E-Book
108,99 €

Helicopter Flight Dynamics E-Book

Gareth D. Padfield

0,0

108,99 €

Sammeln Sie Punkte in unserem Gutscheinprogramm und kaufen Sie E-Books und Hörbücher mit bis zu 100% Rabatt.

Mehr erfahren.

Herausgeber: John Wiley & Sons
Kategorie: Fachliteratur
Serie: Aerospace Series (PEP)
Sprache: Englisch

Beschreibung

The Book The behaviour of helicopters and tiltrotor aircraft is so complex that understanding the physical mechanisms at work in trim, stability and response, and thus the prediction of Flying Qualities, requires a framework of analytical and numerical modelling and simulation. Good Flying Qualities are vital for ensuring that mission performance is achievable with safety and, in the first and second editions of Helicopter Flight Dynamics, a comprehensive treatment of design criteria was presented, relating to both normal and degraded Flying Qualities. Fully embracing the consequences of Degraded Flying Qualities during the design phase will contribute positively to safety. In this third edition, two new Chapters are included. Chapter 9 takes the reader on a journey from the origins of the story of Flying Qualities, tracing key contributions to the developing maturity and to the current position. Chapter 10 provides a comprehensive treatment of the Flight Dynamics of tiltrotor aircraft; informed by research activities and the limited data on operational aircraft. Many of the unique behavioural characteristics of tiltrotors are revealed for the first time in this book. The accurate prediction and assessment of Flying Qualities draws on the modelling and simulation discipline on the one hand and testing practice on the other. Checking predictions in flight requires clearly defined mission tasks, derived from realistic performance requirements. High fidelity simulations also form the basis for the design of stability and control augmentation systems, essential for conferring Level 1 Flying Qualities. The integrated description of flight dynamic modelling, simulation and flying qualities of rotorcraft forms the subject of this book, which will be of interest to engineers practising and honing their skills in research laboratories, academia and manufacturing industries, test pilots and flight test engineers, and as a reference for graduate and postgraduate students in aerospace engineering.

Details

Sie lesen das E-Book in den Legimi-Apps auf:

Android

iOS

von Legimi
zertifizierten E-Readern

Seitenzahl: 1754

Veröffentlichungsjahr: 2018

Bewertungen

0,0

Rezensionen(0 Rezensionen)

Ähnliche

Der Weg zum erfolgreichen Unternehmer

Stefan Merath

Der Weg zum erfolgreichen Unternehmer

Stefan Merath

Denke (nach) und werde reich

Napoleon Hill

30 Minuten Resilienz

Ulrich Siegrist

Krebszellen mögen keine Himbeeren - Der große Bestseller - Vollständig überarbeitet und aktualisiert

Richard Béliveau

Die Hormonrevolution

Michael E Platt

Der Crash ist die Lösung

Matthias Weik

Günter, der innere Schweinehund, lernt verkaufen

Stefan Frädrich

Die Leber wächst mit ihren Aufgaben

Dr. med. Eckart von Hirschhausen

Der größte Raubzug der Geschichte

Matthias Weik

Unsere Hunde - gesund durch Homöopathie

Hans Günter Wolff

Die Jahrhundertlüge, die nur Insider kennen

Heiko Schrang

Organisation für Komplexität

Niels Pfläging

Radikal führen

Reinhard K. Sprenger

30 Minuten Sympathisch und souverän: So geht Vortragen!

Thomas Lorenz

BLACKOUT - Morgen ist es zu spät

Marc Elsberg

The Truth About Employee Engagement

Patrick M. Lencioni

Mensch und Wald

Carsten Wippermann

The Food Truck Handbook

David Weber

Die selbstbestimmte Geburt

Ina May Gaskin

Leseprobe

Cover

Dedication

Series Preface

Preface to Third Edition

Preface to Second Edition

Preface to First Edition

Acknowledgements

Notation

Subscripts

Dressings

List of Abbreviations

Chapter 1: Introduction

1.1 Simulation Modelling

1.2 Flying Qualities

1.3 Missing Topics

1.4 Simple Guide to the Book

Chapter 2: Helicopter and Tiltrotor Flight Dynamics – An Introductory Tour

2.1 Introduction

2.2 Four Reference Points

2.3 Modelling Helicopter/Tiltrotor Flight Dynamics

2.4 Flying Qualities

2.5 Design for Flying Qualities; Stability and Control Augmentation

2.6 Tiltrotor Flight Dynamics

2.7 Chapter Review

Chapter 3 Modelling Helicopter Flight Dynamics: Building a Simulation Model

3.1 Introduction and Scope

3.2 The Formulation of Helicopter Forces and Moments in Level 1 Modelling

3.3 Integrated Equations of Motion of the Helicopter

3.4 Beyond Level 1 Modelling

3.5 Chapter 3 Epilogue

Appendix 3A Frames of Reference and Coordinate Transformations

Chapter 4 Modelling Helicopter Flight Dynamics: Trim and Stability Analysis

4.1 Introduction and Scope

4.2 Trim Analysis

4.3 Stability Analysis

Appendix 4A The Analysis of Linear Dynamic Systems (with Special Reference to 6‐Dof Helicopter Flight)

Appendix 4B The Three Case Helicopters: Lynx, Bo105 and Puma

Appendix 4C. The Trim Orientation Problem

Chapter 5: Modelling Helicopter Flight Dynamics: Stability Under Constraint and Response Analysis

5.1 Introduction and Scope

5.2 Stability Under Constraint

5.3 Analysis of Response to Controls

5.4 Response to Atmospheric Disturbances

Appendix 5A Speed Stability Below Minimum Power; A Forgotten Problem?

Chapter 6: Flying Qualities: Objective Assessment and Criteria Development

6.1 General Introduction to Flying Qualities

6.2 Introduction and Scope: The Objective Measurement of Quality

6.3 Roll Axis Response Criteria

6.4 Pitch Axis Response Criteria

6.5 Heave Axis Response Criteria

6.6 Yaw Axis Response Criteria

6.7 Cross‐Coupling Criteria

6.8 Multi‐Axis Response Criteria and Novel‐Response Types

6.9 Objective Criteria Revisited

Chapter 7: Flying Qualities: Subjective Assessment and Other Topics

7.1 Introduction and Scope

7.2 The Subjective Assessment of Flying Quality

7.3 Special Flying Qualities

7.4 Pilot's Controllers

7.5 The Contribution of Flying Qualities to Operational Effectiveness and the Safety of Flight

Chapter 8: Flying Qualities: Forms of Degradation

8.1 Introduction and Scope

8.2 Flight in Degraded Visual Environments

8.3 Handling Qualities Degradation through Flight System Failures

8.4 Encounters with Atmospheric Disturbances

8.5 Chapter Review

8A HELIFLIGHT, HELIFLIGHT‐R, and FLIGHTLAB at the University of Liverpool

FLIGHTLAB

8A.3 HELIFLIGHT‐R

Chapter 9: Flying Qualities: The Story of an Idea

9.1 Introduction and Scope

9.2 Historical Context of Rotorcraft Flying Qualities

9.3 Handling Qualities as a Performance Metric – The Development of ADS‐33

9.4 The UK MoD Approach

9.5 Roll Control; A Driver for Rotor Design

9.6 Helicopter Agility

9.7 The Future Challenges for Rotorcraft Handling Qualities Engineering

Chapter 10: Tiltrotor Aircraft: Modelling and Flying Qualities

10.1 Introduction and Scope

10.2 Modelling and Simulation of Tiltrotor Aircraft Flight Dynamics

10.3 The Flying Qualities of Tiltrotor Aircraft

10.4 Load Alleviation versus Flying Qualities for Tiltrotor Aircraft

10.5 Chapter Epilogue; Tempus Fugit for Tiltrotors

Appendix 10A Flightlab Axes Systems and Gimbal Flapping Dynamics

Appendix 10B The XV‐15 Tiltrotor

Appendix 10C The FXV-15 Stability and Control Derivatives

Appendix 10D Proprotor Gimbal Dynamics in Airplane Mode

Appendix 10E Tiltrotor Directional Instability Through Constrained Roll Motion: An Elusive, Paradoxical Dynamic

References

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

Chapter 7

Chapter 8

Chapter 9

Chapter 10

Index

End User License Agreement

List of Tables

Chapter 03

Table 3.1 Levels of rotor mathematical modelling

Chapter 04

Table 4.1 Trim forces and moments – Lynx at 80 knots in climbing turn (

f e

= −0.15 rad,

= 0.4 rad/s).

Table 4.2 Approximations for heave damping derivative

Table 4.3 Eigenvectors for the hover phugoid oscillation.

Table 4.4 Comparison of ‘exact’ and approximate hover phugoid eigenvalues.

Table 4.5 Comparison of ‘exact’ and approximate longitudinal subsidences.

Table 4.6 Comparison of ‘exact’ and approximate longitudinal eigenvalues for Puma (exact results shown in parenthesis).

Table 4.7 Lynx stability characteristics with aft centre of mass.

