Different Phases Of Flight Research Articles

Study of EGNOS safety of life service during the period of solar maximum activity

ABSTRACT The Satellite Base Augmentation System (SBAS) - EGNOS (European Geostationary Navigation Overlay Service) has been certified for Safety of Life (SoL) service for aircraft navigation since 2nd of March 2011. Unfortunately for the territory of Poland, located at the edge of EGNOS service area, the quality of the service corrections are still not sufficient for aircraft navigation requirements. Years 2012 and 2013 are forecasted as a maximum of solar activity in a 11-year solar cycle. This time period will be the chance to perform the first tests for the EGNOS Safety of Life service quality in disturbed ionospheric conditions. During the previous maximum of solar activity, the storm on 30 October 2003 resulted in the inability to use WAAS corrections for more than 12 hours. This was caused by a very large gradient of disturbances and its’ very sharp boundaries - vertical TEC (VTEC) varied from ~ 40 to ~ 120 TECU (TEC units) within an hour (over ~ 150 km distance). These circumstances gave the opportunity to carry out the test flights to examine the navigation parameters obtained for EGNOS SoL service in disturbed ionospheric conditions. The paper presents project proposal of study and analyses of such fundamental navigation parameters as: accuracy of determined position, availability, continuity and integrity, determined for selected disturbances in relation to quiet conditions. It can give a possibility to estimate of the quality of EGNOS SoL service in Polish airspace during the different phases of flight and its resistance to critical ionospheric conditions.

Power Harvesting Capabilities of SHM Ultrasonic Sensors

The aim of this work is to show that classical Structural Health Monitoring ultrasonic sensors may provide some power harvesting capabilities from a wide variety of vibration sources. In other words, the authors developed an integrated piezoelectric energy harvesting sensor capable of operating a dual mode, that is, carrying out vibration power harvesting and Structural Health Monitoring. First, vibrations signals of an A380 aircraft recorded during different phases of flight are presented to show the need of a wideband piezoelectric energy harvester. Then, the voltage response of a piezoelectric power harvester bonded onto an aluminium cantilever plate and excited by an electromechanical shaker is measured. A finite element model of the energy harvester system is also presented. This model provides the voltage response of the harvester due to a mechanical excitation of the host structure and allows a better understanding of the energy harvesting process. In many cases, a good agreement with the experimental results is obtained. A power measurement also showed the ability of piezoelectric SHM sensors to harvest power over an extended frequency range present in spectra collected in aircrafts. This result could lead to numerous applications even though this kind of power harvester sensor has been initially designed to operate onboard aircrafts.

Meteorological influences on the design of advanced aircraft approach procedures for reduced environmental impacts

There is increasing interest in the development of aircraft operating procedures that reduce the environmental impacts of commercial aviation through minimization of fuel burn, emissions and noise impacts. Meteorological factors can have a major influence on the behaviour of aircraft in different phases of flight, thus they must be carefully considered in the development of any new procedures. In this paper the most important of these factors are considered (wind profiles and local pressure variations) within the context of development of advanced approach procedures at a major UK airport. Models of the wind characteristics were developed for the region around the airport using data collected from the Natural Environment Research Council Mesosphere-Stratosphere-Troposphere Radar at Aberystwyth and surface wind measurements made at the airport, while an analysis of local pressure effects was based on readings taken at the airport. These models were used in a Monte Carlo flight simulator to determine the suitability of different approach procedure designs in terms of flight and environmental performance. Flight tests of the final procedure design were conducted at the airport with a variety of commercial aircraft. These demonstrated the suitability of the procedures (and hence validated the modelling strategies used) and that significant environmental benefits in terms of reduced noise, fuel burn and emissions were achieved compared to existing procedures. Copyright © 2010 Royal Meteorological Society

Investigation on the flight characteristics of a conceptual fluidic thrust-vectored aerial tail-sitter

