Transport Airplane Research Articles

Analysis of Suitability of Fixed-wing Aircraft for Launching Satellites into Low Earth Orbit

The use of near-Earth space for scientific and commercial purposes has skyrocketed in recent years. However, progress continues to be hampered by the cost and availability of vehicles relied upon for delivering payloads to the Earth’s orbit. The Riga Technical University (Latvia), with the assistance of the Technological University in Kielce (Poland), is developing a concept of a novel payload launch system. The implications of such a system for launching payloads into low Earth orbit (LEO) are presented in the article. The system, intended for launching small spacecraft, comprises the A319 MPA transport airplane used as a platform aircraft and a three-stage payload carrier, codenamed LatLaunch. The first and second stages of the three-stage launch vehicle are unmanned winged aircraft. The third stage is a classic rocket which, once dropped from the launch platform, takes the payload to a specific height, at a given rate of speed and at a predetermined trajectory angle. The article presents the results of a study focusing on designing this system.

Longitudinal Wind Tunnel Tests of the PROSIB 19-Pax Airplane

This research paper delves into the longitudinal wind tunnel tests conducted on the 19-passengers aircraft model of the Italian PROSIB project. The concept is an innovative small air transport airplane with distributed propellers and hybrid-electric powerplant. The primary objective was to assess its stability and control characteristics in power-off conditions. In addition to the usual investigation of the aircraft components, the study introduced a belly-mounted pod, which served as a battery storage unit, and explored two distinct tail configurations: a body-mounted (low) tail and a T-tail (high). The results obtained from these tests generally confirmed the anticipated characteristics of the aircraft design. The experiments provided data on aerodynamic forces and moments, giving useful indications on the effects of a belly-mounted battery storage unit and tail layout on the aircraft stability and control characteristics. This information could be used by aircraft designers to size an airplane of the same class.

A contribution to the investigation of acoustic interferences in aircraft distributed propulsion

The objective of this work is to better understand the acoustic interferences created by distributed propulsion engines based on an approach that combines RANS simulation results for the aerodynamic prediction and analytical models to calculate acoustics. A multi-propeller configuration without wing is considered for this investigation. The propeller geometry and the operating conditions are realistic for a regional transport airplane. In the first part of the paper, the results obtained by two different and independent prediction methods are compared. One method is well-established and serves as validation for the second, low-order method, which is better suited for design-to-noise applications since it requires less details as input and is computationally faster by several orders of magnitude. The good agreement between both methods, obtained for a single propeller as well as for the distributed propeller configuration, is exploited in the second part of the paper to investigate the role of acoustic interferences. Taking acoustic interferences into account drastically affects the directivity of the tonal emission. Compared to the results obtained by considering the propellers as if they were uncorrelated, the far-field sound pressure levels can be significantly lower at the radiation nodes or amplified up to the theoretical limit of 9 dB calculated for eight propellers. The directivity patterns depend on the relative initial angular positions of the propellers. When these positions are randomly varied according to the uniform probability density distribution model, the mean result (expectation) is the same as if the propellers were considered as uncorrelated. Finally, the results show that the probability that the acoustic level is lower than the mean value is higher than 50% because of the positive skewness of the probability distribution of the resulting pressure amplitude. Even though the propeller–propeller and propeller–wing interactions were not considered, the essence of the findings is expected to remain valid for more complex configurations because those interactions are rotor phase-locked.

Effect of Subsonic Compressibility and Constraints on Generation of 3-D Optimal Camber Shapes

A flat surface wing is optimized for minimum induced drag for low and high subsonic Mach numbers. Wing for transport airplane role is considered. Optimal warp is separated into twist and camber. Effect of compressibility is analysed on the camber shape generated for two different Mach numbers. Constraint of lift is firstly used for developing an objective function for drag minimization. Next the lift and wing root bending moment constraints are considered to form objective function. Analysis is made on the resulting camber and twist distributions.

A Reconstructive Approach for Design of 3-D Low Drag Planar Wings

Design of a low induced drag wing results in it twist. Such a wing posses manufacturing difficulties and its profile drag is high. Here a planar 3-D design is worked out through a reconstructive approach. Wing for transport airplane role is considered. First a twisted wing is generated for minimum induced drag. Then the washout at root is used to off- load the angle-of- attack. Thereafter from the resulting 3-D camber an aerofoil is searched that can be commonly used across the span. Search for related angle-of-attack is made those results in minimum drag. The whole process is reconstructive in approach. Results obtained are very encouraging and are application oriented. Camber thus generated is superimposed with thickness to check for the presence of transonic effects.

