Aerodynamic and static stability investigation into aircraft coupled system to suborbital space flights

2021 ◽  
Vol 93 (2) ◽  
pp. 275-283
Author(s):  
Marcin Figat ◽  
Agnieszka Kwiek
Keyword(s):  
Flow Model ◽  
Coupled System ◽  
Inviscid Flow ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Mutual Position ◽  
Content Type ◽  
Space Flights ◽  
Centre Of Gravity ◽  
The Impact

Purpose The aim of the research is to conduct a study into a configuration of an aircraft system with a focus on aerodynamics. In addition, trim condition and static stability constraints were included. The main application of this system is suborbital space flights. The presented concept of a modular airplane system (MAS) consists of two vehicles: a Rocket Plane and a Carrier. Both are designed in tailless configurations but coupled formed a classic tail aircraft configuration, where the Rocket Plane works as the empennage. The most important challenge is to define the mutual position of those two tailless vehicles under the assumption that each vehicle will be operating alone in different flight conditions while joined in one object create a conventional aircraft. Each vehicle configuration (separated and coupled) must fulfil static stability and trim requirements. Design/methodology/approach Aircrafts’ aerodynamic characteristics were obtained using the MGAERO software which is a commercial computing fluid dynamics tool created by AMI Aero. This software uses the Euler flow model. Results from this software were used in the static stability and trim condition analysis. Findings The main outcome of this investigation is a mutual position of the Rocket Plane and the Carrier that fulfils project requirements. Also, the final configuration of both separated vehicles (Rocket Plane and Carrier) and the complete MAS were defined. In addition, it was observed that in the case of classic aircraft configuration which is created by connecting two tailless vehicles increasing horizontal tail arm reduces static stability. This is related to a significantly higher mass ratio of the horizontal tail (the Rocket Plane) with respect to the whole system. Moving backward, the Rocket Plane has a notable effect on a position of a centre of gravity of the whole system static stability. Moreover, the impact of the mutual vehicles’ position (horizontal tail arm) and inclination angle on the coupled vehicle lift to drag ratio was analysed. Research limitations/implications In terms of aerodynamic computation, MGAERO software using an inviscid flow model, therefore, both a friction drag and breakdown of vortex are not considered. But the presented research is for the computation stage of the design, and the MGAERO software guarantees satisfactory accuracy with respect to the relatively low time of computations. The second limitation is that the presented results are for the conceptual stage of the design and dynamic stability constraints were not taken into account. Practical implications The ultimate goal of the coupled aircraft project is to conduct flying tests and the presented result is one of the milestones to achieve this goal. Originality/value A design process for a conventional aircraft configuration is well known however, there are not many examples of vehicles that consist of two coupled aircrafts where both vehicles have similar mass. The unique part of this paper includes results of the investigation of the mutual position of the vehicles that can fly alone, as well as in coupled form. The impact of the position of the centre of gravity on trim conditions and static stability of the coupled configuration was investigated.

Aerodynamics analysis of the main rotor influence on the static stability of the gyroplane

2017 ◽  
Vol 89 (5) ◽  
pp. 663-670 ◽  
Author(s):  
Marcin Figat
Keyword(s):  
Dynamic Stability ◽  
Static Stability ◽  
Main Rotor ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Flight Condition ◽  
Configuration Change ◽  
Stability Derivatives ◽  
The Impact ◽  
Derivatives Of

