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Browsing CoA. Reports by Publisher "College of Aeronautics, Cranfield"
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Item Open Access Addendum to a theoretical and experimental study of the boundary layer flow on a 45 degrees swept back wing(College of Aeronautics, Cranfield, 1957-11) Walton, J.COA report 109 describes Flight Tests carried out on a swept back half wing of double elliptical section to investigate the nature of the boundary layer flow, with particular reference to Bounday Layer Instability and subsequent transition.Item Open Access The aerodynamic derivatives with respect to rate of yaw for a delta wing with small dihedral at supersonic speeds(College of Aeronautics, Cranfield, 1949-03) Hunter-Tod, J. H.Expressions are derives for the yawing derivatives on the assumptions of the linearised theory of flow for a delta wing with small dihedral flying at supersonic speeds at small incidences. The non-dimensional derivatives are numerically decreasing functions of Mach number. The non-dimensional rolling and yawing derivatives are also numerically decreasing functions of aspect ratio. When the wing lies entirely within the apex Mach cone there is a leading edge suction force proportional to incidence which makes a destabilising contribution to the yawing moment and side force which may be of the same magnitude as that from the inducted excess pressure distribution.Item Open Access Aileron reversal and divergence of swept wings with special consideration of the relevant aerodynamic and elastic characteristics(College of Aeronautics, Cranfield, 1952-03) Radok, J. R. M.Using oblique coordinates, the static problems of Aero-elasticity for swept wings are reduced to the solution of integral – or matrix equations, which may be solved by iteration. The present treatment also indicates the suitability of integral equations for fundamental aero-elastic investigations. Continues …Item Open Access The air resistance of racing cyclists(College of Aeronautics, Cranfield, 1956-10) Nonweiler, T.Tests in the closed-section wind-tunnel on three different cyclists mounted on a racing bicycle are described, and figures quoted for the recorded air resistance. Some comments are also included on the implications of the results concerning the power-output of racing cyclists.Item Open Access Analysis of experiments on swept wing structures(College of Aeronautics, Cranfield, 1953-05) Howe, D.This report is concerned with the application of various theories to the solution of problems investigated experimentally, and in some cases theoretically, by others at the College of Aeronautics. Continues …Item Open Access Analysis of two-cell swept box with ribs parallel to the line of flight under loading by constant couples(College of Aeronautics, Cranfield, 1953-03) Howe, D.The method of oblique co-ordinates is used to analyse the problem associated with the strength and deformation of a uniform, rectangular, two- cell swept box beam having ribs parallel to the line of flight. The case of loading by constant couples is considered, but no account of root effects is taken. Continues…Item Open Access Application of the linear perturbation theory to compressible flow about bodies of revolution(College of Aeronautics, Cranfield, 1947-09) Young, A. D.; Kirkby, S.The linearised theory is developed in some detail in order to clarify the differences between two-dimensional and axi-symmetric flow. In agreement with other authors it is concluded that the perturbation velocity on a thin body of revolution in compressible flow is 1/β2 times the perturbation velocity in incompressible flow on a thinner body at reduced incidence obtained by reducing the lateral dimensions of the original body in the ratio (3:1). This result is applied to a representative family of streamline bodies of revolution at zero incidence. Continues…Item Open Access An approximate solution to the swept wing root constraint problem(College of Aeronautics, Cranfield, 1956-02) Howe, D.This report presents an approximate solution to the problem associated with the root constraint in a swept wing.Item Open Access An assessment of certain methods of stress-analysis of rectangular multi-web box beams(College of Aeronautics, Cranfield, 1956-12) Griffin, K. H.The stress distribution in an unswept multi-web box under shear load applied at the centre of a rigid tip rib is examined, and compared with results obtained by a method which replaces the shear webs by a shear-carrying continuum. Continues ...Item Open Access Assessment of errors in approximate solutions of differential equations(College of Aeronautics, Cranfield, 1947-12) Duncan, W. J.The term assessment is applied to any process which enables us to set rigid bounds to the error or to estimate its value. It is shown that upper and lower bounds can be assigned whenever the Green's function of the problem is one- signed; this is true in many important problems. Another method is applicable to step by step -solutions of ordinary differential equations, linear or non-linear, and depends on use of the "index" of the process of integration. Lastly, the error in a linear problem can be estimated when an approximation to the Green's function is known.Item Open Access Bound and trailing vortices in the linearised theory of supersonic flow, and the downwash in the wake of a delta wing(College of Aeronautics, Cranfield, 1947-10) Robinson, A.; Hunter-Tod, J. H.The field of flow round a flat aerofoil at incidence can/may be regarded in linearised theory as the result of both bound and trailing vortices