Airplane Mode Research Articles

Impact of Smartphone-Induced Mental Fatigue on Resistance Training Performance and Efficiency - The Role of Smartphone Use During Workout

Introduction Resistance training volume is a key determinant of muscle hypertrophy and strength development. However, mental fatigue can significantly impact this volume, ultimately affecting performance. One prominent source of mental fatigue in modern gym environments is smartphone use, which has become pervasive and may reduce workout efficiency and overall training volume. Purpose This review examines the dual effects of smartphone use on resistance training outcomes and offers strategies to balance these impacts effectively. Conclusions Smartphone-induced mental fatigue increases perceived exertion, leading to reduced performance during resistance training by lowering volume-load and endurance, particularly in low- and moderate-intensity exercises. Despite this, maximal strength appears to remain unaffected. Additionally, smartphone use diverts cognitive resources, resulting in mental fatigue and impairing both physical and technical performance due to distractions during workouts. It can also unintentionally prolong rest periods, which disrupts the balance between muscle recovery and mental readiness, further decreasing training efficiency. However, smartphones also offer valuable benefits, such as access to fitness apps, progress tracking, and motivational music, which can help maintain or even enhance performance by improving focus and motivation. To minimize distractions and optimize training outcomes, strategies such as using airplane mode or scheduling specific times for phone use are recommended. While excessive smartphone use can impair training efficiency, careful management and strategic use can enable athletes to capitalize on its benefits and improve resistance training results. Future research should focus on developing best practices for incorporating smartphone use in fitness settings to balance its advantages while minimizing its downsides.

FlyDetect: An Android Application for Flight Detection.

Over the past years, transport mode recognition has become a large field of research. However, flight as a type of transportation has been mostly overlooked. A system for flight detection might be useful for context-aware applications, but more importantly, it can be used to automatically manage airplane mode on smartphones. Smartphones transmit radio frequency signals which could potentially interfere with aircraft systems, and it is therefore important that devices enable airplane mode to avoid this problem. This paper proposes flyDetect, a method for automatic flight mode detection and an embodiment in the form of an app that demonstrates the viability of the method. Thus, the system uses the accelerometer and barometer in an Android smartphone, can detect the start and end of a flight, and notify other apps or systems on the device when this happens. Our evaluation shows that flyDetect meets the requirements set for the solution, and the results are very promising.

A Comparative Study of a Hybrid Experimental–Statistical Energy Analysis Model with Advanced Transfer Path Analysis for Analyzing Interior Noise of a Tiltrotor Aircraft

The excessive noise present within an aircraft cabin during flight operations constitutes a notable origin of fatigue, stress, and communication impediments for both pilots and passengers. Ensuring the comfort, well-being, and safety of passengers and crew members necessitates the accurate anticipation of noise levels. This study concerns the computation of structure-borne noise levels within the cabin of a tiltrotor aircraft. This investigation employed two distinct methodologies: advanced transfer path analysis (ATPA) and statistical energy analysis (SEA). To assess the results obtained with the ATPA approach, the acquired outcomes were compared with empirically measured sound pressure levels during airplane mode operations. The contributions of air-borne and structure-borne noises were calculated with the ATPA methodology. On the other hand, the structure-borne noise was calculated with a hybrid experimental–SEA model with ACTRAN software, and its results were compared with those of the ATPA method. The results show a good agreement between these methods at high frequencies, while at low frequencies, certain adjustments or modifications to the SEA model are necessary to predict the noise levels.

Dynamic Electromagnetic Scattering Simulation of Tilt-Rotor Aircraft in Multiple Modes.

To study the electromagnetic scattering of tilt-rotor aircraft during multi-mode continuous flight, a dynamic simulation approach is presented. A time-varying mesh method is established to characterize the dynamic rotation and tilting of tilt-rotor aircraft. Shooting and bouncing rays and the uniform theory of diffraction are used to calculate the multi-mode radar cross-section (RCS). And the scattering mechanisms of tilt-rotor aircraft are investigated by extracting the micro-Doppler and inverse synthetic aperture radar images. The results show that the dynamic RCS of tilt-rotor aircraft in helicopter and airplane mode exhibits obvious periodicity, and the transition mode leads to a strong specular reflection on the rotor's upper surface, which increases the RCS with a maximum increase of about 36 dB. The maximum micro-Doppler shift has functional relationships with flight time, tilt speed, and wave incident direction. By analyzing the change patterns of maximum shift, the real-time flight state and mode can be identified. There are some significant scattering sources on the body of tilt-rotor aircraft that are distributed in a planar or point-like manner, and the importance of different scattering sources varies in different flight modes. The pre-studies on the key scattering areas can provide effective help for the stealth design of the target.