Purpose This paper aims to present the results of aerodynamic calculation of impact the main rotor on the fuselage and the tail of a light gyroplane. This kind of vehicle is a type of rotorcraft which uses a non-powered rotor in autorotation to develop lift and engine-powered propeller to provide the thrust. Both of them disturb the flow around the gyroplane body (gyroplane fuselage and tail) and influence on its static stability. The main goal of the presented research was to find the magnitude of this influence. To measure this effect, the main stability derivatives changes of gyroplane body were investigated. Design/methodology/approach The CFD analysis of the complete gyroplane was made. Computation was performed for the model of gyroplane which was equipped with the two sub-models of the main rotor and the engine-powered propeller. Both of them were modelled as the actuator discs. This method allows to compute the aerodynamic impact of rotating components on the gyroplane body. All aerodynamic analysis was made by the MGAERO software. The numerical code of the software bases on the Euler flow model. Next, the resulting aerodynamic coefficients were used to calculate the most important stability derivatives of the gyroplane body. Findings The result obtained by computation presents the change in the most important aerodynamic coefficients and stability derivatives of the gyroplane body caused by the impact of its main rotor. Moreover, the result includes the change of the aerodynamic coefficients and stability derivatives caused by change of the main rotor configuration (change of rotation rate and angle of incidence) and change of the flight condition (gyroplane angle of attack sideslip angle and flight speed). Practical implications Analysis of the main rotor impact will be very useful for evaluation of dynamic stability of the light gyroplane. Moreover, the results will be helpful to design the horizontal and vertical tail for the light gyroplane. Originality/value This paper presents the method of the numerical analysis of the static stability of the light gyroplane’s body. The results of analysis present the impact of disturbance generated by the rotating main rotor on the static stability of the gyroplane body. Moreover, the impact of the main rotor configuration change and the flight condition change on the static stability were investigated too. The evaluation of the gyroplane’s body static stability was made by the stability derivatives. The methodology and obtained result will be very useful for analysis of the dynamic stability of the light gyroplanes. Moreover, the results will be helpful during design the main components of the gyroplane like vertical and horizontal tail.

scholarly journals PENELITIAN DAN PENGUJIAN KARAKTERISTIK AERODINAMIKA BOM LATIH PERCOBAAN BLP-500 DAN BLP 25

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Agus Aribowo ◽  
Sulistyo Atmadi ◽  
Yus Kadarusman Markis
Keyword(s):  
Wind Tunnel ◽  
Analytical Calculation ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Supersonic Wind Tunnel ◽  
Centre Of Gravity ◽  
The Stability

Research and aerodynamic testing of BLP-500 and BLP-25 have been conducted in both subsonic and supersonic wind tunnel. Aerodynamic characteristics such as Cl, Cd, and Cm for these types of bomb we obtained. By knowing the aerodynamic characteristics, the stability and trajectory of the bomb can be determined. Both analytical calculation and real tests in the wind tunnel were performed and compared. The results showed that for its static stability, the location of the centre of gravity of BLP-500 and BLP-25 to be less than 115.1 cm and 31.9 cm respectively.

Aerodynamics analysis of rotor’s impact on the aircraft in the tandem wing configuration

2018 ◽  
Vol 92 (3) ◽  
pp. 336-344
Author(s):  
Marcin Figat
Keyword(s):  
Stability Margin ◽  
Static Stability ◽  
Complex Model ◽  
Numerical Code ◽  
Aerodynamic Coefficients ◽  
Sideslip Angle ◽  
Content Type ◽  
Aerodynamic Analysis ◽  
Stability Derivatives ◽  
The Impact

Purpose This paper aims to present the results of aerodynamic calculation of the aircraft in tandem wing configuration called VTOL. A presented vehicle combines the capabilities of the classic aircraft and helicopters. The aircraft is equipped with two pairs of tilt-rotors mounted on the tips of the front and the rear wing. The main goal of the presented research was to find the aerodynamic impact of both pairs of tilt-rotors on aerodynamic coefficients of the aircraft. Moreover, the rotors impact on the static stability of the aircraft was investigated too. Design/methodology/approach The CFD analysis was made for the complete aircraft in the tandem wing configuration. The computation was performed for the model of aircraft which was equipped with the four sub-models of the front and rear rotors. They were modeled as the actuator discs. This method allows for computing the aerodynamic impact of rotating components on the aircraft body. All aerodynamic analysis was made by the MGAERO software. The numerical code of the software was based on the Euler flow model. The used numerical method allows for the quick computation of very complex model of aircraft with a satisfied accuracy. Findings The result obtained by computation includes the aerodynamic coefficients which described the impact of the tilt rotors on the aircraft aerodynamic. The influence of the angle of attack, sideslip angle and the change of rotor tilt angle was investigated. Evaluation of the influence was made by the stability margin analysis and the selected stability derivatives computation. Practical implications Presented results could be very useful in the computation of dynamic stability of unconventional aircraft. Moreover, results could be helpful during designing the aircraft in the tandem wing configuration. Originality/value This paper presents the aerodynamic analysis of the unconventional configuration of the aircraft which combines the tandem wing feature with the tilt-rotor advantages. The impact of disturbance generated by the front and rear rotors on the flow around the aircraft was investigated. Moreover, the impact of rotors configuration on the aircraft static stability was found too.

