Prediction of Rotor Instability at High Forward Speeds. Volume I. Steady Flight Differential Equations of Motion for a Flexible Helicopter Blade with Chordwise Mass Unbalance

Prediction of Rotor Instability at High Forward Speeds. Volume I. Steady Flight Differential Equations of Motion for a Flexible Helicopter Blade with Chordwise Mass Unbalance

Author: Peter J. Arcidiacono

Publisher:

Published: 1969

Total Pages: 73

ISBN-13:

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The differential equations of motion for a linearly twisted rotor blade having chordwise mass unbalance and operating under steady flight conditions are derived. The motions include flapping and lagging for the articulated blade, as well as flatwise, edgewise, and torsional deformations for the articulated and nonarticulated blades. The fully coupled aerodynamic forcing functions are based on quasi-steady theory. The differential equations of motion are expanded in terms of the uncoupled vibratory modes of the blade in order to facilitate their numerical solution on a digital computer. (Author).


Rotorcraft Aeromechanics

Rotorcraft Aeromechanics

Author: Wayne Johnson

Publisher: Cambridge University Press

Published: 2013-04-29

Total Pages: 949

ISBN-13: 1107028078

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A rotorcraft is a class of aircraft that uses large-diameter rotating wings to accomplish efficient vertical take-off and landing. The class encompasses helicopters of numerous configurations (single main rotor and tail rotor, tandem rotors, coaxial rotors), tilting proprotor aircraft, compound helicopters, and many other innovative configuration concepts. Aeromechanics covers much of what the rotorcraft engineer needs: performance, loads, vibration, stability, flight dynamics, and noise. These topics include many of the key performance attributes and the often-encountered problems in rotorcraft designs. This comprehensive book presents, in depth, what engineers need to know about modelling rotorcraft aeromechanics. The focus is on analysis, and calculated results are presented to illustrate analysis characteristics and rotor behaviour. The first third of the book is an introduction to rotorcraft aerodynamics, blade motion, and performance. The remainder of the book covers advanced topics in rotary wing aerodynamics and dynamics.


Helicopter Theory

Helicopter Theory

Author: Wayne Johnson

Publisher: Courier Corporation

Published: 1994-01-01

Total Pages: 1126

ISBN-13: 9780486682303

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The history of the helicopter may be traced back to the Chinese flying top (c. 400 BC) and to the work of Leonardo da Vinci, who sketched designs for a vertical flight machine utilizing a screw-type propeller. In the late 19th-century, Thomas Edison experimented with helicopter models, realizing that no such machine would be able to fly until the development of a sufficiently lightweight engine. When the internal combustion gasoline engine came on the scene around 1900, the stage was set for the real development of helicopter technology. While this text provides a concise history of helicopter development, its true purpose is to provide the engineering analysis required to design a highly successful rotorcraft. Toward that end the book offers thorough, comprehensive coverage of the theory of helicopter flight: the elements of vertical flight, forward flight, performance, design, mathematics of rotating systems, rotary wing dynamics and aerodynamics, aeroelasticity, stability and control, stall, noise and more. Wayne Johnson has worked for the U.S. Army and NASA at the Ames Research Center in California. Through his company Johnson Aeronautics, he is engaged in the development of software that is used throughout the world for the analysis of rotorcraft. In this book, Dr. Johnson has compiled a monumental resource that is essential reading for any student or aeronautical engineer interested in the design and development of vertical-flight aircraft.


Analysis of Helicopter Maneuver-loads and Rotor-loads Flight-test Data

Analysis of Helicopter Maneuver-loads and Rotor-loads Flight-test Data

Author: Edward A. Beno

Publisher:

Published: 1973

Total Pages: 100

ISBN-13:

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A study was conducted in which available airload and blade response data for the NH-3A and CH-53A rotors were analyzed in an attempt to provide greater insight into the sources of rotor vibratory loads in both level and maneuvering flight. Primary emphasis in the study was placed on examining and understanding causes of high-frequency rotor control loads. Secondary objectives were: (1) to examine the effect of number of rotor blades on hub vibratory shear forces and (2) to assess which of the many terms appearing in the hub vibratory shear force expression were of most significance.