Search results

The purpose of the paper is to analyze changes in the selected characteristics of an aircraft aided by a ground-based system using magnetic levitation (MAGLEV) to support safe take-off.

The analysis of the mass characteristics of the main aircraft units with conventional constructing solutions was carried out in this paper. It allowed determining the mass of these units and verifying the obtained results on the basis of the known examples. Thanks to such an approach it was possible to determine the mass of the aircraft modified for the requirements of the ground and on-board system for support of the aircraft safe take-off and landing (GABRIEL) system taking into account the change in the weights of the modified units (fuselage, wings, power unit, landing gear, etc.). The weight of the aircraft in its basic version was determined on the basis of the common knowledge and methods described in the scientific literature which are based on the statistical analysis. The weight of the modified units for the needs of the GABRIEL system was determined on the basis of similar formulas taking into account the constructional changes in the airframe. The thrust required of the power unit was determined on the basis of the analysis of the steady state of the horizontal flight for the calculating aerodynamic characteristics determined by conventional methods. The characteristics in the take-off phase were determined solving the equation of motion of the aircraft influenced by the aerodynamic, electrodynamic forces and the forces that come from the power unit.

The preliminary analysis shows that the take-off aid system that uses the phenomenon of MAGLEV is possible to be created using the present-day technology. However, the costs of its realization would make it economically unproved. But it could increase safety and reduce harmful influence on the environment caused by taking-off and landing aircrafts.

The analysis was carried out only for one chosen version of the solution which according to the author has the greatest chance to succeed. At the present-day state of the art, it seems problematic to use the proposed system to aid landing.

The work shows a practical possibility to implement the proposed solution. The results of the analyses are a separate point for further research of similar systems.

The work presents one of the aspects of the potential application of the innovatory conception of take-off and landing aid of transport aircrafts by the ground-based system using the MAGLEV technology.

THE subject I am to discuss deals with some aspects of aerodrome usability.

THE usual methods for obtaining data on the hydrodynamic characteristics of flying boats during flight tests involve motion pictures of an instrument panel and records of oscillograph traces. The analysis of the photographic records is so time consuming that the results are not always available when needed, and in many cases more data are accumulated than is physically possible to analyse. In order to conserve manpower and to obtain directly usable data, new methods have been developed for making quantitative hydrodynamic flight tests. The test techniques were devised to relate, whenever possible, numerical values to sensations experienced by the pilot of a flying boat during take‐off and landing.

This paper aims to present a control strategy that eliminates the longitudinal and lateral drifting movements of the coaxial ducted fan unmanned helicopter (UH) during autonomous take-off and landing and reduce the coupling characteristics between channels of the coaxial UH for its special model structure.

Unidirectional auxiliary surfaces (UAS) for terminal sliding mode controller (TSMC) are designed for the flight control system of the coaxial UH, and a hierarchical flight control strategy is proposed to improve the decoupling ability of the coaxial UH.

It is demonstrated that the proposed height control strategy can solve the longitudinal and lateral movements during autonomous take-off and landing phase. The proposed hierarchical controller can decouple vertical and heading coupling problem which exists in coaxial UH. Furthermore, the confronted UAS-TSMC method can guarantee finite-time convergence and meet the quick flight trim requirements during take-off and landing.

The designed flight control strategy has not implemented in real flight test yet, as all the tests are conducted in the numerical simulation and simulation with a hardware-in-the-loop (HIL) platform.

The designed flight control strategy can solve the common problem of coupling characteristics between channels for coaxial UH, and it has important theoretical basis and reference value for engineering application; the control strategy can meet the demands of engineering practice.

In consideration of the TSMC approach, which can increase the convergence speed of the system state effectively, and the high level of response speed requirements to UH flight trim, the UAS-TSMC method is first applied to the coaxial ducted fan UH flight control. The proposed control strategy is implemented on the UH flight control system, and the HIL simulation clearly demonstrates that a much better performance could be achieved.

IN connexion with the development of the modern transport aeroplane it is of growing importance to pay proper attention to the take‐off characteristics of these aeroplanes and to consider the means suitable to improve them. For the realization of economically justified air transport two trends have been indicated; both having an unfavourable effect on take‐off performance. These trends are:

This paper aims to introduce the take-off and landing performance analysis modules of the software library named Java toolchain of Programs for Aircraft Design (JPAD), dedicated to the aircraft preliminary design. An overview of JPAD is also presented.