The More Control, the Better?

2014 ◽  
Vol 26 (2) ◽  
pp. 81-91 ◽  
Author(s):  
Jeeyun Oh ◽  
Mun-Young Chung ◽  
Sangyong Han
Keyword(s):  
Mixed Design ◽  
Negative Effects ◽  
Story Structure ◽  
Content Type ◽  
High User ◽  
User Control ◽  
Rigorous Research ◽  
Control Versus ◽  
The Media ◽  
The Impact

Despite of the popularity of interactive movie trailers, rigorous research on one of the most apparent features of these interfaces – the level of user control – has been scarce. This study explored the effects of user control on users’ immersion and enjoyment of the movie trailers, moderated by the content type. We conducted a 2 (high user control versus low user control) × 2 (drama film trailer versus documentary film trailer) mixed-design factorial experiment. The results showed that the level of user control over movie trailer interfaces decreased users’ immersion when the trailer had an element of traditional story structure, such as a drama film trailer. Participants in the high user control condition answered that they were less fascinated with, absorbed in, focused on, mentally involved with, and emotionally affected by the movie trailer than participants in the low user control condition only with the drama movie trailer. The negative effects of user control on the level of immersion for the drama trailer translated into users’ enjoyment. The impact of user control over interfaces on immersion and enjoyment varies depending on the nature of the media content, which suggests a possible trade-off between the level of user control and entertainment outcomes.

Perceived workplace gender-bias and psychological impact

2019 ◽  
Vol 43 (3/4) ◽  
pp. 339-353 ◽  
Author(s):  
Siham Lekchiri ◽  
Cindy Crowder ◽  
Anna Schnerre ◽  
Barbara A.W. Eversole
Keyword(s):  
Gender Bias ◽  
Critical Incident ◽  
Psychological Impact ◽  
Working Women ◽  
Content Type ◽  
Treatment Bias ◽  
Male Dominated ◽  
The Impact ◽  
Organizational Mechanisms ◽  
Practical Implications

Purpose The purpose of this paper is to explore the experiences of working women in a male-dominated country (Morocco) and unveil the unique challenges and everyday gender-bias they face, the psychological impact of the perceived gender-bias and, finally, identify a variety of coping strategies or combatting mechanisms affecting their motivation and retention in the workplace. Design/methodology/approach Empirical evidence was obtained using a qualitative research method. The Critical Incident Technique (CIT) was used to collect incidents recalled by women in the select institution reflecting their perceptions of their managers’ ineffective behaviors towards them and the impact of these behaviors. The critical incidents were inductively coded, and behavioral statements were derived from the coded data. Findings The qualitative data analysis led them to structure the data according to two theme clusters: The perceived gender-bias behaviors (Covert and evident personal and organizational behaviors) and Psychological impacts resulting from the perceived bias. These behavioral practices included abusive behaviors, unfair treatment, bias and lack of recognition. The psychological impact elements involved decreased productivity, depression, anxiety and low self-esteem. Practical implications Understanding these experiences can facilitate the identification of strategies geared towards the retention of women in the workforce, and Moroccan organizations can develop and implement strategies and policies that are geared towards eliminating gender-bias in the workplace and to retaining and motivating women who remain ambitious to work in male-dominated environments and cultures. Originality/value This paper provides evidence that sufficient organizational mechanisms to support women in male-dominated environments are still unavailable, leaving them to find the proper coping mechanisms to persevere and resist.

