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The purpose of this paper is to discuss published research in rotorcraft which has taken place in India during the last ten years. The helicopter research is divided into the following parts: health monitoring, smart rotor, design optimization, control, helicopter rotor dynamics, active control of structural response (ACSR) and helicopter design and development. Aspects of health monitoring and smart rotor are discussed in detail. Further work needed and areas for international collaboration are pointed out.

The archival journal papers on helicopter engineering published from India are obtained from databases and are studied and discussed. The contribution of the basic research to the state‐of‐the‐art in helicopter engineering science is brought out.

It is found that strong research capabilities have developed in rotor system health and usage monitoring, rotor blade design optimization, ACSR, composite rotor blades and smart rotor development. Furthermore, rotorcraft modeling and analysis aspects are highly developed with considerable manpower available and being generated in these areas.

Two helicopter projects leading to the “advanced light helicopter” and “light combat helicopter” have been completed by Hindustan Aeronautics Ltd These helicopter programs have benefited from the basic research and also provide platforms for further basic research and deeper industry academic collaborations. The development of well‐trained helicopter engineers is also attractive for international helicopter design and manufacturing companies. The basic research done needs to be further developed for practical and commercial applications.

This is the first comprehensive research on rotorcraft research in India, an important emerging market, manufacturing and sourcing destination for the industry.

This study aims to investigate the effects of mass and stiffness imbalance in a tail rotor induced by damage in forward flight.

An aeroelastic analysis based on finite element in space and time and capable of modeling dissimilar blades is carried out to study the effect of damage occurring in one, two, and three blades in a four‐bladed tail rotor system in forward flight. The effect of damage growth on vibratory hub loads and blade responses is studied using a comprehensive aeroelastic code.

The diagnostic chart which is the summary of damage analysis of tail rotor shows that the root hub vibration spectrum gives enough indication to predict damage growth in the tail rotor blade. Hence, this can be useful towards development of health monitoring system for tail rotor blades.

The proposed analysis helps in understanding the basic physics behind the damaged tail rotor and also gives qualitative assessment of damaged tail rotor where obtaining the flight test data with damaged tail rotor is difficult.

To investigate the use of centre of gravity location on reducing cyclic pitch control for helicopter UAV's (unmanned air vehicles) and MAV's (micro air vehicles). Low cyclic pitch is a necessity to implement the swashplateless rotor concept using trailing edge flaps or active twist using current generation low authority piezoceramic actuators.

An aeroelastic analysis of the helicopter rotor with elastic blades is used to perform parametric and sensitivity studies of the effects of longitudinal and lateral center of gravity (cg) movements on the main rotor cyclic pitch. An optimization approach is then used to find cg locations which reduce the cyclic pitch at a given forward speed.

It is found that the longitudinal cyclic pitch and lateral cyclic pitch can be driven to zero at a given forward speed by shifting the cg forward and to the port side, respectively. There also exist pairs of numbers for the longitudinal and lateral cg locations which drive both the cyclic pitch components to zero at a given forward speed. Based on these results, a compromise optimal cg location is obtained such that the cyclic pitch is bounded within ±5° for a BO105 helicopter rotor.

The reduction in the cyclic pitch due to helicopter cg location is found to significantly reduce the maximum magnitudes of the control angles in flight, facilitating the swashplateless rotor concept. In addition, the existence of cg locations which drive the cyclic pitches to zero allows for the use of active cg movement as a way to replace the cyclic pitch control for helicopter MAV's.

This paper seeks to present a feedback error learning neuro‐controller for an unstable research helicopter.

Three neural‐aided flight controllers are designed to satisfy the ADS‐33 handling qualities specifications in pitch, roll and yaw axes. The proposed controller scheme is based on feedback error learning strategy in which the outer loop neural controller enhances the inner loop conventional controller by compensating for unknown non‐linearity and parameter uncertainties. The basic building block of the neuro‐controller is a nonlinear auto regressive exogenous (NARX) input neural network. For each neural controller, the parameter update rule is derived using Lyapunov‐like synthesis. An offline finite time training is used to provide asymptotic stability and on‐line learning strategy is employed to handle parameter uncertainty and nonlinearity.