A Reconstructive Approach for Design of a Planar Supercritical Wing

Effort is made to design an efficient planar wing that can support transonic pressure distribution. Wing for transport airplane role is considered. First optimal warp is generated for minimum induced drag for a Mach number that is just below transonic Mach number. Optimal warp thus generated is split into twist and camber. The resulting camber is used to form a planar wing. The camber of this aerofoil is varied along span. Twist is no more considered. Aerofoil thickness is superimposed on this camber. Mach number is increased till supercritical flow appears.The whole process is reconstructive in approach. Results obtained are very encouraging and are application oriented. Pattern of supercritical pressure distribution is studied from point of view of suction peaks, shock wave location, and aft loading intensity occurring towards trailing edge. Main effort of our exercise is to create shock free transonic wing.

Probabilistic Risk Assessment of Accidental Damage to Civil Aircraft Composite Structures

<div>In view of the structural accidental events in the ongoing airworthiness stage of civil aircraft, it is necessary to conduct a risk assessment to ensure that the risk level is within an acceptable range. However, the existing models of risk assessment have not effectively dealt with the risk of accidental structural damage due to random failure. This article focuses on probabilistic risk assessment using the Transport Airplane Risk Assessment Methodology (TARAM) of accidental structural damage of civil aircraft. Based on the TARAM and probability reliability integral, a refined failure frequency probability calculation model is established to elaborate on composite structure failure frequency. A case study is analyzed for the outer wing plane of an aircraft having impact damage of composite materials. Finally, results of the risk assessment without correction and risk assessment with correction are presented for detailed visual inspection and general visual inspection.</div>

Stimulus Perception in Long-Distance Railway Mode Choice

In the context of countries in the so-called Global South, where passenger railway services are either nonexistent or poorly performed, discrete choice models are useful to identify the attributes that affect users’ choices and provide insights on their behaviour in regional long-distance trips. Several theories and models have been proposed to understand travel behaviour for effective strategical decision in the transport field. The well-knownRandom Utility Maximization (RUM) approach has been widely used for such purposes, while the Random Regret Minimization (RRM) approach has been recently explored in the literature. However, the magnitude in the difference of levels of the attributes, or the stimulus perception, may affect the results of such models and biases the estimations. Therefore, this paper aims to assess the stimulus perception in mode choice to compare conventional rail (CR) and high-speed rail (HSR) services for passenger transport in intercity trips in Brazil. Estimations of RUM and RRM models were performed with a dataset from a stated preference survey comparing two railway technologies (CR and HSR) with other modes of transport (car, bus, and airplanes) for long-distance trips in the Southeast region of Brazil. Findings provide useful insights about the impacts of travel costs, travel times, and frequency of services, as well as sociodemographic characteristics of users. From the modelling outputs, it was found that users are affected by the magnitude of travel costs, time, and frequency only in business trips by HSR in the Brazilian context.

A formulation of industrial conceptual design optimization problem for commercial transport airplanes with turboelectric propulsion

A conceptual design optimization problem for commercial transport airplanes with turboelectric propulsion, with a reasonable fidelity and comprehensiveness suitable for industrial purposes, is formulated, in order to allow for proper assessment of the benefits of turboelectric propulsion. As a sample problem, we carry out conceptual design optimization of a turboelectric propulsion airplane concept in a conventional tube-and-wing configuration with a turbofan and an associated electric fan on each (i.e., left and right) wing, varying the performance of the turboelectric propulsion devices. The results indicate that proper assessment of the benefits of the turboelectric propulsion can be carried out using the formulated optimization problem. The findings from the sample problem, including notable benefits of the turboelectric propulsion and the performance crossover point where the fuel efficiency of an airplane with conventional propulsion and that of an airplane with turboelectric propulsion cross over, are also presented.