Table 4.8 Comparison of flight estimates and theoretical predictions of Puma and Bo105 stability characteristics.

Table 4A.1 Comparison of exact and approximate eigenvalues for longitudinal modes of motion.

Table 4B.1 Configuration data – Lynx.

Table 4B.2 Configuration data – Bo105.

Table 4B.3 Configuration data – Puma.

Table 4B.4 Generalised fuselage aerodynamic coefficients.

Chapter 05

Table 5.1 Eigenvalues for 6‐DoF and 9‐DoF motions – Lynx in hover

Table 5.2 Parameters in matrix A for the three aircraft from Appendix 4.B.

Table 5.3 Eigenvalues for fourth‐ and third‐order roll/regressing flap modes;

= 0.

Table 5.4 Comparison of second and fifth order approximant predictions.

Table 5.5 Comparison of theoretical predictions and flight estimates of Puma derivatives and stability characteristics.

Table 5.6 Variation of longitudinal stability characteristics with tailplane size (Bo105–120 knots).

Table 5.7 Dutch roll oscillation characteristics.

Chapter 06

Table 6.1 Response‐type requirements in different usable cue environments for selected MTEs

Table 6.2 Limiting values of time response parameters for roll rate response type in hover and low‐speed MTEs

Table 6.3 Roll attitude bandwidth results for current helicopters

Table 6.4 Maximum values for time parameters in height response to collective (Ref. 6.5)

Table 6.5 Vertical axis minimum control power requirements (Ref. 6.5)

Table 6.6 Criteria for large amplitude response in hover

Chapter 07

Table 7.1 ADS‐33 flight test manoeuvres (Ref. 7.12)

Table 7.2 Comparison of task description and performance standards for ADS‐33 and DRA ACT sidestep mission task element

Table 7.3 Task performance requirements for lateral jinking MTE

Table 7.4 Response types for Level 1–2 handling qualities in different UCEs (Ref. 7.1)

Table 7.5 Carefree handling features evaluated in Ref. 7.34

Table 7.6 Possible HQRs for same aircraft in different MTEs

Chapter 08

Table 8.1 HQRs and UCEs for terrain‐hugging manoeuvres (Ref. 8.33)

Table 8.2 Average flight parameters for the terrain‐hugging manoeuvres

Table 8.3 Correlation constants and fit coefficients – following the constant acceleration guide

Table 8.4 Failure classification

Table 8.5 Levels for rotorcraft failure states

Table 8.6 AFCS failure criteria (Def Stan 00970, Ref. 8.56)

Table 8.7 Failure transient requirements (ADS‐33)

Table 8.8 Failure transient requirements (Ref. 8.62)

Table 8.9 Helicopter parameters in the vortex encounter study

Table 8.10 Best fit parameter values to LIDAR velocity profiles for the Burnham and dispersion models (Ref. 8.76)

Table 8.11 Transient pitch attitudes following the vortex encounter

Table 8.12 Transient vertical acceleration following the vortex encounter

Table 8.13 EHST data showing average yearly rotorcraft accident numbers over the period 2005–2014 (Ref. 8.87)

Table 8A.1 HELIFLIGHT motion envelope

Table 8A.2 HELIFLIGHT‐R motion envelope

Chapter 10

Table 10.1 Comparison of FXV‐15 eigenvalues (italics) with published data

Table 10.2 Summary of BA609 Mission Task Elements (Ref. 10.8)

Table 10.3 Flying qualities critical MTEs in the civil tiltrotor mission (Refs. 10.61, 10.62); (H – high, M – moderate, L – low; HM – helicopter, CM – conversion, AM – airplane); X indicates when a particular MTE/Mode is critical

Table 10.4 Comparison of exact and approximate phugoid eigenvalues for the FXV−15 at 6000 m

Table 10.5 Levels of urgency in the roll−step FTM defined by forward speeds for different flight modes

Table 10.6 FXV−15 short period flying qualities parameters

Table 10.7 Performance standards for the heave−hop FTM

Table 10.8 Some lessons learned from the XV−15 applicable to the V−22 (from Ref. 10.9)

Table 10.9 Configuration data for the three tiltrotor designs

Table 10.10 Identified critical loads and manoeuvres for the Bell−Boeing V−22 (Ref. 10.90)

Table 10B.1 FXV‐15 Configuration data (see also Appendix 10B and Figure 10B.2 for aircraft geometry)

Table 10B.2 Control ranges at the pilot's controls

Table 10B.3 Airplane mode controls

Table 10B.4 Lateral stick to differential collective pitch (DCP)

Table 10B.5 Longitudinal stick to longitudinal cyclic pitch

Table 10B.6 Pedal to differential longitudinal cyclic pitch

Table 10B.7 Collective lever to blade pitch

Table 10B.8 Collective lever to throttle

List of Illustrations

Chapter 02

Figure 2.1 The four reference points of rotorcraft flight dynamics

Figure 2.2 Flying task hierarchy

Figure 2.3 Elements of a civil mission – offshore supply: (a) offshore supply mission; (b) mission phase: approach and land; (c) mission task element: landing

Figure 2.4 Elements of a military mission – armed reconnaissance: (a) armed reconnaissance mission; (b) mission phase – NoE; (c) mission task element – sidestep

Figure 2.5 Rotor control through a swash plate

Figure 2.6 Control actions as helicopter transitions into forward flight: (a) hover; (b) forward acceleration; (c) translational lift

Figure 2.7 Lynx Mk 5 tail rotor control limits in hover with winds from different directions

Figure 2.8 Rotor flow states in axial flight

Figure 2.9 Features limiting rotor performance in high‐speed flight

Figure 2.10 Variation of incidence and Mach number encountered by the rotor blade tip in forward flight

Figure 2.11 Rotor thrust limits as a function of advance ratio

Figure 2.12 The pilot as sensor and motivator in the feedback loop

Figure 2.13 Response types required to achieve Level 1 handing qualities in different UCEs

Figure 2.14 Frequency and amplitude – the natural modelling dimensions for flight mechanics

Figure 2.15 The modelling components of a helicopter

Figure 2.16 The orthogonal axes system for helicopter flight dynamics

Figure 2.17 Typical presentation of flight mechanics results for trim, stability, and response

Figure 2.18 Sketches of rotor flapping and pitch: (a) rotor flapping in vacuum; (b) gyroscopic moments in vacuum; (c) rotor coning in air; (d) before shaft tilt; (e) after shaft tilt showing effective cyclic path

Figure 2.19 Components of rotor blade incidence

Figure 2.20 The three rotor disc degrees of freedom

Figure 2.21 Variation of flap derivatives with stiffness number in hover: (a) control; (b) damping; (c) cross‐coupling

Figure 2.22 Linear variation of rotor damping with control sensitivity in hover

Figure 2.23 Effects of rotor parameters on roll rate response: (a) rotor stiffness; (b) Lock number

Figure 2.24 Variation of roll/flap exact and approximate mode eigenvalues with rotor stiffness

Figure 2.25 Incidence perturbation on advancing and retreating blades during encounter with vertical gust

Figure 2.26 Variation of static stability derivative,

, with forward speed for Bo105, Lynx, and Puma

Figure 2.27 Constant pitch and heave motions

Figure 2.28 Variation of heave damping,

, with airspeed for rotary‐ and fixed‐wing aircraft

Figure 2.29 (a) Variation of Lynx eigenvalues with forward speed; (b) variation of Puma eigenvalues with forward speed

Figure 2.30 Variation of trim control angles with forward speed for Puma

Figure 2.31 Nonlinear pitch response for Lynx at 100 knots

Figure 2.32 Equation error identification process

Figure 2.33 Output error identification process

Figure 2.34 Inverse simulation as a feedback process

Figure 2.35 The Cooper–Harper handling qualities rating scale – summarised form

Figure 2.36 Presentation of pilot handling qualities ratings showing variation with task, environmental, or configuration parameter

Figure 2.37 Frequency and amplitude characterization of aircraft response

Figure 2.38 Fuselage failure on Sikorsky S‐51 (Ref. 2.31)

Figure 2.39 Long period pitch stability characteristics

Figure 2.40 Task portrait for roll/pitch and stop manoeuvre

Figure 2.41 Comparison of rotary‐ and fixed‐wing aircraft pitch bandwidth requirements

Figure 2.42 Examples of low‐speed mission task elements with performance requirements

Figure 2.43 Variations of pilot HQRs with task time for Puma 200 ft sidestep

Figure 2.44 HQRs versus agility factor for the Puma flying sidestep and quickhop MTEs

Figure 2.45 Time histories of lateral cyclic in a lateral slalom MTE

Figure 2.46 Power spectrum of lateral cyclic in a lateral slalom MTE

Figure 2.47 Conceptual relationship between pilot workload and the bandwidth ratio

Figure 2.48 CAE four‐axis sidestick onboard the Canadian NRC variable stability Bell 205

Figure 2.49 GEC biocular helmet‐mounted display

Figure 2.50 Probability of rating category as a function of HQR

Figure 2.51 Simple feedback augmenting pitch rate damping

Figure 2.52 Variation of long period pitch mode frequency and damping with autostabiliser gains for Lynx at 140 knots