The theoretical results are validated using simulation studies based on a nonlinear six degree‐of‐freedom helicopter undergoing an agile maneuver. The neural controller performs well in disturbance rejection is the presence of gust and sensor noise.

The neuro‐control approach presented in this paper is well suited to unmanned and small‐scale helicopters.

The study shows that the neuro‐controller meets the requirements of ADS‐33 handling qualities specifications of a helicopter.

This paper aims to present the design of a stability augmentation system (SAS) in the longitudinal and lateral axes for an unstable helicopter.

The feedback controller is designed using linear quadratic regulator (LQR) control with full state feedback and LQR with output feedback approaches. SAS is designed to meet the handling qualities specification known as Aeronautical Design Standard (ADS‐33E‐PRF). A helicopter having a soft inplane four‐bladed hingeless main rotor and a four‐bladed tail rotor with conventional mechanical controls is used for the simulation studies. In the simulation studies, the helicopter is trimmed at hover, low speeds and forward speeds flight conditions. The performance of the helicopter SAS schemes are assessed with respect to the requirements of ADS‐33E‐PRF.

The SAS in the longitudinal axis meets the requirement of the Level 1 handling quality specifications in hover and low speed as well as for forward speed flight conditions. The SAS in the lateral axis meets the requirement of the Level 2 handling quality specifications in both hover and low speed as well as for forward speed flight conditions. The requirements of the inter axis coupling is also met and shown for the coupled dynamics case. The SAS in lateral axis may require an additional control augmentation system or adaptive control to meet the Level 1 requirements.

The study shows that the design of a SAS using LQR control algorithm with full state and output feedbacks can be used to meet ADS‐33 handling quality specifications.

The purpose of this paper is to demonstrate the rationale and method for studying product adaptation in rural markets.

The paper takes the form of an exploratory design that includes; review of literature, pilot study, and survey method.

Findings of the study are contrary to the general understanding that rural is perceived very differently and hence operationalised differently by different organisation. However, results indicate that contingency theory holds true in case of product adaptation in rural markets also. With the increase in executives' representation of rurality, product adaptation degree also increased.

This is probably the first academic study on product adaptation in rural markets to the best of our knowledge. The study attempted to contextualise product adaptation construct from international marketing to rural marketing domain.

The paper aims to reduce the aerodynamic drag of a rotorcraft stabilizer in forward flight by taking into account downwash effects from the main rotor wake (power-on conditions).

A shape design methodology based on numerical optimization, CAD-in-the-loop (CAD: computer-aided design) approach and high-fidelity Computational Fluid Dynamics (CFD) tools was set-up and applied to modify the horizontal empennage of a rotorcraft configuration. This included the integration of both commercial and in-house computer-aided engineering tools for parametric geometry handling, adaptive mesh generation, CFD solution and evolutionary optimization within a robust evaluation chain for the aerodynamic simulation of the different design candidates generated during the automatic design loop. Geometrical modifications addressed both the stabilizer planform and sections, together with its setting angle in cruise configuration, accounting for impacts on the equilibrium, stability and control characteristics of the empennage.

An overall improvement of 11.1 per cent over the rotorcraft drag was estimated at the design condition (cruise flight; power-on) for the stabilizer configuration with optimized planform shape, which is increased to 11.4 per cent when combined with the redesigned airfoil to generate the stabilizer surface.

Critical design considerations are introduced with regard to structural and systems integration issues, and a design candidate alternative is identified and proposed as a compromise solution, achieving 8.3 per cent reduction of the rotorcraft configuration drag in cruise conditions with limited increase in the empennage aspect ratio and leading edge sweep angle when compared to the pure aerodynamic optimal design obtained from genetic algorithm evolution.

