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THE long‐awaited statement on the Government's plans for research in outer space was generally greeted as laying the foundations of a logically thought out, if modest, programme. Work is in hand, the emphasis being on the contribution of our fundamental scientists and the instruments which they can develop. Present plans will do little to help any aircraft firms looking for work, but if the studies being made into the possibilities of combining Black Knight and Blue Streak result in their development as first and second stages of a satellite vehicle, more work will of course be provided. As the programme gathers way, there will presumably be research contracts placed with appropriate firms—it being understood that the present investigations are in the hands of the R.A.E. and the Royal Society.

The use of synthetic resins as adhesives for metals or other non‐porous materials, in which there is increasing interest for structural and production reasons, imposes certain restrictions on the components bonded and the type of joint used. In the following paper the general points applicable to adhesive joints are first considered. A large number of strength measurements on simple light alloy lap joints made with ‘Araldite’ by the Eidg. Materialprüfungs und Versuchsanstalt (E.M.P.A.) are used to analyse the manner in which the breaking load under tensile shear loading depends on the geometry of the test specimen. It can be shown that in this special case, which is however of importance in practice, there is an optimum utilization both of the adhesive and of the metal, whose yield point determines the choice of sheet thickness and overlap. The use of synthetic resins as adhesives for metals and other non‐porous materials opens up numerous new developments and possibilities in a whole range of industries. Although comparatively new it has already found many practical applications which steadily increase.

Hydrogen pick‐up during corro‐sion of zirconium alloys. Several factors such as alloy composition, hydrogen content of the alloy, surface hydrides and hydrogen content of the water have been investigated for their effect upon the amount of hydrogen picked up by zirconium alloys during corrosion in 680°F. water. Metallic additions of nickel increase hydrogen pick‐up, antimony, chromium, and iron appear to decrease the hydrogen pick‐up, while the addition of tin has little or no effect. The hydrogen content of the metal (50 to 4,000 p.p.m.) or of the water (0 to 2 atm. of hydrogen pressure) does not appreciably change the amount of hydrogen picked up by the alloys covered in the report (B.M.I.X. 1380, price $0.75).

A CRITICAL stage in the process of making aircraft occurs with alarming frequency in the history of aviation.

The history of SAAB's development of adhesive bonded aircraft structures is briefly commented upon. The lecture deals mainly with Redux bonding of aluminium alloys, and the many design problems associated with bonded structures are treated mainly with the structural designer's interests in mind. He has to deal with a great number of different types of bonded joints, loaded and stressed in more or less complex ways, and often with high service temperatures, for which more design information is needed.

IN discussing possibilities of new uses for wood and plastics in aircraft construction, emphasis is often laid on production problems and economic questions—shortage of aluminium, for instance. But the problem of weight is so important that it is quite impossible to consider new ways of aeroplane designing without touching it.

IN a recent issue of AIRCRAFT ENGINEERING Mr R. H. T. Harper, of Messrs de Havilland Aircraft Co. Ltd., gave an account of the design considerations which led his company into using composite wood and metal spars for the ‘Hornet’ single‐seater fighter. Such a method of construction was made possible by the development of the ‘Redux’ process for bonding metal to wood by Messrs Aero Research Limited, Duxford, and it was the first of a number of advanced designs made possible by this new process. They have already been described at some length in a number of articles in the technical press (see Bibliography), and it is only necessary to state here that when using the ‘Redux’ process for bonding metal to wood the strength of the bond is always greater than that of the wood itself even at 100 deg. C., and that the process can equally well be applied to the gluing of metals to metals (e.g. see the description of the use of ‘Redux’ on the de Havilland ‘Dove‘ given in The Aeroplane, September 20, 1946).

A theoretical analysis is given of the peeling test for Redux‐bonded joints, as devised by Aero Research Ltd. and generally accepted as a standard quality control test for metal‐bonding processes. Numerical values derived from computations appear to be in reasonable agreement with experiments, but more test‐data and better knowledge of the clastic and plastic behaviour of both adhesive and adherent are necessary to make the method more reliable in this respect. The practical value of the method, however, is the indication it gives about the sensitivity of the test for the variables involved. This may make it feasible to introduce corrections for variations of some parameters, thereby improving the reproducibility of the test.

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.

Simple expressions for upper and lower limits to the shear modulus of honeycomb sandwich cores are obtained by application of the Unit Displacement and Unit Load methods in conjunction with simplifying assumptions as to the strain and stress systems respectively in the core. The theory is given for cores built up from foil ribbons to form cells of general honeycomb form. Test methods for the experimental determination of the shear modulus are also discussed. Of these, the three‐point bending test on sandwich beams is considered most satisfactory and results of such tests on steel and aluminium foil honeycombs show good agreement with the theory.