Chapter 03

Fig. 3.1 The helicopter as an arrangement of interacting subsystems

Fig. 3.2 Rotor blade aeroelasticity as a feedback problem

Fig. 3.3 Helicopter response characteristics on a frequency–amplitude plane

Fig. 3.4 Three flap arrangements: (a) teetering; (b) articulated; (c) hingeless

Fig. 3.5 Out‐of‐plane bending of a rotor blade

Fig. 3.6 The centre‐spring equivalent rotor analogue

Fig. 3.7 Aerodynamic loads on a typical aerofoil section

Fig. 3.8 The rotor disc in multiblade coordinates

Fig. 3.9 Eigenvalues of a multiblade coordinate rotor system

Fig. 3.10 The forces and moments acting on a rotor hub

Fig. 3.11 Rotor side force and lateral cyclic variations in trimmed flight: (a) rotor side force (Bo105); (b) lateral cyclic pitch (Bo105)

Fig. 3.12 Rotor flow states in axial motion: (a) hover; (b) climb; (c) descent

Fig. 3.13 Momentum theory solutions for rotor inflow in axial flight

Fig. 3.14 Flow through a rotor in forward flight

Fig. 3.15 General inflow solution from momentum theory

Fig. 3.16 Vortex‐ring boundaries (Ref. 3.19)

Fig. 3.17 Local momentum theory applied to a rotor disc

Fig. 3.18 Different approximate models for a hingeless rotor blade

Fig. 3.19 The offset‐hinge model of rotorblade flapping

Fig. 3.20 Cross‐plot of rotor flap control derivatives

Fig. 3.21 Cross‐plot of roll control derivatives as a function of flap hinge offset

Fig. 3.22 Rotor blade lag motion

Fig. 3.23 Flap and lag mode eigenvalues

Fig. 3.24 Rotor blade pitch motion

Fig. 3.25 Coriolis forces acting to twist a rotor blade

Fig. 3.26 Lynx (a) and Bo105 (b) rotor hubs

Fig. 3.27 Ground effect on a helicopter in hovering flight

Fig. 3.28 Influence of ground effect on rotor thrust (Ref. 3.43)

Fig. 3.29 Influence of ground effect on power (Ref. 3.43)

Fig. 3.30 Sketch of tail rotor subsystem

Fig. 3.31 Typical variation of fuselage aerodynamic force coefficients with incidence angles

Fig. 3.32 Empennage layout

Fig. 3.33 Influence of rotor downwash on tail surfaces

Fig. 3.34 Variation of vertical stabiliser sideforce with sideslip – Puma

Fig. 3.35 Variation of engine time constants with torque

Fig. 3.36 Schematic of helicopter flight control system

Fig. 3.37 Geometry of mechanical interlink between collective and cyclic for Lynx (Ref. 3.54)

Fig. 3.38 Geometry of mechanical link between tail rotor control run and cockpit controls for Lynx (Ref. 3.54)

Fig. 3.39 The integrated helicopter simulation model

Fig. 3.40 Comparison of rotor incidence distribution measured on the RAE research Puma with theory: (a) flight; (b) Helisim (Ref. 3.57)

Fig. 3.41 Types of aerofoil stall: (a) trailing edge stall; (b) leading edge stall

Fig. 3.42 Time delay model for dynamic stall (Ref. 3.62) (T.E., trailing edge; L.E., leading edge; C.P., centre of pressure)

Fig. 3.43 Rotor blade shape at the advancing (90°) and retreating (270°) azimuth angles for Lynx at 150 knots

Fig. 3.44 The tail rotor in quartering flight

Fig. 3.45 Comparison of the tail rotor pedal margin measured on the RAE research Lynx with theory: (a) flight; (b) Helisim; (c) Helisim corrected (Ref. 3.73)

Fig. 3.46 Comparison of flat and free wake predictions for normalised downwash at the horizontal stabiliser location; UH‐60,

= 0.2 (Ref. 3.78)

Fig. 3.47 Comparison of pitch rate response to pedal input; UH‐60, 100 knots (Ref. 3.78)

Fig. 3.48 Committed and expended costs during the life cycle of a product (Refs. 3.82, 3.83)

Fig. 3.49 The UoL HELIFLIGHT‐R ground‐based flight simulator (left) and NRC ASRA in‐flight simulator (right) (Ref. 3.92)

Fig. 3.50 Comparison of pitch (left) and roll (right) bandwidth‐phase delay in hover; FB‐412 vs ASRA, ACAH configuration (Ref. 3.95)

Fig. 3.51 Comparison of pitch (left) and roll (right) attitude quickness in hover; FB‐412 vs ASRA (bare airframe) (Ref. 3.95)

Fig. 3.52 A rating scale for the assessment of flight simulator fidelity

Fig. 3.53 Levels of comparative performance and control strategy adaptation used in the SFR scale

Fig. 3A.1 The fuselage‐fixed reference axes system

Fig. 3A.2 The fuselage Euler angles: (a) yaw; (b) pitch; (c) roll

Fig. 3A.3 Three views of the hub and blade reference axes systems (Ref. 3.83)

Fig. 3A.4 Reference planes for rotor dynamics: (a) longitudinal plane; (b) lateral plane

Chapter 04

Fig. 4.1 The territory of helicopter flight mechanics

Fig. 4.2 Simple consideration of trim in hover: (a) longitudinal (view from port); (b) yaw (view from above); (c) roll (view from front)

Fig. 4.3 The general trim condition of an aircraft

Fig. 4.4 Sequence of calculations in the trim iteration – summary

Fig. 4.5 Part I – Sequence of calculations in the trim iteration – expanded form.

Fig. 4.5 Part II – Sequence of calculations in the trim iteration – expanded form.

Fig. 4.6 Pitch angle in trim: (a) Trim pitch angle as a function of forward speed – comparison of flight and theory; (b) Trim pitch angle as a function of turn rate

Fig. 4.7 Longitudinal flapping for Lynx and Puma as a function of forward speed

Fig. 4.8 Roll angle in trim: (a) Trim roll angle as a function of forward speed; (b) Trim roll angle as a function of turn rate

Fig. 4.9 Lynx trimmed in sideslipping flight at 100 knots

Fig. 4.10 Bo105 control angles in level trimmed flight: (a) longitudinal cyclic; (b) lateral cyclic; (c) main rotor collective; (d) tail rotor collective

Fig. 4.11 Bo105 power required as a function of forward speed

Fig. 4.12 Power required in descending flight (from Ref. 4.3): (a) θ = 0°; (b) θ = 15°

Fig. 4.13 Derivative calculation by backward‐forward differencing: (a) small perturbation; (b) large perturbation

Fig. 4.14 Variation of force/velocity derivatives with forward speed

Fig. 4.15 Variation of longitudinal static stability derivatives with forward speed

Fig. 4.16 Sketch showing pitching moments at the aircraft centre of mass

Fig. 4.17 Contributions to the static stability derivative

at 120 knots for Lynx and Puma

Fig. 4.18 Comparison of

approximate and ‘exact’ results for Lynx

Fig. 4.19 Effect of tail rotor

angle on weathercock stability derivative

Fig. 4.20 Variation of derivative

with ‘v’ velocity perturbation for Puma

Fig. 4.21 Source of rotor hub couple due to inclination of rotor torque to the shaft

Fig. 4.22 Variation of rotor flap derivatives with Stiffness number

Fig. 4.23 Loci of Lynx eigenvalues as a function of forward speed: (a) coupled; (b) uncoupled

Fig. 4.24 Loci of Bo105 eigenvalues as a function of forward speed: (a) coupled; (b) uncoupled

Fig. 4.25 Loci of Puma eigenvalues as a function of forward speed: (a) coupled; (b) uncoupled

Fig. 4.26 Simple representation of unstable pitch phugoid in hover

Fig. 4.27 Effect of centre of mass location on the stability of the longitudinal phugoid for Lynx

Fig. 4.28 Variation of weathercock stability derivative

with speed for different sideslip perturbations for Puma

Fig. 4.29 Loci of Dutch roll and spiral mode eigenvalues with speed for different sideslip perturbations for Puma

Fig. 4A.1 Longitudinal short period eigenvalue – Puma at 100 knots

Fig. 4A.2 Longitudinal short period eigenvector – Puma at 100 knots

Fig. 4A.3 Frequency response as the transfer function evaluated on imaginary axis

Fig. 4B.1 RAE research Lynx ZD559 in flight

Fig. 4B.2 RAE research Lynx ZD559 three‐view drawing

Fig. 4B.3 DLR research Bo105 S123 in flight

Fig. 4B.4 DLR research Bo105 S123 three‐view drawing

Fig. 4B.5 RAE research Puma XW241 in flight

Fig. 4B.6 RAE research Puma XW241 three‐view drawing

Fig. 4B.7 Stability derivatives – longitudinal

Fig. 4B.8 Stability derivatives – lateral

Fig. 4B.9 Stability derivatives – lateral into longitudinal

Fig. 4B.10 Stability derivatives – longitudinal into lateral

Fig. 4B.11 Control derivatives – main rotor longitudinal

Fig. 4B.12 Control derivatives – main rotor lateral

Fig. 4B.13 Control derivatives – tail rotor

Fig. 4C.1 Flight velocity vector relative to the fuselage axes in trim

Fig. 4C.2 Sequence of orientations from velocity vector to fuselage axes in trim: (a) rotation to horizontal through flight path angle

