Testing Stability and Control of Aeroplanes

1939 ◽  
Vol 43 (341) ◽  
pp. 333-369
Author(s):  
A. G. von Baumhauer
Keyword(s):  
Point Of View ◽  
Stability And Control ◽  
Civil Aircraft ◽  
The Subject ◽  
And Control

The subject which I have to discuss to-day is one which can be treated from a standpoint of the scientist or from that of the practical engineer. I am going to try to discuss it from the latter point of view.The testing of the behaviour of aeroplanes in flight, to which I want to draw attention, does not deal with research on stability and control, it only deals with checking the flying characteristics with regard to the requirements which should be fulfilled.In the Dutch requirements for a certificate of airworthiness for civil aircraft there are several detail rules, which all tend to state that the aeroplane should be stable and well controllable within the whole region of flight, and for all conditions which may occur in normal and special use.

THE DYNAMICS OF SYSTEMS OF COMPLEX NONLINEAR OSCILLATORS: A REVIEW

2004 ◽  
Vol 14 (11) ◽  
pp. 3821-3846 ◽  
Author(s):  
GAMAL M. MAHMOUD ◽  
TASSOS BOUNTIS
Keyword(s):  
Phase Space ◽  
Periodic Solutions ◽  
Chaotic Behavior ◽  
Nonlinear Oscillators ◽  
Complex Variables ◽  
Point Of View ◽  
Stability And Control ◽  
Ginzburg Landau Equations ◽  
The Stability ◽  
And Control

Dynamical systems in the real domain are currently one of the most popular areas of scientific study. A wealth of new phenomena of bifurcations and chaos has been discovered concerning the dynamics of nonlinear systems in real phase space. There is, however, a wide variety of physical problems, which, from a mathematical point of view, can be more conveniently studied using complex variables. The main advantage of introducing complex variables is the reduction of phase space dimensions by a half. In this survey, we shall focus on such classes of autonomous, parametrically excited and modulated systems of complex nonlinear oscillators. We first describe appropriate perturbation approaches, which have been specially adapted to study periodic solutions, their stability and control. The stability analysis of these fundamental periodic solutions, though local by itself, can yield considerable information about more global properties of the dynamics, since it is in the vicinity of such solutions that the largest regions of regular or chaotic motion are observed, depending on whether the periodic solution is, respectively, stable or unstable. We then summarize some recent studies on fixed points, periodic solutions, strange attractors, chaotic behavior and the problem of chaos control in systems of complex oscillators. Some important applications in physics, mechanics and engineering are mentioned. The connection with a class of complex partial differential equations, which contains such famous examples, as the nonlinear Schrödinger and Ginzburg–Landau equations is also discussed. These complex equations play an important role in many branches of physics, e.g. fluids, superconductors, plasma physics, geophysical fluids, modulated optical waves and electromagnetic fields.

Paper 26. Stability and Control in Waves: A Survey of the Problem

1972 ◽  
Vol 14 (7) ◽  
pp. 186-193 ◽  
Author(s):  
J. E. Conolly
Keyword(s):  
Mathematical Models ◽  
Orbital Motion ◽  
Model Tests ◽  
Point Of View ◽  
Stability And Control ◽  
Free Running ◽  
And Control

Manoeuvrability in waves is discussed from the point of view of the dangers of broaching-to when a ship is running before the sea. Conditions are assessed under which this may occur, illustrated by documented cases, including the Wahine disaster in 1968. Because of the problems involved in investigating broaching-to by means of free-running model tests, there is an urgent need for reliable mathematical models: however, theories published so far, based on two different simplifications, are shown to have limitations. It is argued that the theory must take account of pitching, surging, rolling and orbital motion of the water particles.

Supersonic Aircraft—Promise and Problems

1960 ◽  
Vol 64 (594) ◽  
pp. 315-334 ◽  
Author(s):  
M. B. Morgan
Keyword(s):  
The United States ◽  
Supersonic Transport ◽  
Supersonic Aircraft ◽  
Stability And Control ◽  
The Subject ◽  
Scientific Adviser ◽  
Mach 3 ◽  
Short Time ◽  
And Control ◽  
Made In

