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THE continual development of helicopter rotor systems has so far resulted in the use of about six main types, and it will be of value briefly to recapitulate their advantages and disadvantages in order to obtain a balanced picture against which the stiff‐hinged rotor can be judged.

A theory is developed to describe the dynamic behaviour, control angles to trim and stability derivatives of an aerodynamic servo‐controlled rotor. The analysis is restricted to constant chord rotor blades which are torsionally deformed by the servo flap to give changes in rotor pitch angle, as this is the form in which the system is most likely to be used. Also, the aerodynamic centre and elemental C.G. lines are assumed to coincide with the blade torsion axis. Since the stiff hinge assumption is used, the analysis is applicable to blades with offset or ‘stiff’ flapping hinges, or to cantilever rotors, which can be simulated by a rigid blade with a stiff hinge. Comparison with some N.A.C.A. test tower results shows that the theory developed gives excellent agreement with the available experimental results. In Appendix I the stability of the tip path plane is examined, using the equations derived in the report, and three regions of instability are shown to be present. A practical rotor must be designed to operate below the lowest instability region, as is the case for the N.A.C.A. test rotor. Equations for ∂a1s/∂µ and ∂a1s/∂q are developed for the low speeds near hovering in Appendix II. Other derivatives can be easily derived from the general equations of motion given in Table 1.

This paper aims to conceptualize and characterize service ecosystems, addressing calls for research on this important and under-researched topic.

The authors draw on four meta-theoretical foundations of S-D logic – resource integration, resource density, practices and institutions – providing a new integrated conceptual framework of ecosystem well-being. They then apply this conceptualization in the context of a complex healthcare setting, exploring the characteristics of ecosystem well-being at the meso level.

This study provides an integrated conceptual framework to explicate the nature and structure of well-being in a complex service ecosystem; identifies six key characteristics of ecosystem well-being; illustrates service ecosystem well-being in a specific healthcare context, zooming in on the meso level of the ecosystem and noting the importance of embedding a shared worldview; provides practical guidance for managers and policy makers about how to manage complex service ecosystems in their quest for improving service outcomes; and offers an insightful research agenda.

This research focuses on service ecosystems with an illustration in one healthcare context, suggesting additional studies that explore other industry contexts.

Practically, the study indicates the imperative for managing across mutually adapting levels of the ecosystem, identifying specific new practices that can improve service outcomes.

Examining well-being in the context of a complex service ecosystem is critical for policymakers charged with difficult decisions about balancing the demands of different levels and actors in a systemic world.

The study is the first to conceptualize and characterize well-being in a service ecosystem, providing unique insights and identifying six specific characteristics of well-being.

In‐plane vibration of a balanced helicopter rotor is caused by variations with azimuth of the in‐plane forces acting on individual blades. These forces may be summarized under three headings: ‘Induced forces’ caused by the inclination of elemental lift vectors relative to the axis of rotation. ‘Profile drag forces’: variations are caused by changes with azimuth angle of the angle and airspeed of the individual blade elements. ‘Coriolis forces’, which are caused by blade flapping, which brings about a variation of blade moment of inertia about the axis of rotation. Equations are developed in this paper for the resultant hub force due to each of these forces, on the assumptions of small flapping hinge offset. It is assumed that blades are linearly twisted and tapered, an assumption which in practice can be applied to any normal rotor. It is shown that by suitably inclining the mechanical axis it is possible to balance out the worst induced and profile drag vibrations by the coriolis one, which can be made to have opposite sign. If the mechanical axis is fixed in the fuselage, this suppression is fully effective for one flight condition only. In multi‐rotor helicopters, vibration suppression can be extended over a much wider range by varying the fuselage attitude. The logical result of this analysis is, for single rotor helicopters, a floating mechanical axis which can be adjusted or trimmed by the pilot. This would be quite simple to do on a tip‐driven rotor, and has already been achieved with a mechanical drive on the Doman helicopter. The more important causes of vibration from an unbalanced rotor are next con‐sidered, attention here being confined principally to fully articulated rotors, which are the most difficult to balance because the drag hinges tend to magnify all in‐accuracies in finish and balance. From a brief discussion of the vertical vibration of an imperfect rotor it is shown that some contemporary methods of ‘tracking’ are fundamentally wrong. Finally the vibration due to tip‐mounted power units is described. In discussing the effect of a vibratory force on a helicopter a simple response chart is developed, and it is thought that its use could well be accepted as a simple standard for general assessment purposes. In the development of equations for vibration the following points of general technical interest are put forward: An equation for induced torque is developed which includes a number of hitherto neglected parameters. A new form of equation for mean lift coefficient of a blade is suggested. The simple Hafner criterion for flight envelopes is shown to give rise to considerable error, and the use of Eq. (28) is suggested in its place. The variation of profile torque with forward speed is given, and the increase due to ? varying round the disk is expressed as an explicit equation, thus allowing considerable improvement in the present methods of allowing for this effect.

THE simple actuator disk theory, first postulated by Froude over sixty years ago, is the basis of most helicopter induced flow theory. This disk is an idealization of a rotor which uniformly accelerates the air with no loss of thrust at the blade tips. It can therefore be regarded as the limit case of a rotor with an infinite number of blades. It is also assumed to be infinitely thin so that no discontinuities in velocity occur on the two sides of the disk.