; (b) rotation through track angle χ

; (c) rotation through Euler pitch angle Θ

; (d) rotation through Euler roll angle Φ

Chapter 05

Figure 5.1 Root loci for longitudinal stability characteristics with varying attitude and rate feedback gains

Figure 5.2 Root loci for varying roll attitude feedback gain for 6‐DoF Lynx in hover

Figure 5.3 Root loci for varying roll attitude feedback gain for 9‐DoF Lynx in hover

Figure 5.4 Root loci for varying roll attitude feedback gain for 4‐DoF Lynx (x – open‐loop poles; o – closed‐loop zeros)

Figure 5.5 Root loci for varying roll attitude feedback gain for 4‐DoF Bo105 (x – open‐loop poles; o – closed‐loop zeros)

Figure 5.6 Root loci for varying roll attitude feedback gain for 4‐DoF Puma (x – open‐loop poles; o – closed‐loop zeros)

Figure 5.7 Root loci for varying roll attitude feedback gain for 3‐DoF Bo105

Figure 5.8 Time response following an initial 1° perturbation in

; Bo105. (a)

= 0, (b)

, (c)

Figure 5.9 How the lateral flapping

changes as the feedback gain is increased; all aircraft are rolling to starboard at the point of zero roll angle

Figure 5.10 Stability limits as a function of roll feedback gain (Ref. 5.6)

Figure 5.11 Root loci for varying vertical velocity gain for 6‐DoF Lynx at 60 knots

Figure 5.12 Root loci for varying vertical velocity gain for 9‐DoF Lynx at 60 knots

Figure 5.13 Helicopter force balance in simple lateral manoeuvre

Figure 5.14 Flight path changes in a slalom manoeuvre (Ref. 5.15)

Figure 5.15 Results from Helisim Lynx constrained to fly a lateral slalom (Ref. 5.15): (a) roll attitude; (b) roll rate; (c) lateral cyclic

Figure 5.16 Comparison of quasi‐steady theory and flight measurement of vertical acceleration response to a step collective pitch input for Puma in hover (Ref. 5.20)

Figure 5.17 Puma collective frequency response in hover (Ref. 5.25)

Figure 5.18 Comparison of equivalent system fit and flight measurements of Puma frequency response to collective in hover (Ref. 5.20): (a) vertical acceleration; (b) multiblade coning

Figure 5.19 Comparison of 3‐DoF estimated model and flight measurements of response to collective for Puma in hover (Ref. 5.20)

Figure 5.20 Response to a 1

step collective input for Bo105

Figure 5.21 Response to a 3211 collective input for Bo105 at 80 knots: comparison of flight and simulation

Figure 5.22 Pitch and roll response to 1° cyclic pitch steps in hover

Figure 5.23 Sketches of helicopter motion following cyclic inputs in hover: (a) lateral cyclic step; (b) longitudinal cyclic step

Figure 5.24 Comparison of short‐term response to lateral cyclic pitch step in hover

Figure 5.25 Response characteristics with varying rotor flap stiffness (

= 5.09)

Figure 5.26 Response characteristics with varying rotor Lock number

Figure 5.27 Variation of response characteristics with forward speed

Figure 5.28 Contribution of the horizontal stabilizer to stability and agility (

= 120 knots)

Figure 5.29 Comparison of flight and simulation response to lateral cyclic 3211 inputs for Bo105 at 80 knots

Figure 5.30 Comparison of flight and simulation response to longitudinal cyclic 3211 inputs for Bo105 at 80 knots

Figure 5.31 Comparison of open‐loop roll attitude frequency response; seventh‐order baseline identified model versus flight test for Bo105 at 80 knots (a) magnitude; (b) phase (Ref. 5.8)

Figure 5.32 Comparison of open‐loop roll attitude frequency response; band‐limited identified quasi‐steady model versus flight test for Bo105 at 80 knots (Ref. 5.8): (a) magnitude; (b) phase

Figure 5.33 Comparison of flight and simulation response to roll cyclic step, showing contribution of dynamic inflow for UH‐60 in hover (Ref. 5.36): (a) roll response; (b) pitch response

Figure 5.34 Response to pedal 3211 input – comparison of flight and simulation for Puma at 80 knots (Ref. 5.37)

Figure 5.35 Response to pedal 3211 input – comparison of flight and identified model – Puma at 80 knots (Ref. 5.37)

Figure 5.36 Response to pedal double input – varying flight path angle for Puma at 100 knots (Ref. 5.39): (a) Run 463/09/13

= −0.1 (descent); (b) Run 467/10/11

= 0 (level); (c) Run 464/01/01

= 0.1 (climb)

Figure 5.37 Variation of Dutch roll oscillation roll/yaw ratio with flight path angle (Ref. 5.39)

Figure 5.38 A helicopter in descending (left) and climbing (right) flight, showing the sideslip velocity during rolling motion; in descent, the dihedral effect is stabilizing, in climb destabilizing

Figure 5.39 Response to a pedal doublet input – comparison of linear and nonlinear solutions for Puma at 120 knots

Figure 5.40 Elemental ramp gust used in the statistical discrete gust approach

Figure 5.41 Influence of Fourier amplitude and phase on the structure of atmospheric turbulence: (a) measured atmospheric turbulence; (b) reconstruction using measured amplitude components; (c) reconstruction using measured phase components (Ref. 5.52)

Figure 5.42 Transient response analysis using the SDG method: (a) gust input; (b) aircraft response; (c) tuned response function

Figure 5.43 Transient response quickness as a ride qualities parameter: (a) quickness extraction; (b) quickness chart

Figure 5A.1 The general form of the drag variation with airspeed

Figure 5A.2 Speed stability below minimum power; stability relationships shown with the drag and power curves for a turbofan powered aircraft (based on Ref. 5A.7)

Figure 5A.3 Drag coefficient variation with lift coefficient (based on Ref. 5A.7)

Figure 5A.4 Variation of speed on approach to carrier landing (Ref. 5A.11)

Figure 5A.5 Profile View of the last 40 s of Asiana Flight 214 (Ref. 5A.12); the letters W and R on the lower part of the figure correspond to White and Red on the

precision approach path indicator

(

PAPI

) guidance lights – according to this data, four red lights would have been visible 19 s before impact at time zero

Figure 5A.6 Puma collective pitch at three‐quarter radius as a function of flight speed; flight test compared with Helisim (Ref. 5A.17)

Figure 5A.7 The limiting speed‐eigenvalue for the Helisim Puma as a function of flight speed showing the transition from instability to stability around the minimum power speed

Figure 5A.8 Comparison of exact and approximate surge eigenvalues as a function of vertical speed control gain over a practical range of values

Figure 5A.9 Flight speed along aircraft

‐axis as a function of time during flight path constrained descent with 6° flight path angle; Comparison of flight (ASRA) and ground‐based simulation (HELIFLIGHT‐R) flown with and without collective assistance (Ref. 5A.14)

Figure 5A.10 Flight Data Recorder (FDR) records for AS332 L2 Super Puma, G‐WNSB, approaching Sumburgh Airport, 23 August 2013 (Ref. 5A.21)

Figure 5A.11 Exponential fit of the pitch attitude increase during the 20‐s period to a maximum of 20°, when the airspeed had decayed below 30kts (Figure 5A.10, Ref. 5A.21)

Figure 5A.12 Root loci for Helisim Puma longitudinal modes; comparison of results for vertical speed and attitude feedback;

40 kts

Chapter 06

Figure 6.1 Mission‐oriented flying qualities (Ref. 6.3)

Figure 6.2 The Cooper–Harper handling qualities rating scale (Ref. 6.2)

Figure 6.3 Conceptual framework for handling qualities specification (Ref. 6.8)

Figure 6.4 Attitude response type following step cyclic control input

Figure 6.5 Equi‐response contours on the frequency–amplitude plane

Figure 6.6 Roll rate requirements as a function of manoeuvre amplitude (Ref. 6.15)

Figure 6.7 Control and response time histories for Lynx flying slalom

Figure 6.8 Phase plane portrait for Lynx flying slalom manoeuvre

Figure 6.9 Lateral cyclic‐roll rate cross‐plot

Figure 6.10 Slalom task signature: (a) roll rate peaks for different attitude changes and (b) roll attitude quickness points

Figure 6.11 Generalised response quickness diagram (Ref. 6.15)

Figure 6.12 Simple rate response to pulse lateral cyclic input

Figure 6.13 Variation of normalized quickness with manoeuvre time ratio

Figure 6.14 Characterization of aircraft response in four regions

Figure 6.15 Minimum roll control power requirements – rate response type (Ref. 6.5)