OPPAV 천이 기동 영역의 틸트 프롭 공력 해석

The aerodynamic characteristics of a three-bladed prop were investigated along the tilt angle in the transition maneuver from hover to forward flight using computational fluid dynamics methodology. According to the change of the forward speed and the collective pitch angle at each tilt angle, it was confirmed that small changes in the two parameters had a linear relationship with the aerodynamic characteristics. Along the transition maneuver line, prop thrust continued to decrease, and torque showed a tendency to decrease initially and increase gradually. It was also confirmed that the hovering efficiency decreased but the propulsive efficiency increased as the forward speed was increased and the prop was changed from the rotorcraft mode to the airplane mode. It was found that the convection of the tip vortex and the wake showed asymmetry and inclination, and the surface pressure of the prop blade appeared asymmetrically due to the different aerodynamic environment by the inflow change except for the tilt angle of 0 degrees and 90 degrees. The aerodynamic characteristics of oscillating at 3/rev during one rotation of the prop was shown and The peak-to-peak value of the oscillating aerodynamic force was maximum at the tilt angle of 60 degrees.

An optimization for alleviating pilot workload during tilt rotor aircraft conversion and reconversion maneuvers

This work was focused on the conversion and reconversion maneuvers of XV-15 tilt rotor aircraft between helicopter and airplane modes. To alleviate pilot workload and improve safety, we proposed a multi-objective optimization method. Firstly, an augmented dynamics model has been developed and validated. Then, the transition maneuver was formulated as a proper optimization problem. The cost function consisted of several factors including transitional time, pilot workload, the power required, control allocation and pitch attitude. The constraints included not only the trajectory constraints and control rate limits, but also safety conditions of the conversion corridor and flight height. Finally, we analyzed the optimization results of two typical nacelle tilting schedules for both maneuvers using the wavelet analysis method to compare the pilot workload. Based on the results, in order to alleviate the pilot workload, it was recommended that during the conversion maneuver nacelles should initially tilt with much slower rate before aircraft reaches a certain forward speed at which the nacelle can tilt with normal rate. While during the reconversion maneuver nacelles were recommended to tilt under a normal rate. The nacelle tilting schedules in both maneuvers should be restricted inside the conversion corridors. As a result, the presented optimization method could identify the pros and cons between the two typical nacelle tilting schedules successfully. The obtained results could be used to provide a better reference for pilots and automatic conversion control systems.

Aerodynamic Interference on Trim Characteristics of Quad-Tiltrotor Aircraft

The aerodynamic interference between the different components of quad-tiltrotor (QTR) aircraft were considered to analyze its influence on trim characteristics. A comprehensive method with the fixed-wake model was developed for multiple aerodynamic interactions, improving the accuracy of the flight dynamics analysis. Additionally, a more general control strategy was developed to tackle the redundant control issue of the QTR, improving its control efficiency by coordinating the authority relationship of various control surfaces across the flight range. Then, the trim features were calculated in the helicopter mode, conversion mode, and airplane mode, and the relevant results with and without interaction were compared. The results show that the aerodynamic interaction mainly influences the body’s vertical force, longitudinal force, and pitching moment. Furthermore, there are significant differences between collective and longitudinal sticks and pitch attitudes. The interference plays a major role in helicopter and conversion modes with a less-than-30-degree tilt angle.

Aerodynamic interaction between tandem overlapping propellers in eVTOL airplane mode flight condition

The architecture of new electric aircraft concepts (eVTOLs) for urban air mobility is typically characterised by multi-propellers in tandem configurations with different degrees of rotor disks overlapping. Consequently, the aerodynamic interaction between front propellers slipstream and rear propellers represents one of the key-phenomena which influenced the performance and design of these novel aircraft configurations. A wind tunnel campaign was performed to investigate the aerodynamic interaction between two propellers in tandem with particular focus to airplane mode flight condition of eVTOLs. A systematic series of tests, including thrust and torque measurements and stereoscopic Particle Image Velocimetry (PIV) surveys, were performed on two co-rotating propellers models. The axial distance was fixed during tests while the lateral separation distance was changed to evaluate the effects of aerodynamic interaction on propellers performance and flow field due to different propeller disks overlapping. Load measurements pointed out a remarkable loss of rear propeller thrust occurring when the degree of overlapping between rotors disks is increased. On the other hand, spectral analysis of measured loads signals showed a higher amount of thrust fluctuations amplitude occurring when the degree of overlapping between propeller disks is partial. Stereo PIV results provided insights on the effects of aerodynamic interaction on rear propeller inflow and wake flow physics. Moreover, numerical simulations performed using a mid-fidelity aerodynamic solver based on vortex particle method (VPM) provided enhanced insights to comprehend the interacting flow mechanisms between front propeller slipstream and rear propeller blades responsible for the detrimental effects observed on rear propeller performance.

