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THE aerodynamic design of a transport aircraft is fixed by the functions it is intended to fulfil. When the Trident 1 design was begun the aim was to provide a performance that…
Abstract
THE aerodynamic design of a transport aircraft is fixed by the functions it is intended to fulfil. When the Trident 1 design was begun the aim was to provide a performance that would make it the ultimate subsonic short range jet, able to remain in front‐line service for at least ten years. Maximum effort was therefore concentrated on achieving low drag at high Mach numbers with good handling qualities to match. Comet experience had shown the value of good low speed handling qualities, and so a continuous programme of wind tunnel and flight testing has been carried through to combine the requirements of high Mach number cruising speeds with those of a competitive CLmax. and an acceptable stall pattern, using, as far as possible, relatively simple and well tried high lift devices.
Adwest Group Limited Stand s.P.40. Companies exhibiting:
Gurkan Ortamevzi and Yalcin Sahin
The purpose of this paper is to make a more precise prediction of the life of servo motors used in aircraft. The variation of the axial load created by the wave washer for…
Abstract
Purpose
The purpose of this paper is to make a more precise prediction of the life of servo motors used in aircraft. The variation of the axial load created by the wave washer for bearing, which is one of the factors affecting the bearing life of the electric motors and servo motors used in aircraft, was analyzed.
Design/methodology/approach
In electric motors and servo motors that body as stator, the height of the stator stack affects the compression amount of the wave washer spring. Working with electric motor and servo manufacturers, production-related variations in stator height were determined by making multiple measurements. The reaction forces resulting from these compression amounts were simulated by mathematical modeling with the finite element method, and also experimentally measured on real parts.
Findings
Results obtained with finite element method and real experiments were compared. By adding the force differences to the general operating conditions, the effect on the bearing life was theoretically determined. In a servo motor with this type of construction, the difference in stator height created different axial loads on the motor shaft. The difference of these loads affected the motor bearing life.
Research limitations/implications
The results implicated in terms of flight safety, maintenance operation and resource efficiency.
Practical implications
The results of this study are effective in determining the maintenance intervals more clearly. This study can be used for the design criteria of aircraft servo motors. These servos, which are especially used to move the flight control surfaces, contribute to flight safety as the life expectancy will be clearer.
Social implications
This study may be effective in preventing aviation accidents caused by servo motors. It can make maintenance management more efficient.
Originality/value
This study investigated the effect of aircraft servo motor design inputs on servo motor life, considering the production.
Details
Keywords
THE Super One‐Eleven aircraft of the European Division of British Airways, currently have the ability to operate in Cat 2 conditions (RVR down to 400 metres and decision heights…
Abstract
THE Super One‐Eleven aircraft of the European Division of British Airways, currently have the ability to operate in Cat 2 conditions (RVR down to 400 metres and decision heights down to 100 ft). They are equipped with a Marconi‐Elliot auto‐pilot which is an extension of the basic E2000 fitted to all but the earliest production One‐Elevens. This auto‐pilot owes its origin to the well‐proven Bendix PB20D which for the 200 Series, was developed and optimised to suit the characteristics of the aircraft and at the same time looked ahead to future lower weather minima operations.
J.H. ARMSTRONG and J.D. McDONNELL
The DC‐9 Super 80 will be delivered with advanced avionics in early 1980. This paper discusses from the aircraft manufacturer's point of view the avionics system architecture, its…
Abstract
The DC‐9 Super 80 will be delivered with advanced avionics in early 1980. This paper discusses from the aircraft manufacturer's point of view the avionics system architecture, its digital implementation, and some hardware details of most major system elements. New operational features are discussed including Category IIIa autoland, some new autopilot and autothrottle cruise modes, a head‐up display system, and a “hot on‐board spare” flight guidance computer. Finally, some of the advantages of the digital system over analog systems are noted.
Huaishu Li, Lizhong Song and Yanhui Lai
In order to improve performance robustness of control systems, the discrete variable structure control (VSC) design for uncertain systems and its application to a ship autopilot…
Abstract
Purpose
In order to improve performance robustness of control systems, the discrete variable structure control (VSC) design for uncertain systems and its application to a ship autopilot are to be discussed in this paper.
Design/methodology/approach
Discrete‐time variable structure control (DVSC) becomes worth investigating and various DVSC methods have been suggested by many papers. The approach that used the reaching law for controller design can describe how the switching function decreases toward zero and easier to obtain the control law, but this conventional method has some defects not to be ignored. First, due to the influence of the conventional discrete reaching law itself, the system trajectory oscillates in a neighborhood of the origin rather than converges to the origin. Second, this method requires that the uncertainty bound is known as a premise to assure robustness, so creates an over‐conservative controller and enlarges chattering.
Findings
It can be shown that the estimation error dynamics can be decoupled from sliding surface dynamics using the proposed scheme. Robust stability of the closed‐loop system can be ensured in the presence of uncertainties with bounded changing rate. No chattering occurs.
Practical implications
To supply useful references to controller design.
Originality/value
A new approach in the design of discrete VSC based on the reaching law approach is presented, a new discrete reaching law, which is stable at the origin, is proposed, and an algorithm for uncertainty estimation is developed in this paper. The proposed algorithm is applied to the control of a ship autopilot servo system. Simulation results show that the controller designed here can track a desired course well and exhibits very good performance robustness.
Details
Keywords
FOR a number of years, a considerable amount of research and experimental effort has been expended on the problem of approach and landing of aircraft in operational circumstances…
Abstract
FOR a number of years, a considerable amount of research and experimental effort has been expended on the problem of approach and landing of aircraft in operational circumstances where the visual references and the atmospheric conditions are below the levels considered safe for the pilot, assisted only by conventional instrumentation.
AS is to be expected, the various systems on the Trident 2E closely follow those evolved for the Tridents 1 and 1E, except for the changes in the fuel system necessitated by the…
Abstract
AS is to be expected, the various systems on the Trident 2E closely follow those evolved for the Tridents 1 and 1E, except for the changes in the fuel system necessitated by the introduction of the fin fuel tank, and the embodiment of a turbine‐compressor type of cold air unit in the air conditioning system.
THE various systems on the Trident 3B are, as is to be expected, logical developments of those evolved for the Tridents 1, 1E and 2E.
G.H. Garbett and AMRAeS
Smiths Industries is to supply the head‐up display system for the Sea Harrier. The company will design, develop and make the electronic head‐up display and weapon aiming computer…
Abstract
Smiths Industries is to supply the head‐up display system for the Sea Harrier. The company will design, develop and make the electronic head‐up display and weapon aiming computer system for the latest version of the HS Harrier which will operate from Royal Navy ships.