for supersonic as well as for low speed flight. This leads to a convenient method, given the lift distribution over an aerofoil, for calculating the flow round it at supersonic speeds. As an application of the results the downwash is calculated in the wake of a delta wing lying within the Mach cone emanating from its apex. The downwash is found to be least just aft the trailing edge and is everywhere less that the downflow at the aerofoil. It increases steadily to a limiting value which is attained virtually within two chord lengths of the trailing edge. The ratio of the downwash at any point in the wake to the downflow at the aerofoil decreases with increasing Mach number and apex angle.Item Open Access The buckling in compression of panels with square top-hat section stringers(College of Aeronautics, Cranfield, 1949-06) Hemp, W. S.; Griffin, K. H.A simplified panel model is described, together with a number of assumptions about the mode of its bucking. The approach to the calculation of the buckling stress is by splitting the panel into a number of flat plates and treating these by the ordinary plate theory. Use of the boundary conditions between these plates leads to a relation between the buckling stress and the variables of the panel geometry. The results thus obtained are compared with two sets of recent experimental work; and an appendix is included to show the effect of initial panel irregularities on the experimental determination of buckling stresses.Item Open Access The calculation of the profile drag of aerofoils and bodies of revolution at supersonic speeds(College of Aeronautics, Cranfield, 1953-04) Young, A. D.The effects of viscosity on the aerodynamic characteristics of wings and bodies at supersonic speeds can be assessed if we can calculate… Continues...Item Open Access The characteristics of systems which are nearly in a state of neutral static stability(College of Aeronautics, Cranfield, 1950-01) Duncan, W. J.It is shown that the rate of subsidence or divergence ﮑ of a system which is near a state of neutral static stability can easily be calculated for knowledge of the mode of displacement in the neutral state and this model is found by solving a set of linear algebraic equations. The first order correction to the mode can also be found and in important cases this can be made the basis for calculating a second approximation to ﮑ; if necessary a further correction to the mode can now be found from this a still more accurate root can be calculated. The method can be extended to continuous systems having infinitely many degrees of freedom.Item Open Access A comparison of the calculated profile drag coefficients of various low drag wing sections(College of Aeronautics, Cranfield, 1950-04) Dowlen, E. M.The profile drag-coefficients of a number of low-drag wings with straight trailing edges have been calculated. A comparison is made with other low-drag and conventional sections which indicates an increase in profile drag, for a given transition point position, with rearward movement of the position of maximum velocity and with increase of trailing edge angle. Some experimental results obtained at low Reynolds number are included for comparison. A shortened method of calculating the profile drag coefficient of an aerofoil is developed.Item Open Access The construction of a new type of spectrograph and its use photographically and photoelectrically as an automatic recording spectrophotometer(College of Aeronautics, Cranfield, 1956-11) Brown, D. C.A new type of concave mirror plane grating spectrograph has been constructed. The mounting is that of a modified Ebert Type and has all the advantages of that mounting whilst being more efficient in its use of the mirror. Continues...Item Open Access The determination in flight of the body drag and the mean blade profile drag coefficient of a helicopter(College of Aeronautics, Cranfield, 1952-04) Bartholomew, F. E.; Marshall, W. S. D.Slight modifications have been made to the energy equation which enables the results of partial climb tests to be plotted as two straight lines, the slopes of which are measures of the body drag of the helicopter and the mean profile drag coefficient of the rotor blades. Sufficient data has been analysed to show that the method can be used to obtain an accurate measurement of the body drag. Continues …Item Open Access The diffusion of loads in non-rigid circular frames(College of Aeronautics, Cranfield, 1950-02) Lewis, S. R.This report extends the work of W. J. Goodey, and gives numerical examples of the shear distribution around a frame subjected to a single concentrated radial load for variations in the parameters, such as, frame stiffness, skin thickness, stringer spacing, etc. Continues …Item Open Access The displacement effect of pitot tubes in narrow wakes at subsonic and supersonic speeds(College of Aeronautics, Cranfield, 1956-10) Marson, G. B.The apparent displacement of the effective centre of a circular pitot tube from it geometric centre when placed in narrow wakes has been measured at sub and super- sonic speeds. Similar effects were found at all speeds. Continues...Item Open Access The distribution of pressure over the surface of wings of small aspect ratio(College of Aeronautics, Cranfield, 1952-02) Marshall, W. S. D.The distribution of pressure over wings of aspect ratio 1.5 and 0.5 have been measure for a range of incidences up to and including the stall at various angles of yaw. This report presents a detailed analysis of the results at two incidences corresponding to ¼ and ¾ of the stalling incidences approximately. Continues …