Figure 6.16 Peak roll rates from triple bend manoeuvre (Ref. 6.17)

Figure 6.17 Roll attitude quickness criteria for hover and low‐speed MTEs (Ref. 6.5): (a) target acquisition and tracking (roll); (b) general MTEs; and (c) definition of attitude parameters

Figure 6.18 Roll quickness results for lateral sidestep manoeuvre (Ref. 6.18)

Figure 6.19 Phase plane portraits for Lynx flying lateral sidestep MTE

Figure 6.20 Roll attitude quickness for lateral slalom manoeuvre

Figure 6.21 Roll attitude quickness measured on Bo105 at 80 knots (Ref. 6.19)

Figure 6.22 Handling qualities parameters from step response

Figure 6.23 Short‐term roll‐handling qualities – damping/sensitivity boundaries (Ref. 6.20)

Figure 6.24 Pilot HQRs for different step response characteristics at constant bandwidth (Ref. 6.23)

Figure 6.25 Definition of bandwidth and phase delay from ADS‐33 (Ref. 6.5)

Figure 6.26 Example of a gain‐margin limited system (Ref. 6.24)

Figure 6.27 Pilot as sensor and motivator in a task feedback loop

Figure 6.28 Root locus of crossover model eigenvalues as pilot gain is increased

Figure 6.29 Sensitivity of HQRs to phase characteristics at frequencies beyond

(Ref. 6.24)

Figure 6.30 ADS‐33C requirements for small amplitude roll attitude changes – hover/low‐speed and forward flight MTEs (Ref. 6.5): (a) target acquisition and tracking (roll) (Refs. 6.26, 6.29); (b) all other MTEs − UCE = 1,

Visual Meteorological Conditions

(

VMC

) and fully attended operations (roll) (Refs. 6.30, 6.32); and (c) all other MTEs − UCE > 1, IMC and/or divided attention operations (pitch and roll) (Refs. 6.33, 6.34)

Figure 6.31 Equi‐damping and time delay contours overlaid on ADS‐33C handling qualities chart (Ref. 6.8)

Figure 6.32 Proposed roll axis bandwidth criteria from European tests (Refs. 6.36, 6.37)

Figure 6.33 Bandwidth/phase delay criteria for roll axis tracking task according to ADS‐33D (Ref. 6.38)

Figure 6.34 Roll axis frequency sweep for Bo105 (Ref. 6.43)

Figure 6.35 Longitudinal cyclic frequency sweeps on RAE research Puma: (a) 60 knots: SCAS on and off and (b) 100 knots: 2 and 4 Hz

Figure 6.36 Fatigue life usage on RAE research Puma due to longitudinal cyclic frequency sweeps

Figure 6.37 Handling qualities boundaries for bandwidth versus control sensitivity (Ref. 6.54)

Figure 6.38 Puma lateral cyclic and pedal positions in sideslip tests: (a) control variations with sideslip at different flight speeds; (b) pedal variations with sideslip in climb/level/descent flight conditions at 100 kn; and (c) lateral cyclic variations with sideslip in climb/level/descent flight conditions at 100 kn

Figure 6.39 Phase plane portraits for Lynx quickhop manoeuvres (Ref. 6.45)

Figure 6.40 Minimum pitch control power requirements – response type (Ref. 6.5)

Figure 6.41 Pitch attitude quickness criteria (Ref. 6.5): (a) target acquisition and tracking (pitch) and (b) general MTEs (pitch)

Figure 6.42 Pitch attitude quickness – envelope from Lynx quickhop tests (Ref. 6.18)

Figure 6.43 Pitch attitude bandwidth boundaries – comparison of rotary‐ and fixed‐wing aircraft (Category A flight phases) for air combat and tracking tasks (Refs. 6.5, 6.6)

Figure 6.44 Pitch attitude bandwidth boundaries – comparison of rotary‐ and fixed‐wing aircraft for general MTEs and Category C flight phases (Refs. 6.5, 6.6)

Figure 6.45 Stability of long‐period pitch oscillations – comparison of rotary‐ and fixed‐wing requirements (Refs. 6.5, 6.6)

Figure 6.46 BK117 at 130 knots cruise – influence of pitch rate and attitude feedback gains on phugoid mode (Ref. 6.61)

Figure 6.47 Effects of speed stability; impact on cyclic trim (Ref. 6.62)

Figure 6.48 Effects of speed stability; true and apparent speed stability (Ref. 6.62)

Figure 6.49 Effects of manoeuvre stability (Ref. 6.62)

Figure 6.50 Bob‐up MTE

Figure 6.51 Puma height responses in bob‐up MTE (Ref. 6.62)

Figure 6.52 Puma response characteristics in 25‐ft bob‐up (Ref. 6.62)

Figure 6.53 Puma height quickness in bob‐up task

Figure 6.54 Heave‐handling qualities boundaries on damping versus T/W diagram (Ref. 6.69)

Figure 6.55 First‐order shape of height rate response

Figure 6.56 ADS‐33C requirements on displayed torque in terms of overshoot rates and time to first peak (Ref. 6.5)

Figure 6.57 Fit of handling qualities model to step collective response – AH‐64 (Ref. 6.72)

Figure 6.58 Vertical rate response to collective – Bo105 in forward flight (Ref. 6.19)

Figure 6.59 Decelerating profiles into the vortex‐ring region (Ref. 6.62)

Figure 6.60 Puma sideslip and sideways flight limits: (a) sideslip envelope in forward flight and (b) pedal margin for hover in wind

Figure 6.61 Yaw axis quickness – hover and low‐speed flight (Ref. 6.5): (a) target acquisition and tracking and (b) general MTEs

Figure 6.62 Minimum yaw control power requirements – rate response type (Ref. 6.5)

Figure 6.63 Short‐term yaw response requirements in air‐to‐air tracking task (Ref. 6.77)

Figure 6.64 Yaw axis bandwidth/phase delay boundaries (Ref. 6.5): (a) (low speed) target acquisition and tracking – (forward flight) air combat (yaw) and (b) general MTEs

Figure 6.65 Lateral/directional oscillatory requirements: (a) military (Ref. 6.5) and (b) civil (Ref. 6.13)

Figure 6.66 Variation of Dutch roll damping with airspeed – BK117 (Ref. 6.61)

Figure 6.67 Contours of equi‐response on cross‐coupling chart

Figure 6.68 (a) Comparison of ADS‐33C and Pausder–Blanken criteria for roll–pitch coupling requirements (Ref. 6.85); (b) proposed frequency domain format for roll–pitch–roll coupling (based on Ref. 6.85)

Figure 6.69 Contribution of aircraft components to the pitching moment due to sideslip – UH‐60 (Ref. 6.87)

Figure 6.70 TRC response sensitivity boundaries (Ref. 6.5): (a) Definition of equivalent rise time,

; (b) control/response requirement for centre‐stick controllers; and (c) control/response requirement for sidestick controllers

Figure 6.71 Polar plot of speed/azimuth control logic for FPVS AH‐64 (Ref. 6.88)

Figure 6.72 Comanche VELSTAB characteristics (Ref. 6.90)

Figure 6.73 Differentiating agility and stability criteria on the frequency–amplitude chart

Figure 6.74 Requirements for small amplitude (roll–pitch) attitude changes in hover and low‐speed flight

Figure 6.75 Dynamic response criteria for cross‐couplings or off‐axis response

Figure 6.76 Pitch–roll cross‐coupling requirements for target acquisition and tracking MTEs

Chapter 07

Figure 7.1 The influences on pilot control strategy

Figure 7.2 The Cooper–Harper handling qualities rating scale

Figure 7.3 The contributions of workload and task performance to the HQR

Figure 7.4 The DLR score factor (Ref. 7.7)

Figure 7.5 HQRs for various aircraft flying ADS‐33 tasks (Ref. 7.9)

Figure 7.6 Layout of the RAE/DRA sidestep MTE (Ref. 7.13)

Figure 7.7 Comparison of flight and simulation results for rate command aircraft in sidestep MTE (Ref. 7.11)

Figure 7.8 Elements of DRA simulation trials

Figure 7.9 The MTEs flown in the DRA simulation trials (Ref. 7.13): (a) sidestep; (b) quickhop; (c) lateral slalom; (d) hurdles

Figure 7.10 Plan view of lateral slalom MTE (Ref. 7.13)

Figure 7.11 CSM configurations overlaid on ADS‐33 roll bandwidth chart (Ref. 7.13)

Figure 7.12 HQRs for lateral slalom MTE versus roll attitude bandwidth (Ref. 7.13)

Figure 7.13 Roll attitude quickness for slalom (Ref. 7.13)

Figure 7.14 Comparison of ground tracks in slalom MTE (Ref. 7.13)

Figure 7.15 HQRs for lateral sidestep MTE versus roll attitude bandwidth (Ref. 7.13)

Figure 7.16 Plan view of helicopter/ship landing MTE (Ref. 7.18)