The 1,157th lecture to be given before the Society, “Supersonic Aircraft—Promise and Problems” by M. B. Morgan, Esq., C.B., M.A., F.R.Ae.S., Scientific Adviser to the Air Ministry, was given on 17th March 1960, at the Institution of Mechanical Engineers. Mr. Peter G. Masefield, M.A., F.R.Ae.S., Hon.F.l.A.S., M.Inst.T., President of the Society, presided. Opening the meeting Mr. Masefield said he thought this would be one of the most interesting and stimulating lectures of the session. The subject of the supersonic aeroplane had been freely discussed in the United States and probably in Russia also. In this country they had been more reticent so he hoped they would have a really good discussion after this lecture. One significant point was that people no longer wondered whether a supersonic transport could, or should, be built but only whether it should cruise at a Mach number of 2 and be made in light alloy, or whether it should be around Mach 3 and be made of steel or more exotic materials. That sooner or later—and many believed sooner—transports would fly at supersonic speeds at 70,000 ft. was taken for granted.Mr. Morgan was well known to them all. Born in Wales, he was educated at Rutlish, Merton and St. Catharine's College, Cambridge, where he took the Mechanical Sciences Tripos and won the John Bernard Seely Prize in Aeronautics in 1934. In fact, he and Mr. Morgan used to enjoy the Cam together and Mr. Morgan looked little different today than he had in those days. Mr. Morgan was apprenticed to Mather and Piatt Ltd. and also spent a short time at Vickers, Weybridge before joining the R.A.E., Farnborough in 1935. Since then he had specialised in aerodynamics, flight research and development, stability and control and, he had taken his Pilot's Licence in 1944. He was Head of the Aero Flight Section of the R.A.E. from 1946-1948, Head of the Guided Weapons Department from 1948-1953 and Deputy Director of the Establishment from 1954 until 1959. He had then been appointed to his present position of Scientific Adviser to the Air Ministry and had also been Chairman of what had come to be known as “STAC”–Supersonic Transport Aircraft Committee. He felt that they could have no better person than Mr. Morgan to talk on the Supersonic Transport.

scholarly journals Highlighting the complex interrelationship between the concepts of trust and control

2012 ◽  
Vol 2 (2) ◽  
pp. 33-50
Author(s):  
Peter Beusch
Keyword(s):  
Management Control ◽  
Point Of View ◽  
Control Mechanisms ◽  
Organizational Setting ◽  
Accounting Systems ◽  
Personal Trust ◽  
Fresh Perspective ◽  
The Subject ◽  
The Right ◽  
And Control

This paper presents the area of management control and trust in an inter-organizational setting with an attempt to offer a fresh perspective on the complex relationship between and different understandings of the two concepts of trust and control. This is done with help of two case studies in a cross-cultural setting and involving five multinational companies that were involved in two large acquisitions. Obviously, different actor groups’ cultural and educational heritage has brought with it that dissimilar opinions exist on the subject of mainly system-based versus inter-personal based trust.The paper first demonstrates that trust and control can mean different but also the same things to different people, depending very much on the logic and values applied but also depending on if the actors were motivated more intrinsically or extrinsically. Further, what impact certain control mechanisms, or the lack thereof, have on individual’s behavior is outlined. The paper also reveals that it is difficult to find the right balance between diverse types of control and trust as time went on after the acquisitions. The main reason for this is that actors with different socio-cultural heritage use different references regarding trust and control and put unlike emphasis on what should be focused on, what should be counted, and what should be accounted for. Trust and control can mean almost identical things but the cases illustrate that, from a rhetorical and convincing point of view, system trust appears to be stronger in certain settings than inter-personal trust, as it, to particular actors, provides the impression of being in control. The contrary is true in other settings, where having ‘facts and figures’ and ‘a whole bunch ‘of accounting systems and accounting techniques not automatically mean to be in control, thus leaving more room for the use and appreciation of inter-personal trust.

VIRUSES OF THE ACUTE COMMUNICABLE DISEASES

PEDIATRICS ◽  
1960 ◽  
Vol 25 (1) ◽  
pp. 119-126
Author(s):  
Frederick C. Robbins
Keyword(s):  
Herpes Zoster ◽  
Present Status ◽  
Clinical Manifestations ◽  
Active Immunization ◽  
Point Of View ◽  
Virus Infections ◽  
Real Possibility ◽  
The Subject ◽  
And Control ◽  
Near Future

THE GROUP of acute and extremely common communicable virus infections has been greatly enlarged in recent years since the recognition of the Coxsackie and ECHO viruses. The clinical manifestations of infections with this large group of agents are gradually being sorted out, and include aseptic meningitis, pleurodynia, herpangina, diarrhea, various minor illnesses and a variety of exanthems. The observation that several of them produce diseases with rash has greatly complicated the diagnostic problems of the pediatrician. This group of illnesses is of great interest and importance, but will not be discussed here. Rather, the scope of this presentation will be limited to three infections, namely, measles (rubeola), rubella, and those due to the viruses of varicella and herpes zoster. The purpose is to review briefly the present status of our knowledge concerning them and to point out some of the problems yet to be solved. No attempt will be made at exhaustive coverage. MEASLES Experimental Considerations As the result of the work of Enders and his associates, it is now possible to study the virus of measles in the laboratory, and control of this disease by active immunization would appear to be a real possibility within the near future. From the historic point of view measles has been the subject of a great deal of attention from the clinician, epidemiologist and virologist. The early workers, such as Anderson and Goldberger in 1911, Blake and Trask in 1921, and others at about the same time, were able to produce measles in monkeys by inoculating them with blood and other materials from patients.