The feasibility of integrating co-flow fluidic thrust-vectoring idea into the dynamics of a small flapless aerial tail-sitter is investigated in this article. The aircraft trimmability in different phases of flight and stability in take-off and level flight, are the main issues of concern for the study presented herein. In this respect, the vehicle's characteristic equations are derived by linearization of the general non-linear equations of motion. Since the vehicle was supposed to be merely controlled by fluidic thrust-vectoring, the concept was novel and some new derivatives are introduced. Margins of the required thrust-vector angle, to obtain a steady-state flight condition, are provided by use of the trim analysis. In addition, stability in take-off transition and level flight is considered utilizing the values of the system poles. Non-linear simulation is developed to examine the aircraft responses to the command inputs and to generate the aircraft trajectory. It is found that the integrated fluidic thrust-vectoring system can be employed as a viable means to achieve both conventional and transition flight for the proposed vehicle. The obtained mathematical model reveals the dependence of the aircraft performance and design criteria on the presented method. This model will be used for further studies on the general aspects of flight dynamics and control systems design for such vehicle.

Structure and neural control of the pectoralis in pigeons: implications for flight mechanics.

The pectoralis muscle in pigeons (Columba livia) is composed of two heads (sternobrachialis, thoracobrachialis) that are separately innervated and have different fiber orientations. High-speed film and electromyographic studies of free-flying pigeons reveal that the pectoralis is activated prior to wing depression (the power stroke) and that its two heads are differentially recruited during takeoff, level flight, and landing. The electrical activity patterns of both heads support an interpretation that intramuscular elasticity provides energy storage. The pectoralis is not only the prime wing depressor but is also capable of adjusting the excursion of the wing during different phases of flight.

Doppler-shift compensation behavior of Pteronotus parnellii parnellii during avoidance of stationary and moving obstacles

The Doppler-shift compensation behavior of the CF-FM bats was studied by making three Pteronotus parnellii parnellii fly through an array of seven vertically strung nylon monofilament lines (1.0 mm in diameter) placed near the center of a flight room (12.4 m long, 2.5 m wide, and 2.0 m high). By means of an electric motor. the aluminum frame in which the lines were strung could be made to oscillate in the horizontal direction parallel to the alignment of the obstacles. The maximum amplitude of oscillation was 31 cm and the average speed was 10.3 cm/s. All three bats negotiated moving lines more successfully than stationary ones. The flight speed was about 2.0–2.8 m/s as a bat approached and passed the lines, but it was only about 0.5–0.7 m/s during the final phase of negotiation of lines. Analysis of the emitted signals indicated that each bat appropriately adjusted its emission frequency according to its flight speed during different phases of flight in order to accurately compensate the positive Doppler-shifted echoes. [Work supported by NSF BNS 80 07348 and USPH 1-KO4-NS00433-01.]

Noise levels measured within aircraft during conditions of takeoff, climb and low, and normal and high cruise

Most aircraft cockpits contain noise that may interfer with communications, result in auditory fatigue, and cause permanent noise-induced hearing loss. Also, noises that cause crewmembers to employ sustained loud vocal effort may contribute to increased general fatigue. The author has completed a study of noises encountered within various fixed- and rotary-wing aircraft during different phases of flight and this presentation summarizes the results. A-weighted levels are reported for 12 groups of aircraft during takeoff, climb and low, normal and high cruise. The aircraft groups are classified according to engine type and the manner of power-plant-to-vehicle mating used. Mean. variance, and standard deviation are reported for each group. Although the number of aircraft sampled within each category varied, the totals for each condition of flight are reasonably representative. For example, during conditions of normal cruise, 492 fixed-wing and 87 rotary-wing vehicles are reported and ambient mean A-levels ranged from 89.5 to 101.9 for fixed-wing aircraft and from 98.1 to 103.5 for rotary-wing vechicles.

Some navigational and air traffic control problems of civil aviation and the application of radio to their reduction

This, paper reviews certain Navigational and Air Traffic Control problems, and discusses the application of radio to them. The international background is mentioned, but details are left to other papers.The problems are considered under the different phases of flight in which they occur, and possible developments to meet them are outlined. These include consideration of the use of long-distance and short-distance radar surveillance in present Air Traffic Control Systems, and to developments needed in equipments and the techniques of use. Reference is made to current thinking on these problems in the United States.A general account is given of the requirements likely to arise from the introduction of turbine-engined aircraft into civil aviation.The particular problems of long- and short-distance routes over sparsely inhabited territories are considered and some factors mentioned relating to general international standardization on particular facilities.