Figure 7.17 HQRs for helicopter/ship landing MTE versus roll attitude bandwidth (Ref. 7.18)

Figure 7.18 Task performance in helicopter/ship landing MTE (Ref. 7.18): (a) touchdown velocity; (b) landing scatter

Figure 7.19 Variation of HQRs with

showing the cliff edge of handling deficiencies (Ref. 7.24)

Figure 7.20 Variation of HQR with

for different notional configurations (Ref. 7.25)

Figure 7.21 Response characteristics on the frequency–amplitude plane: equi‐response contours

Figure 7.22 CSM parameters on frequency‐amplitude diagram (Ref. 7.25)

Figure 7.23 Bank and stop MTE

Figure 7.24 Variation of

with normalized bandwidth for bank and stop MTE (Ref. 7.25)

Figure 7.25 The three piloting activities

Figure 7.26 The three dimensions of flight in DVE

Figure 7.27 The outside visual cue scale (Ref. 7.27): (a) quantification of outside visual cues (OVC); (b) required outside visual cues for control

Figure 7.28 Usable cue environment (Ref. 7.1)

Figure 7.29 HQRs for different response types flying various MTEs (Ref. 7.30)

Figure 7.30 Ten contiguous MTEs (Ref. 7.30)

Figure 7.31 Low‐speed display symbology format used in the AH‐64A Apache (Ref. 7.26)

Figure 7.32 Pilot–vehicle display block diagram (Ref. 7.26)

Figure 7.33 Central symbology variables in AH‐64A display format (Ref. 7.26)

Figure 7.34 Comparison of control inputs and aircraft responses for various display dynamics (Ref. 7.26)

Figure 7.35 Comparison of HQRs with various display dynamics (Ref. 7.26)

Figure 7.36 Sources of flight envelope limits

Figure 7.37 Comparison of simulation results with different carefree handling systems (Ref. 7.34): (a) mean HQRs; (b) peak lateral velocity excursions

Figure 7.38 Torque and height variations showing response shaping (Ref. 7.35)

Figure 7.39 Air‐to‐air combat MTEs flown in carefree handling simulation (Ref. 7.35): (a) 90° turn, climb, and accelerate to acquire target; (b) 180° turn and climb to acquire target

Figure 7.40 Comparison of results with torque command carefree handling system on and off (Ref. 7.35): (a) task time; (b) maximum torque; (c) handling qualities ratings

Figure 7.41 Control force versus control displacement for centre‐sticks (Refs. 7.1, 7.37)

Figure 7.42 Typical nonlinear shaping function for sidestick controllers

Figure 7.43 Notional distribution of pilot HQRs for a given aircraft (Ref. 7.25)

Figure 7.44 Relationship between mean HQR and P(LOC) (Ref. 7.44)

Figure 7.45 Relationship between mean HQR and probability of mission success, failure, and loss of control (Ref. 7.25)

Chapter 08

Figure 8.1 The usable cue environment process summarised

Figure 8.2 Summary of the effect of the DVE on attentional demand.

Figure 8.3 Projected differential velocities (optical flow‐field) on the ground in a helicopter vertical landing

Figure 8.4 Optical flow‐field for motion over a flat surface (speed 3 eye‐heights s

−1

, snapshot 0.25 s)

Figure 8.5 Viewing eccentricity and elevation angles

Figure 8.6 Angular velocity versus distance along ground plane.

Figure 8.7 Visual resolution as a function of eccentricity.

Figure 8.8 Normalised flow vectors as a function of eccentricity.

Figure 8.9 Resultant motion threshold function across the retina

Figure 8.10 Differential motion parallax as an optical invariant to aid way finding.

Figure 8.11 Optical flow‐field approaching a 60° slope.

Figure 8.12 Optical looming when approaching an object: (a)

of horizontal velocity in a deceleration manoeuvre; (b)

of flight path angle in a climb manoeuvre; (c)

of heading angle in a turn manoeuvre

Figure 8.13 Motion

's in helicopter manoeuvres as a function of normalised time

Figure 8.14 Deceleration profile for helicopter descending to a landing pad.

Figure 8.15 Kinematics of the acceleration–deceleration manoeuvre

Figure 8.16 Kinematics of the acceleration–deceleration manoeuvre

Figure 8.17 Time to stop as a function of time in the deceleration phase

Figure 8.18 Pigeon approaching a landing perch.

Figure 8.19 Time to land for pigeon approaching a perch.

Figure 8.20

gaps for a helicopter approaching a hover.

Figure 8.21 Following a constant acceleration

guide in an accel–decel manoeuvre

Figure 8.22 Profiles of motions following the constant acceleration guide

Figure 8.23 Correlation of

and

for helicopter in accel–decel manoeuvre.

Figure 8.24 Terrain following – UCE chart for different fog cases

Figure 8.25 Flight parameters for terrain‐hugging manoeuvre

Figure 8.26 Distance to the slope surface (in meters and eye‐heights)

Figure 8.27 Times to the slope surface (

to surface)

Figure 8.28 Flight path angle

Figure 8.29

during the climb

Figure 8.30 Variation of

for climb transient

Figure 8.31

versus

variations for three cases

Figure 8.32 Correlation between times to close the flight path gap for the motion and guides

Figure 8.33 Normalised collective pitch for a flight path angle change following a constant acceleration

guide – variations with

and

Figure 8.34 Normalised flight path response for a flight path angle change following a constant acceleration

guide–variations with

Figure 8.35 Comparisons of normalised pilot control activity and flight path with

‐following strategy

Figure 8.36 A possible relationship between

and UCE defining safe margins from flight in the DVE.

Figure 8.37 Conceptualization of flying qualities improvements in the DVE

Figure 8.38 ‘Dutch‐roll’ mode type dynamics with varying

ζ;

response to a step input

Figure 8.39 ‘Dutch‐roll’ mode type dynamics with varying

; (a) motion gap response, common to all, (b)

controls for different

cases

Figure 8.40 The Fa 223 twin rotor helicopter at Beaulieu in British markings

Figure 8.41 Sequence of events following high‐pitch tail rotor failure in cruise

Figure 8.42 Sequence of events following a tail rotor drive failure in cruise

Figure 8.43 The general form of the control malfunction.

Figure 8.44 Example of the roll angle response to aileron failure for the tiltrotor in airplane mode.

Figure 8.45 Handling qualities levels for roll response shown as a function of passivation time and aileron hard‐over amplitude.

Figure 8.46 Failure transient and recovery rating scale.

Figure 8.47 Integrated classification of failures.

Figure 8.48 Control and responses in a hover turn manoeuvre.

Figure 8.49 Comparison of SHOLs for front and aft spots on RFA.

Figure 8.50 The wake vortex structure

Figure 8.51 Pitch axis quickness

Figure 8.52 Pitch axis control power

Figure 8.53 Velocity distribution in Boeing 747 vortex wake

Figure 8.54 Velocity flow‐field of Boeing 747 vortex around Lynx rotor

Figure 8.55 Helicopter lifted above vortex core during encounter

Figure 8.56 Helicopter encountering vortex core

Figure 8.57 Pitch attitude response

Figure 8.58 Pitch rate response

Figure 8.59 Pitch quickness (Lynx)

Figure 8.60Figure 8.60 Pitch quickness (FGR)

Figure 8.61 Height response in encounter

Figure 8.62 Height rate response in encounter

Figure 8.63 Vertical acceleration response

Figure 8.64 Upset severity rating scale

Figure 8.65 Vertical response during encounter (FGR – SCAS on)

Figure 8.66 Distribution of US civil rotorcraft accidents of a 40‐year period.

Figure 8.67 Estimated US civil rotorcraft accident rate per 100 000 flying hours of a 10‐year period.

Figure 8A.1 Schematic of the HELIFLIGHT configuration

Figure 8A.2 Flight simulation laboratory at The University of Liverpool (2000–2008)

Figure 8A.3 Collimated display system in the HELIFLIGHT

Figure 8A.4 Outside world field of view in HELIFLIGHT simulator

Figure 8A.5 Typical pilot's eye view in HELIFLIGHT capsule

Figure 8A.6 HELIFLIGHT‐R with HELIFLIGHT in background (Left); views from crew station (Right)

Figure 8A.7 Field‐of‐View; HELIFLIGHT vs HELIFLIGHT‐R

Chapter 09

Figure 9.1 Two Prototype Helicopters – Igor Sikorsky flying the VS‐300 in 1941 (left); Floyd Carlson flying the Bell Model 30‐1A in 1944, with Arthur Young on the ground (right) (www.aviastar.org)

Figure 9.2 Two Production Helicopters – the military Sikorsky R4 in 1944 (left); the civil‐certified Bell Model 47 in 1945 (right) (www.aviastar.org)

Figure 9.3 Incident on Sikorsky S‐51 VW209, 19 April 1948; airspeed, height, normal acceleration and control variations during a phugoid test (Ref. 9.29)

Figure 9.4 Longitudinal cyclic and normal acceleration variations during dynamic stability test, Sikorsky R‐4 (Ref. 9.30)

Figure 9.5 Effects on different fuselage configurations on directional stability (Ref. 9.42)

Figure 9.6 Roll response requirements (Ref. 9.49) compared with Mil‐H‐8501 boundaries (Ref. 9.6)

Figure 9.7 The Control quickener concept adopted in Ref. 9.49

Figure 9.8 Effects of quickener on roll rate response (Ref. 9.49)

Figure 9.9 The AH‐1G Hueycobra featured a mission‐oriented SCAS.

