Airplane Takeoff Research Articles

Control of Floating Body Waves Due to an Airplane Takeoff from a Very Large Floating Airport

Control of Floating Body Waves Due to an Airplane Takeoff from a Very Large Floating Airport

Computational Mechanics for Turbofan Engine Blade Containment Testing: Fan Case Design and Blade Impact Dynamics by Finite Element Simulations

The harsh environment during airplane take-off and flights with complex operating conditions require a high dynamic and impact resistance capability of airplane engines. The design, development, and performance evaluation of new turbofan engines are generally performed through numerical simulations before a full-scale model or prototype experiment for certification. Simulations of fan blade containment tests can reduce trial–error testing and are currently the most convenient and inexpensive alternative for design; however, certification failure is always a risk if the calibration of material models is not correctly applied. This work presents a three-dimensional computational model of a turbofan for designing new engines that meet the certification requirements under the blade containment test. Two calibrated Johnson–Cook plasticity and damage laws for Ti64 are assessed in a simulation of a turbofan blade containment test, demonstrating the ability of the models to be used in the safe design of aircraft engine components subjected to dynamic impact loads with large deformations and adequate damage tolerance.

Application of GNSS/INS and an Optical Sensor for Determining Airplane Takeoff and Landing Performance on a Grassy Airfield.

The performance of a PZL 104 Wilga 35A airplane was determined and analyzed in this work. Takeoff and landing distances were determined by means of two different methods: one which utilized a Global Navigation Satellite System/Inertial Navigation System (GNSS/INS) sensor and another in which airplane ground speed was measured with the use of an optical non-contact sensor. Based on the airfield measurements, takeoff and landing distances as well as rolling resistance coefficients were determined for the used airplane on a grassy runway at the Radawiec airfield, located near Lublin, southeast Poland. The study was part of the “GARFIELD” project that is expected to deliver an online information system on grassy airfield conditions. It was concluded that both sensors were suitable for the aimed research. The results obtained in this study showed the effects of high grass upon the takeoff and landing performances of the test airplane. Also, the two methods were compared against each other, and the final results were compared to calculations of ground distances by means of the chosen analytical models.

Effect of Paving Runway and Atmospheric Conditions on Airplane Takeoff Distance and Time

Effect of Paving Runway and Atmospheric Conditions on Airplane Takeoff Distance and Time

Effects of Atmospheric Refraction on an Airborne Weather Radar Detection and Correction Method

This study investigates the effect of atmospheric refraction, affected by temperature, atmospheric pressure, and humidity, on airborne weather radar beam paths. Using three types of typical atmospheric background sounding data, we established a simulation model for an actual transmission path and a fitted correction path of an airborne weather radar beam during airplane take-offs and landings based on initial flight parameters and X-band airborne phased-array weather radar parameters. Errors in an ideal electromagnetic beam propagation path are much greater than those of a fitted path when atmospheric refraction is not considered. The rates of change in the atmospheric refraction index differ with weather conditions and the radar detection angles differ during airplane take-off and landing. Therefore, the airborne radar detection path must be revised in real time according to the specific sounding data and flight parameters. However, an error analysis indicates that a direct linear-fitting method produces significant errors in a negatively refractive atmosphere; a piecewise-fitting method can be adopted to revise the paths according to the actual atmospheric structure. This study provides researchers and practitioners in the aeronautics and astronautics field with updated information regarding the effect of atmospheric refraction on airborne weather radar detection and correction methods.