Characteristics of Austrian passenger transport policy development since the 1950s

Abstract This paper investigates the transport policy development and characteristics of the Austrian passenger transport sector from the 1950s onwards. The analysed performance indicators deal with the three most prevalent modes of transport (cars, trains and airplanes) and are linked to independent decision-making units (passengers) and their motives (price, quality and time to destination) as well as to goals and decisions involved in government policies. In this theoretical framework, we identified three developmental phases, using an interdisciplinary approach to assess the development of three variables of interest (number of car, air and train passengers). In the long term, transport policy aimed to solve the rigidity and lack of vision in train transport and the extensive use of cars. Air transport was a steadily growing segment in a close and positive relationship with trains, which is in line with the transport political orientation towards Vienna Airport and train connections to the capital city. The post-war phase (1945–1970) was characterised by enormous growth in the number of cars, an upswing in air transport and stagnant train transport. The second phase (1970–1994) was defined by a progressive liberalisation of rail transport and a plan to balance the growth rates of car, train and airplane performance variables. Finally, in the 1995–2019 phase, the growth in train transport increased; however, this growth remained far below the growth rates of air and car performance variables. Transport policy achievements and shortcomings for future research are suggested.

A Formulation of the Industrial Conceptual Design Optimization Problem for Commercial Transport Airplanes

A realistic industrial conceptual design optimization problem for commercial transport airplanes was formulated with reasonable fidelity and comprehensiveness by selecting appropriate design parameters, constraints, and objectives, in order to provide a baseline to facilitate research on developing robust and efficient optimization methods for the industrial conceptual design of such airplanes. As a sample problem, a multiobjective simultaneous optimization of the design parameters for two types of civil passenger transport airplanes that constitute a family, with identical wing and tail geometries but different performance specifications, was performed using a genetic algorithm coupled with a constraint-handling technique. The results indicated that a realistic industrial conceptual design optimization of commercial transport airplanes, including simultaneous optimization of family airplanes, could be performed with the formulation. The findings from the sample optimization were also presented.

Estimation of Atmospheric Gusts Using Integrated On-Board Systems of a Jet Transport Airplane—Flight Simulations

Currently, quite accurate measurements of atmospheric gusts are carried out by airport systems only in the vicinity of the runways. There is a still open issue of availability of information about real wind gusts at cruising altitudes and during approach at a considerable distance from the airfield. Standard on-board systems of a jet transport airplane provide some information which is desirable to have knowledge of how flight parameters reflect real gust parameters and their impact on the aircraft dynamics. The paper proposes an algorithm for headwind gust magnitude estimation in relation to aircraft response. The analysed estimation algorithms assume the use of data available from the existing on-board systems only without the employment of any extra sensors or ground and satellite systems. In this way, many problems caused by different structures, configurations, and ways of installation of additional sensors and structural changes are rejected. The algorithms use the classical method for estimation of wind parameters as well as a linear longitudinal model of aircraft dynamics, taking into account the influence of wind gusts. Data fusion was realised with the use of three filtration methods. Results were evaluated to select the most accurate method of the estimation. Test data were obtained from advanced flight simulation. The experimental scenario considered a flight of a passenger twin-engine jet airplane through a layer of programmed gusts. The results of the flight simulations allowed us to determine the accuracy of the proposed gust estimation algorithms in reference to the ideal wind-speed data analysis obtained directly from the simulation environment (with the accuracy of the simulation process). The use of the proposed gust estimation algorithms may provide more accurate signal for integrated on-board systems, especially for wind shear detection and sped-up response time of flight control systems, protecting aircrafts against the adverse impact of encountered wind shear or gusts, e.g., auto-thrust or auto-throttle systems. The dedicated algorithm presented in the paper may increase the safety level of take-off and approach phases in gusty conditions and also during significant changes in wind speed at cruising altitudes in the case of crossing the area of jet stream occurrence.

Un train au milieu des voitures et des avions en Floride ? Le projet ferroviaire privé Brightline dans la première région touristique des États-Unis

The state of Florida is a major hub of the US tourist economy, particularly renowned for its beaches and its extensive commercial and leisure infrastructure (not least its many theme parks). The state is a popular destination for Americans, with US citizens accounting for ¾ of all visitors. Florida is also one of the US states with the highest rate of dependency on carbon-heavy modes of transport (cars and airplanes), for both everyday and occasional forms of mobility. In this unlikely context, a private company by the name of Brightline has been working since 2015 to create a rail link between Miami and Orlando, with the first section of the line (Miami-West Palm Beach) inaugurated in late 2017. This project is original in more than one respect: it is being led by a private company, with no initial public investment and without the involvement of any government bodies; it also runs through a territory which, in theory, has an aversion to train travel and where tourist mobility is virtually synonymous with car and air travel. My objective in this article is three-fold: to examine the key role played by transport in the emergence of Florida as a tourist mecca; to analyse the key features of the Brightline project and its relation to the tourism sector; and to weigh up the territorial potential of this new line and its capacity to change established ideas and mobility patterns among tourists visiting Florida. I draw several conclusions from this analysis: the Brightline project has the potential to capture substantial tourist flows thanks to its proximity to many tourist attractions; tourism has been systematically prioritised in the company’s strategy and communication efforts; stations have an important role to play in attracting passengers; and mobility practices in Florida are evolving.