An empirical examination of firm financial performance along dimensions of supply chain resilience

2017 ◽  
Vol 40 (3) ◽  
pp. 254-269 ◽  
Author(s):  
Xun Li ◽  
Qun Wu ◽  
Clyde W. Holsapple ◽  
Thomas Goldsby
Keyword(s):  
Supply Chain ◽  
Financial Performance ◽  
Three Dimensions ◽  
Empirical Examination ◽  
Content Type ◽  
Supply Chain Resilience ◽  
Critical Dimensions ◽  
Firm Financial Performance ◽  
Supply Chain Agility ◽  
The Impact

Purpose This paper aims to investigate the impact of three critical dimensions of supply chain resilience, supply chain preparedness, supply chain alertness and supply chain agility, all aimed at increasing a firm’s financial outcomes. In a turbulent environment, firms require resilience in their supply chains to prepare for potential changes, detect changes and respond to actual changes, thus providing superior value. Design/methodology/approach Using survey data from 77 firms, this study develops scales for preparedness, alertness and agility. It then tests their hypothesized relationships with a firm’s financial performance. Findings The results reveal that the three dimensions of supply chain resilience (i.e. preparedness, alertness and agility) significantly impact a firm’s financial performance. It is also found that supply chain preparedness, as a proactive resilience capability, has a greater influence on a firm’s financial performance than the reactive capabilities including alertness and agility, suggesting that firms should pay more attention to proactive approaches for building supply chain resilience. Originality/value First, this study develops a comparatively comprehensive definition for supply chain resilience and explores its dimensionality. Second, this study provides empirically validated instruments for the dimensions of supply chain resilience. Third, this study is one of the first to provide empirical evidence for direct impact of supply chain resilience dimensions on a firm’s financial performance.

Proprietary information and the cost of bank debt

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
HyunJun Na
Keyword(s):  
Least Square ◽  
Bank Loan ◽  
Content Type ◽  
Loan Contracts ◽  
Proprietary Information ◽  
Banking Deregulation ◽  
Interstate Banking ◽  
Innovative Firms ◽  
Bank Loan Contracts ◽  
The Impact

PurposeThis study explores how the firm’s proprietary information has an impact on the bank loan contracts. It explains the propensity of using the competitive bid option (CBO) in the syndicate loans to solicit the best bid for innovative firms and how it changes based on industry competition and the degree of innovations. This research also examines how the interstate banking deregulation (Interstate Banking and Branching Efficiency Act) in 1994 affected the private loan contracts for innovative borrowers.Design/methodology/approachThe study uses various econometric analyses. First, it uses the propensity score matching analysis to see the impact of patents on pricing terms. Second, it uses the two-stage least square (2SLS) analysis by implementing the litigation and non-NYSE variables. Finally, it studies the impact of the policy change of the Interstate Banking and Branching Efficiency Act of 1994 on the bank loan contracts.FindingsFirms with more proprietary information pays more annual facility fees but less other fees. The patents are the primary determinants of the usage of CBO in the syndicate loans to solicit the best bid. While innovative firms can have better contract conditions by the CBO, firms with more proprietary information will less likely to use the CBO option to minimize the leakage of private information and the severe monitoring from the banks. Finally, more proprietary information lowered the loan spread for firms dependent on the external capital after the interstate banking deregulation.Originality/valueThe findings of this research will help senior executives with responsibility for financing their innovative projects. In addition, these findings should prove helpful for the lawmakers to boost economies.

The effect of emotions, eWOM quality and online review sequence on consumer intention to follow advice obtained from digital services

2020 ◽  
Vol 31 (3) ◽  
pp. 465-487 ◽  
Author(s):  
Carla Ruiz-Mafe ◽  
Enrique Bigné-Alcañiz ◽  
Rafael Currás-Pérez
Keyword(s):  
Structural Model ◽  
Online Reviews ◽  
Moderating Effect ◽  
Online Information ◽  
Bias Effect ◽  
Content Type ◽  
Digital Services ◽  
Information Cues ◽  
Cognitive Information ◽  
The Impact

PurposeThis paper analyses the interrelationships between emotions, the cognitive information cues of online reviews and intention to follow the advice obtained from digital platforms, paying special attention to the moderating effect of the sequencing of review valence.Design/methodology/approachThe data were collected from 830 Spanish Tripadvisor users. In a two-step approach, a measurement model was estimated and a structural model analysed to test the proposed hypotheses. SmartPLS 3.0 software was used. The moderating effect of sequencing of reviews is tested.FindingsThe data analysis showed a bias effect of review sequence on the impact of online information cues and emotions on intention to follow advice obtained from Tripadvisor. When the online reviews of a restaurant begin with positive commentaries, their perceived persuasiveness is a stronger driver of the pleasure and arousal elicited by online reviews than when they begin with negative reviews. On the other hand, the perceived helpfulness of online reviews only triggers arousal when the user reads negative, followed by positive, comments. The impact of pleasure on intention to follow the advice provided in an online travel community is higher with positive-negative than with negative-positive sequences.Originality/valueWhile researchers have demonstrated the benefits of customer reviews on company sales, a largely uninvestigated issue is the interplay between emotions and cognitive information cues in the processing of online reviews. This is one of the first studies to examine the moderating effect of conflicting reviews on the impact of emotions and cognitive information cues on consumer intention to follow the advice obtained from digital services.