Direct Time Domain Numerical Analysis of Transient Behavior of a VLFS during Unsteady External Loads in Wave Condition

The transient response of the VLFS subjected to arbitrary external load is systematically investigated by a direct time domain modal expansion method, in which the BEM solutions based on time domain Kelvin sources are used for hydrodynamic forces. In the analysis, the time domain free-surface Green functions with sufficient accuracy are rapidly evaluated in finite water depth by the interpolation-tabulation method, and the boundary integral equation with a quarter VLFS model is established taking advantage of symmetry of flow field and structure. The validity of the present method is verified by comparing with the time histories of vertical displacements of the VLFS during a mass drop and airplane landing and takeoff in still water conditions, respectively. Then the developed numerical scheme is used in wave conditions to study the combined action taking into account the mass drop/airplane landing/takeoff loads as well as incident wave action. It is found that the elevation of structural waves due to mass drop load can be significantly changed near the impact region, while the vertical motion of runway in wave conditions is dominant as compared with that only generated by airplane.

Tactile stimulation can suppress visual perception

An input (e.g., airplane takeoff sound) to a sensory modality can suppress the percept of another input (e.g., talking voices of neighbors) of the same modality. This perceptual suppression effect is evidence that neural responses to different inputs closely interact with each other in the brain. While recent studies suggest that close interactions also occur across sensory modalities, crossmodal perceptual suppression effect has not yet been reported. Here, we demonstrate that tactile stimulation can suppress the percept of visual stimuli: Visual orientation discrimination performance was degraded when a tactile vibration was applied to the observer's index finger of hands. We also demonstrated that this tactile suppression effect on visual perception occurred primarily when the tactile and visual information were spatially and temporally consistent. The current findings would indicate that neural signals could closely and directly interact with each other, sufficient to induce the perceptual suppression effect, even across sensory modalities.

Optimal aircraft take-off with thrust vectoring

AbstractThe short take-off capability is of paramount importance for a fighter airplane to enable its operation from short and damaged runways. This paper analyses the airplane take-off process from the viewpoint of reducing the ground roll/take-off distance with the use of thrust vectoring. The airplane take-off is modelled incorporating the ground reactions on the landing gear and the thrust vector forces and moments. The take-off problem is formulated as an optimal control problem with appropriate constraints. Though many researchers have applied optimal control techniques for designing airplane manoeuvres, its application to the airplane take-off problem is rarely available in the open literature. It is expedient to use such methodology to understand the use of thrust vectoring features of an aircraft to maximise the benefits in shortening the ground roll/take-off distance. An optimal control methodology has been applied in this paper with the objectives stated above to a twin-engine fighter nonlinear aircraft model popularly known as F-18/HARV. Computation of flight path and control schedules using optimal control has been carried out with and without the use of vector nozzles. A reduction of about 6% in take-off distance and about 29% in ground roll distance is obtained with the use of thrust vector for the configuration studied.

A Optimized Model for Runway Takeoff Scheduling

Runway operations planning as the main runway operation tactical planning tool, its performance affects a variety of operational activites safety and efficiency of airport and terminal area. In order to reduce the take-off delay, this paper proposed a runway scheduling model based on multi-objective for airplane takeoff scheduling optimization. The experiment shows that compared with the algorithm of first come first serve, the new model has better runway throughout, less delay and less cost.

Smart Runways-Use of Residual Vibration Energy from Air Wake to Produce Electricity

The importance of aviation industry in modern era is long familiar. The industrial sector has been suffering energy crises from decades and consequently paves way for the need of energy regeneration and utility. Runways are heart of an airport and currently runways are used as pathways for airplane takeoff and landing. The proposed idea emphasizes use of residual mechanical vibrational energy from aircraft during takeoff and landing. Air Wakes are huge source of vibrational energy and these vibrations are harnessed using energy regenerative engineering technology. The lifting aircraft produces turbulent air wakes, which strike light weight swinging elliptical dish plates along sides of the runway. These are made to vibrate continuously and impact the piezoelectric media which consequently produces electric potential. Varieties of efficient piezoelectric harnessers are being developed using different vibration analysis and many have embarked upon the idea. But this paper is unparallel to those in many ways.