A REVIEW ON BASE DRAG REDUCTION METHODS.

In this project-based learning we are going to know about how the base drag are acting on an object to automobile and aircrafts and it deals with the equations of the drag in fluid dynamics and aerodynamics, and we come to know that what steps are we going to follow how to overcome the drag in vehicles. Reducing base drag of two dimensional and axisymmetric bodies having a blunt base. These methods include splitter plates, both thin and thick, splitter wedges, base bleed. boat-tailing and various types of serrated trailing edges. These methods include splitter plates, both thin and thick, splitter wedges, base bleed, boat-tailing and various types of serrated trailing edges. The effectiveness of the various devices in reducing base drag is shown and compared. In some cases, their influence on the lift of an airfoil is also indicated. Axisymmetric bodies, e.g., missiles, often have a blunt base. The corresponding base drag usually is an appreciable part of the total drag and, if the base drag is not reduced by suitable means, can remarkably reduce the overall performance of the system. Under most circumstances it is desirable to have as small a base drag as possible. Therefore, during the last 25 years many methods for reducing base drag have been developed. Often the periodic lift forces inducing vibrations also decrease if the base drag is reduced. By making CFD analysis also we can predefine the drag on the airfoil and automobile. There are various drag reduction method existing in the present world of transport vehicles and airplane. In general, the dynamics of the system subjected to both internal and external flow concurrently is similar to that with just one of the two flows. It would be of practical importance if it were possible to determine an equivalent flow which would have the same dynamical effect on a given beam as the two flows simultaneously.

Ground effect aerodynamics of twin fuselage aircraft

The paper presents experimental study results of ground effect influence on the aerodynamic characteristics of the twin fuselage transport airplane in a low-speed wind tunnel. The aerodynamic configuration has the two fuselages distributed under high-wing, and a “TT”–shaped tail. The twin fuselage transport airplane model consists of two fuselages, wing, empennage and external tank. The analysis includes studying the ground effect on the longitudinal and lateral aerodynamic characteristics and horizontal tail effectiveness. The effect of installing an external cryogenic fuel tank under the wing between the fuselages of the model was considered too. The obtained data shows the typical behaviour of the aerodynamic characteristics near the ground plate for aircraft model with high-wing and high placed horizontal tail. Ground proximity significantly increases the maximum lift-to-drag ratio and slightly changes the longitudinal moment characteristics. Horizontal tail effectiveness is maintained for all tailplane angles near the ground plate. The longitudinal and lateral stability of the twin fuselage transport airplane model is maintained in all considered modes near the ground plate.

A study of the damage tolerance of composite-metal hybrid joints reinforced by multiple and penetrative thin pins

The application of adhesive bonding technology in aircraft structures can reduce the total wight greatly, but the bonded joints are very sensitive to the possible manufacturing defects and damages during service operations, which makes them difficult to meet the damage tolerance requirements of the current transport airplane structures. In this study, the damage tolerance of composite-metal hybrid joints reinforced by multiple and penetrative thin pins was studied. The damage tolerance performance of the composite-metal joint is supposed to be enhanced by multiple through-the-thickness penetrative thin reinforcements in the bonding region, and the thin reinforcements were bonded together with both the composite and metallic joint plates. Both experimental tests and finite element simulations were conducted to investigate the effects of the through-the-thickness reinforcements on the damage tolerance performance of the joints with and without pre-fabricated disbond defects. Through the comparative analyses, it was found that the penetrative thin pins in the bonding region significantly improved the static load carrying capacity, the failure strain, the fracture energy, and the fatigue lives of the composite-metal bonded joints. Moreover, the reinforcements decreased the sensitivity of the bonded joints to the disbond defects in the bonding region. The damage tolerance performance of the composite-metal adhesively bonded joints was significantly increased by the through-the-thickness penetrative reinforcements and the enhancement mechanism was revealed by the combined analysis of test results and simulation results.