The potential impact of adverse aircraft-pilot couplings on the safety of tilt-rotor operations

AbstractThis paper addresses the potential impact of adverse aircraft-pilot couplings on tiltrotor safety, when a pilot or autopilot attempts to constrain flight dynamics with strong control. The work builds on previously published research on the theory and application of constrained flight to fixed- and rotary-wing aircraft. Tiltrotor aircraft feature characteristics from both types of aircraft and how these determine behaviour in a unique manner is investigated using a FLIGHTLAB simulation model of the XV-15 aircraft. Two different scenarios are explored in detail, using linearised models that reflect the flight-physics of stability for small deviations from trim. First, the control of vertical flight path with longitudinal cyclic pitch and elevator, and the consequences for the stability of the aircraft surge mode and short-period pitch-heave mode. The classical surge-mode instability for flight at speeds below minimum power is shown to apply to the tiltrotor in helicopter mode but alleviated in conversion and airplane modes. The impact on the short–period mode is seen to be a trade-off between the stabilising pitch attitude and destabilising incidence (angle-of-attack) contributions to the flight-path angle. The second example concerns strong control of roll attitude in the presence of adverse aileron-yaw. Here, the yaw-sway motion can be driven unstable, a problem encountered on fixed-wing aircraft with weak weathercock stability, but rare in the rotorcraft world. For both examples, the loss of stability is expressed as the change in sign of effective damping or stiffness stability derivatives. The explanatory theory for these non-oscillatory or low-frequency aircraft-pilot couplings is presented, along with interpretations in terms of handling qualities criteria. The paper also addresses the question of how to translate the findings into a form of aeronautical knowledge useful for the pilot training community.

Tilt-rotor aircraft fuselage wall aeroacoustics radiation suppression using Higher harmonic control

Aeroacoustics radiation is one of the main sources of tilt-rotor aircraft interior noise. In order to reduce the noise radiation on the surface of tilt-rotor aircraft fuselage, an active rotor control technology based on Higher Harmonic Control (HHC) is proposed. Its control effect is verified by simulation and the control mechanism is studied at the same time. Firstly, a tilt-rotor aeroacoustics prediction model is established based on FW-H equation and Beddoes unsteady aerodynamic model. And the accuracy of the above model is verified according to the flight test data of the XV-15 tilt-rotor aircraft. Furthermore, taking XV-15 as the object, a simulation research of rotor aeroacoustics active control is carried out in both airplane mode and helicopter mode. The simulation research reveals that: the HHC can suppress the aeroacoustics radiation of tilt-rotor to the fuselage through the principle of sound pressure cancellation. By applying appropriate control inputs, the maximum aeroacoustics radiation can be reduced by 9.2 dB in airplane mode; and the maximum aeroacoustics radiation can be reduced by 13.5 dB in helicopter mode.

Experimental Study of the Aerodynamic Interaction between Side-by-Side Propellers in eVTOL Airplane Mode through Stereoscopic Particle Image Velocimetry

Side-by-side propellers characterise the architecture of most new electric aircraft (eVTOLs) designed in recent years for urban air mobility. The aerodynamic interaction between side-by-side propellers represents one of the key phenomena that characterise the flow field and performance of these novel aircraft configurations. The present article describes the main results of a wind tunnel campaign that aimed to investigate the flow features that characterise this aerodynamic interaction, with a particular application to cruise flight conditions in eVTOLs. With this aim, stereo particle image velocimetry (PIV) measurements were performed in the wake of two co-rotating propeller models in a side-by-side configuration. The three-dimensional flow surveys provided detailed insights into the flow physics of the interacting propellers, with a particular focus on the interactional effects on the trajectory of the tip vortices and the wake topology provided at two different advance ratios by reproducing a moderate and a fast cruise speed of eVTOLs in urban areas.

The Investigation onL1Adaptive Control of the Tilt-Rotor Aircraft

Considering the uncertainty of the flight dynamics model of the tilt-rotor aircraft in different flight modes, anL1adaptive controller for full flight modes control system of tilt-rotor aircraft is designed. Taking advantage of the separation of robustness and adaptive design of theL1adaptive controller, adaptive gain, and low-pass filter are designed to achieve the desired control performance and meet the requirements of flight quality. The simulations of XV-15 tilt-rotor aircraft in helicopter mode and airplane mode are carried out. Then, the simulation of conversion mode is further carried out. The results show that the tilt-rotor aircraft can track the reference signal well under theL1control system. In addition, the changes of states as well as controls in conversion mode flight are quite smooth which is very meaningful for engineering application.