The nation is in one of its worse crises for a long time and for this reason I intend to take a broad view of the role that research associations can play in helping industry rather than dwell overmuch on methodology of communication. If the present crisis is to be solved it will have to be through the products of industry. Industry is changing and is itself changed by the world situation oil recession. The balance between developed and developing countries may be changing.

High-involvement work processes (HIWPs) are associated with high levels of employee influence over the work process, such as high levels of control over how to handle individual job tasks or a high level of involvement at team or workplace level in designing work procedures. When implementations of HIWPs are accompanied by companion investments in human capital – for example, in better information and training, higher pay and stronger employee voice – it is appropriate to talk not only of HIWPs but of “high-involvement work systems” (HIWSs). This chapter reviews the theory and practice of HIWPs and HIWSs. Across a range of academic perspectives and societies, it has regularly been argued that steps to enhance employee involvement in decision-making create better opportunities to perform, better utilization of skill and human potential, and better employee motivation, leading, in turn, to various improvements in organizational and employee outcomes.

However, there are also costs to increased employee involvement and the authors review the important economic and sociopolitical contingencies that help to explain the incidence or distribution of HIWPs and HIWSs. The authors also review the research on the outcomes of higher employee involvement for firms and workers, discuss the quality of the research methods used, and consider the tensions with which the model is associated. This chapter concludes with an outline of the research agenda, envisaging an ongoing role for both quantitative and qualitative studies. Without ignoring the difficulties involved, the authors argue, from the societal perspective, that the high-involvement pathway should be considered one of the most important vectors available to improve the quality of work and employee well-being.

The theory of rotor dynamics given in Ref. 1 is extended to include the effects of coupling between feathering and flapping (δ3 angle) and flapping hinge offset. Both introduce considerable modification to the classic equations, and instead of simple explicit equations for flapping amplitudes, coning angle, collective pitch and inflow angles, five simultaneous equations have now to be solved. Data sheets have been constructed which enable this to be done quickly and accurately for any design of linearly tapered and twisted blade. It is suggested that the intelligent use of such data sheets is of great assistance in a design office, not only because of the very considerable time savings achieved, but also because they eliminate the most fruitful sources of error in numerical calculation. It is shown that a high offset rotor enables much higher speeds to be achieved with a conventional helicopter—an effect which has already been fairly well publicized. A penalty is paid for this in the form of hub pitching moments which have to be balanced out externally; either by the use of two rotors, offset C.G., aerodynamic surfaces, or inclination of the mechanical axis. These effects will be considered in detail in a further article. Finally, equations are developed for a convenient method of calculating blade elemental angle of attack which is claimed to be superior to classic methods for design office purposes.

A NUMBER of approaches to the calculation of rotor downwash have already been discussed. Broadly spsaking, the methods of Castles and DeLeeuw and Squire and Mangler are the same. In both methods the downwash at the rotor disk is assumed to be perpetrated in a helical downwash sheet which, as the slipstream, extends below the rotor to infinity. The downwash in the disk due to the bound vortices, and the additional downwash in the disk which is induced by the helical sheets in the slipstream (Castles and DeLeeuw substitute downwash rings for helices, in the interest of mathematical simplicity) is calculated, on the assumption of an infinite number of lightly loaded blades. The final results of Castles and DeLeeuw on the one hand, and Squire and Mangier on the other, are in very wide disagresment. This disagreement is principally due to the fact that, whereas the first investigation assumes constant circulation along the blade (ideal twist and taper), Mangier and Squire assume a ‘practical’ variation of the form likely to be encountered on an untwisted untapered blade. We conclude that the radial distribution of lift on a helicopter blade will have a profound effect on the downwash pattern: which in turn will affect the calculated lift.

Drawing on value cocreation, this study examines health-care customers’ perceptions of patient-centered care (PCC) in hospital and online primary care settings. This study aims to address how are the key principles of PCC related, how the relationships between key PCC principles and outcomes (subjective well-being and service satisfaction) vary depending on the channel providing the care (hospital/online primary care) and what differences are placed on the involvement of family and friends in these different settings by health-care customers.

This study comprises four samples of health-care customers (Sample 1 n = 272, Sample 2 n = 278, Sample 3 n = 275 and Sample 4 n = 297) totaling 1,122 respondents. This study models four key principles of PCC: service providers respecting health-care customers’ values, needs and preferences; collaborative resources of the multi-disciplinary care team; health-care customers actively collaborating with their own resources; and health-care customers involving family and friends, explicating which principles of PCC have positive effects on outcomes: subjective well-being and service satisfaction.

Findings confirm that health-care customers want to feel respected by service providers, use their own resources to actively collaborate in their care and have multi-disciplinary teams coordinating and integrating their care. However, contrary to prior findings, for online primary care, service providers respecting customers’ values needs and preferences do not translate into health-care customers actively collaborating with their own resources. Further, involving family and friends has mixed results for online primary care. In that setting, this study finds that involving family and friends only positively impacts service satisfaction, when care is provided using video and not voice only.

By identifying which PCC principles influence the health-care customer experience most, this research shows policymakers where they should invest resources to achieve beneficial outcomes for health-care customers, service providers and society, thus advancing current thinking and practice.

This research provides a health-care customer perspective on PCC and shows how the resources of the health-care system can activate the health-care customer’s own resources. It further shows the role of technology in online care, where it alters how care is experienced by the health-care customer.