In the melting‐pot againdoi: 10.1108/eb031302pmid: N/A
BRITISH Civil Aviation has been dragged into the arena of party politics and has become the handmaiden of political expediency. That is what the recently announced Government scheme for the nationalization of this country's Air Lines means; because the new organization differs in no way, but for this ideological change, from that laid down by the National Government in the White Paper issued last March.
Deflexion of Tapered BeamsTatham, R.; Price, H.L.
doi: 10.1108/eb031303pmid: N/A
IN the following investigation we consider the deflection due to bending of a tapered cantilever beam carrying concentrated end and lateral loads at the free tip. The mode of taper of the beam is assumed of a generalized form, and is such that the second moment of the area of the cross‐section at any point varies as the nth power of its distance from the unsupported vertex. Detailed calculations are given for the cases n = 1,2,3,4 corresponding to the types of beams most commonly arising in practice. It is shown that fairly substantial errors may arise if the commonly used approximate treatments are adopted. The theory may also be extended to yield the value of the critical end loads for tapered struts conforming to any value of n.
Adiabatic Air FlowSaksena, G.B.
doi: 10.1108/eb031304pmid: N/A
IN most aerodynamical problems it is convenient to consider the aircraft to be stationary and the air to be flowing with a speed equal to the flight speed in a direction opposite to the direction of the flight. This practice simplifies the investigation of the motion of the aircraft and is perfectly legitimate from the mathematical point of view. Thus, if the flight speed is v, the kinetic energy or the dynamic head, q, of unit mass of air is ½ρv2. It the air is allowed to flow through a restriction, for example, a radiator or an air intake duct, the velocity of flow is reduced, and the dynamic energy thus lost is converted into the pressure energy. In most problems it is sufficiently accurate to assume that air is an incompressible fluid so that the density remains constant, and the flow changes can be investigated by applying the well‐known Bernoulli's Equation, viz., p+½ρv2=constant. This assumption is not strictly true, as the flow changes are usually brought about very quickly and there is little chance for the heat generated to be dissipated. However, the error made by this simplified assumption is not very large if the flight speed is fairly low. But in the case of high‐speed aircraft, e.g. a fighter aircraft, the above assumption involves a considerable error. To make a due allowance for the suddenness of the change, it would be necessary to discard the notion of the incompressibility of air and to use the adiabatic law between the pressure and the density of air. Thus, a better and a truer picture of the actual state of affairs would be obtained by assuming the air to be compressible and to investigate its effect on the pressure, density, and the temperature of the air. It is proposed to make a theoretical investigation of this problem on these lines and to present the results in the form of tables, graphs, and nomograms which could be easily applied in the solution of any practical problem on the flow changes.
Aeronautical Research Council Reportsdoi: 10.1108/eb031307pmid: N/A
Measurements have been made of the drag of circular cylinders of 3/16 to 1 in. diameter at speeds up to M=0·85 by means of the electrical balance in the Circular High‐Speed Tunnel and by pressure plotting round cylinders of ⅜ in. and ¾ in. diameter in the Rectangular High Speed Tunnel. The measurements were confined in the main to cylinders which did not show the usual critical drop in CD at a Reynolds number near 0·26 × 106. The value of CD started to rise at about M = 0·35 after which it rose at an increasing rate to a maximum at about M=0·7; this was succeeded by a minimum at M = ·75 and a sharp rise at M=0·85. The speeds at which the maxima and minima of the curves occurred for cylinders of various diameters were used to correct for tunnel interference in the circular tunnel. Photographs were taken of the shock wave system in the Rectangular Tunnel at various speeds.
Design and Production TechniqueSchroeder, A.J.
doi: 10.1108/eb031308pmid: N/A
DRAWING technique comprises the methods of working in which hollow components are formed from plane material by means of a drawing die ring and a drawing punch and, if necessary, by using blank holders so that a more or less considerable movement of material takes place.
U.S. Patent Specificationsdoi: 10.1108/eb031309pmid: N/A
In a wing construction for an aeroplane, the combination of a sheet metal surface, a channel‐shaped stringer member having outwardly extending flanges secured to said sheet metal surface to co‐operate in supporting the same, said channel member being cut away at portions of said flanges to form transverse passages adjacent to the sheet metal surface, a web member extending transversely of and substantially perpendicular to said stringer member provided with a strengthening channel of slightly greater size than the channel of the stringer member, the top surface of the channel of the web member at the end of the web member being cut away to fit about the channel of the stringer member, and a holding member having a slot to accommodate the channel of the stringer member, said holding member having a part secured to said web member and a part at substantially right angles to the first part secured to the sheet metal surface.