The proposed methodology faces the empennage design problem by explicitly taking into account the effects of main rotor wake impinging the stabilizer surface in forward flight conditions and using an automated optimization approach which directly incorporates professional CAD tools in the design loop.

The purpose of this paper is to identify the dimensions of service quality as well as of service loyalty in the context of medical tourism. It seeks to demonstrate the conceptualization of medical tourism service loyalty (MTSL) construct. This research also attempts to examine the effect of service quality dimensions on service loyalty dimensions of medical tourism.

The dimensions of service quality as well as of service loyalty are identified using an exploratory factor analysis. Next, the reliability and validity of the quality factors and loyalty factors are established through confirmatory factor analysis using AMOS 18.0 version. The related hypotheses are tested using structural equation modeling (SEM).

The paper identifies eight-factor construct for medical tourism service quality and three-factor construct for MTSL. It is found that the treatment satisfaction dimension of service quality has positive and significant impact on MTSL. It is also observed that, overall, medical tourism service quality has positive impact on MTSL.

These dimensions of service quality should be viewed as the levers of improving perceived service quality with respect to medical tourism. Examining the service quality dimensions’ impact on customer loyalty for medical tourism sector can offer the industry valuable insights regarding which aspects of the service to focus on in order to improve medical tourist’s satisfaction and loyalty toward the firms.

This paper introduces the concept of service quality and service loyalty in medical tourism sector. In conceptualizing MTSL, the authors propose an integration of behavioral measures, attitudinal measures and cognitive measures. The interrelationship between the service quality construct and medical loyalty construct was established using SEM. This is useful for the healthcare manager to measure the medical tourist’s perceptions of service quality on these dimensions as related to medical tourism performance.

Addressing probable complexities of climate change on rural livelihoods, food security, and poverty reduction, requires mainstreaming of cross-sectoral interventions and adaptations into existing frameworks. Indigenous communities due to their isolation, reluctance to current practices, and knowledge deprivation are difficult to reach by many developmental programs. The purpose of this paper is to identify relevant adaptations from indigenous rural Jharkhand (India), applicable to improving livelihoods through integrated natural resource management (NRM). Prospects of rainwater harvest and management for supporting local rural livelihoods were also examined.

Tested and applicable models of participatory research methods widespread in sociological research were used. Focussed group discussions and structured interviews were conducted for primary data collection from micro-watershed units of this study.

In-situ soil and water conservation methods showed increased availabilities of freshwater both for food and non-food consumption in the area. Construction of rural infrastructure and land husbandry practices improved agricultural productivity and resulted in subsequent reductions in women's drudgeries. Culture fishery provided ample scope for livelihood diversification, food and nutrition security of households. Overall, micro-watershed area developmental approach improved food and nutrition securities, generated employment opportunities, improved agricultural productivity, diversified livelihoods and were widely accepted by communities.

Creating greater sense of ownership among grass-root communities was an important thrust behind the success of this particular project. By entrusting tribal communities with fund management, rural planning, and execution of various interventions, a successful replicable model was produced, which has wider community implications extending beyond societies and geographies.

The demand for electricity supply increases day by day due to the rapid growth in the number of industries and consumer devices. The electric power supply needs to be improved by properly arranging distributed generators (DGs). The purpose of this paper is to develop a methodology for optimum placement of DGs using novel algorithms that leads to loss minimization.

In this paper, a novel hybrid optimization is proposed to minimize the losses and improve the voltage profile. The hybridization of the optimization is done through the crow search (CS) algorithm and the black widow (BW) algorithm. The CS algorithm is used for finding some tie-line systems, DG locations, and the BW algorithm is used for finding the rest of the tie-line switches, DG sizes, unlike in usual hybrid optimization techniques.

The proposed technique is tested on two large-scale radial distribution networks (RDNs), like the 119-bus radial distribution system (RDS) and the 135 RDS, and compared with normal hybrid algorithms.

The main novelty of this hybridization is that it shares the parameters of the objective function. The losses of the RDN can be minimized by reconfiguration and incorporating compensating devices like DGs.