Structural Coupling and Whirl-Flutter Stability with Pilot-in-the-Loop

This paper investigates structural coupling problems for tiltrotors, considering not only the interaction of the flight control system with the flexible structure but also the potentially adverse effects on the aeroservoelastic stability that may be caused by the pilot's involuntary, high-frequency, biodynamic response. The investigation is focused on the analysis of the side effects that could appear at high speed in the airplane flight regime, where the whirl flutter boundaries may be significantly reduced. A detailed tiltrotor model, representative of the Bell XV-15 and of a flight control system has been built and joined with a pilot biodynamic model acting on the power-lever and on the center stick, available in the literature. Additionally, a modified version of the XV-15 using differential collective pitch for yaw control in airplane mode instead of rudder has been investigated to show the effect of different yaw control designs. The stability analyses presented demonstrate that the structural coupling analysis and the flutter boundaries for tiltrotors must be evaluated not only considering the closed loop created by the flight control system but also the effect of involuntary pilot response. Sensitivity analyses examine the most critical parameters impacting tiltrotor aeroservoelastic stability. Finally, the employment of notch filters as a means of prevention is discussed.

Local nonlinear stores induce global modal interactions in the steady-state dynamics of a model airplane

Local nonlinear attachments can affect the global dynamics of their linear host structures through modal interactions. This was shown previously in experimental and computational studies of a model airplane with local nonlinear attachments at its wings, under impulsive forcing. Here we study nonlinear modal interactions in the model airplane subject to harmonic excitation. We consider the case of both attachments locked (L-L – baseline linear system), and compare it to two nonlinear cases, i.e., left-wing attachment unlocked (U-L), and both attachments unlocked (U-U). Nonlinear output response functions are used to study the nonlinear modal interactions due to the local attachments in the frequency domain; these are detected only in a certain frequency band. Proper orthogonal decomposition, in conjunction with a weighted modal assurance criterion, are used to quantify these modal interactions. At some frequency bands the nonlinearities facilitate energy transfer to non-resonant airplane modes, despite being widely separated in frequency from resonant modes. Our findings apply to general linear systems with local nonlinear attachments.

PID vs LQR controller for tilt rotor airplane

The main thematic of this paper is controlling the main manoeuvers of a tilt rotor UAV airplane in several modes such as vertical takeoff and landing, longitudinal translation and the most important phase which deal with the transition from the helicopter mode to the airplane mode and visversa based on a new actuators combination technique for specially the yaw motion with not referring to rotor speed control strategy which is used in controlling the attitude of a huge number of vehicles nowadays. This new actuator combination is inspired from that the transient response of a trirotor using tilting motion dynamics provides a faster response than using rotor speed dynamics. In the literature, a lot of control technics are used for stabilizing and guarantee the necessary manoeuvers for executing such task, a multiple Attitude and Altitude PID controllers were chosen for a simple linear model of our tilt rotor airplane in order to fulfill the desired trajectory, for reasons of complexity of our model the multiple PID controller doesnt take into consideration all the coupling that exists between the degrees of freedom in our model, so an LQR controller is adopted for more feasible solution of complex manoeuvering, the both controllers need linearization of the model for an easy implementation.

Recent Advances in Ad-Hoc Social Networking: Key Techniques and Future Research Directions

Ad-hoc Social Networks are formed by groups of nodes, designating a similarity of interests. The network establishes a two-layer hierarchical structure that comprises communication within-group and joining with other groups. This paper presents survey and future directions in four areas of establishing ad-hoc social network using mobile ad-hoc social network (MANET) that includes architecture or implementation features, Profile Management of users, Similarity Metric, and Routing Protocols. The survey presents the need to provide social applications over MANET, optimizing profile matching algorithms of users, and context aware routing protocols. Future directions include multi-hop social network applications that can be useful for users even in airplane mode and notifying over MANET when a user of profile with similar interest is nearby.