The role of innovation in building competitive advantages: an empirical investigation

2018 ◽  
Vol 21 (1) ◽  
pp. 44-69 ◽  
Author(s):  
Prodromos Chatzoglou ◽  
Dimitrios Chatzoudes
Keyword(s):  
Competitive Advantage ◽  
Conceptual Framework ◽  
Empirical Investigation ◽  
Primary Data ◽  
Empirical Literature ◽  
Competitive Advantages ◽  
Manufacturing Companies ◽  
Content Type ◽  
The Impact ◽  
Structured Questionnaire

Purpose Nowadays, innovation appears as one of the main driving forces of organisational success. Despite the above fact, its impact on the propensity of an organisation to develop and sustain a competitive advantage has not yet received sufficient empirical investigation. The purpose of this paper is to enhance the existing empirical literature by focusing on the antecedents of innovation and its impact on competitive advantage. It proposes a newly developed conceptual framework that adopts a three-step approach, highlighting areas that have rarely been simultaneously examined before. Design/methodology/approach The examination of the proposed conceptual framework was performed with the use of a newly developed structured questionnaire that was distributed to a group of Greek manufacturing companies. The questionnaire has been successfully completed by chief executive officers (CEOs) from 189 different companies. CEOs were used as key respondents due to their knowledge and experience. The reliability and the validity of the questionnaire were thoroughly examined. Empirical data were analysed using the structural equation modelling technique. The study is empirical (based on primary data), explanatory (examines cause and effect relationships), deductive (tests research hypotheses) and quantitative (includes the analysis of quantitative data collected with the use of a structured questionnaire). Findings Results indicate that knowledge management, intellectual capital, organisational capabilities and organisational culture have significant direct and indirect effects on innovation, underlining the importance of their simultaneous enhancement. Finally, the positive effect of innovation on the creation of competitive advantages is empirically validated, bridging the gap in the relevant literature and offering avenues for additional future research. Originality/value The causal relationship between innovation and competitive advantage, despite its significant theoretical support, has not been empirically validated. The present paper aspires to bridge this gap, investigating the impact of innovation on the development of competitive advantages. Moreover, the present study adopts a multidimensional approach that has never been explored in the existing innovation literature, making the examination of the proposed conceptual framework an interesting research topic.

Farm wages and public works

2015 ◽  
Vol 8 (1) ◽  
pp. 19-72 ◽  
Author(s):  
Kanika Mahajan
Keyword(s):  
Theoretical Model ◽  
Wage Rate ◽  
Fixed Effects ◽  
Positive Impact ◽  
Wage Growth ◽  
State Level ◽  
Random Allocation ◽  
Farm Sector ◽  
Content Type ◽  
The Impact

Purpose – The purpose of this paper is to examine the impact of National Rural Employment Guarantee Scheme (NREGS) on farm sector wage rate. This identification strategy rests on the assumption that all districts across India would have had similar wage trends in the absence of the program. The author argues that this assumption may not be true due to non-random allocation of districts to the program’s three phases across states and different economic growth paths of the states post the implementation of NREGS. Design/methodology/approach – To control for overall macroeconomic trends, the author allows for state-level time fixed effects to capture the differences in growth trajectories across districts due to changing economic landscape in the parent-state over time. The author also estimates the expected farm sector wage growth due to the increased public work employment provision using a theoretical model. Findings – The results, contrary to the existing studies, do not find support for a significantly positive impact of NREGS treatment on private cultivation wage rate. The theoretical model also shows that an increase in public employment work days explains very little of the total growth in cultivation wage post 2004. Originality/value – This paper looks specifically at farm sector wage growth and the possible impact of NREGS on it, accounting for state specific factors in shaping farm wages. Theoretical estimates are presented to overcome econometric limitations.

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