In the paper by Messrs. Wood and Hammond it has been shown that titanium is likely to save weight compared with steel, where complexity together with the cost of manufacture make it necessary to have some material which is “structurally inert”. The presentation also showed that at high complexity factors, changing from aluminium to titanium would add weight. If the presentation could have included the effect of increasing the operating temperature it would have shown a narrowing gap until at temperatures above about 250 °C, aluminium is no longer viable.

In common with other pneumatic and electronic cabin pressure control installations the two new pneumatic systems discussed in this paper have been designed to control cabin pressure automatically by throttling the out-flow of the cabin conditioning air. For those unfamiliar with the subject Fig. 1 shows diagrammatically a typical modern military aircraft installation. Both the systems discussed should however be of particular technical interest warranting general description, as for the first time with this type of equipment low cost and robust integrated fluidic circuits have been extensively used in their design. Patents covering these have now been granted in the United Kingdom, the United States and other countries.

When I accepted the invitation, to speak at this meeting on “Some Outstanding Developments and Activities” it was presumed that in preparing this paper, it would be possible for me to make a selective use of information presented at our IVth International Agricultural Aviation Congress held in August 1969 in Canada. Unfortunately this is not possible. Therefore, I am unable to pass on to you a comprehensive summary of the interesting technical details of various congress papers. So, I have to take the risk, when addressing you, of spoiling my reputation.

These reservations being made, I would like to give you some facts regarding the IVth International Agricultural Aviation Congress of August 1969. The registered participation was 259 (35% of this number from the host country). It was therefore sufficiently international, although the participation from Asia and Africa was very small indeed.