Figure 9.10 The Sud‐Aviation (now Airbus Helicopters) SA‐330 Puma; the RAE Research Aircraft XW241 was used extensively to support handling qualities and agility criteria and simulation modelling developments in the 1980s.

Figure 9.11 Rate Command Attitude Hold Concept adopted in the SA‐330 Puma

Figure 9.12 The Westland (now Leonardo Helicopters) WG13 Lynx; the RAE Research Aircraft ZD559 was used extensively to support handling qualities and agility criteria development in the 1980–1990s.

Figure 9.13 Rate Command Attitude Hold Concept adopted in the WG‐13 Lynx

Figure 9.14 Prototype Lynx with experimental underfins to improve yaw stability. (photo courtesy David Gibbings)

Figure 9.15 MBB Bo105; the DLR Research Aircraft; S3 ATTHeS and S123 (behind) were used extensively to support ADS‐33 criteria development.

Figure 9.16 The Lockheed XH‐51 research aircraft hovering over the airfield at RAE Bedford in 1971.

Figure 9.17 The Cooper‐Harper Handling Qualities Rating Scale (Ref. 9.61)

Figure 9.18 Handling Qualities Influencing Factors

Figure 9.19 Handling Qualities Ratings for the hover task (based on Ref. 9.62)

Figure 9.20 Hover performance and pilot workload (based on Ref. 9.62)

Figure 9.21 Handling Qualities Boundaries from various studies on the damping versus sensitivity chart

Figure 9.22 The Bell 205 in‐flight simulator operated by the NRC Flight Research Laboratory.

Figure 9.23 Flight/Ground‐based simulation comparison; roll attitude bandwidth with attitude response type (Ref. 9.94)

Figure 9.24 ADS‐33D/E roll attitude bandwidth/phase‐delay boundaries for tracking tasks (Ref. 9.95)

Figure 9.25 ADS‐33 Roll attitude quickness boundaries with envelopes from RAE research Lynx flight data

Figure 9.26 Time loading effects on handling qualities; the variation of awarded HQRs with task duration

Figure 9.27 Variation of Handling Qualities Rating with Agility Factor; Lynx and Puma flight tests at RAE (Ref. 9.97)

Figure 9.28 Handling Qualities Tailoring Process using ADS‐33 (Ref. 9.114)

Figure 9.29 The probability of an HQR category as a function of mean HQR (Ref. 9.98)

Figure 9.30 Dynamic stability requirements from Ref. 9.133 (EASA Certification Specification) overlaid on ADS‐33 HQ level areas

Figure 9.31 Hoh's split‐path architecture with blend‐out function for realising ACAH (Ref. 9.164)

Figure 9.32 The new‐generation rotorcraft in‐flight simulators – from left to right, the NRC ASRA, the DLR ACT‐FHS, and the US Army/NASA RASCAL

Chapter 10

Figure 10.1 The Bell XV‐3 Research Aircraft (NASA)

Figure 10.2 The XV‐15 tiltrotor in airplane mode (NASA)

Figure 10.3 XV‐15 height‐velocity flight envelope (Ref. 10.3)

Figure 10.4 XV‐15 conversion corridor (Ref. 10.3)

Figure 10.5 The AW609 tiltrotor in conversion mode (top left) and helicopter mode (bottom) (photos Leonardo Helicopters) and in airplane mode (top right) (photo courtesy Jay Miller – AHS International)

Figure 10.6 The conversion corridor for the BA609 (now AW609) showing the nacelle ‘control laws’ (Ref. 10.8)

Figure 10.7 The Bell‐Boeing V‐22 Osprey tiltrotor in conversion mode (photo courtesy Jay Miller – AHS International; showing Bell's experimental V‐22 testbed)

Figure 10.8 The conversion corridor for the Bell‐Boeing V‐22 Osprey (Ref. 10.9)

Figure 10.9 Rotor and wing lift sharing as a function of airspeed for different V‐22 nacelle angles (Ref. 10.9)

Figure 10.10 XV‐15 control functions in helicopter and airplane modes

Figure 10.11 Twin co‐axial rotor configuration with six blades

Figure 10.12 A view from the FLIGHTLAB Model Editor (FLME) GUI showing the data for the blade properties of an articulated rotor

Figure 10.13 Simple representations of the Cardano/Hooke joint (upper) and the double Cardano/Hooke joint (lower); the latter enables constant velocity and angular momentum to be transferred through a mechanism (based on Ref. 10.21)

Figure 10.14 Flapping of a gimbal rotor model showing the longitudinal and lateral gimbal rotation angles

and

Figure 10.15 Response of FXV‐15 to a 1 deg longitudinal cyclic input in hover; gimbal spring strength and

angle set to zero; gimbal pitch angle (

) and gimbal roll angle (

) and their cross‐plot are shown

Figure 10.16 Exploded view of the CV joint on the ERICA tiltrotor concept developed in the European NICETRIP project (courtesy Airbus and Leonardo Helicopters, Refs. 10.27)

Figure 10.17 Schematic of a FLIGHTLAB tiltrotor simulation model with some of the many components highlighted

Figure 10.18 XV‐15 wind tunnel test showing flow patterns around the empennage; 40 kts level flight (Ref. 10.29)

Figure 10.19 Computational Fluid Dynamics (CFD, OVERFLOW‐D) velocity magnitude contours around a V‐22 tiltrotor configuration in hover (left) and 35kts forward flight (right) (Refs. 10.31, 10.32)

Figure 10.20 Johnson's VRS model for axial and forward flight (Ref. 10.33)

Figure 10.21 Flight dynamics stability boundaries predicted by Johnson VRS model (Ref. 10.33)

Figure 10.22 V‐22 vs HH‐65 steady descent VRS boundary (Ref. 10.39)

Figure 10.23 The merging of tip vortices below the rotor is the first stage of the vortex ring state (Ref. 10.40)

Figure 10.24 The origin of hysteresis in stable ring positions: (a) Accumulated ring above the rotor causes newly emitted rings to ‘expand’, whereas (b) accumulated ring below the rotor causes newly emitted rings to contract. The diameter of newly emitted rings is the main factor in determining the direction of subsequent ring convection and provides a mechanism that strongly favors keeping the current position of the accumulating ring (Ref. 10.40)

Figure 10.25 Rotor wake in hover, descent and VRS conditions; the toroidal ring concept (Ref. 10.42)

Figure 10.26a and 10.26b (a,b) Trim results for FXV‐15 in helicopter and conversion modes. (c,d) Trim results for FXV‐15 in airplane mode, and comparison with Ref. 10.12 data

Figure 10.27a and 10.27b (a) Response results for FXV‐15; helicopter mode. (b) Response results for FXV‐15; conversion mode (120 kts). (c) Response results for FXV‐15; airplane mode (220 kts)

Figure 10.28 Comparison of the FXV‐15 response entering a 1.8 g turn in conversion mode with flight test data (Ref. 10.53)

Figure 10.29 Comparison of FXV‐15 response to pilot controls entering a high‐g turn in airplane mode with flight test data (Ref. 10.53)

Figure 10.30 Certification basis for BA609 (now AW609, Ref. 10.4)

Figure 10.31 EUROTILT (left, Eurocopter/Airbus) and ERICA (right, AgustaWestland/Leonardo) tiltrotor concepts

Figure 10.32 Examples of flying qualities critical mission task elements (Ref. 10.61)

Figure 10.33 Rapid conversion test manoeuvre, level flight, fixed power

Figure 10.34 The roll‐step test manoeuvre

Figure 10.35 (a) FXV‐15 eigenvalues in helicopter mode; full picture. (b) FXV‐15 eigenvalues in helicopter mode; low frequency modes

Figure 10.36 FXV‐15 spiral mode in helicopter mode; exact compared with simple approximation

Figure 10.37 In‐plane velocity distribution due to yaw rate leading to positive

Figure 10.38 (a) FXV‐15 eigenvalues in conversion mode; full picture. (b) FXV‐15 eigenvalues in conversion mode; low frequency modes

Figure 10.39 (a) FXV‐15 eigenvalues in airplane mode; full picture. (b) FXV‐15 eigenvalues in airplane mode; low frequency modes

Figure 10.40 FXV‐15 open‐loop stability on the ADS‐33 chart; limits on pitch (roll) oscillations in hover and low−speed flight (Ref. 10.65)

Figure 10.41 FXV‐15 open loop stability of the ADS‐33 chart; lateral‐directional oscillatory requirements (Ref. 10.65)