Flow Control Techniques for Transport Aircraft

A set of flow control approaches have been recently investigated for improved aerodynamic performance in a range of transport aircraft applications. Active flow control concepts are employed for improving airplane takeoff and landing performance, reducing operational hazards during airplane ground maneuvering, and alleviating trailing wakes for higher air traffic efficiency. Computational fluid dynamics has been used to gain insight into complex flows subject to various modes of actuation and to develop promising techniques of flow control. The use of numerical simulations is especially important in scenarios involving powered systems, intricate vortex structures, separated flows, and active flow control devices, for which alternative testing is extremely expensive and often impractical. This study represents an essential element in The Boeing Company's approach to development of flight- worthy integrated active flow control systems.

Motion Drive Algorithm for Flight Simulator Based on the Stewart Platform Kinematics

To improve the fidelity of the motion cueing in the flight simulator, an improved adaptive motion drive algorithm was presented. In this algorithm, the motion limits of single degree of freedom, which calculate according to the Stewart platform kinematics, was introduced in to reduce the possibility of actuators exceeding theirs motion limits. So the algorithm parameters can be tuned more “open up” to improve the fidelity of motion cueing. The improved motion drive algorithm was verified in the airplane takeoff and landing. The results show that the algorithm can improve the fidelity when the platform has more available motion space; and can avoid exceeding motion limits when the platform has small motion space.

Three-Dimensional Time-Domain Analysis of Very Large Floating Structures Subjected to Unsteady External Loading

The strong interest in very large floating structure (VLFS) is a result of a need to utilize effectively the ocean space for transportation, industrial use, storage, habitats, and military bases, among others. The VLFS has great width and length and relatively small flexural rigidity, therefore, investigation of its hydroelastic behavior including fluid-structure interaction is of greater importance than studies of its motion as rigid bodies. In addition to the most important wave-induced responses, the operation of the VLFS also requires determination of its dynamic responses with respect to the effect of unsteady external loading due to intense traffic, load movement, takeoffs and landings of airplanes, missile takeoffs, etc. Therefore, the transient responses of a VLFS to impulsive and moving loads must be studied by a reliable calculation method. In this study, a finite element procedure developed directly in time domain for solution of transient dynamic response of the coupled system consists of a VLFS and a fluid domain subjected to arbitrary time-dependent external loads is presented. The hydrodynamic problem is formulated based on linear, inviscid, and slightly compressible fluid theory and the structural response is analyzed under the thin plate assumption. For numerical calculations, a scaled model of the Mega-Float is exemplified. Three tests—weight pull-up test, weight drop test, and weight moving test which idealize the airplane landing and takeoff—are carried out and compared with published experimental data. The overall agreement was favorable which indicates the validation of the present method.

Computation of pollutant dispersion during an airplane take-off

The fact that airports contribute to the downgrading of the air quality of the nearby cities arouses the interest of examining the planes’ emissions and dispersion in detail. Hence this study focuses on a single take-off and investigates the pollutant dispersion of two different airplane types, for various wind directions each. Calculations are performed with ADREA-HF, a 3D unsteady Reynolds Averaged Navier-Stokes (RANS) computational fluid dynamics code using a one-equation turbulence closure model. Moving plane source is considered as a series of jets emitting the one after the other. Concentration levels are presented through time and space and different cases’ results are compared and discussed. The main objective of this work was to identify the high concentration areas throughout the take-off, in order to help in determining the best positioning for remote optical pollutant measurement instruments. Modelling reveals interesting plume propagation as the airplane moves, with a characteristic blister near the brake release point. The latter is proven to be the best place to have measurements, regardless of wind speed and direction.

