doi: 10.1108/eb032572pmid: N/A
THIS month we publish an article by Mr B. R. Noton based on a thesis describing an investigation he made while a student at the College of Aeronautics at Cranfield.
doi: 10.1108/eb032573pmid: N/A
A two‐spar cantilever box beam with forty‐five degrees sweep and oblique ribs placed parallel to the root clamping section was the subject of a series of static tests. Stress and strain distributions were determined, primarily in a region distant from the root and tip disturbances, to permit a stringent comparison with three well‐known swept wing theories and the simple theory of bending. Torsional and flexural stiffnesses were also measured and compared with these theories. The sequence of calculation for each method is presented and it is found that two of the theories provide accurate predictions of the stresses, strains and stiffnesses. The influence of rivet slip and rivet flexibility on the stiffnesses of the box is mentioned. As a secondary aim of the investigation, the distribution of normal and shear strain has been measured in the cover skin and spar webs at the root connexion. The design of swept box examined has been the subject of research in a number of establishments and a review of this other work is included.
Levy, Alan V.; Wickham, Robert
doi: 10.1108/eb032574pmid: N/A
The great fluidity of titanium metal in the molten condition lends itself to fusion welding without the addition of filler metal. The resulting welds are flush with the base metal and have high ductility, comparable to the ductility of the base metal. The welded joints can be made by hand or automatic methods. A critical requirement of this type of weld is fit‐up of the parts to be joined. The back‐up and hold‐down fixtures also have a decided effect on the resulting weld. A sheared surface resulting in a joint without gaps is required for a satisfactory weld. Fused welds have been principally used, to date, for longitudinal tight butt joints in material up to .062 in. thick. Further testing and experience should extend the limits of application. Bend tests made on welded samples have bent 180 deg. over a 2T bend radius exhibiting equal or greater ductility than the base metal. Welds tested in tension have exhibited over 100 per cent efficiency in all cases. The elimination of welding rod has reduced the amount of contamination in the weld and the weld area.
Morris, J.; Gouriet, G.G.; Head, J.W.
doi: 10.1108/eb032575pmid: N/A
The problem of rotating a single large mass through a given angular distance so that the performance shall meet given specifications is considered. Initially it is assumed that the general nature of the torque which can be applied is prescribed, but that certain parameters are at our disposal; the practical determination of the best values of the parameters is considered. For the analogous electrical problem, this is equivalent to determining the best values of certain resistances, capacitances and inductances in a given network containing variable elements. But in order to solve the problem it is more effective to make alterations and additions to the network, so that it becomes equivalent to one having the required performance, and the way in which this can be achieved for the single rotating mass is discussed. The restriction to a single‐mass system is merely for convenience and simplicity; the procedure here discussed is perfectly general.
doi: 10.1108/eb032576pmid: N/A
IT is an accepted principle that primary controls should have full consideration during the initial design of an aircraft but there is a general tendency to ignore secondary controls and systems, such as electrics and hydraulics, until all other requirements have been satisfied, basic shapes and sizes determined and structural members laid out.
doi: 10.1108/eb032577pmid: N/A
TODAY aviation is a most influential factor in our lives and Brooklyn a most influential factor in aviation. This was clear to all who attended the very successful conference on High Speed Aeronautics organized as a feature of the Centennial year by the Department of Aeronautical Engineering and Applied Mechanics of the Institute. Over 600 research workers and technicians assembled at the Engineering Societies Building, New York, to hear and to discuss papers by scientists and engineers from America, England, France, Germany, Italy and Sweden.
doi: 10.1108/eb032578pmid: N/A
This paper covers British European Airways' experience with the operation of turboprop aircraft and concludes with some thoughts on their future possibilities.
doi: 10.1108/eb032579pmid: N/A
ON June 2 a small group of people interested in non‐destructive testing assembled in London to hear an informal and most informative lecture on the use of such methods in the U.S. aircraft industry. The speaker was Mr William C. Hitt, Assistant Chief, Quality Control, Douglas Aircraft Co. Inc., Santa Monica, California. The meeting was organized by Inspection Equipment of 19 Drury Lane, London, W.C.2.
doi: 10.1108/eb032580pmid: N/A
There can be few scientific and engineering subjects which have progressed as rapidly as the theory and practice of high‐speed aerodynamics and jet propulsion during recent years. The number and scope of papers that have poured out from research establishments, universities and the industry are such that it has been impossible for all but the very gifted to keep ahead of developments in more than a few limited aspects of the subjects.
doi: 10.1108/eb032581pmid: N/A
Milliard Ltd. have produced a machine for ‘fatiguing’ a metal test specimen by means of sound waves instead of the more conventional mechanical strains. Ultrasonic power is generated electronically and applied to a magneto‐striction transducer. The vibrations produced are increased in amplitude by a step‐up velocity transformer and applied to the specimen, a short rod of the metal under test. The specimen is designed to be resonant at the applied frequency, so that standing waves are produced. At the point of minimum movement the strain is at a maximum, and eventually the specimen breaks there. The strains can be as much as 30 tons/sq. in. and can be applied at a rate of up to 20,000 times per second.
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