The strain energy analysis of swept boxes with ribs normal to the spars

The root constraint problem associated with uniform rectangular swept boxes, having ribs normal to the spars is considered. A strain energy method using self-equilibrating internal end load systems is used. Continues

Aeroplane design study STOL airliner (A71). Part 2- detail design features

This report is concerned with a description of the detail design features of the A71 project study. This aircraft is an airliner designed for operation off single 2000 ft long runways. The overall description of the design and its aerodynamic characteristics are contained in Part I of the report (Ref.1). The detail design of the structure and systems is conventional in most respects. The need to provide a long stroke undercarriage for STOL operations incurred a large weight penalty and it is concluded that further work is necessary to establish acceptable requirements for this type of undercarriage. A separate investigation (Ref.3) has shown that the aircraft does not meet its stipulated design objectives due to an inability to cope with engine failure and gusting cross wind conditions. A study to investigate the potential of the cross-coupling of adjacent powerplants to mitigate engine failure control problems suggests that the weight penalty is not justified (Ref.-)

Aircraft design studies - counter insurgency aircraft with suction boundary layer control

A design study of a counter insurgency aircraft with a suction boundary layer controlled wing to give high lift has been undertaken. The work was carried out by the students in the Department of Aircraft Design during the 1966 academic year and was intended to provide evidence on the feasibility of the configuration employed. The aircraft has a gross weight of 9800 lb. and is designed to carry a variety of payloads of up to 2000 lb. at a maximum speed of 380 m. p. h. The flight usable lift coefficient of five is achieved at an incidence of approximately 30 o which introduced particular layout and undercarriage problems. A twin boom configuration with a variable geometry undercarriage was adopted. It is concluded that the use of a suction boundary layer control system can confer significant performance benefits but the aircraft might well be handicapped by climatic operational limitations. The variable geometry undercarriage is complex and an alternative layout using a tilt wing might be preferable

Aeroplane design studies conventional and V.T.O.L. freighter aircraft (Academic Years 1959 and 1961)

During the second year of their course in the Department of Aircraft Design, students have the option of working as a member of a team engaged in a design study. The subjects for the studies are chosen to represent the current interests of the industry and include unusual features considered to be worthy of investigation. Examples of these design studies are the F-59 freighter and its derivative the F-61, V. T.O. L. freighter. In a conventional role these designs are intended to carry a payload of up to 77000 lb. , over 800 nautical miles range, using four turboprop engines. V. T.O. L. capability is given to the F-61 design by the addition of two wing pods, each of which houses 22 lift engines. The application of boundary layer control in the form of blown ailerons and flaps has been investigated for the F-59 design. Both aircraft have been designed in detail. The major conclusion of the studies is that the application of V. T.O. L. to large freight aircraft is feasible, but further detailed work is necessary to resolve some flutter and noise problems

A Calibration Bound for the M-Theory Fivebrane

We construct a covariant bound on the energy-momentum of the M-fivebrane which is saturated by all supersymmetric configurations. This leads to a generalised notion of a calibrated geometry for M-fivebranes when the worldvolume gauge field is non-zero. The generalisation relevant for Dp-branes is also given.Comment: 9 pages, LaTeX2e, uses vmargin.sty. Typos corrected, a reference and a new discussion on conserved charges added. v4: A typo in the expression for the D-fourbrane energy correcte

Influence of design parameters on cogging torque in permanent magnet machines

The influence of various design parameters on the cogging torque developed by permanent magnet machines is investigated. It is shown that the slot and pole number combination has a significant effect on the cogging torque, and influences the optimal value of both skew angle and magnet arc, as well as determining the optimal number of auxiliary teeth/slots. A simple factor, which is proportional to the slot number and the pole number and inversely proportional to their smallest common multiple, has been introduced to indicate the “goodness”β of the slot and pole number combination. In general, the higher the “goodness” factor the larger the cogging torqu

Tubular modular permanent-magnet machines equipped with quasi-Halbach magnetized magnets - Part II: Armature reaction and design optimization

Using the analytical formulas derived in Part I for predicting the magnetic field distribution, thrust force, and electromotive force of a three-phase tubular modular permanent-magnet machine equipped with quasi-Halbach magnetized magnets, this paper analyzes the armature reaction field, and addresses issues that are pertinent to the design optimization of the machine. It shows that optimal values of the ratio of the axial length of the radially magnetized magnets to the pole pitch exist for both maximum force capability and minimum force ripple. The utility and accuracy of the analytical predictions and design optimization technique are demonstrated on a 9-slot/10-pole machine

On the Energy Momentum Tensor of the M-Theory Fivebrane

We construct the energy momentum tensor for the bosonic fields of the covariant formulation of the M-theory fivebrane within that formalism. We then obtain the energy for various solitonic solutions of the fivebrane equations of motion.Comment: 12 pages, LaTeX2e, uses vmargin.sty and amstex.st

Tubular modular permanent-magnet machines equipped with quasi-Halbach magnetized magnets - Part I: Magnetic field distribution, EMF, and thrust force

This paper describes the analysis, design, and experimental characterization of three-phase tubular modular permanent-magnet machines equipped with quasi-Halbach magnetized magnets. It identifies feasible slot/pole number combinations and discusses their relative merits. It establishes an analytical expression for the open-circuit magnetic field distribution, formulated in the cylindrical coordinate system. The expression has been verified by finite-element analysis. The analytical solution allows the prediction of the thrust force and electromotive force in closed forms, and provides an effective tool for design optimization, as will be described in Part II of the paper

Enhancing preschoolers reasoning skills : an intervention to optimise the use of justificatory speech acts during peer interaction

It has long been acknowledged that justificatory speech is linked with both social and cognitive development. Yet many studies suggest that pre-school children might lack the ability or experience to produce such discourse in routine interaction. In contrast, researchers such as Eisenberg and Garvey (1981) have found evidence of pre-schoolers' justifications in conflictual play contexts. Although this has positive implications for child development, the conflictual context may sit uneasily with parents' and teachers' expectations. It is encouraging therefore that McWilliam (1999) has demonstrated that pre-schoolers can produce justificatory dialogue in both conflictual and nonconflictual situations, even if occurrence in the latter context is less frequent. Based on this, the aim of the present study was to encourage pre-schoolers' production of justificatory discourse during peer exchanges in a non-conflictual context. Twenty-two dyads from a state-run nursery were subject to verbal modelling of either justificatory speech (experimental condition) or a more commonly used alternative (control condition) in daily ten-minute sessions over five consecutive days. All interactions were videorecorded for subsequent coding and analysis. Results showed that both 'why' questions and 'justifications' were significantly higher in the experimental condition, indicating that pre-schoolers' explanatory speech can be effectively enhanced by a cooperative intervention programme