicopter: Insight and Optimization

Rand¹,

Khromov²

2015

j am helicopter soc

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μ rotor advance ratio ρ air density ψ F , θ F , ϕ F fuselage Euler attitude angles (heading, pitch, roll) rotor rotational speed Superscripts LR, (2) lower rotor UR, (1) upper rotor (or single rotor) Prop rotor system propulsive force Subscripts F fuselage-related quantities P thruster (pusher)-related quantities R rotor-related quantities S rotor shaft-related quantities W wing-related quantities w wind system-related quantities

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“…The test was a teetering rotor, which was shown analytically in Ref. 8 to be stable at advance ratios up to three for rigid blades.…”

Section: High Advance Ratio Correlationmentioning

confidence: 99%

“…The results of the stability and control investigation are found in Ref. 8. In this paper, performance was calculated using the comprehensive analysis CAMRAD II (Ref.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of the Slowed-Rotor Compound Helicopter Configuration

Floros¹,

Johnson²

2009

j am helicopter soc

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The calculated performance of a slowed-rotor compound aircraft, particularly at high flight speeds, is examined. Correlation of calculated and measured performance is presented for a NASA Langley high advance ratio test to establish the capability to model rotors in such flight conditions. The predicted performance of an isolated rotor and a wing and rotor combination are examined in detail. Three tip speeds and a range of collective pitch settings are investigated. A tip speed of 230 ft/s and zero collective pitch are found to be the best condition to minimize rotor drag over a wide speed range. Detailed rotor and wing performance is examined for both sea level and cruise altitude conditions. Rotor and wing power are found to be primarily from profile drag, except at low speed where the wing is near stall. Increased altitude offloads lift from the rotor to the wing, reducing total power required.

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Stability and Control Analysis of the Slowed-Rotor Compound Helicopter Configuration

Cited by 17 publications

References 6 publications

Experimental Investigation and Fundamental Understanding of a Full-Scale Slowed Rotor at High Advance Ratios

Experimental Investigation and Fundamental Understanding of a Full-Scale Slowed Rotor at High Advance Ratios

Compound Helicopter: Insight and Optimization

Performance Analysis of the Slowed-Rotor Compound Helicopter Configuration

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