Features of flow around transport aircraft model with running propellers by modelled engine failure in wind tunnel

This paper presents the experiment results of modelling the one engine failure at the landing mode on a model of a light transport airplane in the T-102 TsAGI low speed wind tunnel. The effect of starboard and port engines failure on the aerodynamic characteristics and stability of the model is researched. The model maximum lift coefficient is reduced about ≈8% and there are the same moments in roll and yaw for starboard and port engines failure case. It was found that the failure of any engine has little impact on the efficiency of control surfaces. Approaches of compensation of forces and moments arising in the engine failure case were investigated.

Effects of release pressure on the transportation characteristics in pipeline and the diffusion behaviors in enclosure space of typical gas extinguishing agent

Reducing the release pressure of fire extinguishing systems can decrease potential safety hazards in large transport airplanes. To explore whether reducing the release pressure can achieve the release effect required by the airworthiness standards or not, the transportation characteristics in the pipeline and diffusion behaviors in the enclosure space of a typical fire extinguishing agent (Halon 1301) were investigated under five release pressures in the present study. The effects of the release pressure on the degree of superheat, injection duration, jet structure, and concentration distribution of Halon 1301 were analyzed. The results show that both of the degree of superheat and the injection duration decrease with an increase in the release pressure. The supplement of bubble expansion in the fire extinguishing agent can slow down the pressure decrease in the vessel. Both of the maximum and mean values of the pipeline differential pressure increase with an increase in release pressure. The maximum value of the jet angle decreases linearly with the increase in release pressure, and the jet deflects upward owing to the effects of buoyancy. The maximum concentration value decreases with an increase in the distance from the nozzle. The maximum concentration values in the near field from the nozzle increase with an increase in the release pressure. Under five release pressures, the concentration and holding time (duration above 6% volume concentration) of Halon 1301 on the centerline of the jet meet the requirements of airworthiness provisions.

Why time‐limited individuals can make populations more vulnerable to disturbance

Individual variation in disturbance vulnerability (i.e. the likelihood that disturbance negatively affects an individual's fitness) can affect how disturbance impacts animal populations, as even at low disturbance levels some individuals could be severely affected and die. Individual variation in vulnerability can arise due to different responses to disturbance. We propose a new hypothesis that even when individuals respond similarly to disturbance, time‐limited individuals are more at risk that their condition deteriorates since they have limited ability to extend their foraging time to compensate for disturbance. We investigate this ‘time‐limitation hypothesis' both empirically and mathematically by studying how individuals that differ in their average foraging time (presumably due to differences in foraging efficiency) are affected by disturbance. We used tracking data of 22 wintering Eurasian oystercatchers Haematopus ostralegus to compare time budgets between disturbed and undisturbed tidal periods. In three tidal periods with severe disturbance by transport airplanes, more than a third of the variation in additional flight time and foraging time loss was explained by individual differences. Inefficient individuals that foraged longer in undisturbed tidal periods experienced higher costs in disturbed tidal periods, since they lost more foraging time. We next used an analytical energy balance model to study how time‐limited individuals differed in their maximum disturbance thresholds. Both our theoretical model and empirical study suggest that inefficient individuals in a time‐limited environment may be unable to increase their foraging time to compensate for the effects of disturbance. Consequently, the magnitude of individual variation in time budgets strongly determines what proportion of the population is at risk that their condition deteriorates due to disturbance. Our hypothesis implies that, when assessing disturbance effects on a population, it is not only important to consider individual variation in disturbance responses, but also variation in time budgets that determine the consequences of disturbance.

Study on a twin-fuselage transport airplane model in a low speed wind tunnel

This paper presents the results of experimental studies of the twin-fuselage transport airplane model at the cruising configuration in the T-102 TsAGI low-speed wind tunnel. The researched twin-fuselage transport airplane is a tri-engine transport aircraft intended for transportation of cargo weighted up to 40 tons at a distance up to 3000 km with speed 700-740 km/h. The aerodynamic configuration has the two fuselages distributed under high-wing, and a “TT” – shaped tail. The research purpose was the determination of the aerodynamic characteristics of the twin-fuselage transport airplane model without engine nacelles and assessment of the twin-fuselage layout impact on control surfaces efficiency. The effect of installing an external cryogenic fuel tank under the wing between the fuselages of the model was considered too.