The calculation of the take-off and landing distances has been implemented using a simulation-based approach. This expects to solve an appropriate set of ordinary differential equations, which describes the aircraft equations of motion during all the take-off and landing phases. Tests upon two aircraft models (ATR72 and B747-100B) have been performed to compare the obtained output with the performance data retrieved from the related flight manuals.

The tool developed has proven to be very reliable and versatile, as it performs the calculation of the required performance with almost no computational effort and with a good accuracy, providing a less than the 5 per cent difference with respect to the statistical trend and a difference from the flight manual or public brochure data around 10 per cent.

The use of a simulation-based approach to have a more accurate estimation of the ground performance with respect to classic semi-empirical equations. Although performing the simulation of the aircraft motion, the approach shown is very time-saving and can be easily implemented in an optimization cycle.

A simple chart is presented for the rapid evaluation of either unstick or landing roll distance. The method is incomplete in that it docs not deal with the airborne phase of take‐off and landing manoeuvres; it is necessary to estimate this part separately. The chart is strictly applicable only when wing incidence remains constant for the whole of the ground run. In the case of the landing roll, some uncertainty exists as to the precise value of µ, the braking coefficient of friction. An attempt is made to relate an equivalent value of µ to touchdown speed for the standard wet and dry runway as adopted by I.C.A.O. assuming that automatic brakes are fitted, with a maximum braking force equal to 0.35 of the landing weight.

THE shortened runway has become an order of the day. Commercial operators want to offer jet service to communities with small airports. Military services seek to use small, unprepared fields—or no fields at all, just clearings.

The purpose of the paper is to determine the optimal conditions of the take-off and the optimal trajectory of the initial climb minimizing the fuel consumption of the aircraft aided in the ground phase of the take-off by the system using the MAGLEV technology.

The study concerned determining the optimal trajectory of the initial phase of the transport aircraft climb aided in the phase of acceleration by the system using the magnetic levitation phenomenon. The simplified algorithm of the Ritz–Galerkin method was used in this work which uses an approximate solution to boundary value problems for determining the optimal flight trajectory. It uses the method of approximation of the flight path by the third-degree polynomial. The method allows determining the optimal trajectory of the flight satisfying the initial/final conditions and control functions and path constrains for an aircraft. General stating of the task supposes determining the optimal trajectory of movement of a flying vehicle described by the system of ordinary differential equations. The resulting sparse non-linear programming problem has been solved using own elaborated software. The typical profiles computation has been performed with a tool combining three degree of freedom flight dynamics differential equations with procedure-oriented flight control.

Different conditions of the take-off of the aircraft aided by the ground system using the MAGLEV technology give possibilities to shape the trajectory of the initial stage of the aircraft climb after the lift-off to decrease the negative influence on the environment. Optimization of the departure trajectory minimizing fuel consumption or noise emissions can become the basis for working out new procedures for a new kind of take-off modified in relation to the optimal solution which will increase the safety of this segment of the flight.

The analysis was carried out only for the departure trajectory to minimize fuel consumption, without investigation of possibilities of noise reduction. The trajectory guaranteeing minimization of the fuel consumption would also give a solution characterized by minimal emission of substances harmful for the environment.

Application of the innovatory solution of aided take-off is connected with modification of the climbing procedures after the take-off to minimize the negative effect of the aircraft on the surrounded environment. The results can become the basis for working out new procedures which will minimize negative influence to the natural environment in the vicinity of the airports of air transport and increase safety of the take-off and landing operations.

Innovative method of the take-off implies new shape of the trajectory. The study presents the results of the climb trajectory optimization of the aircraft supported at the ground stage by the technology using magnetic levitation phenomenon.

A study of the main parameters to be resolved for civil V/S.T.O.L. aircraft, the necessity for all weather operation, the airport requirements and the competition from other forms of transport. FROM a choice of a wide range of V/S.T.O.L. applications, this paper is concerned with the civil aircraft aspects. It deals with the main parameters to be studied in resolving V.T.O.L. and S.T.O.L. aircraft characteristics, the weighting of these toward favourable performance and to meeting the proposed certification rules for this form of transport. The part to be played by electronics in all weather operations is also discussed. Competition from surface transport, and V/S.T.O.L. airport requirements are referred to, and some general characteristics of the many different aircraft configurations are discussed. Some conclusions are reached suggesting the direction and weighting of future work.