Figure 10.42Figure 10.42 Handling qualities ratings awarded for the V‐22 flying 20 MTEs (Ref. 10.9)

Figure 10.43 The FXV‐15 conversion corridor showing the configurations under investigation (Ref. 10.61)

Figure 10.44 FXV‐15 Roll attitude quickness in helicopter and conversion flight modes (Ref. 10.61)

Figure 10.45 The roll‐step manoeuvre used in the tiltrotor simulation trials (Ref. 10.61)

Figure 10.46 Handling qualities ratings distribution for the roll‐step manoeuvre (Ref. 10.61)

Figure 10.47 HQRs from the roll‐step MTE presented on the roll bandwidth−phase delay chart; airspeed 100kts, nacelle angle 60 deg (Ref. 10.61)

Figure 10.48 FXV‐15 pitch attitude quickness (SCAS off, Ref. 10.62)

Figure 10.49 FXV‐15 pitch short‐period mode root loci; helicopter, conversion, and airplane modes (Ref.10.62)

Figure 10.50 FXV‐15 pitch short‐period characteristics in airplane mode shown on the ‘thumbprint’ chart (Refs. 10.62, 10.69)

Figure 10.51 FXV‐15 on the control anticipation parameter chart (Ref. 10.68, Cat B flight phases)

Figure 10.52 Pitch attitude bandwidth vs phase delay results for FXV‐15 (Ref. 10.62)

Figure 10.53 FXV‐15 response to a one‐inch step longitudinal control input, SCAS off; comparison between flight modes (Ref. 10.62)

Figure 10.54 Proprotor tilt during pitch‐up manoeuvre (Ref. 10.62)

Figure 10.55 Pitch response to pulse longitudinal control input – parameters in Gibson's drop‐back criteria (Ref. 10.71)

Figure 10.56 FXV‐15 flying qualities parameters on Gibson's drop‐back criteria (Ref. 10.66)

Figure 10.57 Effect of incidence lag on pitch attitude, rate, incidence and flight path from a pulse elevator input (Ref. 10.64)

Figure 10.58 FXV‐15 response to 2 deg (elevator) longitudinal pulse (Ref. 10.64)

Figure 10.59 FXV‐15 Pitch response; with and without SCAS engaged, 200 kts IAS, 6000 m

Figure 10.60 Sketch of the heave‐hop flight test manoeuvre with desired and adequate performance standards (Ref. 10.62)

Figure 10.61 The heave‐hop flight test manoeuvre (Ref. 10.62)

Figure 10.62 Handling qualities ratings as a function of speed in the heave‐hop FTM, AR = 0.2; FXV‐15 in helicopter and conversion modes (Ref. 10.62)

Figure 10.63 Handling qualities ratings in the heave‐hop FTM, AR = 2; FXV‐15 in airplane mode

Figure 10.64 The XV‐15 converting from helicopter (right) to airplane (left) flight mode (NASA)

Figure 10.65 HQRs awarded for the conversion test manoeuvre, phases 1 and 2 (Ref. 10.63)

Figure 10.66 Comparison of Pilot A (left, HQR 7) and Pilot B (right, HQR 5) flying phase 2 of the conversion manoeuvre (see Figure 10.33)

Figure 10.67 Root loci for longitudinal (left) and lateral (right) phugoid modes with varying rate feedback gains; FXV−15 in hover

Figure 10.68 Root loci for the spiral and lateral phugoid modes with varying proportional yaw rate feedback gain; FXV−15 in hover

Figure 10.69 Root loci for the short period (left) and Dutch roll (right) modes with varying proportional pitch and roll rate feedback gains; FXV‐15 in airplane mode, 280 kts, 6000 m

Figure 10.70 Root loci for the Dutch roll mode with varying proportional yaw rate feedback gain; FXV−15 in airplane mode, 280 kts, 6000 m

Figure 10.71 The V‐22 power lever to thrust linear model showing the governor feedforward circuit (Ref. 10.72)

Figure 10.72 Thrust and proprotor RPM response to a 1 in. power lever step input (Ref. 10.72)

Figure 10.73 V‐22 torque command/limiting system (Ref. 10.72)

Figure 10.74 Optimal tailoring of lateral control authority subject to mast torque limits showing the design spaces at reduced mast torque (Ref. 10.75)

Figure 10.75 Three tiltrotor configurations; top to bottom − The Bell/NASA/Army XV‐15 (CTR‐S), Eurocopter's EUROTILT (CTR‐M) and EUROFAR (CTR‐L) concepts

Figure 10.76 Simplified command control concept for flying qualities augmentation (Ref. 10.78)

Figure 10.77 Pitch and roll attitude quickness in hover on the ADS‐33 chart (Refs. 10.77, 10.78)

Figure 10.78 Yaw attitude quickness in hover on the ADS‐33 chart (Ref. 10.78)

Figure 10.79 Yaw attitude Bandwidth and Phase Delay in hover on the ADS‐33 chart (Ref. 10.78)

Figure 10.80 Artist's impression of NASA's Large Civil Tiltrotor2 (LCTR, second generation, image NASA)

Figure 10.81 Impact of pilot station offset on handling qualities ratings in the LCTR2 90 deg hover turn MTE (Ref. 10.80)

Figure 10.82 V‐22 yoke chord bending load limiter (based on Ref. 10.93)

Figure 10.83 In‐plane component of lift in airplane mode

Figure 10.84 Correlation of F‐EUROTILT peak in‐plane load with total rotor pitch rate (

) (Ref. 10.94)

Figure 10.85 In‐plane moment at the blade root for a 2.5 g pull‐up manoeuvre; F‐EUROTILT (Ref. 10.94)

Figure 10.86 F‐EUROTILT response to elevator pulse (200 kts EAS, 3000 m) showing the gimbal longitudinal (

and

) and lateral flapping (

and

) for right and left rotors (Ref. 10.96)

Figure 10.87 F−EUROTILT response to a pulse right rudder input at 200 kts EAS 3000 m showing the gimbal proprotors flapping with the yaw rate (Ref. 10.96)

Figure 10.88 Correlation of EUROTILT in‐plane load with combined yaw rate (

) (Ref. 10.96)

Figure 10.89 Loads of EUROTILT to elevator pulse input at 200 kts condition (Ref. 10.96)

Figure 10.90 Controller output for elevator pulse input at 200 kts condition (Ref. 10.96)

Figure 10.91 Response of EUROTILT to elevator pulse input at 200 kts condition (Ref. 10.96)

Figure 10.92 The Leonardo tiltrotor concept in the European Clean Sky2 Fast Rotorcraft programme (image Leonardo Helicopters)

Figure 10.93Figure 10.93 Bell V280 Valour on its first flight, Monday 18th December 2017 (photo courtesy Jay Miller – AHS International)

Figure 10A.1 Body‐fixed axis system

Figure 10A.2Figure 10A.2 Hub axis system for the left (port) and right (starboard) rotors in helicopter (dashed) and airplane mode

Figure 10A.3 Non‐rotating gimbal axis system for the right (counter‐clockwise) rotor in helicopter (left) and airplane (right) modes

Figure 10A.4Figure 10A.4 Non‐rotating gimbal axis system for the left (clockwise) rotor in helicopter (left) and airplane (right) modes

Figure 10A.5 Rotating blade axes on starboard and port proprotors

Figure 10A.6Figure 10A.6 Flapping of a gimbal rotor

Figure 10B.1Figure 10B.1 The XV‐15 in helicopter, conversion and airplane modes (NASA)

Figure 10B.2Figure 10B.2 Three‐view of XV−15

Figure 10C.1 Stability derivatives – longitudinal; helicopter mode

Figure 10C.2 Stability derivatives – lateral; helicopter mode

Figure 10C.3 Control derivatives – longitudinal, helicopter mode

Figure 10C.4 Control derivatives – lateral (roll), helicopter mode

Figure 10C.5 Control derivatives – directional (yaw), helicopter mode

Figure 10C.6 Stability derivatives – longitudinal; conversion mode

Figure 10C.7 Stability derivatives – lateral; conversion mode

Figure 10C.8 Control derivatives – longitudinal, conversion mode

Figure 10C.9 Control derivatives – lateral (roll), conversion mode

Figure 10C.10 Control derivatives – directional (yaw), conversion mode

Figure 10C.11 Stability derivatives – longitudinal; airplane mode

Figure 10C.12 Stability derivatives – lateral; airplane mode

Figure 10C.13 Control derivatives – longitudinal, airplane mode

Figure 10C.14 Control derivatives – lateral (roll), airplane mode

Figure 10C.15 Control derivatives – directional (yaw), airplane mode

Figure 10D.1 Forces and flow angles on a rotorblade section

Figure 10E.1 Root loci for FXV‐15 lateral‐directional dynamics with varying

; −

= 0

Figure 10E.2 Root loci for FXV‐15 lateral‐directional dynamics with for 0 <

< –1.0;

= –0.08

Figure 10E.3 Root loci for FXV‐15 lateral‐directional dynamics for 0 <

< –1.0;

= –0.1