Discontinuous Dynamics and Bifurcation for Morphing Aircraft Switching on the Velocity Boundary

2020 ◽  
Author(s):  
Jianzhe Huang ◽  
Xilin Fu ◽  
Zhongliang Jing ◽  
Siyuan Xing
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Point Of View ◽  
Intermediate Structure ◽  
Morphing Aircraft ◽  
Low Speed ◽  
Stability And Control ◽  
System A ◽  
The Moment ◽  
And Control

Abstract The concept of morphing aircraft was developed many decades ago, and many researches on the morphing aircraft such as stability and control have been published. As the point of view of the dynamic theory, the dynamic system of the morphing aircraft is consisted with multiple subsystems, and each subsystem represents the morphing aircraft with specific structure to fulfill a particular flight task. The switching process from one structure to another for such a morphing aircraft is considered to be smooth and stable, and the switching time is also assumed to be infinitely small. In this paper, a morphing aircraft with high-speed structure, intermediate-structure and low-speed structure is studied. Such a morphing aircraft is set to switch between high-speed structure and low-speed structure when the speed of aircraft arrives a preset critical speed, and the analytical conditions for switchability is developed. If such a morphing aircraft cannot switch to a low-speed structure or high-speed structure at the moment when it arrives the critical speed, it will switch to an intermediate-structure and control to keep the speed remain constant. The analytical conditions for onset and vanish of such a morphing aircraft switching to the intermediate-structure are also provided. Mapping structure is defined to describe the periodic motions of such a morphing aircraft. The bifurcation scenario is calculated to show the complexity of such a hybrid dynamical system. A periodic motion is given to illustrate the flow of such a morphing aircraft switching on the velocity boundary.

Our Future

2017 ◽  
pp. 361-379
Author(s):  
Maija R. Korhonen
Keyword(s):  
Information Society ◽  
Essential Role ◽  
Structural Changes ◽  
Point Of View ◽  
Good Information ◽  
End User ◽  
Common Goal ◽  
The Future ◽  
The Subject ◽  
And Control

We live in an ever-changing world. Despite that many new and excellent reforms are achieved, this period of time is also very confusing when many things that were regarded as concrete are becoming virtual. In spite of all this incompleteness, our common goal should be a good information society and the purpose of this chapter is to find out some factors that reveal the steps toward it. The question we ask is how to find a balance between a good life and eServices from the human point of view. The key findings pointed to issues in the needs of structural changes in the society. Another challenge that can be observed and which will be in the most essential role in the future, is the ownership and control over My Data. Agreements are a common practice in the business and when the subject is eServices in the future, we cannot avoid discussion of the end-user agreements, too.

Our Future

2018 ◽  
pp. 1541-1559
Author(s):  
Maija R. Korhonen
Keyword(s):  
Information Society ◽  
Essential Role ◽  
Structural Changes ◽  
Point Of View ◽  
Good Information ◽  
End User ◽  
Common Goal ◽  
The Future ◽  
The Subject ◽  
And Control

We live in an ever-changing world. Despite that many new and excellent reforms are achieved, this period of time is also very confusing when many things that were regarded as concrete are becoming virtual. In spite of all this incompleteness, our common goal should be a good information society and the purpose of this chapter is to find out some factors that reveal the steps toward it. The question we ask is how to find a balance between a good life and eServices from the human point of view. The key findings pointed to issues in the needs of structural changes in the society. Another challenge that can be observed and which will be in the most essential role in the future, is the ownership and control over My Data. Agreements are a common practice in the business and when the subject is eServices in the future, we cannot avoid discussion of the end-user agreements, too.

The Spinning of Aeroplanes

1927 ◽  
Vol 31 (199) ◽  
pp. 619-688 ◽  
Author(s):  
L. W. Bryant ◽  
S. B. Gates
Keyword(s):  
Wind Tunnel ◽  
Preliminary Report ◽  
Full Scale ◽  
Wind Tunnel Experiments ◽  
Research Committee ◽  
Stability And Control ◽  
The Subject ◽  
Ready Access ◽  
The Stability ◽  
And Control

We should like to preface our essay on the subject of spinning by mentioning the circumstances under which our investigations were carried out and the sources of our information. The Panel of the Aeronautical Research Committee which has been appointed to deal with all questions connected with the stability and control of aeroplanes was requested in 1924 to consider the urgent problems connected with the alarming accidents due to certain machines failing to retover from a spin. After the issue of a preliminary report on the situation by the Panel, the writers of this paper were asked to go into the whole question as far as existing information from full-scale and wind tunnel experiments would permit. We have had ready access to all available data, coming chiefly from Farnborough on the full-scale side, and from the N.P.L. on the model side.

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