Labor/leisure decisions in their natural context: The case of the smartphone

In this research, we attempt to understand a common real-life labor/leisure decision, i.e., to perform cognitive work or to interact with one’s smartphone. In an ecologically valid experiment, participants (N = 112) could freely switch back and forth between doing a 2-back task and interacting with their own smartphone. We manipulated the value of the 2-back task (by varying the value of monetary rewards; within-subjects) and of the smartphone (by switching on and off airplane mode; within-subjects) while we recorded incoming notifications, such as text messages. Our study produced three main findings: (1) the current value of the smartphone did not increase our statistical model’s ability to predict switches from labor to leisure when the current task value was also taken into account; (2) however, participants reacted strongly to naturally incoming notifications, which were the strongest predictor of labor-to-leisure switches; (3) there was no evidence that taking into account individual differences (in the value assigned to labor and leisure) improved the model’s ability to predict labor-leisure switches. In sum, using a situated approach to studying labor/leisure decisions, our findings highlight the importance of high task motivation, as well as the temporary distractive potential of smartphone notifications, when people face the challenge of staying focused on their productive tasks.

Conceptual Sizing of Vertical Lift Package Delivery Platforms

Conceptual sizing and performance estimation of four vertical takeoff and landing (VTOL) configurations for a package delivery mission is presented in this Paper. The multifidelity VTOL design framework HYDRA is used to size a notional quadrotor, hexarotor, quadrotor biplane tailsitter (QBiT), and a lift-augmented tricopter for weight classes of 10, 15, 20, and 25 kg. Sizing is performed using a combination of physics-based empty weight models for the airframe, rotor blades, and wings, along with statistical models for predicting motor and battery weights. A gradient-based optimization methodology was implemented to identify the best designs for each configuration under each weight class. An optimization-based longitudinal trim methodology was used to identify the appropriate shaft power settings for each vehicle at various trimmed flight conditions along the mission profile. Representative payload delivery and return scenarios were constructed from different cruise speeds and ranges to identity a vehicle design in each configuration that can complete the highest number of payload drop missions successfully. The hexarotor performed better than the quadrotor in terms of requiring lower installed power and deliver heavier payload packages for a given radius of action. Wing-borne designs such as the QBiT and tricopter are capable of delivering packages in a short time owing to full/partial conversion to airplane mode during cruise flight but may require careful fine-tuning of the trimline and flight control system to successfully transition between hover and cruise flight modes.

Extended state observer based smooth switching control for tilt-rotor aircraft

A tilt-rotor aircraft has three flight modes: helicopter mode, airplane mode and conversion mode. Unlike the traditional aircraft, the tilt-rotor aircraft, which combines the characteristics of helicopters and fixed-wing aircraft, is a complex multi-body system with the violent variation of the aerodynamic parameters. For these characteristics, a new smooth switching control scheme is provided for the tilt-rotor aircraft. First, the reference commands for airspeed and nacelle angles are calculated by analyzing the conversion corridor and the conversion path. Subsequently, based on the finite-time switching theorem, an average dwell time condition is designed to guarantee the stability in the switching process. Besides, considering the state vibrations and bumps may appear in switching points, the fuzzy weighted logic is employed to improve the system transient performance. For disturbance rejection, three extended state observers are designed separately to estimate the disturbances in the switched systems. Compared with the traditional auto disturbance rejection control and proportion integration differentiation control, this method overcomes the conservatism of wasting the whole model information. The control performances of robustness and smoothness are verified with simulation, which shows that the new smooth switching control scheme is more targeted and superior than the traditional design method.

Six degrees of freedom flight simulation of tilt-rotor aircraft with nacelle conversion

This paper presents six degrees of freedom flight simulation with mode conversion between airplane mode and helicopter mode as an application for realizing Digital Flight of the tiltrotor aircraft. The tiltrotor aircraft has the characteristics of both helicopters and propeller planes with changing the flight mode by tilting the engine nacelles. However, much less work with continuously changing these modes has been done so far. In this paper, the main components such as rotors, engine nacelles, fixed wings and a fuselage are considered. In order to perform large deformations of mesh geometry such as the rotation of the rotor and nacelle as well as the change of the position and attitude of the aircraft, the computational domain is decomposed into multiple domains corresponding to each component. Independently moving these domains makes possible to perform the characteristic behavior of a tiltrotor aircraft. To deal with rotations of multiple decomposed domains, the multi-axis sliding mesh approach is applied. As the solver for simulating unsteady flow driven by complicated moving boundaries, the unstructured Moving-Grid Finite-Volume method is adopted. Based on this solver, the Moving Computational Domain method enables the aircraft to fly in any size of region without restriction of mesh size. The airframe is treated as a rigid body, and the coupled simulations considering interaction with surrounding fluid of the aircraft are demonstrated. The result shows complicated fluid phenomena around the tiltrotor aircraft that occur when it flies with mode change.