Transient responses of a VLFS during landing and take-off of an airplane

The transient elastic deformation of a pontoon-type very large floating structure (VLFS) caused by the landing and take-off of an airplane is computed by the time-domain mode-expansion method. The memory effects in hydrodynamic forces are taken into account, and great care is paid to numerical accuracy in evaluating all the coefficients appearing in the simultaneous differential equations for the elastic motion of a VLFS. The time-histories of the imparted force and the position and velocity of an airplane during landing and take-off are modeled with data from a Boeing 747-400 jumbo jet. Simulation results are shown of 3-D structural waves on a VLFS and the associated unsteady drag force on an airplane, which is of engineering importance, particularly during take-off. The results for landing show that the airplane moves faster than the structural waves generated in the early stage, and the waves overtake the airplane as its speed decreases to zero. The results for take-off are essentially the same as those for landing, except that the structural waves develop slowly in the early stage, and no obstacle exists on the runway after the take-off of airplane. The additional drag force on an airplane due to the elastic responses of the runway considered in this work was found to be small in magnitude.

Monitoring airplane takeoff performance - Prototype instrument with learning capability

An instrument has been developed that gives easily interpreted real-time quantification of aircraft groundroll takeoff performance. The instrument has the capability of evaluating and remembering (i.e., learning) nominal takeoff performance and does not depend on Pilot Operating Handbook values. The analytical model used to predict the expected aircraft acceleration and distances uses input values for field elevation; pressure; temperature; runway direction, slope, and friction condition; wind direction and magnitude; aircraft gross weight; reference airspeed; and power or thrust setting. The instrument requires no interface with aircraft systems except electric power. The actual parameter that is measured is the longitudinal axis acceleration. The real-time takeoff performance quantification is displayed to the pilot in two forms: 1) an acceleration ratio displayed on a screen as a continuous time-line function and 2) a digital display of pertinent ground-roll distances. These displays would appear in a panel instrument similar in size to current stormscopes and/or incorporated in a heads-up display. The takeoff performance is available to the crew as soon as the takeoff power is set. By utilizing this information the pilot is aided in making critical NO-GO decisions early in the takeoff roll when a rejected takeoff can be safely accomplished from low speed.

Takeoff performance monitoring system display options

This article summarizes the development of head-up and head-down cockpit displays for an airplane takeoff performance monitoring system (TOPMS). Basic TOPMS displays provide pilots with real-time graphic information concerning their airplane's current and projected runway performance. The displays also indicate the status of associated airplane systems (e.g., flaps, engines) and optionally, they provide advice and a continually updated prediction of where the airplane can be braked to a stop. The displays have been developed and evaluated on the NASA Transport System Research Vehicle (TSRV) B-737 simulator by more than 40 government, airline, and industry pilots who rated the displays favorably and judged them easy to monitor. The TOPMS has also been flight tested successfully on the TSRV B-737. Based on these evaluations and on discussions with the commercial aircraft community, the displays have evolved to a baseline final configuration containing basic performance and system-status data to which GO/NO-GO advisory and predicted stop point information can be added as options.

Rapid sizing method for airplanes

A method for rapidly determining airplane takeoff weight, empty weight, and mission fuel weight for a given mission specification is presented. The method applies to a wide range of airplane types and relies on statistical relations between empty weight and takeoff weight of production airplanes. The method can also be used to predict the sensitivity of takeoff weight with respect to changes in the mission specifications as well as to changes in airplane lift-to-drag ratio, specific fuel consumption, and/or propeller efficiency.

Kneeling landing gear

THE BASIC MILITARY NEED for the C‐5 relates to the ‘Remote Presence’ concept involving rapid deployment of troops and all heavy equipment to any remote location thereby allowing for minimised standing army and equipment requirements. This ‘Remote Presence’ concept requires that a 300 ton airplane land and takeoff from an unsurfaced field. This takes a very special sort of landing gear. The C‐5 has been designed to land, unload and load, and take off from a strip similar to a dry football field without any damage to the gear or aircraft.

Airplane Take-off and Landing Paths

The problem of tracking airplanes in the approach zone of a major airport was solved using ordinary cameras, descriptive geometry, and vector computations. Mean errors in elevation were about ±15 ft, and in plan about ±100 ft when the airplanes were within about 5,000 ft of the end of the runway. The methods are explained in detail using a room-sized analog to the actual field situation. The vectorial methods are programmed as for routine computations.