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A PROPOSAL to replace the 7‐ft. No. 1 wind tunnel at the N.P.L. by two new tunnels of the open jet type, housed in the old tunnel building, was put forward in 1930, and one of the new tunnels has now been completed and tested. The present report deals mainly with preliminary experiments on models, which were carried out to ensure that the projected tunnels should give the best possible aerodynamic performance.

THE wind tunnel described in this report forms one of the major items of equipment of the Division of Aeronautics of the Council for Scientific and Industrial Research. The primary purpose of the tunnel is for tests of firms' designs. The size of the working section was chosen so that some full size aircraft components could be tested, while the power was selected so that the Reynolds number obtained at normal speed in tests of complete models would be great enough to avoid large‐scale effects. However, as it was the only tunnel to be built, at any rate for some time, research had to be borne in mind in the design, and in addition to the requirements already stated, the air flow was to be as uniform and free from random turbulence as possible.

IN the May issue of AIRCRAFT ENGINEERING Captain J. Morris describes a method for the solution of linear algebraic equations by iteration. The main objects of the present note are to show how the statement of the method and the proof of its convergence may be greatly condensed by the use of matrices, and to indicate an alternative computational scheme which involves far less recording of numbers, and therefore less risk of error, than that proposed by Morris.

This work originated in a request from an aircraft firm for information on the effect of the ground on the elevator power of one of their designs, a model of which was being tested in the Duplex Tunnel. It was suspected from earlier experience that there might be some difficulty in getting the tail down during landing and the firm wished to be certain that the elevator power would be adequate.

THE paper selects for brief discussion a very few of the successful aeronautical researches conducted in the United Kingdom in recent years. The selection includes illustrations of the work of government establishments, of industry, and of universities. Moreover, the choice made is intended to exemplify the principal fields of activity of the Aeronautical Research Council, as represented by its standing committees and group of special committees: aerodynamics, mechanics, propulsion, and special topics. The paper concludes with a plea for continued research on as large a scale as possible.

THE general theorems given in Sections 4 and 6 include, from the fundamental point of view, all that is required for the analysis of redundant structures. However, to facilitate practical calculations it is helpful to develop more explicit methods and formulae. To find these is the purpose of this Section.

THE orthodox solution of Lagrangian frequency equations involves the expansion into polynomial form of the characteristic determinantal equation in the latent roots, but this method becomes exceedingly laborious if a large number of frequencies and their associated modes are required accurately for any system of equations of high order, say above the sixth. We define a system of Lagrangian frequency equations to be of the nth order if it consists of n equations for n homogeneous unknowns, which we call modes. A useful contribution to the problem was made by the iteration solution of Duncan and Collar, which is especially valuable when only the highest one or two latent roots are required. But when an aircraft propeller vibration problem required the first seven frequencies and their associated modes for a 12th‐order equation whose coefficients involved a variable pitch angle, the labour of calculation by this method appeared at that time (1941) to be prohibitive. The ‘Escalator’ method was therefore devised jointly by the author and Captain J. Morris of the Royal Aircraft Establishment as an alternative. In the propeller problem all the latent roots involved were necessarily real. Dr L. Fox, using relaxation methods, has recently solved a similar problem in a remarkably short time. Unfortunately, relaxation methods cannot easily be extended to the case of complex latent roots, which can occur in connexion with flutter, radio circuits and other problems. In this paper it is shown how the Escalator method can be adapted without essential change to cases in which complex quantities occur.

THE Department of Aeronautical Engineering in the University of Bristol was founded in 1945, when the Bristol Aeroplane Company generously presented the University with funds sufficient for the endowment of a Chair, to be known as the Sir George White Chair of Aeronautical Engineering. This was the fourth aeronautical Chair to be founded in Great Britain, having been preceded some quarter of a century earlier by the Mond Chair at Cambridge and the Zaharoff Chair at Imperial College, and a decade earlier by the Wakefield Chair, subsequently abolished, at University College, Hull. In addition, before 1945, a number of universities and colleges—in particular, Queen Mary College1—had offered courses with an aeronautical content, but not in independent departments headed by a professor. The present writer was appointed to the new Chair at Bristol in the summer of 1945; but owing to his commitments at the Royal Aircraft Establishment was not able to take up the appointment until January 1946. Meanwhile the first students, to a total of five, had been recruited and, in October 1945, had begun their general engineering studies in other departments of the Faculty of Engineering.

THIS paper seeks to draw from current research work on flutter and related problems results of general design significance ; and, avoiding mathematics, endeavours to set these results out in relation to past and present problems.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued.